Green-Synthesized Alternanthera sessilis-Mediated ZnO Nanospheres: Antioxidant Activity, DNA Interaction, and Molecular Docking Studies

A cost-effective and green synthetic route was adopted to synthesize zinc oxide nanoparticles (ZnO-NPs) using Alternanthera sessilis leaf extracts as a bioreductant and stabilizing agent. The synthesis of the nanoparticles was systematically confirmed using UV, FT-IR, XRD, FE-SEM, EDX, and TEM analyses followed by antioxidant potential and DNA interactions studies using both spectroscopic and molecular docking findings. The aqueous suspension of these nanoparticles exhibited maximum absorption at 361 nm. The FT-IR spectra revealed the different functional groups of the leaf extract responsible for the stabilization of the ZnO nanoparticles and the peak observed at 539 cm⁻¹ is designated to ZnO. The powder x-ray diffraction (XRD) pattern indicated the hexagonal crystal structure of ZnO-NPs with average crystallite size 22.85 nm. The uniform semispherical morphology is confirmed using FE-SEM and TEM analyses. The elemental composition of Zn-NPs was confirmed by EDX analysis. The 22.5 nm average particle size of Zn-NPs was measured by image J software. The −46.9 mV zeta potential value confirmed the stability of the synthesized Zn-NPs with an average particle size 22.4 nm. The antioxidant potential was studied using a DPPH assay, employing BHT as a standard. At 60 µg mL⁻¹, ZnO-NPs showed 65.2% DPPH scavenging activity as compared to standard BHT and a paired t-test was performed to compare the results. DNA interaction studies showed bathochromic shift of ZnO-NPs-DNA complex indicating intercalation binding with DNA strands. Significant DNA interaction ability and antioxidant potency were demonstrated by both experimental and docking studies, which have applications in various medical domains.