Antibacterial compounds from Carissa lanceolata R.Br.

The dichloromethane extract of the wood of Carissa lanceolata R.Br. (Apocynaceae) afforded the eudesmanes carissone, dehydrocarissone and carindone. This is the first account of carissone being isolated from the wood of C. lanceolata, and of carindone being isolated from this Carissa species. Dehydrocarissone has not been isolated previously from any Carissa species. The antibacterial activity of these natural products were examined against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. All three compounds showed activity, with dehydrocarissone and carindone having a minimum inhibitory concentration less than 0.5 mg/ml against S. aureus and E. coli.