In vitro, Cytotoxic and anti-proliferative effect of hydro-alcoholic extract of Hippophae rhamnoides Linn (HEHR) seeds was investigated on human leukemia (HL-60) and normal (BHK21) cells while in vivo anti-proliferative effect of HEHR was evaluated on Ehrlich ascite carcinoma (EAC) induced Swiss albino mice. Cytotoxic and anti-proliferative effect of HEHR (50-500 μg.ml-1) was assayed on HL-60 and BHK-21 by MTT reduction assay, clonogenic assay and extent of DNA fragmentation of HL-60 cells using agarose gel electrophoresis. MTT and clonogenic assay helps to determine the effect of test drug on proliferation and cytotoxicity. DNA fragmentation test is to know the mechanism involved in cytotoxicity since DNA fragmentation is hallmark of cell death. In vivo anti-proliferative effect of HEHR (286 and 667 mg.ml-1) was also assayed by glutathione assay on EAC induced mice since glutathione play a vital role in regulation of proliferation of cells. HEHR produced significant (p<0.001) and time dependent anti-proliferative effect in terms of percentage cell viability and inhibition of colony growth, on both cancer (HL-60) and normal (BHK-21) cells but cytotoxicity was observed only on HL-60 cells. HEHR showed significant and time dependent cytotoxic effect against HL-60 cells, with IC50 value 70.67±8.1 and 50.0±13.3 μg.ml-1 after 48 and 72 h respectively. Treatment for 72 h with HEHR (500 μg/ml) produced maximum DNA fragmentation of HL-60 cells. The level of GSH significantly decreased in all treated groups compare to tumor induced control group on 6th, 10th and 15th day of cancer induction. Our results suggested that anti-proliferative effect of HEHR due to its interference with the cell kinetics which was indicates the reduction in the GSH levels and colony growth. The cytotoxic effect of HEHR is produced by apoptosis mechanism which involved DNA fragmentation.
