The microbial transformation of Astragalus sp. derived sapogenins, namely cycloastragenol, astragenol and cyclocanthogenol, by Cunninghamella blakesleeana NRRL 1369 and Glomerella fusarioides ATCC 9552 were investigated. The unique enzyme system of both fungi resulted hydroxylation, cyclization, dehydrogenation and oxidation reactions. Structures of the new metabolites were elucidated by 1-D (H-1, C-13, NOESY), 2-D NMR (DQF-COSY, HMBC, HMQC, NOESY) and HR-MS analyses. (C) 2015 Elsevier B.V. All rights reserved.