Evaluation of antimicrobial effect of green synthesized silver nanoparticles from Sapindus mukorossi pericarp extract

The present study is focused on the biosynthesis of silver nanoparticles derived from Sapindus mukorossi pericarp extract. Silver nanoparticles were synthesized successfully by employing biological methods. In the present research, silver nitrate was used as a precursor and Sapindus mukorossi pericarp extract was used as a reducing agent for synthesis. The obtained nanoparticles were characterized using UV-Vis spectroscopy, X-ray diffraction (XRD), Fourier transform electron microscopy (FTIR) and High-resolution transmission electron microscopy (HR-TEM). The UV-Vis spectra and visual observation showed that the color of pericarp extract of S. mukorossi turned from golden yellow to dark brown after the addition of AgNO₃ precursor and showed the highest absorption peak at 410 nm. In addition, XRD pattern revealed the face-centered cubic structure of silver nanoparticles. The FTIR measurements confirmed the presence of different functional groups within the extract that were directly involved in the reduction and stability of biosynthesized silver nanoparticles. HR-TEM images revealed the particles to be nearly spherical with a few irregular shapes and particles size ranging from 5 to 50 nm. The study highlights the antimicrobial activity and MIC of biosynthesized nanoparticles that were tested against gram negative bacterium viz., Pseudomonas aeruginosa, Escherichia coli and gram-positive bacterium Staphylococcus aureus, Bacillus subtilis. The results confirmed that the nanoparticles showed better antimicrobial potential against all the tested microorganisms as compared to control. The antioxidant potential of aqueous extract and biosynthesized silver nanoparticles was evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl) method and revealed that S.mukorossi nanoparticles exhibit significant antioxidant activity.