Plant-Mediated Synthesis of Selenium Nanoparticles Via Juglans Regia and Mentha Piperita: A Dual-Source Approach for Antimicrobial Applications

Abstract

The present study examines two selenium nanoparticles were synthesized at room temperature using extracts of Juglans regia L (green husk walnut) and Mentha piperita L (peppermint). The characteristic structures of GHW-SeNPs and MP-SeNPs were investigated using analytical techniques such as UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray diffraction (XRD). These characterization techniques have revealed both the reducing and stabilizing properties of the organic compounds in the structure of the plants used in the formation of SeNPs. GHW-SeNPs were found to have a polydisperse structure with an average diameter of 66.43 nm, while MP-SeNPs were observed to have a spherical structure and smaller dimensions (average diameter of 23.86 nm). The crystallite size of GHW-SeNPs was determined to be 57.74 nm, while MP-SeNPs were found to be quite pure and measured 29.1 nm. FTIR graphs show that the organic compounds surrounding the selenium atom significantly contribute to the reduction of selenium and the formation of nanoparticles. The biological activities of SeNPs were tested on 3 Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus megaterium), 4 Gram-negative bacteria (Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Enterobacter aerogenes) and 3 fungi (Candida albicans, Yarrowia lipolytica, Saccharomyces cerevisiae). GHW-SeNPs used at increasing concentrations exhibited the best antibacterial activity against Staphylococcus aureus and Klebsiella pneumoniae with inhibition zone diameters of 25 mm. MP-SeNPs exhibited more antifungal activity, showing high activity against Candida albicans with an inhibition zone diameter of 24 mm. The data obtained on the activities of the MP-SeNP and GHW-SeNP particles we synthesized using an environmentally friendly method will contribute to future pharmacological studies. © 2025 Elsevier B.V.