Microbial transformation of glycyrrhetinic acid and potent neural anti-inscommatory activity of the metabolites

The microbial transformation of glycyrrhetinic acid (1) by Cunninghamella blakesleana CGMCC 3.970 led to the production of five new metabolites (2-6). Compounds 2, 5, and 6 showed significant neural anti-inscommatory activity by inhibiting lipopolysaccharide-induced NO production in mouse microglia BV2 cells with IC50 values of 0.76, 0.94, and 0.16 μmol/L, respectively.