Microbial transformation of 10-deacetyl-7-epitaxol and 1beta-hydroxybaccatin I by fungi from the inner bark of Taxus yunnanensis.

摘要

Fungi present in the inner bark of T. yunnanensis (collected from Yunnan, China) were studied for the capability to biotransform natural taxoids. On the basis of screening, 3 fungi, Microsphaeropsis onychiuri, Mucor sp. and Alternaria alternata, were able to selectively hydrolyse and epimerize 2 taxoids, 10-deacetyl-7-epitaxol and 1beta-hydroxybaccatin I, previously isolated from the bark of T. yunnanensis. After preparative-scale incubation of 10-deacetyl-7-epitaxol with Microsphaeropsis onychiuriand Mucor sp., 3 metabolites were isolated and characterized as 10-deacetylbaccatin V, 10-deacetyltaxol and 10-deacetylbaccatin III. Incubation of 1beta-hydroxybaccatin I with A. alternata gave 5-deacetyl-1beta-hydroxybaccatin I, 13-deacetyl-1beta-hydroxybaccatin I and 5,13-dideacetyl-1beta-hydroxybaccatin I.