title: Stereoselective oxidation at C-4 of flavans by the endophytic fungus Diaporthe sp. isolated from a tea plant.
abstract: The microbial transformation of five flavans (1-5) by endophytic fungi isolated from the tea plant Camellia sinensis was investigated. It was found that the endophytic filamentous fungus Diaporthe sp. oxidized stereoselectively at C-4 position of (+)-catechin (1) and (-)-epicatechin (2) to give the correspondent 3,4-cis-dihydroxyflavan derivatives (6, 10), respectively. (-)-Epicatechin 3-O-gallate (3) and (-)-epigallocatechin 3-O-gallate (4) were also oxidized by the fungus into 3,4-dihydroxyflavan derivatives (10, 12) via (-)-epicatechin (2) and (-)-epigallocatechin (11), respectively. Meanwhile, (-)-gallocatechin 3-O-gallate (5), (-)-catechin (ent-1) and (+)-epicatechin (ent-2), which possess a 2S-phenyl substitution, resisted the biotransformation.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Sanzo, Hiroshima, Japan.
authors.forename: Andria
authors.initials: A
authors.lastname: Agusta
authors.forename: Shoji
authors.initials: S
authors.lastname: Maehara
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Ohashi
authors.forename: Partomuan
authors.initials: P
authors.lastname: Simanjuntak
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Shibuya
mesh_terms: D001203:Ascomycota / Q000737:chemistry*; D028244:Camellia / Q000382:microbiology*; D002392:Catechin / Q000031:analogs & derivatives / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004271:DNA, Fungal / Q000096:biosynthesis / Q000235:genetics; D005415:Flavins / Q000737:chemistry*; D008745:Methylation; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013237:Stereoisomerism
chemical_list: D004271:DNA, Fungal; D005415:Flavins; D002392:Catechin; C062669:epicatechin gallate; D010100:Oxygen