p-Terphenyl and Diterpenoid Metabolites from Endophytic Aspergillus sp YXf3

Six new p-terphenyl derivatives, named 4-deoxy-3-hydroxyterphenyllin (1), 4-deoxy-5'-desmethylterphenyllin (2), 5'-desmethylterphenyllin (3), 4-deoxycandidusin A (4), 4,5-dimethoxycandidusin A (5), and terphenolide (6), four new diterpenoids with norcleistanthane (aspergiloid A (12) and aspergiloid B (13)), cleistanthane (aspergiloid C (14)), and isopimarane (aspergiloid D (15)) type skeletons, and five known p-terphenyl compounds (7-11) were isolated from the fermentation broth of the plant endophytic fungus Aspergillus sp. Their structures were elucidated on the basis of detailed spectroscopic analysis and by comparison of their NMR data with those reported in the literature. Compounds 4, 6, 7, and 9 displayed moderate neuraminidase inhibitory activity with IC50 values ranging from 4.34 to 9.17 mu M.