Ursolic acid [(3b)-3-Hydroxyurs-12-en-28-oic
acid] rarely occurs without its isomer oleanolic acid [(3b)-3-Hydroxyolean-12-en-28-oic
acid] They may occur in their free acid form, as shown in Figure 1, or as aglycones for
triterpenoid saponins which are comprised of a triterpenoid aglycone linked to one or more
sugar moieties. Ursolic and oleanolic acids are similar in pharmacological activity1.
Several ursolic acid
derivatives, both natural and synthetic, have been reported. Novel ursolic acid
derivatives, including ursane-type triterpenoid saponins, naturally occur as secondary
metabolites through complex metabolic processes in different parts of the plants5,8-12.
Synthetic derivatives obtained from ursolic acid have been reported and evaluated for
their pharmacological action 3,13-16
ã Sabinsa Corporation 2000-2001