Penicamins\nA–L, Polyoxygenated Diterpenes from <i>Penicillium camemberti</i> JSB-7212

Penicamins A–L (<b>1</b>–<b>12</b>),\n12 highly oxygenated novel diterpenes, were obtained from the fungus <i>Penicillium camemberti</i> JSB-7212. Compounds <b>1</b>–<b>12</b> share the same 7/6/5 tricyclic skeleton as\nvalparane-type diterpenes but differ in the absolute configurations\nat C-7, C-11, and C-14, as well as in the oxidation levels at C-6\nand C-8, which were determined through extensive spectroscopic data\ninterpretation. Stereochemical assignments of compounds <b>1</b>, <b>2</b>, and <b>4</b>–<b>12</b> were\nestablished by single-crystal X-ray diffraction, and the absolute\nconfiguration of <b>3</b> was determined by analysis of the\nNOESY data and biogenetic consideration. Compounds <b>2</b> and <b>3</b> were immunosuppressive against lipopolysaccharide (LPS)-induced\nB cells, with IC<sub>50</sub> values of 3.0 and 7.9 μM, respectively.\nThey also moderately suppressed concanavalin A (ConA)-induced T cell\nproliferation, with IC<sub>50</sub> values of 19 and 20 μM,\nrespectively.