Peniandranoids A-E: Meroterpenoids with Antiviral and Immunosuppressive Activity from a Penicillium sp.

Peniandranoids A-E ( 1 - 5 ), five new meroterpenoids, together with three known analogues ( 6 - 8 ), were isolated from the fermentation of a soil-derived fungus, Penicillium sp.sb62. Their structures including absolute configurations were determined by extensive spectroscopic analysis, and the absolute configurations of compounds 1 and 5 were further elucidated by single-crystal X-ray diffraction. Peniandranoids A-E belong to a rare class of andrastin-type meroterpenoids incorporating an extra polyketide unit (a C 10 polyketide unit for 1 and 2 , a C 9 polyketide unit for 3 and 4 , and a furancarboxylic acid unit for 5 ). Compounds 1 and 6 exhibited favorable inhibitory activities against influenza virus A (H1N1) with EC 50 values of 19 and 14 μg/mL, respectively. Compounds 3 - 8 exhibited potent immunosuppressive activities against concanavalin A-induced T cell proliferation with EC 50 values ranging from 4.3 to 27 μM and lipopolysaccharide-induced B cell proliferation with EC 50 values ranging from 7.5 to 23 μM, respectively.