Phytochemical investigation on the root bark of Garcinia edulis (Clusiaceae) gave a new isoprenylated xanthone, 1,4,6-trihydroxy-3-methoxy-2-(3-methyl-2-butenyl)-5-(1,1-dimethyl-prop-2-enyl)xanthone (1), a known xanthone, forbexanthone (2) together with three known pentacyclic triterpenoids, friedelin, lupeol and lupeol acetate. The structure of the new compound was fully characterised by NMR spectroscopic analysis. Compound 1 showed significant anti-HIV-1 protease activity with IC(50) value of 11.3 microg/mL. Furthermore, compound 1 showed potent cytotoxic activity with LC(50) value of 2.36 microg/mL against brine shrimp larva in vitro.