Isolation of an anti-tumour terpenoid from stem bark of Spondianthus preussii var. preussii Engl.

We report a biologically monitored phytochemical separation of stem bark of Spondianthus preussii var. preussii against a panel of human cancer cell lines in vitro and the P-388 murine lymphocytic leukemia cells in culture. An ethylacetate extract of the stem bark exhibited selective cytotoxicity against human melanoma (ED50 = 10.0 ug/ml). Further activity-guided fractionation of the ethylacetate extract by flash chromatography and subsequent purification on preparative thin layer chromatography led to the identification of a lupane-type triterpene, 3beta-hydroxy-20(29)--lupenoic acid, by spectroscopic methods. This is the first report of the occurrence of this compound in S. preussii var. preussii. It is also the first time this triterpene is being shown to exhibit in vitro anti-tumor activity against human melanoma (ED50 = 2.4 ug/ml). This compound could be a promising bioactive natural product since it has been previously reported to exhibit a range of biological activities including in vivo and in vitro antiplasmodial activity and it is not toxic.