Microbial transformation of rubijervine.
Preparative-scale fermentation of rubijervine (1), the known 22,26-epiminocholestane Veratrum alkaloid, with Cunninghamella echinulata ATCC 9244 has resulted in the isolation of the new metabolites 7alpha-hydroxyrubijervine (2) and solanid-5-ene-3beta,12alpha-diol-1-one (3). Structure elucidation of these metabolites was based primarily on 1D- and 2D-NMR analyses. The microbe C. echinulata ATCC 9244 was able to metabolize rings A and B of rubijervine but failed to metabolize rings C, D or its N-containing side chain, a finding which is analogous to the results of previous fermentation studies of steroidal alkaloids.