Stereo- and region-specific biotransformation of physapubescin by four fungal strains

AbstractBiotransformations of physapubescin (1) were performed by four fungal strains —Mucor subtilissimus AS 3.2454,Mucor polymorphosporus AS 3.3443,Aspergillus niger AS 3.795, andSyncephalastrum racemosum AS 3.264. Four metabolites were prepared in the biotransformation process of1, and their structures were elucidated as 15α-acetoxy-5,6β:22,26:24,25-triepoxy-26α-hydroxy-3β-methoxy 4β-hydroxyergost-1-one (2), 15α-acetoxy-5,6β:22,26-diepoxy-4β,24β,25α,26(α,β)-tetrahydroxyergost-3β-methoxy-1-one (3a/3b), 15α-acetoxy-5,6β:22,26-diepoxy-4β,24β,25α,26(α,β)-tetrahydroxyergost-2-en-1-one (4a/4b), and physapubescin D (5), by spectroscopic data analysis. Among them, metabolites2 and3 are new. All of these fungal strains showed the ability to be highly stereo- and region-specific for the bioconversion of substrate (1). Our research provides a reference for the structural derivatization of withanolides or possibly even other natural products.
Source: Journal of Natural Medicines - Category: Drugs & Pharmacology Source Type: research