Experimental antitumor agents from Solanum indicum L.

beta-Sitosterol (SI-0), beta-sitosterol glucoside (SI-1), dioscin (SI-2), methyl protoprosapogenin A of dioscin (SI-3), methyl protodioscin (SI-4) and protodioscin (SI-5) were isolated and characterized from the whole plant of Solanum indicum L. (Solanaceae). Except for beta-sitosterol, these compounds have not been previously isolated from Solanum indicum L. Both CHCl3 soluble (SI-IV) and insoluble (SI-V) fractions of the ethanolic extract (SI-I) showed cytotoxicity on seven cancer cell lines: Colo-205 (colon), KB (nasopharynx), HeLa (uterine cervix), HA22T (hepatoma), Hep-2 (laryngeal epidermoid), GBM8401/TSGH (glioma) and H1477 (melanoma). The purified constituents, SI-2 and SI-4 showed more potent effects by DEA and MTT assay. SI-2,3,4 and 5 also demonstrated cytotoxicity on cultured C6 glioma cells by PRE assay, ans SI-3,4 and 5 showed a tumor inhibitory effect in vivo in C6 glioma cells. In addition, SI-2 had an inhibitory effect on the DNA synthesis of C6 glioma cells at 10 micrograms/ml.