Microbial transformation of cycloastragenol

The microbial transformation of cycloastragenol by the fungi Cunninghamella blakesleeana NRRL 1369 and Glomerella fusarioides ATCC 9552, and the bacterium Mycobacterium sp. NRRL 3805 were investigated. Both fungi mainly provided hydroxylated metabolites together with products formed by cyclization, dehydrogenation and Baeyer-Villiger oxidation resulting in a ring cleavage. The bacteria yielded only a single oxidation product, namely, 3-oxo-cycloastragenol. Structures of the metabolites were elucidated by 1-D (H-1,C-13), 2-D NMR (COSY, HMBC, HMQC) and HRMS analyses. (C) 2013 Elsevier Ltd. All rights regerved.