Green Synthesis of Silver Nanoparticles Using Mushroom Extract of Pleurotus giganteus: Characterization, Antimicrobial, and α-Amylase Inhibitory Activity

The present study was carried out to synthesize silver nanoparticles (AgNPs) using extracts of wild edible mushroom, Pleurotus giganteus, and to characterize the synthesized AgNPs and also to evaluate the synthesized AgNPs for antimicrobial and α-amylase inhibitory activity. Green synthesized AgNPs were characterized by UV–Vis spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, Atomic force microscopy (AFM), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), selected area electron diffraction (SAED), Energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Antibacterial activity of AgNPs was studied by disc diffusion method along with minimum inhibitory concentration (MIC) and α-amylase inhibition assay of AgNPs were also studied. UV–Vis spectra of reaction mixture of AgNPs exhibited surface plasmon resonance peak around at 420 nm. FTIR study revealed that mainly carboxyl, hydroxyl, and amine functional groups were present in a mushroom extract which mainly reduced Ag+ to Ag0. AFM, TEM, SEM, SAED, and XRD pattern analysis supported that synthesized AgNPs were mostly spherical shaped within average size 2–20 nm and crystalline in nature. Biosynthesized AgNPs showed more antibacterial potentiality against Gram (–) bacteria. MIC of green synthesized AgNPs were found against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus as 12, 10, 14, and 15 μg/ml, respectively. α-Amylase inhibition assay of green synthesized AgNPs revealed that percent inhibition of α-amylase decreased with increasing concentration of green synthesized AgNPs. Wild edible mushroom P. giganteus can be used as a source of reducing and capping agents of spherical metallic silver nanoparticles which offers potential medicinal properties.