Antioxidant Potential of Green and Black Teas of Selected South India Cultivars.

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 [(μmol Trolox equivalent
(TE)/g)] values ranged from 2730-5031 (GT), 1429-2766 (BT) and DPPH-RSA (μmol 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.