Tannic acid exhibits therapeutic effects against azole-resistant invasive candidiasis and enhances the antifungal activity of fluconazole.

Candida albicans is a priority threat to global health due to the emergence of strains resistant to antifungal drugs, such as azoles, and their high mortality rates, especially in hospital settings. Therefore, the search for new therapeutic strategies is crucial. Tannic acid is a phenolic compound that has shown potential antifungal activity against Candida species in vitro. This study evaluated the therapeutic effects of tannic acid alone and in combination with fluconazole in a murine model of invasive candidiasis. BALB/c mice were intravenously injected with either fluconazole-susceptible or -resistant Candida albicans, and then received the experimental treatments intraperitoneally for 3 days. Therapeutic efficacy was evaluated by determining animal survival, as well as fungal burden, tissue invasion and cytokine levels in the spleen, brain and kidney. Tannic acid increased the survival of mice with invasive candidiasis; Furthermore, treatment with tannic acid reduced fungal burden, tissue invasion and proinflammatory cytokine levels in disseminated organs during invasive candidiasis. Combination therapy of tannic acid plus fluconazole demonstrated a greater antifungal effect compared with monotherapy of both drugs during azole-resistant invasive candidiasis. These findings demonstrate the therapeutic efficacy of tannic acid against azole-resistant Candida albicans, representing a promising potential option for the adjuvant treatment of candidiasis.