Characterization, synergistic antibacterial and free radical scavenging efficacy of silver nanoparticles synthesized using Cassia roxburghii leaf extract

In this work, we report for the first time, synthesis of silver nanoparticles using Cassia roxburghii leaf extract and evaluate its synergistic antibacterial efficacy and antioxidant potential. The synergistic antimicrobial activity of silver nanoparticles with commercial antibiotics against Gram-positive, Gram-negative bacteria and fungi was evaluated. The antioxidant potential of synthesized silver nanoparticles was evaluated by FRAP and ABTS radical scavenging antioxidant assays. UV–Vis spectra peak at 473 and color change from colorless to brown color confirmed the formation of AgNPs. X-ray diffraction (XRD) and selected area electron diffraction (SAED) pattern confirmed the crystalline nature of synthesized nanoparticles. Transmission electron microscopy (TEM) analysis revealed the average size of particles to be 15–20 nm. Fourier transform infrared spectroscopy (FTIR) revealed the functional groups C. roxburghii leaf that was responsible for the reduction and capping process of nanoparticles. C. roxburghii leaf extract synthesized AgNPs showed good synergistic antimicrobial against Gram-negative bacteria even better than some of the antibiotics used as positive control; they also showed antioxidant potential. The results suggest that the synthesized nanoparticles can be used to treat multidrug resistant microorganisms and stress related diseases and disorders.