Two 1H-naphtho[2,3-c]pyran-1-one metabolites from the fungus Paecilomyces variotii

Abstract

The fungus Paecilomyces variotii Bainier, isolated from larvae of Dendroctonus ponderosa Hopk. (mountain pine beetle), is antagonistic to Ophiostoma clavigerum, the fungus believed responsible for tree mortality caused by blue stain fungi. The metabolites produced by P. variotii when grown in liquid culture have been studied and two new 1H-naphtho[2,3-c]pyran-1-ones related to semi-vioxanthin (4) have been isolated. The structures of these two metabolites, semi-viriditoxin (1) and semi-viriditoxic acid (2), have been determined by chemical and spectroscopic methods. Key words: fungal metabolites, blue stain disease, Paecilomyces variotii, semi-viridotoxin, semi-viridotoxic acid.