Purpurolide A, 5/5/5 Spirocyclic Sesquiterpene Lactone in Nature from the Endophytic Fungus Penicillium purpurogenum

Purpurolide A ( 1 ), an unprecedent sesquiterpene lactone with a rarely encountered 5/5/5 spirocyclic skeleton, along with two new 6/4/5/5 tetracyclic sesquiterpene lactones ( 2 and 3 ), were isolated from the cultures of the endophytic fungus Penicillium purpurogenum IMM003. The structures and absolute configurations of 1 – 3 were established by spectroscopic analysis, single-crystal X-ray diffraction, and calculations of the 13 C NMR and ECD data. Compounds 1 – 3 showed significant inhibitory activity against pancreatic lipase.