QUANTITATIVE AND QUALITATIVE PORTRAIT OF GREEN TEA CATECHINS (GTC) THROUGH HPLC

Green tea (Camellia sinensis) is a prosperous source of polyphenols, especially catechins. In the current research, an effort was made to optimize the extraction conditions for maximum yield of catechins from the local green tea Qi-Men. For the purpose, three different solvents were used, i.e., aqueous ethanol (50%), aqueous methanol (50%), and water at different time intervals (20, 40, and 60 min). Green tea catechins were quantified through HPLC using a C18 column and UV detector. The antioxidant activity of green tea catechins was measured through in vitro tests including DPPH radical scavenging ability and antioxidant activity. Results showed that extraction through aqueous ethanol resulted in maximum yield of green tea catechins (17400 +/- 0.19 mg/100 g green tea leaves. Moreover, epigallocatechin, epigallocatechin gallate, epicatechin gallate, and epicatechin ranged from 4.26 +/- 0.09 to 6.4 +/- 0.2, 12.1 +/- 0.123 to 17.7 +/- 0.3, 1.32 +/- 0.03 to 1.81 +/- 0.02, 5.48 +/- 0.099 to 8.6 +/- 0.2 g/100 g of dry-extract, respectively. Furthermore, highest antiradical (80.65 +/- 3.69%) and antioxidant activity (67.12 +/- 3.08%) were observed in catechins extracted through aqueous ethanol.