| An investigation of the cytotoxic activity of the non-polar extracts from the stem bark of Kokoona ochracea (Elm.) Merrill (Celastraceae) resulted into the isolation of nine compounds. The structures of these compounds were identified or elucidated mainly by one- and two-dimensional NMR spectroscopic methods. These compounds were determined to be triterpenes of the friedelane and lupane groups. The former group included the known quinone-methides celastrol, tingenone, and 20-hydroxy-20-epi-tingenone, and a saturated friedelane, salaspermic acid. All of the lupane triterpenes were new compounds, for which the names ochraceolides A-E have been proposed. Their structures were determined as 3-oxolup-20(29)-en-30,21;A study aimed at the isolation of the molluscicidal constituents of the stem bark of Tetrapleura tetraptera (Schum. et Thonn.) Taub. (Leguminosae) led to the isolation of three active compounds and an inactive triterpene. The most active isolate was identified as the known compound, aridanin ;During the course of preliminary safety evaluation of T. tetraptera the water and methanol extracts of the stem bark were found to be mutagenic on Salmonella typhimurium strain TM677. The results demonstrated that the stem bark contains a direct-acting mutagen, and that none of the molluscicidal constituents isolated were associated with the observed mutagenic activity. From these observations, the use of the stem bark of T. tetraptera in ethnomedicine should be discouraged.;The isolates were evaluated for their in vitro cytotoxicity against P-388 (murine lymphocytic leukemia) cells and a battery of cultured human cancer cell lines (breast, fibrosarcoma, lung, melanoma, colon, oral epidermoid carcinoma, epdermoid carcinoma, glioblastoma, hormone-dependent breast and prostate cancer). Quinone-methide triterpenes demonstrated general cytotoxicity, while salaspermic aid was inactive. Among the lupanes, ochraceolides A, C, and E were cytotoxic against several cell lines, but the activity was more pronounced on P-388 and KB (oral epidermoid carcinoma) cells than on other cancer cell types. |
