Cyclic Colisporifungin and Linear Cavinafungins, Antifungal Lipopeptides Isolated from Colispora cavincola

Colisporifungin (1), a cyclic depsilipopeptide structurally related to the aselacins, and cavinafungins A and B, two linear peptides, were isolated from liquid culture broths of the hitherto unstudied fungus Colispora cavincola using a Candida albicans whole-cell assay as well as a bioassay to detect compounds potentiating the antifungal activity of caspofungin. The structural elucidation, including the absolute configuration of the new molecules, was accomplished using a combination of spectroscopic and chemical techniques, including 1D and 2D NMR, HRMS, and Marfey's analysis. The cyclic peptide colisporifungin displayed a strong potentiation of the growth inhibitory effect of caspofungin against Aspergillus fumigatus and, to a lesser extent, against Candida albicans. The linear peptides displayed broad-spectrum antifungal activities inhibiting growth of Candida species (MIC values 0.5-4 mu g/mL) as well as A. fumigatus with a prominent inhibition of 8 mu g/mL.