DESCRIPTION (Adapted from the application): Deep-seated mycoses are being increasingly observed in immunocompromised patients and in patients receiving aggressive cancer chemotherapy. The use of available drugs for the treatment of these infections is limited by toxicity and the emergence of resistant fungal species. The impact of fungal infections in the clinical management of inimunocompromised patients underscores the clear need for new antifungals. Historically, microorganisms and plants have been rich sources of drugs for the treatment of human disease. We have identified a novel, broadly-active antifungal compound from the dried fruit of Capsicum spp. (cayenne pepper). CAY-1, the active agent, was purified to homogeneity and, based on chemical analysis, is a novel saponin with a molecular mass of 1243 Da. In this Phase I proposal, we plan to extend our preliminary work and characterize more fully CAY-1's potential as an antifungal therapeutic. We will accomplish this in three specific aims: A. Aim One: Purify 500 mg of CAY-1 for the work described in Aims Two through Four C. Aim Two: Characterize the antifungal activity of CAY-1. D. Aim Three. Determine the in vitro toxicity of CAY-1 and the in vivo efficacy of CAY-1 against Candida albicans PROPOSED COMMERCIAL APPLICATION: The research outlined in this Phase I SBIR proposal will lead to the evaluation of a novel antifungal compound. We estimate that the market potential for a novel and safe antifungal drug to be greater than $200,000,000 per year.