Synthesis and anti- <i>Candida albicans</i> activity of oleanolic acid derivatives

With the increase incidence of <i>Candida albicans</i> infections and the widespread use of azole drugs, particularly fluconazole, the emergence of drug-resistant strains has become a significant concern. In this study, the derivatives were prepared by nucleophilic substitution at the 3-OH position of oleanolic acid, utilizing the reactivity of triphosgene, and by electrophilic coupling at the 28-COOH position through photoredox reactions. The antifungal activity of all compounds was evaluated, revealing that most derivatives exhibited good synergistic antifungal activity with fluconazole against the drug-resistant <i>Candida albicans</i> strain ATCC14053, with FICI values ranging from 0.45 to 0.14.