Hydroxylation of diosgenin by Absidia coerulea

Abstract

Microbial transformation of diosgenin (1) using Absidia coerulea yielded five new polar metabolites, which were identified as (25R)-spirost-5-en-3β, 7β,12β,25α-tetrol (2), (25S)-spirost-5-en-3β,7α, 12β,25β-tetrol (3), (25S)-spirost-5-en-3β,7β,12β, 25β-tetrol (4), (25R)-spirost-5-en-3β,7α,12β,25α- tetrol (5), and (25R)-spirost-5-en-3β,7β,12β,24β-tetrol (6). Their structures were established on the basis of mass spectrometry and multi-dimensional NMR spectroscopy. The characteristic transformations observed were C-7α, C-7β, C-12β, C-24β, C-25α, and C-25β hydroxylation. The cytotoxicity of compounds 1-6 was evaluated against the human myelogenous leukemia K562 cell line and squamous cell carcinoma KB parental cell lines. Compounds 2-6 exhibited weak cytotoxicity against K562 and KB cells and were less potent than the parent compound 1.