Aerva lanata flower extract mediated green synthesis of silver nanoparticles: Their characterization, in vitro antioxidants and antimicrobial investigations

The production of nanoparticles (NPs) using biological methods may lead to the enhancement of clean, non-hazardous, and environmentally acceptable procedures. With this context, in the present study silver nanoparticles (AgNPs) were synthesized using the flower extract of Aerva lanata (A. lanata). The following techniques, including UV-visible spectroscopy, XRD, Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR), are used to study the crystalline nature, size, shape, and elemental composition of the biosynthesized AgNPs, and antimicrobial applications of the NPs also studied. In UV-visible spectroscopy results a strong absorbance peak at 425 nm confirmed the AgNPs. The SEM results confirmed the spherical shape of the NPs and their average size of 45.05 nm. X-ray diffractometry XRD spectra confirmed the crystalline nature of the AgNPs. Against the DPPH (2,2-diphenyl-1-picrylhydrazyl), nitric oxide and superoxide radicals, Alf-AgNPs and ascorbic acid had significant scavenging effects at higher concentration of 250 mu g/mL, exhibited 65.76 +/- 0.41% and 86.42 +/- 0.69%, 78.39 +/- 0.49% and 72.72 +/- 0.14% and 70.79 +/- 0.87% and 72.79 +/- 0.33% inhibition, respectively. As produced AgNPs had strong antibacterial and moderate antifungal activities against pathogenic test bacterial strains viz. Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), Escherichia coli (E. coli), and Klebsiella pneumonia (K. pneumonia) with the maximum zone of inhibition 15 +/- 1.07 mm, 12 +/- 0.96 mm, 14 +/- 1.05 mm, and 15 +/- 2.54 mm, respectively at maximum (75 mu g/mL) concentration of AgNPs, and the zone of inhibition of fungal strains Aspergillus fumigatus (A. fumigatus) (9 +/- 0.67 mm) and Candida albicans (C. albicans) (7 +/- 0.75 mm) at 75 mu g/mL. It was eventually concluded that the biosynthesized Alf-AgNPs showed promising antioxidant and antimicrobial agents with very low concentrations.