Isolation, Structure Elucidation, and Biological Activity of Virgineone from Lachnum virgineum Using the Genome-Wide Candida albicans Fitness Test

A glycosylated tetramic acid, virgineone (1), was isolated from saprotrophic Lachnum virgineum. The antifungal activity of the fermentation extract of L. virgineum was characterized in the Candida albicans fitness test as distinguishable from other natural products tested. Bioassay-guided fractionation yielded 1, a tyrosine-derived tetramic acid with a C-22 oxygenated chain and a beta-mannose. It displayed broad-spectrum antifungal activity against Candida spp. and Aspergillus fumigatus with a MIC of 4 and 16 mu g/mL, respectively. Virgineone was also identified in a number of Lachnum strains collected from diverse geographies and habitats.