Green Synthesis and Characterization of Silver Nanoparticles from Stem Bark Extract of Cordia dichotoma G. Forst and Evaluation of their Antioxidant and Antibacterial activities

Background: There is a lack of scientific evidence for the fabrication of silver nanoparticles (AgNPs) using stem bark extract of medicinal plant Cordia dichotoma and its potential therapeutic applications. Objectives: In our present study we contemplated using Cordia dichotoma extract for fabricating AgNPs and to analyze their potential applications as antioxidant and biocidal agents. Materials and Methods: AgNPs were fabricated by bio reduction of silver nitrate solution with bark extract of Cordia dichotoma. The fabricated AgNPs were characterized using U.V visible, FT-IR, XRD, SEM, EDAX, particle size analyzer, and zeta potential. Further, evaluated for their potential antioxidant activity and compared with the crude extract of Cordia dichotoma and with standard ascorbic acid. The antibacterial activity was performed against both Gram-positive and Gram-negative bacteria. Results: The AgNPs were synthesized and UV spectra showed maximum absorbance at 430nm, which is the characteristic feature of AgNPs. The XRD peaks at (111), (220), and (311) indicate the existence of silver with a crystalline structure. The FT-IR spectra in the range of 1516 to 1634 cm⁻¹ reflected the presence of phenol groups which acted as the capping agents for synthesized AgNPs. The SEM images confirmed the spherical structure of AgNPs that formed aggregates with phytochemicals and appeared as composites. The average size of AgNPs is 39.8nm and exhibited good stability as evident from the zeta potential value of -33. Conclusion: Phytomediated eco-friendly synthesized and structurally characterized AgNPs can act as antioxidants and exhibited antibacterial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) pathogenic bacteria.