Microbial transformation of dihydrosarsasapogenin with Mycobacterium sp

Microbial transformation of sarsasapogenin (1) with Mycobacterium sp. (NRRL B-3805) gave 25(S)-neospirost-4-en-3-one (2) as the sole product in 62% yield. Incubation of dihydrosarsasapogenin (3) led to the isolation of seven products in 0.5 (4), 6.6 (5), 5 (6), 16 (7), 1 (8), 1 (9), and 4.5% (10) yields, respectively, while 15% of 3 was recovered. Among these products, 8 and 9 were C22 steroids, and 10 was a C19 steroid. Isolation of these C19 and C22 steroids indicated that this microorganism is capable of cleaving the ether linkage between C-16 and C-22 in 3. In addition, 12 alpha-hydroxylation was also observed in all these three metabolites.