Facile Green Synthesis and Characterization of Titanium Dioxide Nanoparticles Using Kigelia africana (Lam) Benth., Aqueous Leaf Extract and its Antioxidant and Antibacterial Activity

Abstract

Titanium nanoparticles are toxic to bacteria and have a widespread applications in different fields of research. Hence the present study aimed to synthesize the titanium dioxide nanoparticles by adopting green synthesis methodology using Kigelia africana leave extract as a biological reducing agent. The UV absorption spectra show characteristic absorption maxima corresponding to TiO₂ nanoparticles at a wavelength of 512 nm confirms the formation of nanosized tin particles. The FT-IR spectrum of TiO₂ nanoparticles show absorption bands at 3609 cm^-1 and 3227 cm^-1 corresponding to O-H stretching in alcoholic and carboxylic compounds, respectively. Absorption peaks at 1607, 2834, 1654 and 1324 cm^-1 correspond to aromatic C=C vibrations, C-H stretching in aldehydes, C-H bending vibrations and aromatic C-N stretching vibrations, respectively. This confirms the involvement of bioactive compounds from the plant extract. The SEM and EDX studies confirmed that the nanoparticles are spherical to oval shape with an average particle size of 46 nm. The metal content in the nanoparticles was found to be 58.71%. The synthesized nanoparticles have potential growth inhibition activity against Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli). The DPPH radical scavenging activity of the nanoparticles synthesized was compared with that of aqueous leaf extract and standard ascorbic acid and proved that the nanoparticles have enhanced activity than aqueous leaf extract. The IC₅₀ of the leaf extract, nanoparticles and the standard was found to be 31.55, 75.82 and 84.95 μg/mL, respectively. Kigelia africana leaf is shown in this work to be a valuable bioagent in the biosynthesis of TiO₂ nanoparticles with increased biological activity.