Polyphenols in grapes

Grape seed extracts used were commercially available. Polyphenols in grape seed extracts selected were chalcone, pelargonidin, cyanidin, delphinidin and resveratrol. All samples were dissolved in DMSO or DMF to prepare 0.5-2.0 mg/mL for O2 and... 

Cavaliere C, Foglia P, Gubbiotti R, Sacchetti P, Samperi R, Lagana A (2008) Rapid-resolution liquid chromatography/mass spectrometry for determination and quantitation of polyphenols in grape berries. Rapid Commun Mass Spectrom 22 3089-3099... 

Martin-Carron N, Goni I, Larrauri JA, Garcia-Alonso A and Saura-Calixto F. 1999. Reduction in serum total and LDL cholesterol concentrations by a dietary fiber and polyphenol-rich grape products in hypercholesterolemic rats. Nutr Res 19 1371-1381. 

Martin-Carron N, Saura-Calixto F and Goni I. 2000. Effects of dietary fibre and polyphenol-rich grape products on lipidaemia and nutritional parameters in rats. J Sci Food Agric 80 1183-1188. 

The amounts of analytes are compiled in Table 2.74. The results indicated that the concentration of polyphenols in red wines depends on both the grape variety and on the exogenous factors. The validation parameters of the method were good, the recoveries were in each case over 98 per cent, the coefficients of variation were between 1.3 per cent and 4.3 per cent, and the limit of detection ranged from 10/rg/l to 0.1mg/l. It was stated that the method is suitable for the determination of silbene compounds and quercetin in red wines [194],... 

A. Kamangerpour, M. Ashraf-Khorassani, L.T. Taylor, H.M. McNair and L. Charida, Supercritical fluid chromatography (SFC) of polyphenolic compounds in grape seed extract. Chromatographia 55 (2002) 417 -21. 

Methods used for the detection of PAs in cmde or partially purified extracts can also be adapted for post-column analysis after fractionation (see below). Direct quantitative analysis of PAs in crude grape phenolic extracts is often impossible due to the complex sample matrix. Thus, fractionation or purification is often necessary before analysis. The Folin-Ciocalteu and Pmssian Blue assays are widely used for the quantification of total polyphenols in plants [27,28]. These methods are not specific for PAs due to the reaction of other phenolic compounds with these reagents. 

Siebert, K. J., Lynn, P. Y., and Carrasco, A. (1996b). Analysis of haze-active polyphenols and proteins in grape juices and wines. In "4th International Symposium on Cool Climate Viticulture and Enology," pp. VII-18-VII-21. Rochester, New York. 

Flamini, R., Mass spectrometry in grape and wine chemistry. Part I polyphenols. Mass Spectrom. Rev., 22, 218, 2003. 

Yanes and coworkers [43] demonstrated an application of IL for aqueous CE for fhe separation of phenolic compounds (flavonoids) found in grape seed exfracfs. By using [C Qlm] (n = 2,4) ILs as additives for the running electrolyte, a simple and reproducible electrophoretic method for the separation of polyphenols was developed. If was speculated that the separation mechanism was based on an association between the imidazolium cations and the polyphenols. The role of fhe alkyl substituents on the imidazolium cations was investigated and discussed [43]. The anion has little effect on the separation while a related study demonstrated that interaction between phenolic compounds and the IL cations in water occurred through n-n interactions. 

Figure 11.3.12 HPLC chromatograms of polyphenolics in Concord grape extract detected at 280 nm. (A) All polyphenolics, including anthocyanins. (B) Nonanthocyanin polyphenolics after fractionation. Peak identification 1, cis-caftaric acid 2, frans-caftaric acid 3, procyanidin B3 4, c/s-coutaric acid 5, frans-coutaric acid 6, epicatechin 7, quercetin galactoside 8, quercetin glucoside. Reproduced from Oszmianski and Lee (1990) with permission from the American Society for Enology and Viticulture.

An interesting case is the prevention of cardio-vascular diseases as a result of the consumption of wine. Like most fruits grapes are rich in polyphenols, and the process of wine making results in the concentration of polyphenols. Wine polyphenols are considered to have beneficial effects on coronary heart disease and atherosclerosis. The presence of polyphenols in wine are thought to be the reason for the French paradox France was shown to have a coronary mortality rate close to that of China and Japan in spite of the high amount of saturated fat and cholesterol levels in the French diet. The consumption of red wine in France, however, is considerably higher than in either China or Japan (Staggs, 1996). 

Gehm BD, McAndrews JM, Chien PY, Jameson JL. 1997. Resveratrol, a polyphenolic compound found in grapes and wine, is an agonist for the estrogen receptor. Proc Natl Acad Sci USA 94 14138-14143. 

Martin AR, Villegas I, La Casa C, de la Lastra CA. 2004. Resveratrol, a polyphenol found in grapes, suppresses oxidative damage and stimulates apoptosis during early colonic inflammation in rats. Biochem Pharmacol 67 1399-1410. 

Kennedy JA, Matthews MA, Waterhouse AL. 2000. Changes in grape seed polyphenols during ripening. Phytochem 55 77-85. 

In addition to heterocycles in grape juice, there are also many acyclic precursors that are converted by fermentation, aging, and other modifications into heterocycles for example, hydroxyl carboxylic acids, polyphenols, and amino acids. 

Among polyphenols, resveratrol and its derivatives are thought to play a special role. Resveratrol occurs naturally in grapes in both cis-and trans-isomers, and in their respective glucosides (cis- and trans-piceids). All forms inhibit the oxidation of low density lipoprotein (LDL) and additional benefits. Resveratrol occurs in most red wines but is undetectable or occurs in negligible amounts in dry white wines (Pour Nikfardjam, 2002). 

Regarding to the individual polyphenols, protocatechuic acid were the most abundant polyphenol in all wines studied, except in the SB, Madeira Island wine. The second most represented polyphenol is ( )-catechin, although it is not present in PT red wine, SB, and LB (Latadas wine produced from Verdelho grape variety) white wines. 

Gebhardt, R. and Beck, H. 1996. Differential inhibitory effects of garlic-derived organosulfur compounds on cholesterol biosynthesis in primary rat hepatocyte culture. Lipids 31, 1269-1276. Gehm, B.D., McAndrews, J.M., Chien, P.Y., and Jameson, J.L. 1997. Resveratrol, a polyphenolic compound found in grapes and wine, is an agonist for estrogen receptor. Proc. Natl Acad. Sci. 94, 14138-14143. 

The antiatherosclerotic effect of proanthocyanidin-rich grape seed extracts was examined in cholesterol-fed rabbits. The proanthocyanidin-rich extracts [0.1% and 1% in diets (w/w)] did not change the serum lipid profile, but reduced the level of the cholesteryl ester hydroperoxides (ChE-OOH) induced by 2,2/-azo-bis(2-amidinopropane-dihydrochloride (AAPH), the aortic malonaldehyde (MDA) content and severe atherosclerosis. The immuno-histochemical analysis revealed a decrease in the number of the oxidized LDL-positive macrophage-derived foam cells on the atherosclerotic lesions of the aorta in the rabbits fed the proanthocyanidin-rich extract. When the proanthocyanidin-rich extract was administered orally to the rats, proantho-cyanidin was detected in the plasma. In an in vitro experiment using human plasma, the addition of the proanthocyanidin-rich extract to the plasma inhibited the oxidation of cholesteryl linoleate in the LDL, but not in the LDL isolated after the plasma and the extract were incubated in advance. From these results, proanthocyanidins of the major polyphenols in red wine might trap ROSs in the plasma and interstitial fluid of the arterial wall, and consequently display antiatherosclerotic activity by inhibiting the oxidation of the LDL [92]. 

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