Antifungal Effects of Pterostilbene on Candida albicans, Candida dubliniensis, and Microcosm Biofilms of Denture Stomatitis.

Natural compound-based strategies have gained attention as alternatives to conventional antifungal therapies, particularly in the management of Candida infections affecting the oral cavity, such as denture stomatitis. Our aim was to investigate the antifungal activity of the polyphenol pterostilbene (PTE) on clinical Candida isolates and microcosm biofilms from denture stomatitis, as well as to evaluate its toxicity and therapeutic efficacy in Galleria mellonella. PTE exhibited fungicidal effects against Candida albicans and Candida dubliniensis at 32 µg/mL. Time-kill assays demonstrated complete inhibition of viability for both strains within 8 h of exposure. In addition, PTE exhibited broad-spectrum antimicrobial activity, significantly reducing the counts of streptococci, mutans streptococci, staphylococci, and yeasts within microcosm biofilms. In vivo, PTE showed no signs of toxicity in G. mellonella at concentrations up to 20× MIC. Prophylactic treatment with PTE enhanced larval survival in experimental candidiasis caused by both C. albicans and C. dubliniensis. Moreover, prophylactic treatment decreased the fungal burden of C. albicans in the G. mellonella hemolymph, while the recruitment of hemocytes involved in host defense mechanisms remained unaltered. In summary, PTE demonstrated antimicrobial activity against Candida planktonic cells and complex biofilms associated with denture stomatitis, exhibiting favorable biocompatibility and in vivo antifungal efficacy in G. mellonella model.