Induction of apoptosis by diphlorethohydroxycarmalol isolated from brown alga, Ishige okamurae

The anti-cancer effect of diphlorethohydroxycarmalol (DC) isolated from Ishige okamurae, a brown alga, via the induction of apoptosis resulting from mitochondrial dysfunction was assessed in human promyelocytic leukemia (HL60) cells. The apoptotic mechanisms of DC induction on tumor cells were studied in this work for the first time. DCs were determined to evidence marked cytotoxicity on HL60 cells in a dose-dependent manner. The induction of apoptosis in HL60 cells by DC was evidenced by the accumulation of sub-G(1) cell population and nuclear condensation. Further investigations into the depletion of mitochondrial membrane potential (Delta psi(m)) determined that DC treatment induced apoptosis via the regulation of the expression of pro-survival and pro-apoptotic Bcl-2 family members. It was demonstrated that the anti-cancer activity of DC was mediated by apoptotic induction resulting from mitochondrial dysfunction. Our study results also indicated dysfunction and that DCs may constitute a new and promising agent for the treatment of human promyelocytic leukemia cells. (C) 2012 Elsevier Ltd. All rights reserved.