Chelerythrine is a benzophenanthridine alkaloid present in the plant Chelidonium majus (greater celandine). It is a potent, selective, and cell-permeable protein kinase C inhibitor in vitro. It is also found in the plants Zanthoxylum clava-herculis and Zanthoxylum rhoifolium, exhibiting antibacterial activity against Staphylococcus aureus and other human pathogens.