Studies on the Mechanism of the Oxidation of Tea Leaf Catechins

Part IV. Formation of Categallin and Fyrogallin, New Compounds of Benzotropolone Nature Derived form Epigallocatechin

Abstract

Oxidations of epigallocatechin in the presence of catechol or pyrogallol with tea oxidase as well as with an oxidizing reagent and the isolation of the oxidation products, categallin (II) and pyrogallin (III), in crystalline form are described. Their absorption spectra are compared with those of pigment P (I) obtained by the oxidation of epigallocatechin and epicatechin, and their structural relationships are discussed.