Chem. Pharm. Bull. 53(2) 244—247 (2005)

130 species, mostly trees, confined to the warm humid tropics of the world. Some species are used in traditional medicine for their antimicrobial, analgesic, gastroprotective activities and many of them are acknowledged for the presence of pyranocoumarins which act as potent inhibitors of HIV-1 replication and cytopathicity. Besides, the genus is considered as a rich source of phenolic compounds and xanthone derivatives which possess antibacterial, antifungal, antiplatelet aggregation, immunomodulatory, cancerchemopreventive as well as anti-HIV-1 virus and topoisomerase inhibitory activities. With the aim of discovering new bioactive compounds from the local flora, we have conducted a phytochemical study of the roots of Calophyllum blancoi Planchon growing in Taiwan. Three new pyranoxanthones, blancoxanthone (1), acetyl blancoxanthone (2) and 3-hydroxyblancoxanthone (3) in addition to two known pyranoxanthones, pyranojacaeubin (4) and caloxanthone (5) were isolated and characterized for the first time from an acetone extract of the roots of this species. The anti-coronavirus activity of the isolated compounds was evaluated.