Microbial transformation of maslinic acid by Cunninghamella blakesleana

The pentacyclic triterpenoid maslinic acid (1) was bioconverted by Cunninghamella blakesleana CGMCC 3.910, four metabolites were obtained. On the basis of nuclear magnetic resonance and high-resolution mass spectral analyses, their structures were identified as 2α,3β,7β-trihydroxyolean-12-en-28-oic acid (2), 2α,3β,15α-trihydroxyolean-12-en-28-oic acid (3), 2α,3β,7β,15α-tetrahydroxyolean-12-en-28-oic acid (4), 2α,3β,7β,13β-tetrahydroxyolean-11-en-28-oic acid (5), all of the metabolites were new compounds. The metabolic pathway was also investigated. This was the first report on the biotransformation of maslinic acid.