Antioxidant and Antibacterial Property of biosynthesised Silver Nanoparticles

Objective(s): The present work shows the green synthesis of silver nanoparticles using C. roseus extract and its antioxidant, free radicals scavenging and antibacterial activities. Methods: The C. roseus extract synthesized silver nanoparticles (CrAgNPs) were characterized by X-ray diffractometry, Scanning Electron Microscopy, Transmission Electron Microscopy and Fourier Transform Infra Red spectroscopy. The antioxidant, hydrogen peroxide scavenging, hydroxyl radicals scavenging, superoxide scavenging and reducing power activity of CrAgNPs were determined by DPPH, hydrogen peroxide scavenging, hydroxyl radicals scavenging, superoxide scavenging and reducing power assay methods. The antibacterial activity of CrAgNPs was analyzed by Agar dilution, Minimum Inhibitory Concentration methods. Results: The CrAgNPs were synthesized by C. roseus extract and silvernitrate. The synthesis of silver nanoparticles was confirmed by color changes and UVvisible spectrophotometer analysis. The CrAgNPs were crystalline, variable size, elemental and spherical shape. The C. roseus extract and CrAgNPs have antioxidant, hydrogen peroxide scavenging, hydroxyl radicals scavenging, superoxide scavenging and reducing power activity. The zone of inhibition and MIC value of CrAgNPs confirmed the antibacterial activity. The CrAgNPs have greater antibacterial activity than C. roseus extract against the S. Typhi and P. vulgaris. The MIC results of CrAgNPs confirmed that CrAgNPs was highly effective against the S. Typhi and P. vulgaris bacteria. Conclusions: Phenols and flavonoids of C. roseus extract reduced the silvernitrate into silver nanoparticles. The CrAgNPs were crystalline, spherical shape, variable particles size and elemental. The C. roseus extract and CrAgNPs have antioxidant, hydrogen peroxide scavenging, hydroxyl radicals scavenging, superoxide scavenging, reducing power activity and antibacterial activity.