Abstract
| - Antioxidant activities of phenolic extracts from fourteen differenttypes of fresh grapes wereinvestigated by measuring the inhibition of human low-densitylipoprotein (LDL) oxidation in vitro.The inhibition of LDL oxidation ranged from 22% to 60% at 10μM gallic acid equivalents (GAE) oftotal phenols and from 62% to 91% at 20 μM GAE. Theantioxidant activities were thus comparableto those previously found for wines. The relative LDL antioxidantactivity correlated with theconcentration of total phenols (r = 0.89, p<0.01), with the level of anthocyanins (r = 0.56,p<0.05) and flavonols (r = 0.54, p< 0.05) inthe grape extracts as analyzed by high-performance liquidchromatography (HPLC). When seed crushing and longer extractiontimes were employed, highamounts of flavan-3-ols and hydroxybenzoates were extracted. Withthese extracts relative LDLantioxidant activity correlated highly with the levels of flavan-3-ols(r = 0.86, p< 0.01), totalphenols(r = 0.79, p< 0.05), and hydroxybenzoates(r = 0.77, p< 0.05). Keywords: LDL oxidation; flavonoids; hydroxycinnamates; anthocyanins;flavan-3-ols; flavonols;HPLC
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