Inhibition by biscoclaurine alkaloid of lipid peroxidation in biological membranes.

Biscoclaurine-type alkaloids were examined for ability to act as membrane-stabilizing agents and to protect against lipid peroxidation and deterioration of biological membrane. The following results were obtained. Biscoclaurine-type alkaloids inhibit Fe2+-induced lipid peroxidation of biological membrane. Cepharanthine protects against decrease in membrane compartmentation due to Fe2+-induced lipid peroxidation. Peroxidation of membrane lipid causes decrease in membrane fluidity but cepharanthine protects against this decrease. These protective actions are structure specific. They are also biscoclaurine-type specific and do not apply to coclaurine-type alkaloids such as papaverine. Based on these findings, the biological action of the alkaloid is discussed relative to membrane-stabilizing action and protective action against leukopenia induced by X-ray irradiation or mitomycin treatment in cancer therapy.