Bioactive compounds and antioxidant activities of Camellia sinensis var. assamica in different leave maturity from Northern Thailand

The aim of this study was to compare the bioactive compounds [total phenolic content (TPC), total flavonoid content (TFC), and proanthocyanidin content] and antioxidant activities [DPPH, ABTS and FRAP activities] of 3 different maturity of tea leaves, shoot (first 1-3 leaves), young leaves (4-6 leaves) and mature leaves (1-3 from bottom tea shrub) by using different solvents [hot DI water (80OC), DI water, 70% ethanol and 70% acetone] for extraction. Results showed that the highest extractable yields were found on the shoot tea with hot DI water extraction (21.33 +/- 9.15% dry basis). Shoot tea with ethanol extraction composed of high amount of TPC (65.26 mg trolox equivalent antioxidant capacity TEAC/mg sample). Shoot and young tea leaves in ethanol extract tended to have high proanthocyanidin content (35.94 and 32.15 mg epicatechin equivalent (ECE)/g sample, respectively) and DPPH free-radical scavenging activity (31.39 and 29.93 mg TEAC/g sample, respectively). Mature leaves by 70% acetone extracted showed obviously high amount of flavonoid content (57.39 mg quercetin equivalent (QE)/g sample) and FRAP activity (1.938 mg TEAC/mg sample). Therefore, the young and mature tea leaves that did not be used for tea processing, may be used as an alternative source of natural antioxidant for cosmetic and other products. (C) All Rights Reserved