A study of the antifungal activity of LY121019, a new echinocandin derivative.

LY121019 is a cyclic peptide antibiotic of the echinocandin group, which is characterized by strong anti-Candida activity (in particular against Candida albicans) as well as by low experimental toxicity. Its anti-Candida activity is thought to be due to an inhibition of the synthesis of beta-glucan, an essential cell wall polysaccharide. The different composition of culture media or the presence of animal serum did not show adverse effects on LY121019's anti-Candida activity and the addition of reducing compounds such as cysteine and hydroquinone did not manifest a negative influence. Analogously the anti-Candida activity was not influenced when C. albicans was grown under aeration. The activity of LY121019 was very high against the mycelial form of C. albicans even when this form was developed in the presence of animal serum.