Green synthesis of Ag-ZnO nanocomposites using Trigonella foenum-graecum leaf extract and their antibacterial, antifungal, antioxidant and photocatalytic properties

In the present study, biological synthesis of Ag-ZnO nanocomposites was performed using hydroalcoholic extract of fenugreek leaves. Metal/semiconductor oxide nanocomposites are excellent owing to their optical, electrical, magnetic, and chemical properties that are not detected in single individual constituents. The synthesized Ag-ZnO nanocomposites were investigated through the use of methods such as FTIR, UV vis DRS, SEM-EDX, TEM, XRD, zeta potential analysis, and DLS. The synthesized Ag-ZnO nanocomposites had an average particle size of about 75 nm and a zeta potential of -37.5 mV. The XRD results confirmed that Ag was successfully introduced into the Ag-ZnO nanocomposites via a hydrothermal method. The antimicrobial and antifungal activities of Ag-ZnO nanocomposites were evaluated by agar well diffusion method against three microbial and fungal strains; it was found that the Ag-ZnO nanocomposites were toxic against all the tested microbial and fungal strains. Ag-ZnO nanocomposites was observed to have significant antioxidant activity against DPPH (2,2-diphenyl-1-picrylhydrazyl) free radicals. The Ag-ZnO nanocomposites exhibited excellent photocatalytic activity and stability against the degradation of malachite green under visible light irradiation. The study successfully applied a simple and eco-friendly method for synthesizing efficient multifunctional Ag-ZnO nanocomposites using green synthetic approach.

Keywords: Ag-ZnO nanocomposites; Antibacterial activity; Antifungal activity; Leaf extract; Photocatalytic property; Trigonella foenum-graecum.