Joe A. Vinson*, Jinhee Jang, Yousef A. Dabbagh,
Mamdouh M.
Serry, and Songhuai Cai
J. Agric. Food Chem. 43, 2798-2799 (1995)
ABSTRACT:
There is now considerable epidemiological evidence that dietary
flavonoids are protective against heart disease. Since lower density
lipoproteins are rendered atherogenic by oxidation in the wall of
the artery, only those antioxidants that bind to LDL and VLDL can be
protective. In an ex vivo spiking experiment we have investigated
the effect of 8 phenols on lipoprotein binding and the resulting protection of
the lipoproteins from oxidation. Phenol antioxidants were spiked at
concentrations of 50 to 200 ?M in plasma. After equilibration the LDL+VLDL
was isolated by an affinity column method. It was subjected to a standard
oxidation at pH 7.4 with cupric ion and the lag time of oxidation
determined. The control value with no added antioxidants was74 ? 5
min. Plots of phenol concentration added vs. lag time produced a straight
line for all phenols. Epigallocatechin gallate was the best
antioxidant in this model. The concentration to increase lag time 50% vs.
the control was determined and represents the lipoprotein-bound antioxidant
activity. This CLT50 should be useful criteria for screening
antioxidants for in vivo supplementation since after absorption both binding and
antioxidant activity are necessary.
PHENOL ANTIOXIDANT INDEX: COMPARATIVE
ANTIOXIDANT EFFECTIVENESS OF
RED AND WHITE
WINES.
Joe A. Vinson* and Barbara A. Hontz
J. Agric. Food Chem. 43, 401-403 (1995)
ABSTRACT:
Phenols present in wines are responsible for its antioxidant
properties. Total phenols in red and white wines were determined
according to the Folin method. Red wines had a much higher phenol contents
than white wines. The concentration for %0% inhibition of lower density
lipoproteins (IC50) was measured. The white wines had a significantly
lower IC50 and thus were better antioxidants than red wines. The phenol
antioxidant index was defined as the ratio of phenol
concentration/IC50. Red wines had a significantly higher
antioxidant index than white wines and are a better source of
antioxidants. All wines were better antioxidants than ascorbic acid or
tocopherol under these experimental conditions. The index should be useful
criterion to compare antioxidants in foods and juices.
PLANT FLAVONOIDS, ESPECIALLY TEA FLAVONOLS, ARE POWERFUL ANTIOXIDANTS USING AN IN VITRO OXIDATION MODEL FOR HEART DISEASE.
Joe A. Vinson*, Yousef A. Dabbagh, Mamdouh M. Serry,
and Jinhee
Jang
J. Agric. Food Chem. 43, 2800-2802 (1995).
ABSTRACT:
33 flavonoids, commonly occurring antioxidants in foods, have been
compared in a dose-response manner with vitamins C and E and ?-carotene and
synthetic phenol antioxidants and found to be powerful antioxidants using an in
vitro lipoprotein oxidation model. This model simulates the oxidation of
low-density lipoproteins, which results in atherosclerosis. Of the
flavonoids and flavonoid-related compounds, flavonols found in tea are the most
powerful natural antioxidants. These results provide a mechanism for the
beneficial epidemiological effect of dietary flavonoids on heart disease.
EFFECT OF GREEN AND BLACK TEA SUPPLEMENTATION ON LIPIDS, LIPID OXIDATION AND FIBRINOGEN IN THE HAMSTER: MECHANISMS FOR THE EPIDEMIOLOGICAL BENEFITS OF TEA DRINKING.
Joe A. Vinson* and Yousef A. Dabbagh
FEBS Lett. 433, 44-46 (1998)
ABSTRACT:
There is considerable epidemiological evidence that tea drinking lowers
the risk of heart disease. However, the mechanism by which tea can be
protective is unknown. Hamsters were fed a normal or high cholesterol diet
for 2 weeks and drank green or black tea ad libitum. The plasma lipid
profile was significantly improved by both teas compared to controls. Also
in vivo lipid oxidation as measured by plasma lipid peroxides and LDL+VLDL
oxidizability were significantly decreased by the teas. In the normal fed
tea groups fibrinogen was decreased but not in the high cholesterol
groups. Green tea was significantly more effective than the black
tea. These results show in the hamster model that black and green tea
improve the risk factors for heart disease by both hypolipemic and antioxidant
mechanisms and possibly a fibrinolytic effect.
TEA PHENOLS: ANTIOXIDANT EFFECTIVENESS OF TEAS, TEA COMPONENTS, TEA FRACTIONS AND THEIR BINDING WITH LIPOPROTEINS.
Joe A. Vinson* and Yousef A. Dabbagh
Nutr. Res. 18, 1067-1075 (1998)
ABSTRACT:
Phenols in tea are responsible for its antioxidant activity. The pure
catechins and phenolic acids found in tea are more powerful than the antioxidant
vitamins C, E and ?-carotene in an in vitro lipoprotein oxidation model.
Comparison of the tea fractions indicated that both catechins and theaflavins
contribute to the teas’ antioxidant characteristics. Black and green teas
were not significantly different in phenol content, in antioxidant strength as
measured by IC50 , or in antioxidant potential as measured by the phenol
antioxidant index (PAOXI). The PAOXI of teas was significantly higher than
grape juices and wines. Tea catechins and both green and black tea
exhibited potent lipoprotein-bound antioxidant activity. Phenol
antioxidants from tea were calculated to be a large source of antioxidants in
the U.S. diet.
SELENIUM YEAST IS AN EFFECTIVE IN VITRO AND IN VIVO ANTIOXIDANT AND HYPOLIPEMIC AGENT IN NORMAL HAMSTERS.
Joe A. Vinson*, Jennifer M. Stella, and Thomas J. Flanagan
Nutr. Res. 18, 735-742 (1998)
ABSTRACT:
Selenium as the selenite, selenomethionine, ebselen and yeast was
investigated in an in vitro low density lipoprotein oxidation model to mimic the
first step in atherogenesis. Ebselen and selenium yeast were found to be
the best antioxidants of the forms of selenium. Selenium yeast was then
given in two doses as a supplement to chow-fed hamsters for 15 days. The
yeast significantly decreased total plasma cholesterol and the atherogenic index
but did not significantly diminish HDL and triglycerides. Selenium yeast
significantly decreased plasma lipid peroxides, low density lipoprotein
oxidation lag time, and maximum slope of oxidation. These results indicate
that selenium yeast is a powerful in vitro and in vivo antioxidant as well as a
hypolipemic agent. These two actions could explain the benefit of selenium
seen in epidemiology studies.
A CITRUS EXTRACT PLUS ASCORBIC ACID DECREASES LIPIDS, LIPID PEROXIDES, LIPOPROTEIN OXIDATIVE SUSCEPTIBILITY, AND ATHEROSCLEROSIS IN HYPERCHOLESTEROLEMIC HAMSTERS.
Joe A. Vinson*, Sheu-Ju Hu, Sunah Jung, and Ann M. Stanski
J. Agric. Food Chem. 46, 1453-1459 (1998)
ABSTRACT:
A citrus extract containing flavonoids and ascorbic acid was used as a
supplement to investigate its effect on lipids in hypercholesterolemic
hamsters. Ascorbic acid or the flavonoids were without effect except that
ascorbate did significantly raise HDL. After 1 month of feeding, the
citrus extract plus ascorbic acid synergistically caused a significant reduction
of 77, 66%, and 40% in plasma total cholesterol, LDL + VLDL, and trigylcerides,
respectively, in comparison to the control group. The extract was also a
synergistic inhibitor of in vitro cupric ion LDL + VLDL oxidation compared with
ascorbic acid or the flavonoids alone. In a second 10-week hamster study,
citrus extract plus ascorbate also significantly lowered plasma lipids, lipid
peroxides, and ex vivo
LDL + VLDL oxidizability vs. a control group.
Citrus extract plus ascorbate strongly inhibited atherosclerosis, and there was
a significant correlation between several indices of oxidative susceptibility
and atherosclerosis.
FLAVONOIDS IN FOODS AS IN VITRO AND IN VIVO ANTIOXIDANTS.
Joe A. Vinson
Flavonoids in the Living System, Plenum Press, New York, 1998.
ABSTRACT:
This chapter reviews published work on flavonoids and includes our
recent work in this area with 51 references. The chemistry of these molecules of
this class of compounds is discussed along with structure-activity relationships
of their antioxidant activity. Epidemiological studies of vegetables, fruits and
most recently flavonoids against cancer and heart disease are reviewed and The
French paradox provided the recent interest in flavonoids. Lipids and the
oxidative theory of atherosclerosis is discussed in detail. Our research
on the quantity and quality of polyphenol antioxidants in foods and beverages is
highlighted. Most importantly, the in vivo absorption of these molecules
is reviewed for tea, wine, vegetables and fruit juices. In vivo activity
of antioxidants in red wine and black tea is reviewed. The author’s work
in this are is discussed.
PHENOL ANTIOXIDANT QUANTITY AND QUALITY IN FOODS: VEGETABLES.
Joe A. Vinson*, Yong Hao, Xuehui Su, and Ligia Zubik
J. Agric. Food Chem. 46, 3630-3634 (1998)
ABSTRACT:
Fruits and vegetables in the diet have been found in epidemiology
studies to be protective against several chronic diseases. Epidemiological
evidence suggests that flavonoid consumption in the diet is protective against
heart disease. Phenols in 23 vegetables have been measured by extraction
with and without acid hydrolysis to determine the percent of conjugated and free
phenols. Phenols were measured colorimetrically using the Folin-Cocialteu
reagent with catechin as the standard. The extracts’ antioxidant quality
was assayed by the inhibition of lower density lipoprotein oxidation mediated by
cupric ions. Vegetables had antioxidant quality comparable to that of pure
flavonols and were superior to vitamin antioxidants. The phenol
antioxidant index, measuring both the quantity and the quality of antioxidants
present, was used to evaluate 23 vegetables. Isolated lower density
lipoproteins from plasma spiked with two vegetable extracts were enriched with
phenol antioxidants and showed decreased oxidizability. The average per
capita consumption of vegetable phenols in the United States was estimated to be
218 mg/day of catechin equivalents. This is 3 times higher than the
recommended intake of vitamin antioxidants.
THE FUNCTIONAL FOOD PROPERTIES OF FIGS
J. A. Vinson
Cereal Foods World 44, 82-87 (l999).
ABSTRACT:
The importance of “nutraceuticals,” also known as “functional
foods,” in the American diet is highlighted by the fact that consumers
paid out $9 billion/year for these products. This is review with 45 references
of the functional food properties of figs. The history of fig consumption
and cultivation is discussed. The nutrient composition of figs are highlighted
with the fact that figs are extremely high in fiber, providing 20% of the daily
value in a single serving of 40 grams. The non-nutrients in figs are discussed
and their relationship to cancer are reviewed.
Polyphenols and coumarins in figs are two classes of compounds which have potent
anti-cancer properties. The mechanisms leading to heart disease with emphasis
on the oxidative theory of atherosclerosis are reviewed. Polyphenols,
powerful antioxidants, are compared for nuts, cereals, fruits and beverages.
Using 100 grams as a comparison serving size, it is evident that figs contain
one of the highest content of polyphenols. A serving size of 40 grams
of figs provides 444 milligrams of polyphenols, which is more than the daily
per capita consumption of polyphenols from vegetables in the USA.
_________________________________________________________________
MINI-REVIEW
BLACK AND GREEN TEA AND HEART DISEASE: A REVIEW.
Joe A. Vinson
BioFactors 13, 127-132 (2000)
ABSTRACT:
Tea is the second most consumed beverage around the world behind water. Epidemiological evidence points to both green and black tea consumption being protective with respect to heart disease. However, epidemiology evidence does not prove cause and effect and is potentially flawed by confounding variables. The recent evidence with respect to teas' beneficial effects from in vitro and in vivo studies in both animals and humans will be covered in this review. The comparative benefits of green vs. black tea will be considered. Articles published through December, 1999 will be included.
____________________________________________________________
MEGANATURAL® GOLD GRAPESEED EXTRACT: IN VITRO
ANTIOXIDANT AND IN VIVO HUMAN SUPPLEMENTATION STUDIES
Joe A. Vinson*, John Proch, and Pratima Bose
J. of Medic. Food 4, 17-26 (2001)
ABSTRACT:
Epidemiological studies have produced solid evidence that consumption of fruits
results in a reduction of cancer and cardiovascular disease. Red wine has been
hypothesized to reduce the risk of heart disease as a result of its antioxidant,
endothelial relaxation, and antiplatelet aggregation mechanisms. We investigated
a commercial California wine grapeseed extract, MegaNatural® Gold, and compared
it to grapes, grape juice, red wine, other grapeseed extracts, and commercial
extracts with respect to antioxidant activity, using an oxidation-reduction
colorimetry assay. The quality of the antioxidants was determined with the use
of an in vitro model of heart disease, a dose-response inhibition of low-density
lipoprotein oxidation. MegaNatural® Gold had a superior quantity/quality
antioxidant index compared with all other samples tested. In nine subjects given
600 mg of MegaNatural® Gold, the plasma antioxidant activity as measured
by the RANDOX assay was significantly increased by 12% after both 1 and 2 hours.
This was equivalent to drinking 300 ml of red wine or consuming 1,250 mg of
vitamin C, as found in a previous study. We then determined the dose-response
human plasma bioavailability of one of the polyphenols in MegaNatural® Gold
(epicatechin) in nine human subjects after giving 200 and 300 mg of the product.
The in vivo antioxidant activity was also measured. The higher dose was much
more effective. A long-term human supplementation study with 2 x 300 mg/day
of MegaNatural® Gold was then done on 17 (9 normal and 8 hypercholesterolemic)
subjects. Plasma cholesterol, low-density lipoprotein cholesterol, and high-density
lipoprotein cholesterol concentrations were significantly decreased in the subjects
with high cholesterol. Triglycerides were significantly increased in the high-cholesterol
subjects but were still in the normal range after supplementation. Plasma antioxidant
capacity was significantly improved in the high-cholesterol subjects. There
was no change in plasma lipids or antioxidant capacity in the normal subjects.
_________________________________________________________________
GRAPE JUICE, BUT NOT ORANGE JUICE, HAS IN VITRO, EX VIVO
AND IN VIVO ANTIOXIDANT PROPERITES
Joe A. Vinson*, Jihong Yang, John Proch, and Xiquan Liang
J. of Medic. Food 3, 167-171 (2000)
ABSTRACT:
Polyphenols and particularly flavonoids are well known in vitro antioxidants. Their consumption in foods has been shown to decrease the risk of heart disease in epidemiological studies. We examined two commonly consumed nonalcoholic juices (grape juice and orange juice) for their ability to act as in vitro plasma antioxidants, enrich lower-density lipoproteins after plasma spiking, and protect these lipoproteins from oxidation after supplementation to healthy subjects. We found that grape juice, but not orange juice, possesses all of these antioxidant properties and is an excellent nonalcoholic alternative to red wine. Grape juice is a powerful in vivo antioxidant, and this property, in combination with its platelet aggregation inhibition ability, can potentially reduce the risk of heart disease.
_____________________________________________________________
RED WINE, DEALCOHOLIZED RED WINE, AND ESPECIALLY GRAPE JUICE,
INHIBIT ATHEROSCLEROSIS IN A HAMSTER MODEL
Joe A. Vinson*, Karolyn Teufel, and Nancy Wu
Atherosclerosis l56, 67-72 (2001)
ABSTRACT:
The French have low coronary heart disease mortality with high fat consumption; this epidemiological anomaly is known as the 'French Paradox' and is commonly attributed to the consumption of red wine. However, epidemiology studies have not convincingly shown a superiority of red wine vs. alcohol or other alcoholic beverages. We have used the hamster model of atherosclerosis to determine the active ingredient(s) of red wine responsible for the beneficial effect. Hamsters (nine in each group) were given a cholesterol/saturated fat for 10 weeks to induce foam cell formation. Water or 6.75% ethanol was given to the control groups. Beverages tested included red wine, dealcoholized red wine, and red grape juice, all diluted in half. Ethanol and all beverages caused a significant reduction in atherosclerosis. The combination of ethanol in red wine had the largest effect in decreasing atherosclerosis by both hypolipemic and antioxidant mechanisms. When compared with dealcoholized wine and normalized to polyphenol dose, red wine's beneficial effects can be attributed entirely to the polyphenols. Grape juice had a red wine or dealcoholized red wine at the same polyphenol dose in inhibiting atherosclerosis and improving lipids and antioxidant parameters. This data suggests that polyphenolic beverages from grapes are beneficial in inhibiting atherosclerosis by several mechanisms. Grape juice or non-alcoholic red wine are an excellent alternative to red wine in this model of atherosclerosis.
_______________________________________________________
PHENOL ANTIOXIDANT QUANTITY AND QUALITY IN FOODS: FRUITS
Joe A. Vinson*, Xuehui Su, Ligia Zubik, and Pratima Bose
CITATION TO ADD:
ABSTRACT:
The free and bound phenols have been measured in 20 fruits commonly consumed
in the American diet. Phenols were measured colorimetrically using the Folin-Ciocalteu
reagent with catechin as the standard after correction for ascorbic acid contribution.
On a fresh weight basis, cranberry had the highest total phenols, and was distantly
followed by red grape. Free and total phenol quality in the fruits was analyzed
by using the inhibition of lower density lipoprotein oxidation promoted by cupric
ion. Ascorbate had only a minor contribution to the antioxidants in fruits with
the exception of melon, nectarine, orange, white grape, and strawberry. The
fruit extracts' antioxidant quality was better than the vitamin antioxidants
and more pure phenols, suggesting synergism among the antioxidants in the mixture.
Using our assay, fruits had significantly better quantity and quality of phenol
antioxidants than vegetables. Fruits, specifically apples and cranberries, have
phenol antioxidants that can enrich lower density lipoproteins and protect them
from oxidation. The average per capita consumption of fruit phenols in the U.S.
is estimated to be 255 mg/day of catechin equivalents.
______________________________________________________________
EFFECTS OF COCOA POWDER AND DARK CHOCOLATE ON LDL OXIDATIVE
SUSCEPTIBILITY AND PROSTAGLANDIN CONCENTRATIONS IN HUMANS
Ying Wan, Joe A. Vinson, Terry D. Etherton, John Proch, Sheryl A. Lazarus,
and
Penny M. Kris-Etherton
Am. J. Clin. Nutr. 74, 596-602 (2001)
ABSTRACT:
Background: Flavonoids are polyphenolic compounds of plant origin with antioxidant
effects. Flavonoids inhibit LDL oxidation and reduce thrombotic tendency in
vitro. Little is known about how cocoa powder and dark chocolate, rich sources
of polyphenols, affect these cardiovascular disease risk factors.
Objective: We evaluated the effects of a diet high in cocoa powder and dark
chocolate (CP-DC diet) on LDL oxidative susceptibility, serum total antioxidant
capacity, and urinary prostaglandin concentrations.
Design: We conducted a randomized, 2-period, crossover study in 23 healthy subjects
fed 2 diets: an average American diet (AAD) controlled for fiber, caffeine,
and theobromine and an AAD supplemented with 22 g cocoa powder and 16 g dark
chocolate (CP-DC diet), providing "466 mg procyanidins/d.
Results: LDL oxidation lag time was "8% greater (P = 0.01) after the CP-DC
diet than after the AAD. Serum total antioxidant capacity measured by oxygen
radical absorbance capacity was "4% greater (P = 0.04) after the CP-DC
diet than after the AAD and was positively correlated with LDL oxidation lag
time (r = 0.32, P = 0.03). HDL cholesterol wsa 4% greater after the CP-DC diet
(P = 0.02) than after the AAD; however, LDL-HDL ratios were not significantly
different. Twenty-four-hour urinary excretion of thromboxane B2 and 6-keto-prostaglandin
F1a
and the ratio of the 2 compounds were not significantly different between the
2 diets.
Conclusion: Cocoa powder and dark chocolate may favorably affect cardiovascular
disease risk status by modestly reducing LDL oxidation susceptibility, increasing
serum total antioxidant capacity and HDL-cholesterol concentrations, and not
adversely affecting prostaglandins.