X-Message-Number: 26205 Date: Thu, 19 May 2005 20:55:06 -0700 (PDT) From: Doug Skrecky <> Subject: grapes as a health food [Grapes or grape products can lower blood pressure, inhibit atherosclerosis, inhibit cancer, and protect the heart from ischemic damage. Consume at your risk.] Biofactors. 2004;22(1-4):145-7. Concord grape juice supplementation reduces blood pressure in Korean hypertensive men: double-blind, placebo controlled intervention trial. Many of the flavonoids found in grapes and grape products such as juice or wine have been known to exert antioxidant, anti-inflammatory, platelet inhibitory and arterial relaxing effects either in vitro, in animal studies and in human trials. This study was designed to test the effect of Concord grape juice consumption on altering blood pressure in hypertensive patients. Forty subjects were given 5.5 ml/kg body weight/day of either Concord grape juice (CGJ) or a calorie-matched placebo drink every day for 8 weeks. Blood pressure (BP) was measured on weeks 0, 4 and 8. Compared to baseline, in the CGJ group systolic BP was reduced on average by 7.2 mm Hg (p = 0.005) and diastolic BP was reduced on average by 6.2 mm Hg (p = 0.001) at the end of 8 weeks. Comparable changes in the group getting the placebo product were -3.5 mm Hg (NS) and -3.2 mm Hg (p = 0.05) Consuming Concord grape juice, which is high in polyphenolic compounds, may favorably affect BP in hypertensive individuals. Publication Types: J Med Food. 2005 Spring;8(1):41-6. Comparison of the antioxidant activities of nine different fruits in human plasma. Oxidative stress in humans is associated with damage to DNA, proteins, and biological membranes. Oxidative stress, which often arises as a result of an imbalance in the human antioxidant status, has been implicated in aging and a number of human diseases such as cancer, atherosclerosis, and rheumatoid arthritis. This study was performed to test the hypothesis that the consumption of fruit juices may improve antioxidant status in human plasma. Ten healthy men 25-26 years old were recruited for the study. After overnight fasting, study subjects were fed 150 mL of fruit juice, and blood was collected at 0, 30, 60, 90, and 120 minutes after consumption. After a 1-day wash-out period, subjects were fed with the next sample of fruit juice until all nine juices (pear, apple, orange, grape, peach, plum, kiwi, melon, and watermelon) had been evaluated. All juices were prepared from pure fruits ground in a home-style mixer. Dietary food records and anthropometric measurements were used to evaluate the nutritional status of subjects. The antioxidant activities of fruit juices were estimated by measuring antioxidant status in the plasma using dichlorofluorescein (DCF) fluorescence. Except for pear juice, eight kinds of juices exhibited potent antioxidant effects in human plasma. Within 30 minutes after consumption, orange, melon, grape, peach, plum, apple, and kiwi juices already effectively suppressed reactive oxygen species generation. This radical scavenging effect of fruit juices was maintained for up to 90 minutes post-consumption, but the relative DCF fluorescence had rebounded to near the initial levels at 2 hours post-consumption in most samples tested. Interestingly, however, grape juice continuously exerted persistent antioxidant activity until 2 hours after supplementation. These results suggest that the consumption of fruits or fruit juices may reduce damage from oxidative stress, and that this effect may be a consequence of the antioxidant activity of fruits in scavenging the reactive oxygen species generated in human plasma. However, long-term studies with more subjects are needed to provide additional supportive evidence and better characterize the antioxidant properties of natural fruit juices. J Pharm Pharmacol. 2002 Nov;54(11):1515-20. Antihypertensive, vasodilator and antioxidant effects of a vinifera grape skin extract. Cumulative evidence suggests that moderate wine consumption exerts a cardioprotective effect. We investigated the occurrence of an antihypertensive effect of an alcohol-free hydroalcoholic grape skin extract (GSE) obtained from skins of a vinifera grape (Vitis labrusca) in experimental rodent hypertension models. The vasodilator effect of GSE (polyphenols concentration 55.5 mg g(-1)) was also assessed in the isolated mesenteric vascular bed of Wistar rats and the antioxidant effect was studied on lipid peroxidation of hepatic microsomes. Oral administration of GSE significantly reduced systolic, mean and diastolic arterial pressure in Wistar rats with desoxycorticosterone acetate-salt and N(G)-nitro-L-arginine methyl ester (L-NAME) induced experimental hypertension. In the rat isolated mesenteric vascular bed pre-contracted with norepinephrine, bolus injections of GSE induced endothelium-dependent vasodilatation that was substantially inhibited by L-NAME, but not by indometacin, tetraethylammonium or glibenclamide. Lipid peroxidation of hepatic microsomes estimated as malondialdehyde production was concentration-dependently inhibited by GSE. In conclusion, the antihypertensive effect of GSE might be owing to a combination of vasodilator and antioxidant actions of GSE. These findings also suggest that the beneficial effect of moderate red wine consumption could be owing to an antihypertensive action induced by compounds occurring in the skin of vinifera grapes. Cancer Lett. 2005 May 5; [Epub ahead of print] Purple grape juice inhibits 7,12-dimethylbenz[a]anthracene (DMBA)-induced rat mammary tumorigenesis and in vivo DMBA-DNA adduct formation. There has been considerable interest in identifying specific foods and phytochemicals that may have breast cancer preventive properties. Concord grapes are rich in polyphenolic chemicals and anthocyanin pigments that may have biological properties which could suppress cancer such as having antioxidant, antiproliferative, and proapoptotic actions. To determine the potential breast cancer protective action of purple grape juice, we examined the effect of grape juice consumption on the initiation stage of 7,12-dimethylbenz[a]anthracene (DMBA)-induced rat mammary tumorigenesis and on the in vivo formation of rat mammary DNA adducts in female Sprague-Dawley rats. Consumption of grape juice significantly inhibited mammary tumor mass at termination and the growth of tumors for the first 5 weeks of detectable tumor development. Consumption of grape juice phenolics by rats also significantly inhibited in vivo mammary DMBA-DNA adduct formation by 34 and 56% for animals fed phenolics at 346 and 692mg/dL, respectively, compared to controls. Mammary 8-oxo-deoxyguanosine (8-oxo-dG) levels decreased by 25 and 37%, respectively, but the differences were not statistically significant. Liver DMBA-DNA adducts decreased by 10-30%, while 8-oxo-dG adducts remained unchanged, following grape juice intake. Liver glutathione S-transferase activity was significantly increased following grape juice consumption, but only at the highest level of intake. In addition, liver activities of catalase increased and xanthine oxidase decreased significantly, but only at the highest grape juice dose. Thus, these studies indicate that specific constituents or combinations of phytochemicals in purple grape juice can block the initiation stage of DMBA-induced rat mammary tumorigenesis. This tumor inhibitory effect was associated with a suppression of mammary DMBA-DNA adduct formation, which in part may be explained by increased liver activity of the phase II metabolizing enzyme, glutathione S-transferase. Mammary and liver 8-oxo-dG levels were not significantly altered by grape juice consumption. Thus, grape juice constituents appear to have benefit in decreasing susceptibility of the rat mammary gland to the tumor-initiating action of DMBA. Ann N Y Acad Sci. 2002 May;957:302-7. Reduction of myocardial ischemia reperfusion injury with regular consumption of grapes. Recently several polyphenolic antioxidants derived from grape seeds and skins have been implicated in cardioprotection. This study was undertaken to determine if the grapes were equally cardioprotective. Sprague Dawley male rats were given (orally) standardized grape extract (SGE) for a period of three weeks. Time-matched control experiments were performed by feeding the animals 45 microg/100 of glucose plus 45 microg/100 g fructose per day for three weeks. After 30 days, rats were sacrificed, hearts excised and perfused via working-mode. Hearts were made ischemic for 30 min followed by two hours of reperfusion. At 100 mg/kg and at 200 mg/kg, SGE provided significant cardioprotection as evidenced by improved post-ischemic ventricular recovery and reduced amount of myocardial infarction. No cardioprotection was apparent when rats were given grape samples at a dose of 50 mg/100 g/day. In vitro studies demonstrated that the SGE could directly scavenge superoxide and hydroxyl radicals which are formed in the ischemic reperfused myocardium. The results demonstrate that the heats of the rats fed SGE reduced myocardial ischemia reperfusion injury by functioning as in vivo antioxidant. J Nutr. 2000 Jan;130(1):53-6. Grape juice, but not orange juice or grapefruit juice, inhibits human platelet aggregation. Coronary artery disease is responsible for much mortality and morbidity around the world. Platelets are involved in atherosclerotic disease development and the reduction of platelet activity by medications reduces the incidence and severity of disease. Red wine and grapes contain polyphenolic compounds, including flavonoids, which can reduce platelet aggregation and have been associated with lower rates of cardiovascular disease. Citrus fruits contain different classes of polyphenolics that may not share the same properties. This study evaluated whether commercial grape, orange and grapefruit juices, taken daily, reduce ex vivo platelet activity. In a randomized cross-over design, ten healthy human subjects (ages 26-58 y, five of each gender) drank 5-7.5 mL/(kg. d) of purple grape juice, orange juice or grapefruit juice for 7-10 d each. Platelet aggregation (whole blood impedance aggregometry, Chronolog Model #590) at baseline was compared to results after consumption of each juice. Drinking purple grape juice for one week reduced the whole blood platelet aggregation response to 1 mg/L of collagen by 77% (from 17.9 +/- 2.3 to 4.0 +/- 6.8 ohms, P = 0.0002). Orange juice and grapefruit juice had no effect on platelet aggregation. The purple grape juice had approximately three times the total polyphenolic concentration of the citrus juices and was a potent platelet inhibitor in healthy subjects while the citrus juices showed no effect. The platelet inhibitory effect of the flavonoids in grape juice may decrease the risk of coronary thrombosis and myocardial infarction. J Agric Food Chem. 2004 Aug 11;52(16):5297-302 Phenolics from commercialized grape extracts prevent early atherosclerotic lesions in hamsters by mechanisms other than antioxidant effect. The aim of this study was to evaluate the antiatherosclerotic effect of commercially available phenolic-rich extracts from grape seeds (ExGrape seeds, EGS; grape seed extract, GSE) and marc (ExGrape total, EGT) in cholesterol-fed hamsters and to investigate possible operating mechanisms. These extracts fed at a moderate dose mimicking two glasses of red wine per meal reduced plasma cholesterol (-11% on average) but did not affect plasma antioxidant capacity of hamsters. The extracts prevented the development of aortic atherosclerosis by 68% (EGS), 63% (EGT), and 34% (GSE). Elsewhere, in an ex vivo experiment using rat aortic rings, EGS (7 microg/mL) induced 77% endothelium-dependent relaxation, whereas EGT and GSE (30 microg/mL) induced 84 and 72%, respectively. These results suggests that phenolic extracts from grape seeds and marc are beneficial in inhibiting atherosclerosis by indirect mechanism(s). Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=26205