Differential modulation of the antifungal activity of amphotericin B by natural and ent-cholesterol.

The addition of exogenous ent-cholesterol suppressed the antifungal activity of the amphotericin B when added to cultures of Candida albicans, but to a lesser extent than natural cholesterol. There were no detectable differences between added 2a or 2b on the antifungal activities of jaspamide or bengazole A, two unrelated antifungal natural products.

Bengazoles C-G from the Sponge Jaspis sp. Synthesis of the Side Chain and Determination of Absolute Configuration.

Five new antifungal bengazoles (C-G) were isolated and fully characterized from a marine sponge of the genus Jaspis sp. Bengazoles C-G, together with the known bengazoles A and B, comprise a homologous series of n, iso, and anteiso fatty acid esters (C(13)-C(16)) of the same heterocyclic bis(oxazolyl)methanol parent. The complete relative and absolute configurations of the bengazoles were determined by application of the modified Mosher method and interpretation of exciton coupling in the CD spectra of the tetra-p-bromobenzoate derivatives of bengazole A and that of a model tetrol synthesized in seven steps from L-fucose.