Cobalt oxide nanoparticles as a promising antifungal agent for Candida species: Eco-friendly synthesis from Platanus orientalis L. leaf extract and its applications

The development of environmentally compatible nanomaterials with biomedical potential has garnered increasing interest. In this study, cobalt oxide nanoparticles (Co3O4-NPs) were synthesized by an eco-friendly method using Platanus orientalis L. leaf extract as a reducing and stabilizing agent. Structural and physicochemical characterizations confirmed the successful formation of spinel-type Co3O4-NPs with controlled size and morphology. Synthesis at pH 12 resulted in smaller (22.70 nm) and more stable nanoparticles which showed increased anticandidal activity. The minimum inhibitory concentrations (MIC: 3.91, 7.81, and 1.95 mg/mL) and the minimum fungicidal concentrations (MFC: 15.63, 62.50, and 7.81 mg/mL) indicated a strong antifungal effect against Candida albicans, Candida tropicalis , and Candida glabrata , respectively. In addition, Co3O4-NPs showed concentration-dependent cytotoxicity on MDA-MB-231 breast cancer cells with the inhibition concentration 50 value (IC50: 0.07 mg/mL 24-h) indicating potential anticancer effect. These results highlight the dual antifungal and cytotoxic capabilities of biogenically synthesized Co3O4-NPs, making them strong candidates for future biomedical applications. © 2025 The Korean Society of Industrial and Engineering Chemistry.