A new cytotoxic amide from the stem wood of Hibiscus tiliaceus

A new coumarin, hibiscusin, and a new amide, hibiscusamide, together with eleven known compounds including vanillic acid, p-hydroxybenzoic acid, syringic acid, p-hydroxybenzaldehyde, scopoletin, N-trans-feruloyltyramine, N-cis-feruloyltyramine, a mixture of beta-sitosterol and stigmasterol, a mixture of beta-sitostenone and stigmasta-4,22-dien-3-one were isolated from the stem wood of Hibiscus tiliaceus. The structures of these new compounds were determined through spectral analyses. Among the isolates, three compounds exhibited cytotoxicity (IC50 values < 4 mu g/mL) against P-388 and/or HT-29 cell lines in vitro.