Antioxidant potential of green and black teas of selected south india cultivars

Abstract

Tea is one of the most popular global beverages. It is widely consumed as a health promoting beverage and its health benefits are mainly due to the presence of polyphenols such as catechins, theaflavins and thearubigins. The purpose of the present study is to evaluate the antioxidant potential of green tea (GT) and black tea (BT) extracts of eight different cultivars by radical scavenging activity (DPPH-RSA) and hydrophilic oxygen radical absorbance capacity (H-ORAC). The extracts of teas were also analyzed for total polyphenol (TP) content and catechins. H-ORAC [(ìmol Trolox equivalent (TE)/g)] values ranged from 2730-5031 (GT), 1429-2766 (BT) and DPPH-RSA (ìmol TE/g) ranged from 1098-1376 and 508-798, respectively. Comparing the same cultivar, GT showed higher antioxidant activities (H-ORAC and DPPH-RSA) than those of BT which is partially attributable to the increased TP and concentration of catechins. Correlation coefficients between parameters of antioxidant activities were TP/H-ORAC (GT: 0.647, BT: 0.79), TP/DPPH -RSA (0.744, 0.976) and DPPH-RSA/H-ORAC (0.686, 0.811) while those of BT exceeded those of GT. Extracts from all the cultivars showed good antioxidant potential. Antioxidant activities were mainly derived from catechins in GT and theaflavins in the case of BT.