Biosynthesis of Silver Nanoparticles Using Endophytic Clonostachys rosea ZMS27 from Medicinal Plant Anemarrhena asphodeloides and its Antagonistic Activity Against Superficial Pathogenic Fungi

Abstract

Superficial fungal infections (SFIs) represent a serious threat to global public health. It is known that silver nanoparticles (AgNPs) are characterized by potent antimicrobial properties. However, the therapeutic potential of biosynthetic AgNPs on superficial fungi have rarely been reported. The objectives of this study were to isolate endophytic fungi from medicinal plants for the biosynthesis of AgNPs and to assess the inhibitory effects of these AgNPs on superficial fungi as well as their biosafety toward skin cells. The endophytic fungal strain ZMS27, capable of biosynthesizing AgNPs, was isolated from medicinal plant Anemarrhena asphodeloides and identified as Clonostachys rosea. The UV‒visible spectroscopic measurements revealed a strong absorption peak at 340 nm, indicating the successful synthesis of the ZMS27-AgNPs. The AgNPs were well-dispersed, globular particles with an average diameter of 7.33 ± 0.18 nm, as determined by transmission electron microscopy (TEM) analysis. The FTIR analysis revealed that various functional molecules from C. rosea ZMS27 are involved in the synthesis of AgNPs. ZMS27-AgNPs significantly inhibited the growth of five superficial pathogenic fungi at minimal inhibitory concentration ranging from 1.56 to 25 µg·mL^-1. Interestingly, the cell counting kit-8 (CCK-8) assay revealed that ZMS27-AgNPs exhibited no significant cytotoxic effects on skin cells within the concentration range of 1.56-25 μg·mL⁻¹. These results suggested that novel AgNPs biosynthesized using fungal endophytes of medicinal plants are promising broad-spectrum antifungal agents for the control of SFIs.

Keywords: Biosynthesis; Endophytic fungi; Medicinal plants; Silver nanoparticles; Superficial fungal infections.