Biological activity of dihydrotanshinone I: effect on apoptosis

Recently, we have found for the first time that dihydrotanshinone I, isolated from Salvia miltiorrhiza, exhibited cytotoxicity against various tumor cell lines. To investigate whether the mechanism underlying dihydrotanshinone I toxicity involved apoptosis in cancer cell lines, we examined cell growth arrest and cell death by flow cytometric analysis and DNA fragmentation assay. Dihydrotanshinone I induced cell growth arrest during the S phase and subsequently, apoptosis, following its application to K562/ADR cells, whereas cryptotanshinone did not have these effects. These results suggest that the mode of action of dihydrotanshinone I involves apoptotic pathways that are different from those involved in cryptotanshinone toxicity.