Bio-inspired multifunctional zinc oxide nanoparticles by leaf extract of Andrographis serpilifolia and their enhanced antioxidant, antimicrobial, and antidiabetic activity-a 3-in-1 system

In this research article, we present a simple and rapid method for synthesis of zinc oxide nanoparticles (ZnONPs) using zinc acetate dehydrate, sodium hydroxide and leaf extract of an important anti-diabetic plant Andrographis serpelifolia (As). The results reveal that UV-visible absorption spectrum indicates peaks at 325 nm which confirms the biosynthesis of ZnONPs. Fourier transform infrared spectroscopy (FT-IR) results indicate the characteristic peak at 511.93 cm(-1) for ZnO nanoparticles. EDX analysis revealed the purity of As-ZnONPs and the particle size was between 70 nm and 80 +/- 10 nm by both dynamic light scattering analysis (DLS) and Transmission electron microscopy (TEM) analysis. The As-ZnONPs were moderately stable with negative zeta potential value -11.1 mV. Atomic force microscopy (AFM) analysis also revealed the same results as TEM and DLS. The x-ray diffraction (XRD) data revealed that the particles are facets of face-centered cubic crystal structure of ZnO. The As-ZnONPs have exhibited potential antioxidant activity and effective antibacterial activity against gram-positive bacteria. The As-ZnONPs have also potential anti-diabetic activity in vivo (rat model). The antidiabetic activity of As-ZnONPs comparable to that of the standard drug glibenclamide was evidenced by various biochemical parameters like HbA1C, serum lipid profiles, liver and renal functional markers.