Green synthesis of MnO2 nanoparticles using Justicia adhatoda leaf extract

Abstract

This paper discusses the biogenesis of manganese dioxide nanoparticles (MnO₂NPs) utilizing Justicia adhatoda leaf extract in a simple, environmentally friendly, and effective manner. Using the leaf extract of J. adhatoda as a reducing agent, potassium permanganate was reduced to synthesize the MnO₂ NPs. The contribution of the biomolecules in the J. adhatoda leaf extract to the synthesis of MnO₂ NPs was revealed by Fourier-transform infrared (FTIR) spectra. The UV–Visible spectra (UV-Visible Spectroscopy) of J. adhatoda-mediated MnO₂ NPs showed absorption peaks around 354 nm, which is the absorption maxima of MnO₂ NPs. X-ray diffraction analysis determined the crystal phase and crystalline size of the J. adhatoda-mediated MnO₂ NPs. The X-ray diffraction pattern (X-ray diffraction analysis) of MnO₂ NPs showed an average size, 49.13 nm. As regards the Field emission scanning electron microscopy (FESEM) study, the sizes of the J. adhatoda-mediated MnO₂ NPs were ranged between 30 and 70 nm and are cube-like. The energy-dispersive X-ray analysis (EDAX) verified the presence of Mn and O in the MnO₂ NPs. The antibacterial activity of J. adhatoda-mediatedMnO₂ NPs was examined against the following bacterial species (Gram-positive: Staphylococcus aureus and Bacillus cereus;Gram-negative: Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumonia). The minimum inhibitory concentration of the MnO₂ NPs was 0.062, 0.125, 0.5, 0.5 and 2.0 μg/ml, respectively, for S. aureus, B. cereus, P. aeruginosa, E. coli and K. pneumonia. The minimum bactericidal concentration of J. adhatoda-mediated MnO₂ NPs was 0.125, 0.500, 1.0, 1.0 and 4.0 μg/ml, respectively, for S. aureus, B. cereus, P. aeruginosa, E. coli and K.pneumonia. These results highlight the significant antibacterial action of the J. adhatoda-mediated MnO₂ NPs on the studied bacterial species, underscoring the potential of our research in combating bacterial infections.