Ethyl acetate extract of the Vietnamese heartwoods of Artocarpus heterophyllus has shown a good inhibition of tyrosinase with the IC50 value of 0.78 mg/mL. Investigation on the chemical constituents of this extract has resulted in the isolation of four compounds, cudraflavon B (1), brosimon I (2), artocarpin (3) and morachalcon A (4). Their structures were determined by a combination of HR-MS and 2D NMR spectroscopy. In addition, all four compounds 1-4 have inhibitory activity against tyrosinase. Especially, compound 4 has the strongest activity (IC50 value of 0.18 mg/mL).
