FR209602 and related compounds, novel antifungal lipopeptides from coleophoma crateriformis no. 738. II. In vitro and in vivo antifungal activity.

The biological activities of the novel echinocandin-like lipopeptides, FR209602, FR209603 and FR209604, were evaluated. These compounds showed antifungal activity against Candida albicans and Aspergillus fumigatus attributed to inhibition of 1,3-beta-glucan synthesis. The minimum effective concentrations of these compounds against C. albicans and A1. fumigatus ranged from 0.02 to 0.04 microg/ml by microbroth dilution assay, and the IC50 values on C. albicans 1,3-beta-glucan synthase were 0.49, 0.64 and 0.72 microg/ml, respectively. FR209602 and FR209603 showed good efficacy by subcutaneous injection against C. albicans in a murine systemic infection model, with ED50 values of 2.0 and 1.9 mg/kg, respectively.