New prenylated bi- and tricyclic phloroglucinol derivatives from Hypericumpapuanum

Five new prenylated tricyclic and three new bicyclic acylphloroglucinol der ivatives have been isolated by bioactivity-guided fractionation of the petr oleum ether extract of the dried aerial parts of Hypericum papuanum. The tr icyclic compounds (1-5) were named papuaforins A-E. The bicyclic compounds were isolated together with their corresponding tautomers and were named hy perguinones A and B (6/6a, 7/7a) and hyperpapuanone (8/8a), respectively. T heir structures were elucidated on the basis of extensive 1D and 2D NMR exp eriments, as well as mass spectrometry. Furthermore, the cytotoxicity towar d KB nasopharyngeal carcinoma cells and the antibacterial activity of the i solated compounds were determined.