Isolation and characterization of melanic pigments derived from tea and tea polyphenols

The dark brown pigments derived from tea and tea polyphenols were studied. Physical and chemical properties revealed that pigments directly extracted from tea leaves and derived from tea polyphenols were similar to typical me lanins. Further investigation showed that both melanic pigments possessed s imilar antioxidant capability, due to their chelating and scavenging proper ties. The inhibitory effect of melanic pigments, either from tea or tea pol yphenols, was significantly stronger than that of non-treated tea polypheno ls. According to these properties, we have extracted melanin from tea. In a ddition, oxidation of tea polyphenols also provided an alternative method t o maximize the yields. The extracted melanin is an antioxidant, which inter rupted free radical reactions at a step in the development chain by its sca venging properties and, at the step of initiation, by its ability to chelat e metals. (C) 2001 Published by Elsevier Science Ltd.