Study of polyphenol content in the seeds of red grape (Vitis vinifera L.) varieties cultivated in Turkey and their antiradical activity

The polyphenolic content and antioxidant capacity in the seeds of 11 red grape varieties (five international and six native) widely cultivated in Turkey were investigated. Total phenolic, total flavanol and total polymeric procyanidin content ranged from 79.2 to 154.6. 89.2 to 179.4. and 27.0 to 43.3 mg/g seed, respectively. While (+)-catechin (4.71-23.8 mg/g seed) was found as main flavanol, gal-loylated catechin monomer and dimeric procyanidin amounts varied between 2.89-17.2 and 0.97-2.97 mg/g seed, respectively. All seed extracts showed remarkable DPPH radical scavenging activity (EC50) and oxygen radical scavenging capacity (ORAC) ranging from 2.71 to 4.62 mu g/mL and 1425.9 to 3009.2 mu mol Trolox equivalent/g seed, respectively. With high amount of total phenolic content and antioxidant activity, seeds of Okuzgozu, Papaz Karasi, Ada Karasi and Kalecik Karasi varieties could be evaluated as dietary supplement. (C) 2008 Elsevier Ltd. All rights reserved.