Green synthesis of silver nanoparticles using Solanum sisymbriifolium leaf extract: Characterization and evaluation of antioxidant, antibacterial and photocatalytic degradation activities

The present study conveyed an in-situ synthesis of silver nanoparticles (Ss-AgNPs) using Solanum sisymbriifolium aqueous leaf extract (SsLE) and their biological activities for the first time. The qualitative and quantitative analysis of SsLE imparted significant amounts of reducing entities/secondary metabolites. A surface plasmon resonance peak at similar to 430 nm of UV-visible spectrum evidenced the formation of Ss-AgNPs. The average particle size of the Ss-AgNPs was found to be 29.87 nm through particle size analyzer. Further, FE-SEM, HR-TEM and XRD analysis verified the spherical shape and high degree of crystallinity with face-centred cubic structure of SsAgNPs. The EDX, elemental mapping and FTIR spectral studies, confirmed that various phytochemicals/metabolites of S. sisymbriifolium leaf extract participated in bio-reduction process and capping of Ss-AgNPs, which might be accountable for the antioxidant activities. Moreover, SsLE and Ss-AgNPs were found to be a rich source of antioxidants and exhibited effective DPPH, H2O2, (N) over dotO scavenging activities along with Ferric ion reducing antioxidant power. The synthesized Ss-AgNPs showed significant antibacterial activity against gram -positive and gram-negative bacteria. In addition to this, Ss-AgNPs supported the degradation of methylene blue (a cationic dye), by performing as a strong photocatalyst under UV and solar irradiations.