Inhibitory effects of berberine on Fonsecaea monophora in vitro and in vivo

Chromoblastomycosis (CBM) is a chronic and difficult-to-treat infection caused by dematiaceous fungi, primarily affecting the skin and subcutaneous tissues. In Southern China, Fonsecaea monophora is recognized as a predominant pathogen agent of CBM cases. Effective therapeutic strategies remain limited for this mycosis. However, berberine, a bioactive compound extracted from various traditional medicinal herbs, has attracted considerable attention due to its potent antimicrobial properties. The study evaluated the antifungal efficacy of berberine against F. monophora through a series of in vitro studies, including antifungal susceptibility testing and time-kill curve analysis. Moreover, a Galleria mellonella infection model of F. monophora was also established for the comparative analysis of berberine’s efficacy. Berberine exhibited inhibitory activity against all tested strains. The minimum inhibitory concentrations (MICs) of berberine against F. monophora strains ranged from 16 to 64 µg/mL, with a geometric mean of 49.74 µg/mL. In the Galleria mellonella model, berberine treatment significantly prolonged the survival time of infected larvae. These findings suggest that berberine has the potential, as a complementary treatment, for CBM. However, the current research is limited to in-vivo and preliminary in-vitro model involving a small number of fungal strains. Therefore, further validations through additional studies, such as involving murine model and other advanced experimental systems, will be necessary.