Anti-leukemic activity of Satureja bachtiarica occurs by apoptosis in human cells.

Failure of apoptosis contributes to leukemia progression. We investigated extracts of a native Iranian plant, Satureja bachtiarica, for possible anti-leukemia activity by induction of apoptosis and changes to the cell cycle. Growth inhibition caused by aqueous, butanol, dichloromethane and hexane extracts of S. bachtiarica on K562 and Jurkat leukemia cells was assessed using a colorimetric assay. Extracts were analyzed for induction of apoptosis and cell cycle arrest using flow cytometry and measurement of caspase-3 activity. Dichloromethane and hexane extracts inhibited leukemia cell proliferation in a dose-dependent manner. The IC₅₀ values of these extracts were 22-33 µg/ml. Flow cytometric determination of annexinV/propidium iodide positive cells verified a significantly increased percentage of apoptotic cells compared to negative controls. Both 50 μg/ml dichloromethane and hexane extracts induced apoptosis in 89-97% of K562 and 94-97% of Jurkat cells 48 h after treatment. The effects of extracts on the cell cycle included significantly increased numbers of K562 and Jurkat cells in the subG1 phase and decreased numbers of cells in the G1, S and G2/M phases. After 24 h, we found increased levels of caspase-3 activation in cells treated with 25 μg/ml dichloromethane and hexane extracts compared to untreated cells. Our findings indicate the anti-leukemic effects of dichloromethane and hexane extracts of S. bachtiarica due to induction of apoptosis and inhibition of cell cycle progression.