Candihexin polyene macrolide complex: physicochemical characterization and antifungal activities of the single components.

ABSTRACT

The candihexin complex produced by a natural mutant of Streptomyces viridoflavus has been resolved into eight components. At least six of them, having hexaene chromophores, can be separated directly by thin-layer chromatography. The four major components, candihexins A, B, E, and F, account for about 90% of the total complex. They have been isolated and purified to homogeneity. All the major components were found to have macrolide lactone rings with all-trans hexaene chromophores. Candihexins A and B have compositions and molecular weights similar to candidin, the heptaene polyene macrolide produced by the parent S. viridoflavus, whereas candihexins E and F show smaller molecular weights and rather different elementary compositions. Candihexins A and B yield the amino sugar mycosamine upon hydrolysis, but no sugar was found in hydrolysates of candihexins E and F. Candihexins A and B have high antifungal activity against yeasts and filamentous fungi. The amino sugar-lacking candihexins E and F show no antifungal activity at levels of 100 mug/ml.