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FOOD
TO EAT. DISHES AND MENUS
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ARTICHOKE |
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Hugh Sinclair Unit of Human Nutrition,
The University of Reading, UK.
A recent post-marketing study
indicated that high doses of standardised artichoke
leaf extract (ALE) may reduce symptoms of dyspepsia.
To substantial these findings, this study investigated
the efficacy of a low-dose ALE on amelioration of
dyspeptic symptoms and improvement of quality of life.
The study was an open, dose-ranging postal study.
Healthy patients with self-reported dyspepsia were
recruited through the media. The Nepean Dyspepsia
Index and the State-Trait Anxiety Inventory were completed
at baseline and after 2 months of treatment with ALE,
which was randomly allocated to volunteers as 320
or 640 mg daily. Of the 516 participants, 454 completed
the study. In both dosage groups, compared with baseline,
there was a significant reduction of all dyspeptic
symptoms, with an average reduction of 40% in global
dyspepsia score. However, there were no differences
in the primary outcome measures between the two groups,
although relief of state anxiety, a secondary outcome,
was greater with the higher dosage (P = 0.03). Health-related
quality of life was significantly improved in both
groups compared with baseline. We conclude that ALE
shows promise to ameliorate upper gastro-intestinal
symptoms and improve quality of life in otherwise
healthy subjects suffering from dyspepsia.
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The Hugh Sinclair Unit of Human
Nutrition, School of Food BioSciences, The University
of Reading, PO Box 226, Whiteknights, Reading RG6 6AP,
UK.
Irritable bowel syndrome (IBS) is
a problem reported to affect 22% of the general population.
It is characterized by abdominal pain and altered
bowel habit, but has so far defied elucidation of
its pathogenesis and proved difficult to treat. There
is a growing body of evidence which indicates therapeutic
properties for artichoke leaf extract (ALE). Dyspepsia
is the condition for which the herb is specifically
indicated, but the symptom overlap between dyspeptic
syndrome and IBS has given rise to the notion that
ALE may have potential for treating IBS as well. A
sub-group of patients with IBS symptoms was therefore
identified from a sample of individuals with dyspeptic
syndrome who were being monitored in a post-marketing
surveillance study of ALE for 6 weeks. Analysis of
the data from the IBS sub-group revealed significant
reductions in the severity of symptoms and favourable
evaluations of overall effectiveness by both physicians
and patients. Furthermore, 96% of patients rated ALE
as better than or at least equal to previous therapies
administered for their symptoms, and the tolerability
of ALE was very good. These results provide support
for the notion that ALE has potential value in relieving
IBS symptoms and suggest that a controlled trial is
justified.
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Chair of Clinical Biochemistry
and Laboratory Diagnoastic, Regional Ctr. Atherosclerosis
Research, Pomeranian Academy of Medicine, ul. Powstancow
Wlkp. 72, PL-70-111, Szczecin, Poland.
It is currently believed that oxidative
stress and inflammation play a significant role in
atherogenesis. Artichoke extract exhibits hypolipemic
properties and contains numerous active substances
with antioxidant properties in vitro. We have studied
the influence of aqueous and ethanolic extracts from
artichoke on intracellular oxidative stress stimulated
by inflammatory mediators (TNFalpha and LPS) and ox-LDL
in endothelial cells and monocytes. Oxidative stress
which reflects the intracellular production of reactive
oxygen species (ROS) was followed by measuring the
oxidation of 2', 7'-dichlorofluorescin (DCFH) to 2',
7'-dichlorofluorescein (DCF). Agueous and ethanolic
extracts from artichoke were found to inhibit basal
and stimulated ROS production in endothelial cells
and monocytes in dose dependent manner. In endothelial
cells, the ethanolic extract (50 microg/ml) reduced
ox-LDL-induced intracellular ROS production by 60%
(p<0,001) while aqueous extract (50 microg/ml)
by 43% (p<0,01). The ethanolic extract (50 microg/ml)
reduced ox-LDL-induced intracellular ROS production
in monocytes by 76% (p<0,01). Effective concentrations
(25-100 microg/ml) were well below the cytotoxic levels
of the extracts which started at 1 mg/ml as assessed
by LDH leakage and trypan blue exclusion. Penetration
of some active substances into the cells was necessary
for inhibition to take place as juged from the effect
of preincubation time. These results demonstrate that
artichoke extracts have marked protective properties
against oxidative stress induced by inflammatory mediators
and ox-LDL in cultured endothelial cells and monocytes.
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Department of Complementary Medicine,
University of Exeter, 25 Victoria Park Road, Exeter,
Devon, UK, EX2 4NT.
BACKGROUND: Hypercholesterolaemia
is directly associated with an increased risk for
coronary heart disease and other sequelae of atherosclerosis.
Artichoke leaf extract (ALE), which is available as
an over-the-counter remedy, has been implicated in
lowering cholesterol levels. Whether ALE is truly
efficacious for this indication, however, is still
a matter of debate. OBJECTIVES: To assess the evidence
of ALE versus placebo or reference medication for
treating hypercholesterolaemia defined as mean total
cholesterol levels of at least 5.17 mmol/L (200 mg
/dL). SEARCH STRATEGY: We searched MEDLINE, Embase,
Amed, Cinahl, CISCOM and the Cochrane Controlled Trial
Register. All databases were searched from their respective
inception until June 2001. Reference lists of articles
were also searched for relevant material. Manufacturers
of preparations containing artichoke extract and experts
on the subject were contacted and asked to contribute
published and unpublished material. SELECTION CRITERIA:
Randomized controlled trials of ALE mono-preparations
compared with placebo or reference medication for
patients with hypercholesterolaemia were included.
Trials assessing ALE as one of several active components
in a combination preparation or as a part of a combination
treatment were excluded. DATA COLLECTION AND ANALYSIS:
Data were extracted systematically and methodological
quality was evaluated using a standard scoring system.
The screening of studies, selection, data extraction
and the assessment of methodological quality were
performed independently by two reviewers. Disagreements
in the evaluation of individual trials were resolved
through discussion. MAIN RESULTS: Two randomised trials
including 167 participants met all inclusion criteria.
In one trial ALE reduced total cholesterol levels
from 7.74 mmol/l to 6.31 mmol/l after 42 +/- 3 days
of treatment whereas the placebo reduced cholesterol
from 7.69 mmol/l to 7.03 mmol/l (p=0.00001). Another
trial did state that ALE significantly (p<0.05)
reduced blood cholesterol compared with placebo in
a sub-group of patients with baseline total cholesterol
levels of more than 230 mg/dl. Trial reports and post-marketing
surveillance studies indicate mild, transient and
infrequent adverse events. REVIEWER'S CONCLUSIONS:
Few data from rigorous clinical trials assessing ALE
for treating hypercholesterolaemia exist. Beneficial
effects are reported, the evidence however is not
compelling. The limited data on safety suggest only
mild, transient and infrequent adverse events with
the short term use of ALE. More rigorous clinical
trials assessing larger patient samples over longer
intervention periods are needed to establish whether
ALE is an effective and safe treatment option for
patients with hypercholesterolaemia.
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ASPARAGUS |
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Department of Pharmacology, Institute
of Medical Sciences, Banaras Hindu University, 221005,
Varanasi, India.
Asparagus racemosus is an Ayurvedic
rasayana, which finds mention in ancient Indian texts
for treatment of gastric ulcers. The ulcer protective
effect of methanolic extract of fresh roots of A. racemosus
(ARM), 25-100mg/kg given orally, twice daily for 5 days,
was studied on different gastroduodenal ulcer models.
ARM 50mg/kg, twice daily, orally (total saponins 0.9%)
showed significant protection against acute gastric
ulcers induced by cold restraint stress (CRS), pyloric
ligation, aspirin plus pyloric ligation, and duodenal
ulcers induced by cysteamine. ARM in the above dose
also significantly healed chronic gastric ulcers induced
by acetic acid after 10 days treatment. However, ARM
was ineffective against aspirin- and ethanol-induced
gastric ulcers. Further, gastric juice and mucosal studies
showed that ARM significantly increased the mucosal
defensive factors like mucus secretion, cellular mucus,
life span of cells and also possessed significant anti-oxidant
effect, but had little or no effect on offensive factors
like acid and pepsin.
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Department of Pharmacology, College
of Medical Sciences, University of Maiduguri. P.M.B.
1069, Maiduguri, Nigeria.
The effect of methanolic extract
of Asparagus pubescens root on experimentally-induced
diarrhoea and ulceration was investigated in rats.
The extract (500-1500 mg/kg) dose-dependently, reduced
significantly the intestinal propulsive movement,
castor oil-induced diarrhoea and intestinal fluid
accumulation. Yohimbine an alpha(2)-adrenoceptor blocker
attenuated the antidiarrhoeal effect of the extract.
The extract also reduced the ulcer indices induced
by indomethacin and ethanol in a dose-related manner.
The results indicate that its antidiarrhoeal and antiulcerogenic
effects might in part be due to its alpha(2)-adrenoceptor
stimulation and its active constituents respectively.
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Cell Biology Division, Bhabha Atomic
Research Centre, 400 085, Mumbai, India.
The possible antioxidant effects
of crude extract and a purified aqueous fraction of
Asparagus racemosus against membrane damage induced
by the free radicals generated during gamma-radiation
were examined in rat liver mitochondria. gamma-Radiation,
in the dose range of 75-900 Gy, induced lipid peroxidation
as assessed by the formation of thiobarbituric acid
reactive substances (TBARS) and lipid hydroperoxides
(LOOH). Using an effective dose of 450 Gy, antioxidant
effects of A. racemosus extract were studied against
oxidative damage in terms of protection against lipid
peroxidation, protein oxidation, depletion of protein
thiols and the levels of the antioxidant enzyme, superoxide
dismutase. An active fraction consisting of polysaccharides
(termed as P3) was effective even at a low concentration
of 10 microg/ml. Both the crude extract as well as
the P3 fraction significantly inhibited lipid peroxidation
and protein oxidation. The antioxidant effect of P3
fraction was more pronounced against lipid peroxidation,
as assessed by TBARS formation, while that of the
crude extract was more effective in inhibiting protein
oxidation. Both the crude extract and P3 fraction
also partly protects against radiation-induced loss
of protein thiols and inactivation of superoxide dismutase.
The inhibitory effects of these active principles,
at the concentration of 10 microg/ml, are comparable
to that of the established antioxidants glutathione
and ascorbic acid. Hence our results indicate that
extracts from A. racemosus have potent antioxidant
properties in vitro in mitochondrial membranes of
rat liver.
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BEETS |
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Department of Food Science,
Institute of Technology and Storage of Agricultural
Products, Agricultural Research Organization, P.O. Box
6, Bet Dagan 50250, Israel.
Antioxidant nutrients from fruits
and vegetables are believed to be a class of compounds
that exert their effects in humans by preventing oxidative
processes which contribute to the onset of several
degenerative diseases. This study found a new class
of dietary cationized antioxidants in red beets (Beta
vulgaris L.). These antioxidants are betalains, and
the major one, betanin, is a betanidin 5-O-beta-glucoside.
Linoleate peroxidation by cytochrome c was inhibited
by betanin, betanidin, catechin, and alpha-tocopherol
with IC(50) values of 0.4, 0.8, 1.2, and 5 microM,
respectively. In addition, a relatively low concentration
of betanin was found to inhibit lipid peroxidation
of membranes or linoleate emulsion catalyzed by the
"free iron" redox cycle, H(2)O(2)-activated
metmyoglobin, or lipoxygenase. The IC(50) inhibition
of H(2)O(2)-activated metmyoglobin catalysis of low-density
lipoprotein oxidation by betanin was <2.5 microM
and better than that of catechin. Betanin and betanidin
at very small concentrations were found to inhibit
lipid peroxidation and heme decomposition. During
this reaction, betanidin was bleached completely,
but betanin remained unchanged in its absorption.
This difference seems to derive from differing mechanisms
of protection by these two compounds. The high affinity
of betanin and betanidin for membranes was demonstrated
by determining the rate of migration of the compounds
through a dialysis tube. Betanin bioavailability in
humans was demonstrated with four volunteers who consumed
300 mL of red beet juice, containing 120 mg of the
antioxidant. The betacyanins were absorbed from the
gut and identified in urine after 2-4 h. The calculated
amount of betacyanins found in the urine was 0.5-0.9%
of that ingested. Red beet products used regularly
in the diet may provide protection against certain
oxidative stress-related disorders in humans.
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BROCCOLI |
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Division of Carcinogenesis
and Molecular Epidemiology, American Health Foundation,
Valhalla, NY 10595, USA.
The cancer-chemopreventive
effects of broccoli may be attributed, in part, to
isothiocyanates (ITCs), hydrolysis products of glucosinolates.
Glucosinolates are hydrolyzed to their respective
ITCs by the enzyme myrosinase, which is inactivated
by heat. In this study, the metabolic fate of glucosinolates
after ingestion of steamed and fresh broccoli was
compared in 12 male subjects in a crossover design.
During each 48-hour baseline period, no foods containing
glucosinolates or ITCs were allowed. The subjects
then consumed 200 g of fresh or steamed broccoli;
all other dietary sources of ITCs were excluded. Blood
and urine samples were collected during the 24-hour
period after broccoli consumption. Total ITC equivalents
in broccoli and total ITC equivalents in plasma and
urine were assayed by high-performance liquid chromatography
as the cyclocondensation product of 1,2-benzenedithiol.
The content of ITCs in fresh and steamed broccoli
after myrosinase treatment was found to be virtually
identical (1.1 vs. 1.0 micromol/g wet wt). The average
24-hour urinary excretion of ITC equivalents amounted
to 32.3 +/- 12.7% and 10.2 +/- 5.9% of the amounts
ingested for fresh and steamed broccoli, respectively.
Approximately 40% of total ITC equivalents in urine,
25.8 +/- 13.9 and 6.9 +/- 2.5 micromol for fresh and
steamed broccoli, respectively, occurred as the N-acetyl-L-cysteine
conjugate of sulforaphane (SFN-NAC). Total ITC metabolites
in plasma peaked between 0 and 8 hours, whereas urinary
excretion of total ITC equivalents and SFN-NAC occurred
primarily between 2 and 12 hours. Results of this
study indicate that the bioavailability of ITCs from
fresh broccoli is approximately three times greater
than that from cooked broccoli, in which myrosinase
is inactivated. Considering the cancer-chemopreventive
potential of ITCs, cooking broccoli may markedly reduce
its beneficial effects on health.
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Department of Pharmacology and
Molecular Sciences, The Johns Hopkins University School
of Medicine, Baltimore, Maryland 21205, USA.
Broccoli sprouts are a rich source
of glucosinolates and isothiocyanates that induce
phase 2 detoxication enzymes, boost antioxidant status,
and protect animals against chemically induced cancer.
Glucosinolates are hydrolyzed by myrosinase (an enzyme
found in plants and bowel microflora) to form isothiocyanates.
In vivo, isothiocyanates are conjugated with glutathione
and then sequentially metabolized to mercapturic acids.
These metabolites are collectively designated dithiocarbamates.
We studied the disposition of broccoli sprout glucosinolates
and isothiocyanates in healthy volunteers. Broccoli
sprouts were grown, processed, and analyzed for (a)
inducer potency; (b) glucosinolate and isothiocyanate
concentrations; (c) glucosinolate profiles; and (d)
myrosinase activity. Dosing preparations included
uncooked fresh sprouts (with active myrosinase) as
well as homogenates of boiled sprouts that were devoid
of myrosinase activity and contained either glucosinolates
only or isothiocyanates only. In a crossover study,
urinary dithiocarbamate excretion increased sharply
after administration of broccoli sprout glucosinolates
or isothiocyanates. Cumulative excretion of dithiocarbamates
following 111-micromol doses of isothiocyanates was
greater than that after glucosinolates (88.9 +/- 5.5
and 13.1 +/- 1.9 micromol, respectively; P < 0.0003).
In subjects fed four repeated 50-micromol doses of
isothiocyanates, the intra- and intersubject variation
in dithiocarbamate excretion was very small (coefficient
of variation, 9%), and after escalating doses, excretion
was linear over a 25- to 200-micromol dose range.
Dithiocarbamate excretion was higher when intact sprouts
were chewed thoroughly rather than swallowed whole
(42.4 +/- 7.5 and 28.8 +/- 2.6 micromol; P = 0.049).
These studies indicate that isothiocyanates are about
six times more bioavailable than glucosinolates, which
must first be hydrolyzed. Thorough chewing of fresh
sprouts exposes the glucosinolates to plant myrosinase
and significantly increases dithiocarbamate excretion.
These findings will assist in the design of dosing
regimens for clinical studies of broccoli sprout efficacy.
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Department of Nutrition
and Food Studies, New York University, 35 West 4th
Street, 10th Floor, New York, NY 10012-1172.
Cancer is the second leading cause
of death in the United States; it accounts for nearly
one-fourth of annual deaths. Although the rates of
some cancers have been declining, rates of others
have increased. Thus, despite advances in early detection
and treatment, overall death rates from cancer have
remained largely unchanged since the early 1970s,
suggesting the need for a stronger research focus
on prevention. Approaches to prevention necessarily
include smoking cessation and dietary changes, because
each is believed to contribute to about one-third
of annual cancer deaths. For two decades, dietary
advice to prevent cancer has emphasized fruit and
vegetable consumption, and recent recommendations,
such as those listed in Table 1, give highest priority
to consuming plant-based diets. Such advice is entirely
consistent with recommendations for prevention of
heart disease and other diet-related chronic diseases.
It is supported by substantial, increasing, and extensively
reviewed evidence linking intake of plant foods to
impressive reductions in cancer risk at several major
sites. On the basis of this evidence, researchers
recently have estimated that plant-based diets prevent
20% to 50% of all cases of cancer.
Epidemiologic and animal studies have associated certain
food plants with pronounced reductions in cancer risk.
Among such plants are cruciferous (mustard family)
vegetables of the genus Brassica: broccoli, cabbage,
cauliflower, and Brussels sprouts, among others. National
committees have recommended consumption of these vegetables
for cancer prevention since the early 1980s. What
characteristics of these vegetables might protect
against carcinogenesis? Fahey et al. directly address
this important question. Brassica vegetables contain
little fat, are low in energy, and are sources of
vitamins, minerals, and fiber—all aspects linked
to cancer protection. They also contain a large number
of phytochemicals, some of which protect against carcinogenesis
in various in vitro and animal testing systems.
The research of Fahey et al aims to identify specific
phytochemicals in Brassica vegetables that may confer
protection and the mechanisms by which they do so.
The hypothesis underlying this work is that certain
phytochemicals might raise the activity of enzyme
systems that detoxify carcinogens. Several enzyme
systems oxidize, reduce, or hydrolyze (phase 1) and
then conjugate or otherwise affect (phase 2) drugs,
metabolites, carcinogens, and other toxic chemicals,
thereby increasing their polarity and excretability.
Phase 1 enzymes activate or deactivate carcinogens,
depending on the experimental conditions. Phase 2
enzymes are more likely to detoxify. For 20 years
or more, consumption of cruciferous vegetables has
been known to induce enzyme detoxification in experimental
systems. Such observations have led Paul Talalay and
his colleagues to conduct an elegant series of studies
on the effects of cruciferous vegetable extracts on
phase 2 enzyme induction and animal tumorigenesis.
They have developed an in vitro assay to distinguish
bifunctional phytochemicals that induce both phase
1 and phase 2 enzyme systems from monofunctional phytochemicals
that induce only phase 2 enzymes. They then used this
assay to demonstrate that Brassica vegetables are
particularly rich sources of monofunctional phase
2 inducers and to identify the isothiocyanate sulforaphane
as the principal phase 2 inducer in broccoli extracts.
They also have demonstrated that sulforaphane is a
dose-related inhibitor of carcinogen-induced mammary
tumorigenesis in rats.
These impressive accomplishments now have been extended
to identify phase 2 inducer activity in sprouts of
broccoli as well as in mature plants. Most of this
activity derived from the glucosinolate precursor
of sulforaphane, glucoraphanin. Because no net synthesis
of phase 2 inducers occurs after sprouting, their
concentration decreases as the plant grows. Extracts
of broccoli sprouts contain 10–100 times the
phase 2 inducer activity of mature broccoli plants
and are more efficient inhibitors of rat tumorigenesis.
In contrast, mature broccoli also contains significant
amounts of indole compounds that induce phase 1 as
well as phase 2 enzymes. Thus, sprouts would appear
to offer at least two anticarcinogenic advantages
over mature broccoli: they contain higher concentrations
of inducers, and the inducers mainly affect phase
2 enzyme systems. On this basis, Fahey et al. conclude
that small amounts of cruciferous vegetable sprouts
may be just as protective against cancer as larger
amounts of mature plants of the same variety.
These studies leave no doubt that sulforaphane does
indeed induce phase 2 enzymes and inhibit carcinogenesis
under these conditions. At issue, however, is the
clinical significance of induction of such enzyme
systems by single phytochemicals. Both phase 1 and
phase 2 systems are highly multifunctional and inducible
by a wide variety of dietary compounds. Food plants
have evolved to contain thousands of chemicals that
act as protective pesticides against infection or
predation, and humans may consume as many as 10,000
of these compounds and their metabolic products when
eating vegetables. The Ames group has identified 49
such compounds in cabbage, among them several that
have been tested and found mutagenic or carcinogenic
in animal test systems. Table 2 identifies the classes
of phytochemicals in cruciferous vegetables that contain
at least one compound that has proved mutagenic or
carcinogenic in such tests. Thus, cruciferous and
other vegetables contain some phytochemicals that
are carcinogenic and others that are anticarcinogenic
in test systems.
This confusing situation is complicated further by
the ability of both phase 1 and phase 2 enzyme systems
to inactivate some carcinogens, but activate others,
depending on circumstances. Chemicals that induce
activating enzymes also will induce activation of
any other compounds present that are metabolized by
the same system; the same is true of substances that
induce inactivation. This dual nature of the enzyme
systems, the vast number of compounds that can induce
them, the presence in broccoli of chemicals that induce
both activation and inhibition of carcinogenesis,
and the complexity of the interactions among food
phytochemicals and enzyme systems, constitute the
basis of ongoing debates as to whether sulforaphane
or any other single phytochemical or nutrient can
explain the cancer-protective effects of cruciferous
vegetables.
Fortunately, the dietary implications of this work
are less complicated. The precise role in carcinogenesis
of specific vitamins, minerals, fiber, and phytochemicals
may be uncertain, but the overall anticarcinogenic
properties of vegetables clearly outweigh any effects
of their constituent carcinogens or carcinogen-inducers.
The value of eating more vegetables in general, and
Brassica vegetables in particular, is well supported
by current evidence if for no other reason than this
food group is a principal source of antioxidant vitamins;
vegetables provide more than 80% of the carotene,
50% of the vitamin C, and 25% of the folate in the
American food supply.
Dietary recommendations for prevention of cancer and
other chronic diseases always have emphasized the
value of consuming a variety of plant foods. Each
vegetable contributes nutrients, fiber, and phytochemicals,
but in varying amounts and proportions. Fahey et al
found an 8-fold variation in phase 2 inducer activity
among different samples of fresh broccoli, a variation
that was independent of appearance or growing conditions.
Broccoli may be especially rich in sulforaphane, but
tomatoes are especially rich in lycopenes, peppers
in carotenoids, and onions and garlic in allium compounds—all
demonstrably protective against carcinogenesis.
President George Bush did not like broccoli; the mass
appeal of broccoli sprouts is even less certain. My
local health food store sells cruciferous sprouts
of cabbage, radish, and mustard, but not yet broccoli;
broccoli sprouts taste like milder versions of the
mature vegetable and are slightly pungent or peppery.
The store does offer dessicated broccoli in the form
of 500-mg supplements labeled as containing 200 µg
sulforaphane; 50 such tablets cost $14.70.
Price considerations aside, supplements confer little
advantage. Fresh vegetables provide a higher content
of vitamin C, folic acid, and fiber, and a balance
of phytochemicals that favor overall protection against
carcinogenesis. The full range of nutrients contained
in foods must be present to detoxify carcinogens;
iron, niacin, and riboflavin, for example, are essential
cofactors in phase 1 and phase 2 enzyme systems. Just
as single-nutrient approaches to cancer prevention
have yielded disappointing results, single phytochemical
approaches are likely to prove equally disappointing
and are not recommended.
The policy implications of this research also seem
quite straightforward. Policies are needed to promote
consumption of vegetables among a greater proportion
of the population. Recent data suggest that the average
American consumes slightly more than two standard
half-cup servings of vegetables (other than white
potatoes) daily; at least 10% of the population reports
consuming less than one daily serving of any vegetable
whatsoever. Although broccoli and cabbage rank among
the top 10 vegetables purchased in supermarkets, and
U.S. annual production (though not necessarily consumption)
of fresh broccoli rose from 0.8 to 4.1 pounds per
capita from 1973 to 1997, this quantity translates
to just 5 g per day per capita. Thus, the current
situation leaves considerable room for improvement.
From the standpoint of public health policy, existing
data are more than sufficient to promote greater consumption
of broccoli and its sprouts along with other vegetables.
Educational campaigns to encourage fruit and vegetable
consumption have achieved some success, but a greater
range of policies and programs targeted to food producers
as well as to consumers might prove more effective
in raising consumption levels.
From the standpoint of cancer research policy, information
about the role of each nutrient and phytochemical
is of vital interest; such information may well explain
why diet-related cancer risks vary across different
sites and among individuals and populations. The effects
of single anticarcinogenic phytochemicals, however,
no matter how well characterized, cannot be understood
in isolation, just as the anticarcinogenic effects
of single nutrients cannot be understood except as
part of an overall dietary pattern. Dietary patterns,
of course, are difficult to study. If research to
date has focused on the effects of isolated nutrients
and phytochemicals, it is because such systems are
far more amenable to investigation. Debates about
the significance of the effects of sulforaphane on
cancer risk are best interpreted as evidence of the
need for high-quality research on the health effects
of dietary patterns and their determinants—behavioral,
environmental, economic, and cultural—as well
as on the scientific basis of these relationships.
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BRUSSELS SPROUTS |
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Department of Medicinal
Chemistry and Pharmacognosy, College of Pharmacy, University
of Illinois at Chicago 60612.
Cabbage, broccoli, Brussels sprouts,
and other members of the genus Brassica have been
widely regarded as potentially cancer preventative.
This view is often based on both experimental testing
of crude extracts and epidemiological data. The experimental
evidence that provides support for this possibility
is reviewed for the commonly consumed varieties of
Brassica oleracea. In a majority of cases the biological
activities seen in testing crude extracts may be directly
related to specific chemicals that have been reported
to be isolated from one of these closely related species,
thus the chemical evidence further supports the data
from testing extracts and epidemiology.
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Department of Pharmacology,
University of Copenhagen, Panum, Denmark.
The alleged cancer preventive effects
of cruciferous vegetables could be related to protection
from mutagenic oxidative DNA damage. We have studied
the effects of Brussels sprouts, some non-cruciferous
vegetables and isolated glucosinolates on spontaneous
and induced oxidative DNA damage in terms of 8-oxo-7,8-dihydro-2'-deoxyguanosine
(8-oxodG) in groups of 6-8 male Wistar rats. Excess
oxidative DNA damage was induced by 2-nitropropane
(2-NP 100 mg/kg). Four days oral administration of
3 g of cooked Brussels sprouts homogenate reduced
the spontaneous urinary 8-oxodG excretion by 31% (p<0.05)
whereas raw sprouts, beans and endive (1:1), isolated
indolyl glucosinolates and breakdown products had
no significant effect. An aqueous extract of cooked
Brussels sprouts (corresponding to 6.7 g vegetable
per day for 4 days) decreased the spontaneous 8-oxodG
excretion from 92 +/- 12 to 52 +/- 15 pmol/24 h (p<0.05).
After 2-NP administration the 8-oxodG excretion was
increased to 132 +/- 26 pmol/24 h (p<0.05) whereas
pretreatment with the sprouts extract reduced this
to 102 +/- 30 pmol/24 h (p<0.05). The spontaneous
level of 8-oxodG in nuclear DNA from liver and bone
marrow was not significantly affected by the sprouts
extract whereas the level decreased by 27% in the
kidney (p<0.05). In the liver 2-NP increased the
8-oxodG levels in nuclear DNA 8.7 and 3.8 times (p<0.05)
6 and 24 h after dose, respectively. The sprouts extract
reduced this increase by 57% (p<0.05) at 6 h whereas
there was no significant effect at 24 h. In the kidneys
2-NP increased the 8-oxodG levels 2.2 and 1.2 times
(p<0.05) 6 and 24 h after dose, respectively. Pretreatment
with the sprouts extract abolished these increases
(p<0.05). Similarly, in the bone marrow the extract
protected completely (p<0.05) against a 4.9-fold
2-NP induced increase (p<0.05) in the 8-oxodG level.
These findings demonstrate that cooked Brussels sprouts
contain bioactive substance(s) with a potential for
reducing the physiological as well as oxidative stress
induced oxidative DNA damage in rats. This could explain
the suggested cancer preventive effect of cruciferous
vegetables. The correspondence between the urinary
excretion and 8-oxodG levels in 2-NP target organs
supports its being the main repair product that reflects
the rate of guanine oxidation in DNA.
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Department of Pharmacology and
Molecular Sciences, The Johns Hopkins University School
of Medicine, Baltimore, Maryland 21205, USA.
Broccoli sprouts are a rich source
of glucosinolates and isothiocyanates that induce
phase 2 detoxication enzymes, boost antioxidant status,
and protect animals against chemically induced cancer.
Glucosinolates are hydrolyzed by myrosinase (an enzyme
found in plants and bowel microflora) to form isothiocyanates.
In vivo, isothiocyanates are conjugated with glutathione
and then sequentially metabolized to mercapturic acids.
These metabolites are collectively designated dithiocarbamates.
We studied the disposition of broccoli sprout glucosinolates
and isothiocyanates in healthy volunteers. Broccoli
sprouts were grown, processed, and analyzed for (a)
inducer potency; (b) glucosinolate and isothiocyanate
concentrations; (c) glucosinolate profiles; and (d)
myrosinase activity. Dosing preparations included
uncooked fresh sprouts (with active myrosinase) as
well as homogenates of boiled sprouts that were devoid
of myrosinase activity and contained either glucosinolates
only or isothiocyanates only. In a crossover study,
urinary dithiocarbamate excretion increased sharply
after administration of broccoli sprout glucosinolates
or isothiocyanates. Cumulative excretion of dithiocarbamates
following 111-micromol doses of isothiocyanates was
greater than that after glucosinolates (88.9 +/- 5.5
and 13.1 +/- 1.9 micromol, respectively; P < 0.0003).
In subjects fed four repeated 50-micromol doses of
isothiocyanates, the intra- and intersubject variation
in dithiocarbamate excretion was very small (coefficient
of variation, 9%), and after escalating doses, excretion
was linear over a 25- to 200-micromol dose range.
Dithiocarbamate excretion was higher when intact sprouts
were chewed thoroughly rather than swallowed whole
(42.4 +/- 7.5 and 28.8 +/- 2.6 micromol; P = 0.049).
These studies indicate that isothiocyanates are about
six times more bioavailable than glucosinolates, which
must first be hydrolyzed. Thorough chewing of fresh
sprouts exposes the glucosinolates to plant myrosinase
and significantly increases dithiocarbamate excretion.
These findings will assist in the design of dosing
regimens for clinical studies of broccoli sprout efficacy.
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CABBAGE |
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Department of Applied Biological
Science, Tokyo Noko University, Tokyo 183-8509, Japan.
The effect of cabbage extract
on the production of tumor necrosis factor and its
implication in the antitumor effect were examined
in vitro and in vivo. Cabbage extract stimulated the
production of tumor necrosis factor by rat spleen
cells and showed cytotoxic activity in a rat ascites
hepatoma cell line (AH109A) when hepatoma cells were
cultured with cabbage-stimulated spleen cells. When
the extract was adminstered orally to AH109A-bearing
rats in combination with lipopolysaccharide injection,
the hepatoma weights were reduced to one-half of the
vehicle control. The cytotoxic activity of tumor-infiltrating
macrophages was induced by simultaneous treatment
with cabbage extract and lipopolysaccharide. These
results indicate that cabbage extract contains macrophage-stimulating
component(s) and can implement the antitumor effect
by stimulating the cytotoxicity of tumor-infiltrating
macrophages.
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Department of Applied Biological
Science, Tokyo Noko University, Fuchu, Japan.
The effect of cabbage extract
on cholesterol metabolism was studied in Donryu rats
subcutaneously implanted with an ascites hepatoma cell
line (AH109A). The hepatoma-bearing rats exhibited hypercholesterolemia
induced by increasing cholesterogenesis in the host
liver and decreasing steroid excretion into feces. The
cabbage extract intake or administration reduced serum
cholesterol level and enhanced fecal bile acid excretion
and cholesterol 7alpha-hydroxylase activity, the rate-limiting
enzyme of bile acid biosynthesis, in the microsomal
fraction of the liver. Furthermore, S-methyl-L-cysteine
sulfoxide, a component of cabbage, could mimic the effect
of cabbage extract when orally administered. These results
suggest that cabbage suppresses hypercholesterolemia
responding to hepatoma growth by upregulating cholesterol
catabolism and that S-methyl-L-cysteine sulfoxide in
cabbage is one of the factors suppressing hypercholesterolemia
in the hepatoma-bearing rats.
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Department of Bioresource
Engineering, Faculty of Agriculture, Yamagata University,
Tsuruoka-shi, Japan.
The preventive effects of acylated
anthocyanins from red cabbage on paraquat-induced
oxidative stress were determined in rats. Decreased
food intake and body weight gain, and increased lung
weight and atherogenic index by feeding the rats on
a diet containing paraquat were clearly suppressed
by supplementing acylated anthocynins to the paraquat
diet. Paraquat feeding increased the concentration
of thiobarbituric acid-reactive substances (TBARS)
in liver lipids, and decreased the liver triacylglycerol
level. These effects tended to be suppressed by supplementing
acylated anthocynins to the paraquat diet. In addition,
the catalase activity in the liver mitochondrial fraction
was markedly decreased by feeding on the paraquat
diet, this decrease being partially suppressed by
supplementing the paraquat diet with acylated anthocyanins.
An increase in the NADPH-cytochrome-P450-reductase
activity in the liver microsome fraction by paraquat
was suppressed by supplementing the paraquat diet
with acylated anthocyanins. These results suggest
that acylated anthocyanins from red cabbage acted
preventively against the oxidative stress in vivo
that may have been due to active oxygen species formed
through the action of paraquat.
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Interest in the potential of
cabbage and other Brassica species as possible dietary
cancer-inhibitors has been expressed. Preliminary
data in support of this include the following: dietary
cabbage has been reported to enhance the aromatic
hydrocarbon hydroxylase (AHH) microsomal enzyme system
and increase the rate of metabolism of certain drugs
and carcinogens and to affect chemically-induced tumor
formation. Bacterial studies also indicate that cabbage
has demutagenic activity in the Ames assay. Cabbage
has also been reported to have a protective effect
against radiation exposure. In addition, cabbage has
been shown to have a variable ability to induce goiter
formation in otherwise healthy laboratory animals.
Other effects discussed in the literature include
an affect on blood sugar, gastric secretion and antibacterial
activity. Reference is made to claims found in ancient
herbal literature regarding cabbage's alleged therapeutic
benefit in putatively cancerous conditions.
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A randomized, controlled trial
was conducted to evaluate the effect of cabbage leaves
on mothers' perceptions of breast engorgement and
the influence of this treatment on breastfeeding practices.
The subjects, 120 breastfeeding women 72 hours postpartum,
were randomly allocated to an experimental group who
received application of cabbage leaves to their breasts,
or to a control group who received routine care. The
experimental group tended to report less breast engorgement,
but this trend was not statistically significant.
At six weeks, women who received the cabbage leaf
application were more likely to be breastfeeding exclusively,
76 and 58 percent (35/46 vs 29/50; P = 0.09), and
their mean duration of exclusive breastfeeding was
longer (36 vs 30 days; P = 0.04). The greater breastfeeding
success in the experimental group may have been due
to some beneficial effect of cabbage leaf application,
or may have been secondary to reassurance and improved
confidence and self-esteem in these mothers.
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CARROTS |
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Institut fur Pharmakognosie
der Universitat Wien, Althanstrasse 14, A-1090 Wien.
Adherence of microorganisms to the intestinal mucosa
is an important and initial step in the pathogenesis
of gastrointestinal infections and mediated by carbohydrate
structures on the cell surface. Adherence can be blocked
by carbohydrate receptor analogues. Aqueous extracts
from carrots (carrot soup) contain acidic oligosaccharides,
which are able to block adherence of various enteropathogenic
microorganisms to HEp-2 cells and human intestinal mucosa
in vitro. Dependent on the grade of polymerisation the
most potent blocking ability was seen for trigalacturonic
acid. Clinical studies revealed, that aqueous carrot
extracts are significantly superior to the basic glucose-electrolyt-solution
for oral rehydration in acute gastrointestional infections
of children.
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Allergy Unit, Department of Dermatology,
University Hospital, Zurich, Switzerland.
BACKGROUND: Allergic reactions to
carrot affect up to 25% of food-allergic subjects.
Clinical manifestations of carrot allergy and IgE
responses to carrot proteins, however, have never
been studied in subjects with carrot allergy confirmed
by means of double-blinded, placebo-controlled food
challenge (DBPCFC). OBJECTIVE: The purposes of this
investigation were to confirm clinically relevant
sensitizations to carrot by means of DBPCFC, to validate
current diagnostic methods, and to identify IgE-reactive
carrot proteins in patients with true allergy. METHODS:
DBPCFCs were performed in 26 subjects with histories
of allergic reactions to carrot. Patients underwent
skin prick tests with carrot extract, fresh carrot,
and various pollen extracts. Specific IgE to carrot,
celery, birch, and mugwort pollen and to rBet v 1,
rBet v 2, and rBet v 6 were measured through use of
the CAP method. Carrot allergens were identified by
means of immunoblotting and blotting inhibition. RESULTS:
Twenty of 26 patients had positive DBPCFC results.
The sensitivity of the determination of carrot-specific
IgE antibodies through use of the CAP method (>
or =0.7 kU/L) was 90%, the sensitivity for skin prick
testing with commercial extracts was 26%, and the
sensitivity for prick-to-prick tests with raw carrot
was 100%. The Bet v 1--related major carrot allergen
Dau c 1 was recognized by IgE from 85% of patients;
45% were sensitized to cross-reactive carbohydrate
determinants and 20% to carrot profilin. In 1 subject,
a Bet v 6--related carrot allergen was recognized.
In 4 patients, IgE binding to Dau c 1 was not inhibited
or was weakly inhibited by rBet v 1 or birch pollen
extract. CONCLUSION: This study confirmed the allergenicity
of carrot by means of DBPCFC. DBPCFC-positive patients
had exclusively specific IgE antibodies to birch pollen--related
carrot allergens, Dau c 1 being the major allergen.
The lack of inhibition of IgE binding to Dau c 1 by
birch allergens in a subgroup of patients might indicate
an secondary immune response to new epitopes on the
food allergen that are not cross-reactive with Bet
v 1.
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Food Research Center, University
of Lincolnshire and Humberside, Brayford Pool, Lincoln
LN6 7TS, United Kingdom.
Four different colored carrots, orange,
purple with orange core, yellow, and white, were examined
for their content of phenolics, antioxidant vitamins,
and sugars as well as their volatiles and sensory
responses. A total of 35 volatiles were identified
in all carrots, 27 positively. White carrot contained
the highest content of volatiles, followed by orange,
purple, and yellow. In total, 11, 16, 10, and 9 phenolic
compounds were determined for the first time in orange,
purple, yellow, and white carrots, respectively. Of
these, chlorogenic acid was the most predominant phenolic
compound in all carrot varieties. Differences (p <
0.05) in relative sweetness, the contents of vitamin
C and alpha- and beta-carotenes, and certain flavor
characteristics were observed among the colored carrot
varieties examined. Purple carrots contained 2.2 and
2.3 times more alpha- and beta-carotenes (trace in
yellow; not detected in white) than orange carrots,
respectively. Purple carrot may be used in place of
other carrot varieties to take advantage of its nutraceutical
components.
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Department of Physiology
and Pharmacology, The Aga Khan University Medical College,
Karachi, Pakistan.
Daucus carota (carrot) has
been used in traditional medicine to treat hypertension.
Activity-directed fractionation of aerial parts of
D. carota resulted in the isolation of two cumarin
glycosides coded as DC-2 and DC-3. Intravenous administration
of these compounds caused a dose-dependent (1-10 mg/kg)
fall in arterial blood pressure in normotensive anaesthetised
rats. In the in vitro studies, both compounds caused
a dose-dependent (10-200 microg/ml) inhibitory effect
on spontaneously beating guinea pig atria as well
as on the K+ -induced contractions of rabbit aorta
at similar concentrations. These results indicate
that DC-2 and DC-3 may be acting through blockade
of calcium channels and this effect may be responsible
for the blood pressure lowering effect of the compounds
observed in the in vivo studies.
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Groupe de Physiopathologie
Digestive et Nutritionnelle, Hopital Charles Nicolle,
Rouen, France.
The aim of the present study was
to assess, in healthy volunteers and under physiological
conditions, the acceptability, clinical tolerance
and effects on colonic motility of chronic supplementation
of the usual diet with new dietary fibre sources.
Three studies were carried out, one after a period
of habitual diet, and two after randomized 3-week
periods of supplementation with fibre extracted either
from pea hulls or carrots, added to the meals as a
fine powder. The 24 h motility was recorded on an
unprepared colon at five levels to determine the initiation
site and the number of high amplitude propagated contractions
(HAPC) and to quantify motor activity every 30 min,
particularly in the two periods following lunch and
breakfast. With the habitual diet the motility pattern
was an irregular alternation of quiescence and sporadic
non-propagated contractions. HAPC always started from
the ascending colon and occurred mainly after breakfast.
With either type of fibre the 24 h motor profiles,
the 24 h variations and the number of HAPC were not
significantly modified but a more distal initiation
of HAPC was found. The colonic postprandial motor
response was more diffuse after dietary enrichment
with carrot fibre than after enrichment with pea-hull
fibre. In healthy volunteers the long-term addition
of fibre extracted from pea hulls and carrots to the
usual diet was easy and well-tolerated without clinical
side-effects, but with limited colonic motor effects.
However, the more distal initiation of HAPC observed
could be deleterious.
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Department of Nutrition,
National Research Center, Giza, Dokki, Egypt.
Changes in plasma retinol and carotenoids
was measured in 17 young males after daily ingestion
of grated carrots, carrot juice or spinach leaves
for 2 weeks. Regression equations showed that the
supply of 3350 and 4750 micrograms carotenes from
78 ml carrot juice (prepared from 185 g carrots) or
91 g grated carrots, respectively were adequate in
maintaining plasma retinol at a constant level in
subjects with initial plasma retinol of 1.2 mumol/l.
Under similar experimental conditions, 280 g boiled
spinach leaves providing 12,700 micrograms carotenes
were required to maintain plasma retinol at a constant
level. Apparent carotene digestibilities of 47 and
81% were obtained with carrot and spinach, respectively.
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CAULIFLOWER |
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Research Group on Quality,
Safety and Bioactivity of Plan Foods, Department of
Food Science and Technology, CEBAS-CSIC, P. O. Box 4195,
Murcia 30080, Spain.
The present study reports the development
of two extraction protocols, with potential industrial
applicability, to valorize cauliflower (Brassica oleracea
L. var. botrytis) byproducts as a source of antioxidant
phenolics. In addition, the nonionic polystyrene resin
Amberlite XAD-2 was used to obtain purified extracts.
The extract yield, phenolic content, phenolic yield,
and correlation between the antioxidant activity and
the phenolic content were studied. The water and ethanol
protocols yield a phenolic content of 33.8 mg/g freeze-dried
extract and 62.1 mg/g freeze-dried extract, respectively.
This percentage increased considerably when the extracts
were purified using Amberlite XAD-2 yielding a phenolic
content of 186 mg/g freeze-dried extract (water extract)
and 311.1 mg/g freeze-dried extract (ethanol extract).
Cauliflower byproduct extracts showed significant
free radical scavenging activity (vs both DPPH(*)
and ABTS(*)(+) radicals), ferric reducing ability
(FRAP assay), and capacity to inhibit lipid peroxidation
(ferric thiocyanate assay). In addition, the antioxidant
activity was linearly correlated with the phenolics
content. The results obtained indicate that the cauliflower
byproducts are a cheap source of antioxidant phenolics
very interesting from both the industrial point of
view and the possible usefulness as ingredients to
functionalize foodstuffs.
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CHARD |
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Department of Pharmacology, Faculty
of Pharmacy, Marmara University, 81010, Istanbul, Turkey.
In diabetes mellitus, increased free
radical formation raises the incidence of atherosclerosis
and cardiovascular diseases. Regardless of the type
of diabetes, the objective of the therapy is to achieve
normoglycemia and to prevent or delay the complications.
Chard (Beta vulgaris L. var. cicla) is used as a hypoglycemic
agent by diabetic patients in Turkey. The aim of this
study was to investigate the effect of feeding chard
on diabetes-induced free radical- mediated injury
in rat aorta and heart tissues. Female Swiss albino
rats were randomly divided into four groups: control,
diabetic, chard, and diabetic + chard. Rats were subjected
to intraperitoneal streptozotocin (STZ, 65 mg/kg)
to induce diabetes. Chard extract (2 g/kg) was given
for 28 days beginning on the 14th day of the study.
Aorta and heart tissue lipid peroxidation and glutathione
levels as well as blood glucose levels were determined.
The results of the present study indicate that lipid
peroxidation was increased and glutathione levels
were decreased in both aorta and heart tissue of the
diabetic rats. However, treatment with chard extract
reversed the effects of diabetes on blood glucose
and tissue lipid peroxidation and glutathione levels.
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Department of Chemistry, Faculty
of Engineering, Istanbul University, 34850-Avcilar,
Istanbul, Turkey.
The aim of this work was to investigate
the effects of chard (Beta vulgaris L. var. cicla)
extract on serum urea and creatinine concentrations
and on kidney tissue in normal and streptozotocin-diabetic
rats. The extract was administered to rats at a dose
of 2 g/kg every day for 28 days, 14 days after animals
were made diabetic. On day 42, kidney tissue and blood
samples were examined. Significant degenerative changes
in kidney tissue of diabetic rats were observed, but
in the group given chard extract, the morphology of
kidney tissue was found to be nearly the same as the
controls. Serum urea and creatinine levels significantly
increased in the diabetic groups, but the chard extracts
significantly reduced serum urea and creatinine levels.
It is concluded that the extract of this plant may
reduce serum urea and creatinine levels and confer
a protective effect on the kidney of diabetic rats.
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Department of Biochemistry, Faculty
of Dentistry, Marmara University, Nisantasi, Turkey.
Chard (Beta vulgaris L. var. cicla)
is one of the plants used as hypoglycaemic agent by
diabetics in Turkey and it has been reported to reduce
blood glucose. The purpose of this study was to investigate
the effect of feeding chard on diabetes induced impairments
in rat skins. Uncontrolled induced diabetes caused
significant increases in nonenzymatic glycosylation
of skin proteins, lipid peroxidation and blood glucose.
Administration of chard extract inhibited these effects
except the increase in lipid peroxidation. SDS-polyacrylamide
gel electrophoresis revealed no significant differences
in any protein bands between any of the groups. The
data indicate that the use of chard may be effective
in preventing or at least retarding the development
of some diabetic complications.
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CORN |
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Division of Endocrinology, Diabetes
and Metabolism, Washington University, St Louis, MO
63110, USA.
BACKGROUND: Although supplementing
the diet with large quantities of phytosterols reduces
cholesterol absorption and LDL-cholesterol concentrations,
very little is known about the smaller amounts of
phytosterols present naturally in food. Vegetable
oils are the richest dietary source of phytosterols;
corn oil contains 0.77% phytosterols by weight. OBJECTIVE:
We tested the hypothesis that removing phytosterols
from corn oil would increase cholesterol absorption
when measured in single-meal tests containing corn
oil as a source of fat. DESIGN: Free and esterified
phytosterols were removed from corn oil on a kilogram
scale by a new technique of competitive saturation
adsorption to silica. Healthy subjects with a mean
(+/-SEM) serum cholesterol concentration of 5.10 +/-
0.18 mmol/L received an otherwise sterol-free test
breakfast on 2 occasions 2 wk apart that contained
35 mg hexadeuterated cholesterol and 30-35 g of a
corn oil preparation. The plasma enrichment of tracer
was measured by negative ion mass spectrometry. RESULTS:
Cholesterol absorption was 38.0 +/- 10.2% higher after
consumption of the sterol-free corn oil than after
consumption of commercial corn oil with an identical
fatty acid content (P = 0.005; n = 10). When corn
oil phytosterols were added back to sterol-free corn
oil at a concentration of 150 mg/test meal, cholesterol
absorption was reduced by 12.1 +/- 3.7% (P = 0.03;
n = 5) and by 27.9 +/- 9.1% (P = 0.01; n = 10) after
inclusion of 300 mg phytosterols. CONCLUSIONS: Phytosterols
comprising < 1% of commercial corn oil substantially
reduced cholesterol absorption and may account for
part of the cholesterol-lowering activity of corn
oil previously attributed solely to unsaturated fatty
acids.
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The effects of consuming corn bran,
soy hulls, or apple powder on glucose and lipid metabolism
were investigated in two studies of persons with type
II diabetes. Fiber sources, completely or partially
added to bread, were incorporated into subjects' self-selected
diets. Low fiber white bread served as a control.
In study A, 10 subjects consumed 26 g fiber source
daily; in study B, eight subjects consumed 52 g fiber
source. Biochemical tests, including a 2-h postprandial
glucose test using a low fiber formula meal, were
scheduled after 2 and 4 wk of each dietary treatment.
Soy hull consumption slightly improved some measures
of glucose tolerance, with results varying between
the studies. Consumption of 52 g corn bran decreased
very low-density lipoprotein cholesterol, triglycerides,
and glycosylated Hb, but subject tolerance was poor
with the particle size used. Consumption of 52 g apple
powder increased low-density lipoprotein and total
cholesterol levels.
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Research Institute, Nihon Shokuhin
Kako Co., Ltd., Fuji, Japan.
We prepared corn peptide (CP), a
vegetable oligopeptide and tried to discover the effects
of its ingestion on facilitating alcohol metabolism
in healthy adult men. Ten healthy male volunteers
ingested 5 g of CP, wheat peptide (WP), pea peptide
(PP), alanine, or leucine 30 min before alcohol intake
at a dose of 0.5 g/kg, and blood ethanol and plasma
amino acid concentrations were measured during a 2-h
observation period after alcohol intake. In subjects
who ingested CP, the blood ethanol level was lower
than that in the WP, alanine and leucine ingestion
groups, but did not decrease as compared to the control
when they ingested PP. Similarly there was a difference
in the blood ethanol level between alanine and leucine
ingestion groups, and leucine ingestion was more effective
than alanine against the reduction of the increase
in blood ethanol level. On the other hand, there was
no significant difference in the plasma concentrations
of individual amino acids except alanine, leucine,
or lysine after alcohol intake among experimental
groups as compared to the control. CP ingestion significantly
elevated plasma alanine and leucine rather than other
groups during a 2-h observation period. These results
suggested that CP may have the effect on the reduction
of increase in blood ethanol level after alcohol intake
by the marked elevation of plasma alanine and leucine,
especially leucine, but neither by the delay of ethanol
release from the stomach nor malabsorption of ethanol
in the gastrointestinal tracts.
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First Department of Medicine,
Hamamatsu University School of Medicine, Japan.
We examined the effect of soluble
corn bran hemicellulose (CBH, 10 g/day) on glucose
control and serum insulin in three groups: patients
with impaired glucose tolerance (IGT) with (20 subjects)
or without (8 subjects) obesity and with healthy non-obese
controls (10 subjects). Long-term supplementation
(6 months) with CBH decreased the post oGTT curve
for patients with impaired mild Type II diabetes,
but not that for the controls. Hemoglobin A1c decreased
significantly during CBH supplementation in the obese
patients, while the fasting glucose level decreased
in all three groups, although not significantly. A
decreased serum insulin response by oGTT was found
in those patients with IGT. The improved oGTT result
was associated with improved insulin release and perhaps
with peripheral insulin sensitivity. These findings
suggest that CBH at a low dose might contribute to
glycemic control and would play a useful role in treating
Type II diabetes patients.
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Department of Family and
Consumer Sciences, Illinois State University, Normal
61790.
OBJECTIVE: The purpose of this
study was to determine the lipid-lowering effects
of dietary corn bran fed in moderate supplemental
doses to men with hypercholesterolemia consuming a
low-fat diet. DESIGN: The 98-day study was divided
into one 2-week preperiod and two 6-week experimental
periods in a cross-over design. SETTING: The study
was conducted in the metabolic diet kitchen of the
Department of Home Economics and the Nutrition Research
Laboratory of the Department of Agriculture at Illinois
State University, Normal. SUBJECTS: Twenty-nine sedentary
men with hypercholesterolemia, aged 38 to 70 years,
participated in the project. All of them completed
the study. INTERVENTIONS: After a 2-week adjustment
period in which subjects consumed a low-fat controlled
diet, subjects were assigned to one of two experimental
treatments: low-fat controlled diet plus 20 g corn
bran supplement or low-fat controlled diet plus 20
g wheat bran supplement. MAIN OUTCOME MEASURES: Lipid
measurements included total cholesterol, low-density
lipoprotein cholesterol (LDL-C), high-density lipoprotein
cholesterol (HDL-C), very-low-density lipoprotein
cholesterol (VLDL-C), and triglyceride concentrations.
STATISTICAL ANALYSES PERFORMED: Differences in lipid
parameters were analyzed using two-way analysis of
variance with repeated measures (P < .05). A paired
t test was used to assess differences between treatment
periods for each subject. RESULTS: The low-fat controlled
diet significantly lowered all serum parameters analyzed
except HDL-C. Corn fiber supplementation resulted
in an additional lowering of serum total cholesterol,
triglyceride, and VLDL-C concentrations. Serum LDL-C
and HDL-C concentrations were not significantly altered
by corn fiber or wheat fiber supplementation. APPLICATIONS:
This study suggests that supplementing a low-fat diet
with corn bran is affective in reducing serum lipid
concentrations for men with hypercholesterolemia.
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CUCUMBER |
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Geriatrics Institute, 1st
Sanatorium, Dalian.
389 patients with essential hypertension
were divided into two groups randomly. 241 patients
were treated by tablet of cucumber vine compound and
148 patients by tablet of hypotension compound as
control. The symptomatic marked improvement and total
effective rate were 63.1% and 81.7% in the treated
group and 39.2% and 67.0% (P less than 0.01) in the
control group respectively. The marked effective rate
in decrease of blood pressure and total effective
rate were 52.7%, 90.9% and 58.1%, 92.6% (P greater
than 0.05) respectively. Experiments with animals
showed that tablet cucumber vine compound possessed
persistently decreasing effect on the blood pressure
and marked effect on increasing coronary blood flow
and improving myocardial contraction. Clinical observation
and toxicological test proved that tablet cucumber
vine compound had no toxicity and had few side effects
and that it was an effective, safe medicine for essential
hypertension.
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Health Protection Branch,
Burnaby, B.C., Canada.
During May and June of 1985 the Health
Protection Branch and several other agencies were
involved in the investigation of over 300 reports
of illness reported in the Vancouver area of British
Columbia, Canada. Symptoms reported included nausea,
vomiting, dizziness, muscle fasciculation and blurred
vision. A review of the onset of symptoms and food
consumed suggested that at least 140 people had become
ill from eating cucumbers adulterated with a carbamate
pesticide. The presence of residues of aldicarb in
cucumbers from one particular producer was confirmed
by laboratory analysis.
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In the period April 1--15, 1977,
nine residents of one Nebraska town experienced violent
illnesses with short duration following ingestion
of locally grown hydroponic cucumbers. Despite a thorough
investigation, the etiologic agent of illness was
not determined. From July 16--25, 1978, a second similar
outbreak occurred in an adjacent city. Five individuals
experienced illness similar to that which occurred
in 1977, also following ingestion of hydroponic cucumbers
grown at the same greenhouse involved in the 1977
outbreak. The carbamate insecticide, aldicarb, was
detected in some cucumbers grown at the hydroponic
greenhouse. The source of this chemical in the greenhouse
could not be determined.
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EGGPLANT |
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Department of Molecular
and Cell Biology, University of California at Berkeley,
94720-3200, USA.
Delphinidine-3-(p-coumaroylrutinoside)-5-glucoside
(nasunin), an anthocyanin was isolated as purple colored
crystals from eggplant peels, Solanum melongena L.
'Chouja'. Using an electron spin resonance spectrometer
and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), spin
trapping, hydroxyl (.OH) or superoxide anion radicals
(02*-) generated by the Fenton reaction or the hypoxanthine-xanthine
oxidase system were measured as DMPO-OH or DMPO-OOH
spin adducts. L-Ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetra-methyl-2-(4,8,12-trimethyltridecyl)-2
H-1-benzopyran-6yl-hydrogen phosphate] potassium salt
(EPC-K1) and bovine erythrocyte superoxide dismutase
(SOD) were used as standards for .OH and O2*-, respectively.
Nasunin directly scavenged O2*- with a potency of
143+/-8 SOD-equivalent units/mg), and inhibited formation
of DMPO-OH (0.65+/-0.07 EPC-K1 micromol/mg). A spectrophotometric
study showed that nasunin formed an iron complex with
a molar ratio of nasunin : Fe3+ of 2 : 1. Therefore,
hydroxyl radical scavenging by nasunin is not due
to direct radical scavenging but inhibition of .OH
generation by chelating iron. Nasunin (1 microM) significantly
protected against lipid peroxidation of brain homogenates
(p<0.001) as measured by malonaldehyde and 4-hydroxyalkenals.
These findings demonstrate that nasunin is a potent
O2*- scavenger and iron chelator which can protect
against lipid peroxidation.
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Faculdades de Ciencias Medicas,
UNICAMP, Campinas, SP.
PURPOSE: To study the effect of egg
plant on endothelium-dependent relaxation, and plasma
lipids in hypercholesterolemic rabbits, and to assess
influence of this plant on the malondialdehyde (MDA)
content of LDL particles and the arterial wall. METHODS:
Thirteen male rabbits were randomly assigned to control
(C), hypercholesterolemic (H) and egg plant (E) treated
groups (n = 10 each). The H and E rabbits were fed
a diet supplemented with cholesterol (0.5%) and coconut
oil (10%) for 4 weeks. In addition, group E received
10 mL of the fruit juice/day during the last 2 weeks.
The animals were killed and the aorta removed to measure
MDA content and the endothelium dependent relaxation
responses. Total plasma cholesterol, VLDL, LDL, HDL
and triglyceride levels were determined using commercial
kits. MDA was quantified in native and oxidized LDL
and in the arterial wall. RESULTS: After 4 weeks,
the E group rabbits had a significantly lower weight,
plasma cholesterol, LDL, triglyceride and aortic cholesterol
content than group H(p < 0.05). The MDA content
that was significantly increased in the LDL particles
and in the arterial wall of H rabbits was reduced
in the E group (p < 0.05). Endothelium-dependent
relaxation were significantly higher in the E group
compared H group rabbits (p < 0.05). CONCLUSION:
In hypercholesterolemic rabbits egg plant juice significantly
reduced weight, plasma cholesterol levels, aortic
cholesterol content and the MDA concentrations in
native-oxidized LDL and in the arterial wall and increased
the endothelium-dependent relaxations.
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To investigate the mechanism behind
the hypocholesteremic properties of Solanum melongena
diets containing 1% Sol. mel. leaf or fruit powder,
alfalfa, or clofibrate were fed to rats. Sol. mel.
did n ot lower the serum plus liver cholesterol pool
of rats, whereas alfalfa and clofibrate did. However,
all substances tested decreased the absorption of
a single dietary dose of [4-14C] cholesterol. It appears
that Sol. mel. exerts its reported hypocholesteremic
effect in rabbits through an inhibition of absorption
of dietary cholesterol. This inhibition is probably
brought about partially through the binding of bile
salts which are essential for cholesterol absorption.
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GARLIC |
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Tomato (Lycopersicon esculentum)
and garlic (Allium cepa) are important constituents
of the human diet. Compounds like diallyl sulfides,
diallyl disulfides and quercetin, which are active
components of garlic, have known anti-inflammatory,
antimutagenic activities. Similarly, active components
in tomato, such as kaempferol and chlorogenic acid,
have antimutagenic activities and lycopene is the
most active oxygen quencher with potential chemopreventive
activities. In view of this, an endeavour was made
to evaluate the anticarcinogenic effect, if any, of
tomato and garlic consumption individually and in
combination on azoxymethane-induced colonic precancerous
lesion, the aberrant crypt foci in animal model. Sprague-Dawley
rats (4-5 weeks old) were injected with azoxymethane
(15 mg/kg b.w.) and orally administered with 2% (w/v)
of tomato, garlic and a combination of both. After
12 weeks of first azoxymethane injection, colons were
assessed for aberrant crypt foci and compared with
the carcinogen control group. Lipid peroxidation level
and glutathione-S-transferase (GST) activity were
assessed in liver as well as in colon. Furthermore,
in situ cell proliferation and apoptosis were estimated
using the Brdu incorporation method and TUNEL method
respectively. It was observed that aberrant crypt
foci were reduced in all treated groups (by 32.11%
in garlic, by 76.14% in tomato and by 55.96% in the
combination group). Among treated groups, GST activity
was found to be induced in both liver and colon, whereas
considerable reduction in lipid peroxidation level
was observed in liver as well as in colon with respect
to the carcinogen control group. Significant reduction
in Brdu labelling index and increase in apoptotic
index in colon was noted in the treated groups. These
results suggest that tomato and garlic suspensions
have a protective effect on colon carcinogenesis,
which is mediated by modulation of different biological
pathways during carcinogenesis.
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Marmara University, School
of Pharmacy, Department of Pharmacology, Istanbul, Turkey.
Oxygen free radicals have been implicated
in mediating various pathological processes including
burn-induced organ damage. This study was designed
to determine the possible protective effect of aqueous
garlic extract against oxidative organ damage distant
from the original burn wound. Under ether anaesthesia,
rats were subjected to severe skin scald injury covering
30% of total body surface area. Rats were decapitated
either 2 h or 24 h after burn injury. Aqueous garlic
extract (1 ml/kg) was administered i.p. immediately
after burn injury. In the 24-h burn group injection
was repeated once more (at 12 hour) following the
burn injury. Liver, intestine and lung tissues were
taken for the determination of malondialdehyde (MDA)
and glutathione (GSH) levels, myeloperoxidase (MPO)
activity and protein oxidation (PO). Burn injury caused
a significant decrease in GSH level, and significant
increases in MDA and PO levels, and MPO activity at
post-burn 2 and 24 hours. Since garlic extract reversed
these oxidant responses it seems likely that garlic
extract protects tissues against oxidative damage.
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Several epidemiological observations
and a number of laboratory studies have indicated
anticarcinogenic potential of garlic, which has been
traditionally used from time immemorial for varied
human ailments in different parts of the globe. The
anticarcinogenic properties of garlic have been attributed
to a wide variety of chemical compounds identified
to be present in garlic but most studies have focused
on specific thioallyl constituents. Garlic components
have been found to block covalent binding of carcinogens
to DNA, enhance degradation of carcinogens, have antioxidative
and free radical scavenging properties and to regulate
cell proliferation, apoptosis and immune responses.
In view of the variety of effects produced by garlic
and its chemical constituents, renewed interest has
been generated in investigating its medicinal properties,
particularly with reference to cancer prevention and
prophylaxis. There are a number of mechanisms at work
which jointly are responsible for eliciting the anticarcinogenic
effects noted in laboratory studies in a wide range
of experimental systems. This has opened up a new
avenue for researchers in the field of cancer chemoprevention
and merits further scrutiny to establish the role
of garlic in prevention of human cancers.
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Ethiopian Health and Nutrition
Research Institute, P.O. Box 1242, Addis Ababa, Ethiopia.
The antibacterial activity of the
crude aqueous extract of garlic was investigated against
some pneumonia causing bacteria by an agar dilution
technique. The results revealed that Streptococcus
pneumoniae standard test organism was completely inhibited
by 7.8 mg/ml of media and the clinical isolate of
Klebsiella pneumoniae was completely inhibited by
24.38 mg/ml of media, indicating that Streptococcus
pneumoniae is the most sensitive and Klebsiella pneumoniae
the least. Garlic could be used as an effective antibacterial
agent for these pathogenic microorganisms.
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Department of Pharmacology, All
India Institute of Medical Sciences, New Delhi 110029,
India.
Garlic has played an important dietary
and medicinal role throughout the history of mankind.
In some Western countries, the sale of garlic preparations
ranks with those of leading prescription drugs. The
therapeutic efficacy of garlic encompasses a wide
variety of ailments, including cardiovascular, cancer,
hepatic and microbial infections to name but a few.
However, the elucidation of its mechanism for therapeutic
action has proved to be more elusive and a unifying
theory, which could account for its reported multifarious
activities, is yet to emerge. Reactive oxygen species
(ROS) seem to be at the core of many disease processes
and it is an attractive and convenient hypothesis
that garlic might exert its activities through modulatory
effects on ROS. A literature search on garlic and
its antioxidant potential churned up a surprisingly
large amount of data, some of it good, some bad and
some of its definitely ugly.Various preparations of
garlic, mainly aged garlic extract (AGE), have been
shown to have promising antioxidant potential. However,
the presence of more than one compounds in garlic,
with apparently opposite biological effects, has added
to the complexity of the subject. Raw garlic homogenate
has been reported to exert antioxidant potential but
higher doses have been shown to be toxic to the heart,
liver and kidney.So where do we stand today on this
issue of garlic? Is garlic always good for health?
How safe is it? Is it necessary to isolate the antioxidant
compounds for its medicinal use in a more effective
way? These issues are addressed in this review.
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Department of Pathology,
College of Medicine, University of Illinois at Chicago,
Chicago, Illinois, USA.
Although garlic is believed to have
health-promoting benefits, many of the claimed benefits
are not supported by good scientific studies. This
review critically examined current scientific literature
concerning claims of cardiovascular benefits from
regular consumption of garlic or garlic preparations.
The vast majority of recent randomized, placebo-controlled
studies do not support a role for garlic in lowering
blood lipids. There also is insufficient evidence
to support a role in reducing blood pressure. While
there have been indications of antiatherosclerotic
effects associated with garlic consumption, there
are insufficient data in humans. Investigation of
antithrombotic effects of garlic consumption appears
to hold promise, but too few data exist to draw firm
conclusions.
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School of Biomolecular Sciences,
Liverpool John Moores University, Byrom Street, L3 3AF,
Liverpool, UK
There has been an impressive gain
in individual life expectancy with parallel increases
in age-related chronic diseases of the cardiovascular,
brain and immune systems. These can cause loss of
autonomy, dependence and high social costs for individuals
and society. It is now accepted that aging and age-related
diseases are in part caused by free radical reactions.
The arrest of aging and stimulation of rejuvenation
of the human body is also being sought. Over the last
20 years the use of herbs and natural products has
gained popularity and these are being consumed backed
by epidemiological evidence. One such herb is garlic,
which has been used throughout the history of civilization
for treating a wide variety of ailments associated
with aging. The role of garlic in preventing age-related
diseases has been investigated extensively over the
last 10-15 years. Garlic has strong antioxidant properties
and it has been suggested that garlic can prevent
cardiovascular disease, inhibit platelet aggregation,
thrombus formation, prevent cancer, diseases associated
with cerebral aging, arthritis, cataract formation,
and rejuvenate skin, improve blood circulation and
energy levels. This review provides an insight in
to garlic's antioxidant properties and presents evidence
that it may either prevent or delay chronic diseases
associated with aging.
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KALE |
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Creighton University, Omaha,
NE 68178.
Absorption of calcium from intrinsically
labeled kale was measured in 11 normal women and compared
in these same subjects with absorption of calcium
from labeled milk. The average test load was 300 mg.
Fractional calcium absorption from kale averaged 0.409
+/- 0.101 (means +/- SD) and from milk, 0.321 +/-
0.089 (P less than 0.025). In contrast with the poor
absorption previously reported for spinach calcium,
kale, a low-oxalate vegetable, exhibits excellent
absorbability for its calcium.
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LEEKS |
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Department of Pharmacy and Administrative
Sciences, College of Pharmacy and Allied Health Professions,
St. John's University, Jamaica, NY 11439, USA.
OBJECTIVES: To investigate the anticancer
activities of Chinese leek (Allium tuberosum Rottler;
[CL]). DESIGN: Fresh CL was extracted and reconstituted
in phosphate-buffered saline. The in vitro antiproliferation
activities of the extract were tested with two murine
cancer cell lines and four human cancer cell lines.
The in vivo anticancer effects were tested in C57BL
mice with lung metastases of B16-F10 melanoma. The
mice were inoculated with B16-F10 melanoma cells by
intravenous (IV) injection on day 1. CL extract was
given on days 6-8 by either IV injection or oral gavage.
The lung metastases were examined on day 16. RESULTS:
The extract inhibited the in vitro growth of all six
cancer cell lines studied. The dose-response curves
were sigmoidal with IC50 (50% inhibition concentrations)
in the range of 2.5-13.0 mg of raw material per milliliter
for the six cancer cell lines. At the CL concentration
of 8-100 mg of raw material per milliliter, all the
cells underwent apoptosis, and no live cells were
left after being exposed to CL for 4-6 hours. Typical
apoptosis-specific cell morphology changes were observed
under a microscope. The induction of cancer cell apoptosis
by CL extract was further verified by the DNA ladder
assay. Treatment with a daily oral dose of the extract
(equivalent to 2.5 or 12.5 mg of raw material per
gram of body weight) reduced the B16-F10 melanoma
lung metastatic colonies in mice by 40% (p < 0.03).
IV injection of the extract (equivalent to 1.25 or
6.25 mg of raw material per gram of body weight) did
not show any effect. CONCLUSIONS: CL extract inhibited
cancer cell growth and induced apoptosis in vitro.
Oral administration of CL extract significantly reduced
lung metastases in the present animal model.
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LETTUCE |
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Antioxidant Research Laboratory
at the Unit of Human Nutrition, Istituto Nazionale di
Ricerca per gli Alimenti e la Nutrizione (INRAN), Rome,
Italy.
The present study investigated
whether storage under modified-atmosphere packaging
(MAP) affected the antioxidant properties of fresh lettuce
(Lactuca sativa). Eleven healthy volunteers (six men,
five women) consumed 250 g fresh lettuce, and blood
was sampled before (0 h) and 2, 3 and 6 h after consumption.
The protocol was repeated 3 d later with the same lettuce
stored at 5 degrees C under MAP conditions (O2-N2 (5:95,
v/v)). Results showed that after ingestion of fresh
lettuce, plasma total radical-trapping antioxidant potential
(TRAP), measured as area under the curve, was significantly
higher (1.3 (sem 0.3) mmol/l per 6 h; P<0.05) than
the value obtained with MAP-stored lettuce (0.1 (sem
0.2) mmol/l per 6 h). Plasma TRAP, quercetin and p-coumaric
acid were significantly different from baseline values
(P<or=0.05) 2 and 3 h after fresh lettuce ingestion.
Caffeic acid increased significantly at 3 h (P<0.05).
Plasma beta-carotene levels increased significantly
at 6 h (P<0.05). Vitamin C concentrations (mg/l)
rose from 10.9 (sem 2.0) to 12.7 (sem 3.0) (P<0.001),
12.7 (sem 2.0) (P<0.01) and 12.9 (sem 3.0) (P<0.05)
at 0, 2, 3 and 6 h respectively. No changes were observed
after ingestion of MAP-stored lettuce for all the measured
markers. Our present results showed that ingestion of
MAP-stored lettuce does not modify plasma redox status
in healthy subjects. Further research is needed to develop
post-harvesting techniques able to preserve the bioactive
molecule content of plant food.
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Mann Laboratory, Department of
Vegetable Crops, University of California, One Shields
Avenue, Davis, California 95616-8631, USA.
Wounding induced the accumulation
of phenolic compounds in Iceberg and Romaine lettuce
leaf tissue. Phenolic concentrations were quantified
after holding the leaf tissue at 10 degrees C for
48 h as the absorbance of a methanol extract at 320
nm, and by the Folin-Ciocalteu method. Heat-shock
treatments applied by immersing tissue in 45 degrees
C water for 2.5 min before or after wounding reduced
the accumulation of phenolic compounds. Compared to
the nonwounded, nonheat-shocked controls, these and
other wounding and heat-shock treatments produced
leaf tissue with a 4-fold range in phenolic content.
The antioxidant capacity of the tissue, measured as
DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl)-radical
scavenging activity, or as ferric-reducing antioxidant
power (FRAP), increased after wounding. The increase
was linearly correlated with the increase in phenolic
compounds in Iceberg (R(2) > 0.97) and in Romaine
(R(2) > 0.95) lettuce leaf tissue. Increased consumption
of diets rich in phenolic antioxidants may contribute
to reducing human diseases. Treatments that reduce
the browning of wounded lettuce leaf tissue by preventing
the oxidation of the accumulated wound-induced phenolic
compounds may produce a healthier fresh-cut product
than treatments that prevent the wound-induced synthesis
and accumulation of phenolic compounds with antioxidant
properties.
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National Institute of Public Health,
Oslo, Norway.
In the period from May through June
1994, an increase in the number of domestic cases
of Shigella sonnei infection was detected in several
European countries, including Norway, Sweden, and
the United Kingdom. In all three countries epidemiological
evidence incriminated imported iceberg lettuce of
Spanish origin as the vehicle of transmission. The
outbreaks shared a number of common features: a predominance
of adults among the case patients, the presence of
double infections with other enteropathogens, and
the finding of two dominant phage types among the
bacterial isolates. In Norway 110 culture-confirmed
cases of infection were recorded; more than two-thirds
(73%) were adults aged 30 to 60 years. A nationwide
case-control study comprising 47 case patients and
155 matched control individuals showed that the consumption
of imported iceberg lettuce was independently associated
with an increased risk of shigellosis. Epidemiological
investigation of a local outbreak incriminated iceberg
lettuce from Spain, consumed from a salad bar, as
the source. The presence of shigellae in the suspected
food source could not be documented retrospectively.
However, high numbers of fecal coliforms were detected
in iceberg lettuce from patients' homes. Three lettuce
specimens yielded salmonellae. The imported iceberg
lettuce harbored Escherichia coli strains showing
resistance to several antimicrobial agents, including
ampicillin, ciprofloxacin, gentamicin, and trimethoprim-sulfamethoxazole.
During the outbreak it is likely that thousands of
Norwegians and an unknown number of consumers in other
countries were exposed to coliforms containing antibiotic
resistance genes.
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ONION |
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The data on vitamins C, B1, B2, A,
E and carotenoids content in fresh-cut leaves of some
species of genus of Allium cultivated in the Main
Botanical garden (Moscow) are submitted. Their significance
as these nutrients source is evaluated. Onion leaves
usually used as flavor-odour additive (10-20 g) give
only 1-4 per cent of vitamin B group and E daily recommended
allowance. At the same time this quantity supply with
vitamin C (20 per cent of vitamin C daily recommended
allowance) and carotenoids (20-50 per cent).
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TOMATOES |
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Division of Urology, Department
of Surgery, Ohio State University College of Medicine
and Public Health, 4841 UHC, 456 West 10th Avenue, OH
43210, Columbus, USA.
Prostate cancer has become a major
public health issue and the search for etiologic risk
factors and the development of chemopreventive agents
has gained momentum over the last decade. An important
epidemiologic finding has been the association between
the consumption of tomato products and a lower risk
of prostate cancer. Several investigators have proposed
that lycopene, a carotenoid consumed largely from
tomato products, may be the component responsible
for lowering the risk of prostate cancer. Laboratory
and clinical studies have been initiated with the
goal of assessing the ability of pure lycopene to
serve as a chemopreventive agent for prostate cancer.
The focus on lycopene should continue, and an improved
understanding of lycopene absorption, distribution,
role in antioxidant reactions, and metabolism is critical
in the quest to elucidate mechanisms whereby this
compound may possibly reduce prostate cancer risk.
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Dept. of Food Science, North Carolina
State University, Raleigh 27695-7624, USA.
Diet is believed to play a complex
role in the development of cardiovascular disease,
the leading cause of death in the Western world. Tomatoes,
the second most produced and consumed vegetable nationwide,
are a rich source of lycopene, beta-carotene, folate,
potassium, vitamin C, flavonoids, and vitamin E. The
processing of tomatoes may significantly affect the
bioavailability of these nutrients. Homogenization,
heat treatment, and the incorporation of oil in processed
tomato products leads to increased lycopene bioavailability,
while some of the same processes cause significant
loss of other nutrients. Nutrient content is also
affected by variety and maturity. Many of these nutrients
may function individually, or in concert, to protect
lipoproteins and vascular cells from oxidation, the
most widely accepted theory for the genesis of atherosclerosis.
This hypothesis has been supported by in vitro, limited
in vivo, and many epidemiological studies that associate
reduced cardiovascular risk with consumption of antioxidant-rich
foods. Other cardioprotective functions provided by
the nutrients in tomatoes may include the reduction
of low-density lipoprotein (LDL) cholesterol, homocysteine,
platelet aggregation, and blood pressure. Because
tomatoes include several nutrients associated with
theoretical or proven effects and are widely consumed
year round, they may be considered a valuable component
of a cardioprotective diet.
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Department of Food Science and
Institute of Comparative and Environmental Toxicology,
Stocking Hall, Cornell University, Ithaca, New York
14853, USA.
Processed fruits and vegetables have
been long considered to have lower nutritional value
than their fresh commodities due to the loss of vitamin
C during processing. This research group found vitamin
C in apples contributed < 0.4% of total antioxidant
activity, indicating most of the activity comes from
the natural combination of phytochemicals. This suggests
that processed fruits and vegetables may retain their
antioxidant activity despite the loss of vitamin C.
Here it is shown that thermal processing elevated
total antioxidant activity and bioaccessible lycopene
content in tomatoes and produced no significant changes
in the total phenolics and total flavonoids content,
although loss of vitamin C was observed. The raw tomato
had 0.76 +/- 0.03 micromol of vitamin C/g of tomato.
After 2, 15, and 30 min of heating at 88 degrees C,
the vitamin C content significantly dropped to 0.68
+/- 0.02, 0.64 +/- 0.01, and 0.54 +/- 0.02 micromol
of vitamin C/g of tomato, respectively (p < 0.01).
The raw tomato had 2.01 +/- 0.04 mg of trans-lycopene/g
of tomato. After 2, 15, and 30 min of heating at 88
degrees C, the trans-lycopene content had increased
to 3.11+/- 0.04, 5.45 +/- 0.02, and 5.32 +/- 0.05
mg of trans-lycopene/g of tomato (p < 0.01). The
antioxidant activity of raw tomatoes was 4.13 +/-
0.36 micromol of vitamin C equiv/g of tomato. With
heat treatment at 88 degrees C for 2, 15, and 30 min,
the total antioxidant activity significantly increased
to 5.29 +/- 0.26, 5.53 +/- 0.24, and 6.70 +/- 0.25
micromol of vitamin C equiv/g of tomato, respectively
(p < 0.01). There were no significant changes in
either total phenolics or total flavonoids. These
findings indicate thermal processing enhanced the
nutritional value of tomatoes by increasing the bioaccessible
lycopene content and total antioxidant activity and
are against the notion that processed fruits and vegetables
have lower nutritional value than fresh produce. This
information may have a significant impact on consumers'
food selection by increasing their consumption of
fruits and vegetables to reduce the risks of chronic
diseases.
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Western Regional Research Center,
Agricultural Research Service, U.S. Department of Agriculture,
Albany, California, USA.
Consumption of tomato products has
been associated with decreased risk of some cancer
types, and the tomato antioxidant, lycopene, is thought
to play an important role in the observed health effects.
In this study, four carotenoids, trans-lycopene, phytofluene,
phytoene, and zeta-carotene, were quantified in tomato
products. Samples of raw tomatoes, tomato juice after
hot break scalder, and final paste were obtained from
two different processing plants over two years. Comparison
of carotenoid levels throughout processing indicated
that lycopene losses during processing of tomatoes
into final paste (25-30 degrees Brix) ranged from
9 to 28%. The initial Brix level of the raw tomatoes
appeared to influence the amount of lycopene loss
that occurred, possibly due to the differences in
processing time required to achieve the final desired
Brix level of the paste. In general, no consistent
changes in the other carotenoids were observed as
a function of processing. The antioxidant activity
of fresh tomatoes, tomato paste, and three fractions
obtained from these products (i.e., aqueous, methanol,
and hexane fractions) was also determined. In both
a free radical quenching assay and a singlet oxygen
quenching assay, significant antioxidant activity
was found in both the hexane fraction (containing
lycopene) and the methanol fraction, which contained
the phenolic antioxidants caffeic and chlorogenic
acid. The results suggest that in addition to lycopene,
polyphenols in tomatoes may also be important in conferring
protective antioxidative effects.
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Dipartimento di Orto-Floro-Arboricoltura
e Tecnologie Agroalimentari, Universita di Catania,
Via Valdisavoia 5, 95123 Catania, Italy.
The phytonutrient intake associated
with tomato consumption depends also on cultivar and
fruit ripening stage. This work associates the antioxidative
ability, the level of carotenoids, and the amount
of glycoalkaloids to the main carpometric characteristics
of four different typologies of tomatoes: "cherry",
"cluster", "elongated," and "salad".
These typologies have different weights and shapes,
and they are usually consumed in the Mediterranean
area at different ripening stages. Results showed
that the considered tomato typologies also differ
in their antioxidative ability and their carotenoid
and glycoalkaloid contents. Growing conditions are
also important in determining fruit characteristics:
the analysis of the same cultivar of cherry tomato
produced under the influence of moderate salt stress
showed increases in the lipophilic antioxidative ability
and the amount of carotenoid, whereas the level of
glycoalkaloid decreased.
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