A novel phenanthrenolide and C-benzyl dihydrochalcones from Uvaria puguensis.

Two new natural products, the phenanthrenoid puguenolide (6-hydroxy-3-methoxy-4-oxapyren-5-one) and isoangoletin were isolated from the stem bark of the newly described Uvaria species, U. puguensis D.M. Johnson, together with the sesquiterpene guaiol and the usual C-benzyldihydrochalcones previously found in the genus Uvaria, viz. uvaretin, diuvaretin, chamuvaritin and a mixture of triuvaretin and isotriuvaretin. Structural elucidation was achieved through a combination of spectroscopic methods.