Anti-proliferative and cytotoxic effects of Strychnos nux-vomica root extract on human multiple myeloma cell line – RPMI 8226

Multiple myeloma (MM) is an incurable hematological malignancy with high incidence in the elderly. The currently used chemotherapeutic drugs show severe side effects, dose-limiting toxicity and development of resistance. In search of novel plant derived anti-cancer agents, Strychnos nux-vomica L. (SN) root extract was screened using the human MM-cell line, RPMI 8226. SN-extract exhibited anti-proliferative activity in a dose and time dependent manner. The morphological assessment of SN-extract treated cells showed significant features associated with apoptosis. Cell cycle analysis using flow cytometry of cells stained with propidium iodide revealed accumulation of cells at sub-G0/G1 phase. In addition, disruption of mitochondrial membrane potential and subsequent leakage of mitochondrial cytochrome c was observed in SN-extract treated myeloma cells. The anti-proliferative and cytotoxic activity could be due to the alkaloids strychnine and brucine, which have been identified by LC–mass spectral analysis of the SN-extract in comparison to the reference standards analyzed under identical conditions.