5-Hydroxy-4-methoxycanthin-6-one, a natural product isolated and purified from the barks of Picrasma quassioides (D.Don) Benn with anti-inflammatory effect and protective effect on dextran sulfate sodium -induced rat colitis, exhibits significant cytotoxic activity against CNE2 cell line, reduces the development of carrageenan-induced paw edema and complete Freund’s adjuvant (CFA)-induced chronic arthritis in rats.