Chemical constituents of Artocarpus xanthocarpus and their inhibitory effects on melanin biosynthesis
Artocarpus xanthocarpus Merr. is an evergreen monoecious tree with milky juice, distributed in Philippines, Borneo and Taiwan (only on Lanyu) . Various phenolic compounds, including isoprenylated flavonoids, stilbenoids, and 2-arylbenzofurans are widely distributed in plants of the genus Artocarpus. Many of these compounds exhibit cytotoxic, anti-inflammatory, anti-platelet, antibacterial, antimalarial, antitubercular, antiviral and antioxidant activities [2, 3]. In continuation of our research on natural whitening agents, the present study aims to characterize the chemical constituents of A. xanthocarpus and demonstrate their potential whitening potency. Three new compounds, artoxanthocarpuones A-C (1-3), and twelve known compounds (4-15) have been isolated from the root of A. xanthocarpus. Their structures were determined on the basis of spectroscopic evidence. These compounds were evaluated for their antioxidative property, tyrosinase inhibitory potential and cytocoxicity. In B16F10 melanoma cells, compound 1, norartocarpetin (4), oxyreserveratrol (5), albanin A (8) and steppogenin (9) reduced tyrosinase activity and also inhibited the α-MSH induced melanin production. We may conclude that isolates of A. xanthocarpus with antioxidant and tyrosinase reducing activities may be considered as depigmenting agents.
Acknowledgement: The authors are thank to the financial support from the National Science Council of Taiwan (NSC-99–2320-B037–021).
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