New carvotanacetone derivatives from Sphaeranthus africanus.

The dichloromethane extract of the air-dried leaves of Sphaeranthus africanus afforded four new carvotanacetone derivatives (1, 2, 3A, and 3B). Their structures were elucidated by extensive 1D and 2D NMR spectroscopy. Compounds 1- 3 exhibited antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa and antifungal activity against Candida albicans, Trichophyton mentagrophytes and Aspergillus niger.