Synergistic action of zinc oxide nanoparticle using the unripe fruit extract of Aegle marmelos (L.) - Antibacterial, antibiofilm, radical scavenging and ecotoxicological effects

Abstract

In the present study, A. marmelos unripe fruit extract stabilized ZnO NPs (Am-ZnO NPs) was synthesized and characterized by biophysical techniques. A characteristic absorbance peak of ZnO NPs was recorded at 460 nm using UV-Vis spectroscopy. The crystalline size of biologically synthesized ZnO NPs was 19.8 nm. FTIR showed the presence of various functional molecules at 3657, 3486, 2316, 2183, 2032, 1978, 858, 564 and 442 cm−1 which contributed to the stabilization of NPs. SEM micrograph recorded the occurrence of hexagonal wurtzite shaped particles with a mean particle size of 22.5 nm. The weight percentage of elemental zinc was 77.91% as determined by EDX analysis. Am-ZnO NPs have shown greater antibacterial and antibiofilm effects against Gram-negative bacteria when compared to Gram-positive bacteria. The ability to scavenge H2O2 free radicals confirmed the antioxidant potential of Am-ZnO NPs. Inhibition of H2O2 was increased to 88% at 100 μg mL−1 of Am-ZnO NPs. The ecotoxicity assessment attributed that Am-ZnO NPs were toxic to C. cornuta and 100% mortality of test organism was noticed at 125 mg/L (LC50 of 54 mg/L). This study conclude that Am-ZnO NPs have greater medicinal value to be used as antibacterial, antibiofilm and antioxidant agent.