Typical Biotransformations in the Ursane Family

Ursolic acid (87), the simplest carboxy derivative of the ursane family, is widely distributed in various plants in both aglycone and glycosidic forms, and traditional uses of plants containing 87 in folk medicine are abundantly documented. Recent 

Microbial transformations of glycyrretinic epimers at C-18 (18a-glycyrretic acid, 97) or at C-20 (liquiritic acid, 101) or at C-18 and C-20 (18a-liquiritic acid, 105) by various fungal strains [74]. 

Main hydroxylation sites observed in the microbial transformations of olean derivatives. 

3p-Hydroxy-olean-12-en-28-oic acid methyl ester 3p,6p-Dihydroxy-olean-12-en-28-oic acid (35) 3p,6p,2ip-Trihydroxy-olean-12-en-28-oic acid (36) 3p-Hydroxy-21-oxo-olean-12-en-28-oic acid (37) 3p-Hydroxy-ll-oxo-olean-12-en-28-oic acid (31) 3p,15a-Dihydroxy-olean-12-en-28-oic acid (32) 3p,12p-Dihydroxy-olean-ll-en-28(13)-olide (33) 3p-Hydroxy-olean-ll,13(18)-dien-28-oic acid (34) 3p,6p,2ip-Trihydroxy-olean-12-en-28-oic acid (44) 3p-Hydroxy-21-oxo-olean-12-en-28-oic acid (37) 

3-Oxo-15a-hydroxy-olean-12-en-28-oic acid (71) 3-Oxo-7p,15a-dihydroxy-olean-12-en-28-oic acid (72) 

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