摘要：We have examined the cytotoxic effect of rhodexin A isolated from the extract of Rhodea japonica on human leukemia K562 cells using a flow cytometer and compared it with that of ouabain. Rhodexin A at 30 n M started to attenuate growth without affecting viability and further increases in the concentration of rhodexin A (100 n M or more) completely inhibited growth with decreasing viability. Rhodexin A at 30—100 n M increased the G2M population, but decreased the G0G1 population, suggesting cell cycle arrest in the G2M phase. Rhodexin A at 100 n M increased the number of cells with hypodiploid DNA, indicating that rhodexin A induced apoptosis. The potency of rhodexin A to inhibit growth was greater than that of ouabain. The results indicate that rhodexin A exerts a potent inhibitory action on the growth of human leukemia K562 cells by inducing cell cycle arrest and apoptosis. Rhodexin A may also be a candidate for cancer treatment because there have been clinical reports of tumor regression in patients taking cardiac glycosides.
