Viridepyronone, a New Antifungal 6-Substituted 2H-Pyran-2-one Produced by Trichoderma viride

A new antifungal 6-substituted 2 H -pyran-2-one, named viridepyronone, has been isolated from a cultural filtrate of a strain of Trichoderma viride showing antagonistic activity in vitro toward Sclerotium rolfsii, which is the causal agent of crown and stem rot of artichoke. Viridepyronone was characterized as 6-(4-oxopentyl)-2 H -pyran-2-one 2 with spectroscopic methods. Bioassays showed that viridepyronone had a good antifungal activity against S. rolfsii, and its minimum inhibitory concentration (over 90% inhibition) was found to be 196 μg/mL. This is the first report of viridepyronone produced by any species of fungi.