SANGUINARINE, A PHOTOTOXIC H₂O₂‐PRODUCING ALKALOID

Abstract— Sanguinarine chloride, a quaternary salt of a benzophenanthrene alkaloid, was phototoxic to catalase‐deficient strains of Escherichia coli but not to Trichoplusia ni (cabbage looper moth larvae), an insect with high levels of catalase activity. Chemical analyses confirm that sanguinarine is an efficient producer of H₂O₂. This differential toxicity suggests that the mode of phototoxic action involves production of H₂O₂ which could be detoxified in many organisms by catalase.