Antifungal sesquiterpene from the root of Vernonanthura tweedieana

The bioassay-guided fractionation of the antifungal dichloromethane extract from the roots of Vernonanthura tweedieana (Baker) H. Rob. (Asteraceae), using an agar overlay bioautographic method, allowed the isolation of one active sesquiterpene (1), identified as 6-cinnamoyloxy-1-hydroxyeudesm-4-en-3-one. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of 1 showed Trichophyton mentagrophytes as the most sensitive strain, with the same MIC and MFC values (4 μg/ml).