Green Synthesis of Zinc Oxide Nanoparticles by Candida albicans CA26 with Antioxidant and Antifungal Activity Against Nannizzia incurvata

The rise of antifungal resistance in dermatophytosis underscores the need for novel antifungals, driving the green synthesis of zinc oxide nanoparticles (ZnO NPs). In this study, we report the extracellular biosynthesis of ZnO NPs via a clinical isolate of Candida albicans CA26 and evaluate their physicochemical properties, antioxidant capacity, and antifungal efficacy against Nannizzia incurvata TI03. The ZnO NPs were biosynthesized using the extracellular filtrate of C. albicans CA26 and the resulting NPs were characterized via UV-Vis spectroscopy, FTIR, XRD, TEM, and BET analysis. The UV-Vis spectra revealed a characteristic surface plasmon resonance peak at 361.75 nm, confirming the formation of ZnO NP; whereas the FTIR spectra confirmed capping by fungal biomolecules. XRD confirmed a crystalline ZnO phase with an average crystallite size of ~ 30 nm and TEM imaging revealed a rod-to-bar morphology (75–99 nm in length). BET analysis revealed a specific surface area of ~ 24.24 m^2/g and an average pore radius of ~ 4.57 nm. The antioxidant activity of the ZnO NPs was evaluated via DPPH, ABTS, nitric oxide, hydroxyl radical, and superoxide scavenging assays, which revealed moderate but consistent activity across all five assays. These activities were statistically significant compared with those of the reference antioxidants (p < 0.001, Cohen’s d > 17). The antifungal efficacy was tested against N. incurvata TI03, yielding a minimum inhibitory concentration (MIC) of 0.96 µg/mL, which is comparable to that of standard azole drugs. In agar diffusion assays, ZnO NPs produced inhibition zones similar in size to those of fluconazole and itraconazole. The biosynthesized ZnO NPs thus exhibited multimodal antifungal mechanisms, likely involving reactive oxygen species generation, membrane disruption, and enzyme inhibition, in addition to their antioxidant activity. This eco-friendly synthesis, combined with the potent dual-functionality of these ZnO NPs highlights their role as promising topical antifungal therapeutic agents.