In vitro and in vivo antifungal activities of aminopiperidine derivatives, novel ergosterol synthesis inhibitors.

Aminopiperidine derivatives, Compound 1a and 1b, are novel small molecules that inhibit C-14 reduction catalyzed by Erg24p in ergosterol synthesis of Candida albicans. We evaluated the properties of the in vitro and in vivo activities of these compounds against pathogenic fungi and compared their activities with those of fluconazole. Compound 1a and 1b exhibited potent in vitro activities against clinically important fungi such as Candida species, including both of fluconazole-resistant strains of C. albicans and non-albicans Candida, Aspergillus fumigatus, and Cryptococcus neoformans. Against C. albicans, its mode of action was fungistatic. Furthermore, orally administered Compound 1b clearly prolonged the survival of infected mice in systemic lethal infection caused by C. albicans. These results suggest that aminopiperidine derivative is a promising lead compound for an orally available novel antifungal drug with a broad spectrum.