The cytotoxicity of lingshuiol: a comparative study with amphidinol 2 on membrane permeabilizing activities

The cytotoxicity of lingshuiol, a novel polyhydroxy compound with a linear carbon-chain isolated from the cultured marine dinoflagellate Amphidinium sp., and that of amphidinol 2 (AM2) was compared with hepatocytes. Both lingshuiol and AM2 were toxic to primary rat hepatocytes with IC(50) values of 0.21 and 6.4muM, respectively. Meanwhile, lingshuiol or AM2 caused a rapid mitochondrial swelling and leakage of Ca(2+), underlying the change in permeability of mitochondria. Cyclosporin A, a specific inhibitor of mitochondrial permeability transition (MPT), could not affect these effects, indicating that CsA-sensitive MPT was not involved in the permeabilizing effects of lingshuiol or AM2. Sytox green tests further demonstrated that lingshuiol had a much stronger permeabilizing activity than AM2. Taken together, these results disclosed that lingshuiol had potent membrane permeabilizing activities, which might account for its cytotoxic effect.