Leucaena Leucocephala Mediated Green Synthesis of Silver Nanoparticles and Their Antibacterial, Dye Degradation and Antioxidant Properties

The current study demonstrates a green, quick and easy method for producing and characterization of silver nanoparticles from dehydrated leaf extract of Leucaena leucocephala (Lam-AgNPs) to evaluate its antibacterial activity against harmful bacteria, photocatalytic degradation of dyes used in textile dyeing industries and antioxidant activity to reduce oxidative stress. The UV-Visible spectra maximum absorption peak (λmax) of the Lam-AgNPs was noticed at 436 nm. FTIR vibrational spectra revealed the phytoconstituents that cause the reduction and stabilization of AgNPs from the plant extract. The average crystallite size was calculated to be 26 nm using the Debye-Scherrer equation with X-ray diffraction studies. The EDS spectra screening exposed a high concentration of silver with a weight % of 71.67 % and atomic % of 30.49 %. TEM studies showed the nano-sized particles that were spherical to quasi-spherical in shape and polydistributed in nature. Most particles are spread in the 15-20 nm and 30-35 nm size ranges. Lam-AgNPs had effective antibacterial action against four tested strains such as Staphylococcus aureus, Bacillus subtilis, Pseudomonas putida and Klebsiella pneumoniae by the zone of inhibition observed at 20 mm, 19 mm, 15 mm and 16 mm, respectively. The DPPH free radical scavenging assay was used to study the antioxidant activity of Lam-AgNPs and the IC50 value calculated was 240.70µg/ml. In addition, the photocatalytic activity of biogenic Lam-AgNPs for the degradation of Red m5b dye was investigated under solar light irradiation and 100% degradation was noticed after 90 minutes of reaction.