In vitro cytotoxicity of norviburtinal and isopinnatal from Kigelia pinnata against cancer cell lines.

Crude dichloromethane extracts of Kigelia pinnata stem bark and fruit showed cytotoxic activity in vitro against cultured melanoma and other cancer cell lines using the Sulphorhodamine B assay, which was used for bioassay-guided fractionation. Thin layer chromatography (TLC) examination of the most active fractions of both stem bark and fruits showed the presence of the same major components which were found to be norviburtinal and beta-sitosterol. Norviburtinal was found to be the most active compound but had little selectivity for melanoma cell lines whilst isopinnatal also showed some cytotoxic activity. beta-Sitosterol was found to be comparatively inactive. HPLC analysis of the crude extract showed that the amount of norviburtinal present in the plant material did not account for all of the activity of the total extracts.