4,5-Dimethoxycanthin-6-one is a bioactive alkaloid isolated from Picrasma quassioides. It exhibits antimicrobial activity against Staphylococcus aureus and demonstrates cytotoxicity against tumor cell lines like U937 and HepG2. This compound also acts as a potent, non-competitive inhibitor of CYP1A2 and cAMP phosphodiesterase.