Biotransformation of betulin by Mucor subtilissimus to discover anti-inflammatory derivatives.

Biotransformation of lupane-type triterpenoid betulin was carried out with Mucor subtilissimus CGMCC 3.2456. Yielded nine previously undescribed hydroxylated compounds. M. subtilissimus biotransformation provided C-7, C-11, C-15 and C-24 hydroxylated compounds along with C-7 oxidized and C-28 acetylated derivatives. The structures of the metabolites were established based on extensive NMR and HR-ESI-MS data analyses. Furthermore, we found that most of the metabolites exhibited pronounced inhibitory activities on lipopolysaccharides-induced NO production in RAW264.7 cells.