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PROANTHOCYANIDINES



Table of Contents


Free radicals scavenging action and anti-enzyme activities of procyanidines from Vitis vinifera. A mechanism for their capillary protective action.

Arzneimittelforschung (GERMANY) May 1994, 44 (5) p592-601

The scavenging by procyanidines (polyphenol oligomers from Vitis vinifera seeds, CAS 85594-37-2) of reactive oxygen species (ROS) involved in the onset (HO degrees) and the maintenance of microvascular injury (lipid radicals R degrees, RO degrees, ROO degrees) has been studied in phosphatidylcholine liposomes (PCL), using two different models of free radical generation: a) iron-promoted and b) ultrasound-induced lipid peroxidation. In a) lipid peroxidation was assessed by determination of thiobarbituric acid-reactive substances (TBARS); in b) by determination of conjugated dienes, formation of breakdown carbonyl products (as 2,4-dinitrophenylhydrazones) and loss of native phosphatidylcholine. In the iron-promoted (Fenton-driven) model, procyanidines had a remarkable, dose-dependent antilipoperoxidant activity (IC50 = 2.5 mumol/l), more than one order of magnitude greater than that of the monomeric unit catechin (IC50 = 50 mumol/l), activity which is due, at least in part, to their metal-chelating properties. In the more specific model b), which discriminates between the initiator (hydroxyl radical from water sonolysis) and the propagator species of lipid peroxidation (the peroxyl radical, from autooxidation of C-centered radicals), procyanidines are highly effective in preventing conjugated diene formation in both the induction (IC50 = 0.1 mumol/l) and propagation (IC50 = 0.05 mumol/l) phases (the scavenging effect of alpha-tocopherol was weaker, with IC50 of 1.5 and 1.25 mumol/l). In addition, procyanidines at 0.5 mumol/l markedly delayed the onset of the breakdown phase (48 h), totally inhibiting during this time the formation of degradation products (the lag-time induced by alpha-tocopherol was only of 24 h at 10 mumol/l concentration). The HO degrees entrapping capacity of these compounds was further confirmed by UV studies and by electron spin resonance (ESR) spectroscopy, using DMPO as spin trapper: procyanidines markedly reduced, in a dose-dependent fashion, the signal intensity of the DMPO-OH radical spin adduct (100% inhibition at 40 mumol/l). The results of the second part of this study show that procyanidines, in addition to free radical scavenging action, strongly and non-competitively, inhibit xanthine oxidase activity, the enzyme which triggers the oxy radical cascade (IC50 = 2.4 mumol/l). In addition procyanidines non-competitively inhibit the activities of the proteolytic enzymes collagenase (IC50 = 38 mumol/l) and elastase (IC50 = 4.24 mumol/l) and of the glycosidases hyaluronidase and beta-glucuronidase (IC50 = 80 mumol/l and 1.1 mumol/l), involved in the turnover of the main structural components of the extravascular matrix collagen, elastin and hyaluronic acid.



Studies on vaccinium myrtillus anthocyanosides. I. Vasoprotective and antiinflammatory activity

ARZNEIMITTEL-FORSCH. (GERMANY, WEST), 1976, 26/5

A Vaccinium myrtillus anthocyanoside preparation (equivalent to 25% anthocyanidin) demonstrated significant vasoprotective and antioedema properties in experimental animals. In rabbits, the skin capillary permeability increase, due to chloroform, was reduced both after i.p. (25-100 mg/kg) and oral administration (200-400 mg/kg) of anthocyanosides. Their activity was more lasting in comparison to rutin or mepyramine and this did not seem to be due to a specific antagonism towards inflammatory process mediators such as histamine or bradykinin. Experiments carried out in rats demonstrated that Vaccinium myrtillus anthocyanosides were effective both in skin permeability test and on vascular resistance of rats fed a P factor deficient diet. In the former test effective doses were in the range of 25-100 mg/kg (by oral route). In both animal species investigated, anthocyanosides were twice as active as the flavonoid rutin. Vaccinium myrtillus anthocyanosides by oral route inhibited carrageenin paw oedema in rats showing a dose response relationship. An antioedema activity was detected also after i.v. or topical application.



Alcohol, ischemic heart disease, and the French paradox.

Constant J
State University of New York at Buffalo, USA.
Clin Cardiol (UNITED STATES) May 1997, 20 (5) p420-4

Many studies have shown either an inverse relation between alcohol intake and ischemic heart disease or a U-shaped curve in which the equivalent of two drinks per day of any kind of alcohol is associated with a decreased incidence of coronary disease compared with no drinks, while higher doses result in an increased risk of infarction and stroke. Although the cardioprotective effects of most alcoholic beverages are probably due to an elevation of high-density lipoprotein as well as the ability of alcohol to prevent platelet aggregation and increased fibrinolysis, there is an increased favorable effect of red wine. The unique cardioprotective properties of red wine reside in the action of flavonoids which are absent in white wine (with the exception of champagne) and sparse in beer (with the exception of dark beers). The best research flavonoids are resveritrol and quercetin, which confer antioxidant properties more potent than alpha-tocopherol. Grape juice has about half the amount of flavonoids by volume as does red wine. (51 Refs.)



[Alcohol, lipid metabolism and coronary heart disease]

Schneider J; Kaffarnik H; Steinmetz A
Zentrum Innere Medizin, Klinikum der Philipps-Universitat Marburg.
Herz (GERMANY) Aug 1996, 21 (4) p217-26

Numerous epidemiological studies have unequivocally proven a protection from the development of coronary heart disease by moderate long-lasting alcohol consumption. During the past 20 years studies in different ethnic groups starting from an American cohort and spanning to the recently performed analysis in the MONICA-project gave evidence for a decreased morbidity and mortality from coronary heart disease at 1 to 3 drinks a day when compared to total abstainers. A part of the protection is thought to be mediated through alcohol effects on plasma lipoprotein metabolism. Substantial increases in high-density lipoprotein cholesterol and its subfractions occur and are believed to be responsible for as much as half of the alcohol-mediated benefits. In addition, moderate decreases in low-density lipoprotein cholesterol and probably also in lipoprotein(a), established cardiovascular risk factors, may contribute accordingly. Furthermore, antioxidants like flavonoids and polyphenols found in red wines by protecting low density lipoproteins from oxidative modification may explain the "French paradox", the decreased incidence of coronary heart disease in France despite a high consumption of saturated fats. Also, alcoholic vasodilation, decreases in platelet aggregability, changes in prostacyclin/thromboxane ratios and increased fibrinolytic activities are to be considered as additional benefits caused by moderate alcohol consumption. (66 Refs.)



[Cardio-protective effect of red wine as reflected in the literature]

Lugasi A; Blazovics A; Dworschk E; Feher J
Orszagos Elelmezes- es Taplalkozastudomanyi Intezet, Budapest.
Orv Hetil (HUNGARY) Mar 16 1997, 138 (11) p673-8

Many scientific studies have been searching for the reason of so-called Paradox, the anomaly which means that in several parts of France and other Mediterranean countries the morbidity and mortality of coronary heart diseases in absolute value and in consideration of its rate to other manner of death is significantly lower than that is in other developed countries, despite of the high consumption of fat and saturated fatty acids. The reason of this cardioprotective effect might be among others the typical Mediterranean diet and the regularly consumption of red wine. This conception may be proved since the polyphenolic compounds present in red wine in concentration of 1800-3000 mg/l are antioxidants, free radical scavengers and inhibit the lipid peroxidation processes in vitro and in vivo, as well. Beside dietary antioxidants such as tocopherols, ascorbic acid and carotenoids, the polyphenolic compounds of plant origin exert favourable effects on cardioprotective mechanisms. Phenolic compounds of red win (flavonoids and non-flavonoid components) inhibit the oxidation of low-density lipoproteins, the eicosanoid synthesis and platelet aggregation and promote the formation of endothel-dependent relaxation factor (nitrogen oxide). According to scientific results of the last decade it seems to be proved that moderate consumption of red wine - 2-3 unit/day for healthy men, and 1-2 unit/day for healthy women (1 unit = 12 g alcohol) -, cannot be criticised either medically nor socially and have a beneficial effect on reducing coronary heart diseases. (50 Refs.)



Delayed tumor onset in transgenic mice fed an amino acid-based diet supplemented with red wine solids.

Clifford AJ; Ebeler SE; Ebeler JD; Bills ND; Hinrichs SH; Teissedre PL; Waterhouse AL
Department of Nutrition, University of California, Davis 95616, USA
Am J Clin Nutr (UNITED STATES) Nov 1996, 64 (5) p748-56

Ineased consumption of vegetable foods (cereals, legumes, fruits) and some beverages (tea, cider, wine) is associated with reduced risk of cancer. Polyphenols in these foods and beverages are thought to be responsible, based on data from in vitro assays and from in vivo studies that used animals pretreated with carcinogen and given tea or polyphenol-spiked water to drink. We tested the hypothesis that dehydrated-dealcoholized red wine (wine solids), when consumed as part of a precisely defined complete diet, would delay tumor onset in transgenic mice that spontaneously develop externally visible tumors without carcinogen pretreatment. Sibling transgenic mice were weaned onto an amino acid-based diet alone or supplemented with red wine solids. Mice were examined daily; the age at which a first tumor red was recorded as the age of tumor onset. The concentration of the major polyphenol of red wine (catechin) in blood serum was also measured at the end of the study. The supplemented diet was fed continuously for three generations to ensure that it supported normal growth and reproduction. We discovered that the wine solid supplement delayed tumor onset, that intact catechin was absorbed, and that the supplemented diet supported normal growth and reproduction for three generations. Also, our simple experimental protocol offers an alternate and/or complementary way to identify foods, beverages, and their constituents that delay tumor onset and to investigate possible mechanisms involved.



The effect of red and white wines on nonheme-iron absorption in humans.

Am J Clin Nutr (UNITED STATES) Apr 1995

The effect of the phenolic compounds in wine was examined in this study by performing radioiron-absorption measurements from extrinsically labeled test meals in 33 human subjects. In four separate studies we observed that absorption was 2- to 3-fold higher from white wine containing a low concentration of polyphenols than from two red wines containing a 10-fold higher concentration of polyphenols. The interaction between the polyphenols and alcohol in wine was evaluated by reducing the alcohol content of the wines by approximately 90%. When the alcohol concentration was reduced, there was a significant 28% decrease in nonheme-iron absorption with red wine but no effect with white wine. The inhibitory effect of red wines with reduced alcohol content was about twofold greater when they were consumed with a small bread roll than when taken without food. Our findings indicate that the inhibitory effect of phenolic compounds in red wine is unlikely to affect iron balance significantly.