Penicibilaenes A and B, Sesquiterpenes with a Tricyclo[6.3.1.01,5]dodecane Skeleton from the Marine Isolate of Penicillium bilaiae MA-267

Penicibilaenes A (1) and B (2), two sesquiterpenes possessing a tricyclo[6.3.1.0(1,5)]dodecane skeleton, were characterized from Penicillium bilaiae MA-267, a fungus obtained from the rhizospheric soil of the mangrove plant Lumnitzera racemosa. The lack of some key COSY and NOESY correlations made the structure elucidation of compound 1 difficult, which was solved by a X-ray crystallographic study. Compounds 1 and 2 exhibited selective activity against the plant pathogenic fungus Colletotrichum gloeosporioides (MIC = 1.0 and 0.125 mu g/mL, respectively).