Green Synthesis, Physicochemical Characterization, Antioxidant and Antibacterial Activities of Cissampelos pareira-Mediated Silver Nanoparticles

A sustainable alternative to traditional methods for producing silver nanoparticles (AgNPs) is the green production of AgNPs using medicinal plants. The current study used a leaf extract of Cissampelos pareira (an herb) as a natural reducing agent and as a natural stabilising agent for the synthesis of AgNPs. Confirmation of AgNPs formation was completed by the presence of a distinct peak in the UV-Vis. spectrum, which was at 424 nm with the use of surface plasmon resonance (SPR). The characterisation of the AgNPs formed was achieved using multiple techniques, including XRD, TEM, FTIR, DLS, and zeta potential. The mean hydrodynamic diameter of the AgNPs from the DLS analysis was 52.7 ± 2.4 nm (PDI 0.312 ± 0.02), and the TEM showed that the wet-processed AgNPs were primarily spherical and had a size range of 10-20 nm. The high zeta potential value of -25.8 ± 0.6 mV demonstrated good colloidal stability of the biosynthesised AgNPs. The concentration-dependent antioxidant activity of the biosynthesised AgNPs had an average IC50 value of 45.8 µg/mL, and the average % DPPH radical scavenging activity was 80.94% at 200 µg/mL. The AgNPs exhibited higher antibacterial activity against both Gram-positive and Gram-negative bacteria than the other tested bacteria, with the lowest minimum inhibitory concentration (22 µg/mL) observed for Escherichia coli. Therefore, AgNPs from C. pareira would likely have usefulness in biological and pharmaceutical applications.