Fungal melanin inhibitor and related compounds from Penicillium decumbens

Two polyketides, decumbenones A and B, and versiol were isolated from the culture filtrate of the fungus, Penicillium decumbens. Their respective structures were 1-(2.8-dihydroxy-1,2,6-trimethyl-1,2,6,7.8,8a-hexahydronaphthalen-1-yl)-3-hydroxy-1-propanone and 1-(2,8-dihydroxy-1,2,6-trimethyl-1,2,4a.5,6,7,8,8a-octahydronaphthalen-1-yl)-3-hydroxy-1-propanone based on NMR spectroscopic data, chemical conversion, and X-ray analysis. Decumbenone A inhibited melanization in Magnaporthe grisea, the rice blast pathogen, whereas decumbenone B like versiol did not. (C) 2002 Elsevier Science Ltd. All rights reserved.