Inhibitory and cytotoxic activities of salvia officinalis L. Extract on human lymphoma and leukemia cells by induction of apoptosis.

Purpose: Salvia officinalis L., also known as Maryam Goli, is one of the native plants used to Persian medicinal herbs. Hence, the objective of this study was to examine the in vitro cytotoxic activities of a standardized crude methanol extracts prepared from Salvia officinalis L., on a non-Hodgkin's B-cell lymphoma (Raji) and human leukemic monocyte lymphoma (U937), Human acute myelocytic leukemia (KG-1A) and Human Umbilical Vein Endothelial (HUVEC) cell lines.

Methods: The effect of methanolic extract on the inhibition of cell proliferation and cytotoxic activity was evaluated by Dye exclusion and Micro culture tetrazolium test (MTT) cytotoxicity assay. Cell death ELISA was employed to quantify the nucleosome production result from nuclear DNA fragmentation during apoptosis and determined whether the mechanism involves induction of apoptosis or necrosis.

Results: The present results demonstrated that methanolic extract at 50 to 800 μg/ml dose and time-dependently suppressed the proliferation of KG-1A, U937 and Raji cells by more than 80% (p<0.01), with ascending order of IC50 values in 24: KG-1A (214.377 μg/ml), U937 (229.312 μg/ml) and Raji (239.692 μg/ml) when compared with a chemotherapeutic anticancer drug, paclitaxel (Toxol), confirming the tumour-selective cytotoxicity. The crude extract however did not exert any significant cytotoxic effect on normal cell line HUVEC (IC50>800 Ag/ml). Nucleosome productions in KG-1A, Raji and U937 cells were significantly increased respectively upon the treatment of Salvia officinalis L. extract.

Conclusion: The Salvia officinalis L. extract was found dose and time-dependently inhibits the proliferation of lymphoma and leukemic cells possibly via an apoptosis-dependent pathway.