The methanol, n-butanol, chloroform and water extracts obtained from the root of Eurycoma longifolia Jack were assayed using methylene blue assay to evaluate its cytotoxic effect against KB, DU-145, RD, MCF-7, CaOV-3, MDBK cell lines. The results showed that all the root extracts except the water extract of E. longifolia produced significant cytotoxic effect on these cell lines. However, no significant cytotoxic effect was detected on MDBK (kidney) normal cell line. 9-methoxycanthin-6-one, an alkaloid, was detected in each extract with different intensities by reversed-phase high performance liquid chromatography.
Xanthorrhizol is a plant-derived pharmacologically active sesquiterpenoid compound isolated from Curcuma xanthorrhiza. Previously, we have reported that xanthorrhizol inhibited the proliferation of HepG2 human hepatoma cells by inducing apoptotic cell death via caspase activation. Here, we attempt to further elucidate the mode of action of xanthorrhizol. Apoptosis in xanthorrhizol-treated HepG2 cells as observed by scanning electron microscopy was accompanied by truncation of BID; reduction of both anti-apoptotic Bcl-2 and Bcl-X(L) expression; cleavage of PARP and DFF45/ICAD proteins and DNA fragmentation. Taken together, these results suggest xanthorrhizol as a potent antiproliferative agent on HepG2 cells by inducing apoptosis via Bcl-2 family members. Hence we proposed that xanthorrhizol could be used as an anti-liver cancer drug for future studies.