Biooxidation of (+)-Catechin and (−)-Epicatechin into 3,4-Dihydroxyflavan Derivatives by the Endophytic Fungus Diaporthe sp. Isolated from a Tea Plant

Abstract

The microbial transformation of (+)-catechin (1) and (−)-epicatechin (2) by endophytic fungi isolated from a tea plant was investigated. It was found that the endophytic filamentous fungus Diaporthe sp. transformed them (1, 2) into the 3,4-cis-dihydroxyflavan derivatives, (+)-(2R,3S,4S)-3,4,5,7,3′,4′-hexahydroxyflavan (3) and (−)-(2R,3R,4R)-3,4,5,7,3′,4′-hexahydroxyflavan (7), respectively, whereas (−)-catechin (ent-1) and (+)-epicatechin (ent-2) with a 2S-phenyl group resisted the biooxidation.