Background: The emergence of eco-friendly methods for the synthesis of metallic nanostructures have continued to receive wider acceptance.
Objective: The present study investigated the effect of biologically synthesized zinc oxide nanoparticles on free radicals and carbohydrate-hydrolysing enzymes.
Methods: The characterized nanoparticles, DaZnONPs (Dicoma anomala zinc oxide nanoparticles) was obtained using ultraviolet-visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, energy dispersive spectroscopy and x-ray diffraction technique. The activity of the synthesized nanostructure against 1, 1-diphenyl-2-picrylhydrazyl (DPPH), 2, 2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), metal chelating, alpha-amylase and alpha-glucosidase were determined using standard methods.
Results: DaZnONPs was observed to be stable, mostly cubical in shape and within the nanometre size range. The optimum absorption of DaZnONPs was found at 386 nm, the FTIR indicated the presence of functional groups arising from alkaloids, flavonoids, tannins and saponins (previously detected in earlier reports) indicative of potential nucleation and stability of the ZnO nanoparticles. XRD result depicted similar patterns between DaZnONPs and standard ZnO spectra revealing the particles in nanometre range as shown from the obtained peaks. DaZnONPs inhibited DPPH (0.54 µgmL-1) radicals and alpha-amylase (104.34 µgmL-1) enzyme better than the standards, quercetin (349.98 µgmL-1) and acarbose (1594. 54 µgmL-1). Meanwhile, the metal chelating effect of DaZnONPs (30.41 µgmL-1) was observed to be insignificantly (p>0.05) at par with quercetin (27.81 µgmL-1). The kinetics of alpha-amylase and alpha-glucosidase enzymes by DaZnOnPs were observed to be non-competitive inhibitions.
Conclusion: DaZnONPs (as against the bulk extract) could be explored as possible antioxidative and antihyperglycaemic agents mitigating against the ravishing effect of free radicals and hyperglycaemia.