Cytotoxic effect induced by Morinda morindoides leaf extracts in human and murine leukemia cells

We report here the in vitro effect of the toluene, methyl tert-butyl ether (MtBE), ethyl acetate (EtOAc), n-buthanol (n-BuOH) and H2O extracts from Morinda morindoides (rubiaceae) leaves against a human leukemic cell line, K562, and two murine leukemic cell lines, P388 and L1210. We found that both toluene and MtBE extracts exhibited a significant cytotoxic effect on these murine cell lines. The highest cytotoxicity was obtained with toluene extract in P388 (6.0 +/- 1.4 mu g/ml) and L1210 cells (6.5 +/- 2.1 mu g/ml). By contrast, EtOAc, n-BuOH and H2O extracts did not affect cell viability of the three cell lines tested. Effect of toluene and MtBE extracts was also examined on apoptosis induction in K562 human erythroleukemia cells. The results of this preliminary study have shown that the cytotoxic effects of toluene and MtBE extracts from Morinda morindoides leaves observed in K562 cells were mediated through the induction of apoptosis. Possible mechanisms responsible for the induction of apoptosis are discussed.