Mixture design analysis of solvent extractor effects on epicatechin, epigallocatechin gallate, epigallocatechin and antioxidant activities of the Camellia sinensis L. leaves

This paper reports an RP-HPLC-UV-DAD study of the effects of four solvents and their mixtures on the extraction and antioxidant activities of three main catechins, epicatechin (EC), epigallocatechin gallate (EGCG) and epigallocatechin (EGC) of Camellia sinensis L. leaves for two harvests. The extraction efficiency solvent was measured by the chromatographic peak areas. The results showed that the relative abundance of the catechins in the second harvest is somewhat larger than in the first one, although there is no significant difference at the 95% level. The relative abundance found for EGCG is greater than for EGC which is greater than EC for all solvent mixtures. According to the mixture models, the maximum values of relative abundances of EGCG, EGC and EC can be obtained with a (70:30 v/v) ethanol:ethyl acetate binary mixture and the antioxidant activities with a (55:25:20 v/v/v) ethanol:ethyl acetate:dichloromethane ternary mixture.