Cyclic Colisporifungin and Linear Cavinafungins, Antifungal Lipopeptides Isolated from <i>Colispora cavincola</i>

Abstract

Colisporifungin (<b>1</b>), 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 <i>Colispora cavincola</i> using a <i>Candida albicans</i> 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 <i>Aspergillus fumigatus</i> and, to a lesser extent, against <i>Candida albicans</i>. The linear peptides displayed broad-spectrum antifungal activities inhibiting growth of <i>Candida</i> species (MIC values 0.5–4 μg/mL) as well as <i>A. fumigatus</i> with a prominent inhibition of 8 μg/mL