Benzophenanthridine alkaloids of Chelidonium majus; I. Inhibition of 5- and 12-lipoxygenase by a non-redox mechanism.

The benzophenanthridine alkaloids sanguinarine and chelerythrine of Chelidonium majus, L. (Papaveraceae), are potent inhibitors of 5-lipoxygenase in polymorphonuclear leukocytes and 12-lipoxygenase in mouse epidermis, while the activity of soybean lipoxygenase is not influenced. The extract of the herb of Ch.majus also inhibits the 5-LO enzyme. Chelidonine, which cannot form pseudobases, is inactive against LO enzymes. Pro- and antioxidant actions of benzophenanthridine alkaloids can be excluded from the lack of deoxyribose degradation, reactivity against free radicals and inhibition of lipid peroxidation, suggesting that the inhibitory effects against LO enzymes appear to be due to specific enzyme interaction rather than a nonspecific redox mechanism.