Synergy Between Silver Nanoparticles and <i>Allium cepa</i> Extract: A New Era in Antifungal Treatments

An eco-friendly and biocompatible onion (Allium cepa) extract is proposed as a support for silver nanoparticles (AgNPs) to develop a highly effective antifungal agent against Trichophyton mentagrophytes at low concentrations. AgNPs with an average diameter of 16 ± 10 nm were successfully synthesized, achieving complete (100%) fungal inhibition at a concentration of 0.016 mg/mL. Ac_ext (A. cepa extract) was obtained, exhibiting a minimum inhibitory concentration (MIC) of 4.71 mg/mL and demonstrating complete fungal inhibition. The antifungal activity of AgNPs and Ac_ext was evaluated, revealing that nanotechnology outperforms plant extracts, yielding promising results that suggest a safe alternative for antifungal treatments. To enhance antifungal efficacy, Ac_ext was functionalized with AgNPs, yielding Ac_ext-AgNPs. Using an Ac_ext concentration of 0.64 mg/mL (75% below its MIC) and AgNPs at 0.0109 mg/mL (32% below its MIC), 97.92% inhibition of T. mentagrophytes was achieved. The synergistic interaction between Ac_ext and AgNPs enabled potent antifungal activity at sub-MIC concentrations of both components, highlighting their potential as an innovative and efficient antifungal treatment.