Dammarane-type triterpene glycosides from Oncoba manii active against methicillin-resistant Staphylococcus aureus.

Drug-resistant bacteria are becoming more prevalent both in the community and in hospitals. In a search for new antibiotic leads, we used a high-throughput natural products chemistry approach to isolate one new ( 1) and two known ( 2, 3) dammarane-type triterpenes with mass-limited material from the African plant ONCOBA MANII. The new compound was determined by spectroscopic methods to be 1β,2α,3β,20( R)-tetrahydroxydammar-24-ene 3- O-α- L-rhamnopyranosyl-(1 → 2)-β- D-glucopyranoside. Compounds 1 and 2 inhibited the growth of methicillin-resistant STAPHYLOCOCCUS AUREUS (MRSA).