Biosynthesis of hydrophilic zinc oxide nanoparticles using Plumeria obtusa and Tabernaemontana divaricata flower extract for antidiabetic treatment

A large number of people are suffering globally from diabetes due to metabolic disorders characterized by abnormally high blood sugar (glucose), which inflicts severe health issues as well as huge economic burdens. In this study, we have reported an efficient and eco-friendly biosynthesis of hydrophilic zinc oxide nanoparticles (ZnO NPs, labeled as PC1 and C1) for antidiabetic treatment using an aqueous extract of Plumeria obtusa and Tabernaemontana divaricata flowers, respectively. Phase purity, structure, morphology, and dispersibility of the as-synthesized PC1/C1 have been characterized by various analytical techniques such as UV–visible spectroscopy (UV–vis), Powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and dynamic light scattering (DLS). The UV–vis spectrum of the PC1/C1 showed maximum absorbance at ~ 370 nm and the PXRD pattern confirmed their hexagonal wurtzite crystalline structure. Besides, SEM displayed sheet and honeycomb-like shape of the PC1 and C1 while FTIR and TGA revealed the attached surface coatings of the PC1/C1. DLS results showed narrow size distribution of the PC1 and C1 in the range of 150–156 and 315–400 nm, respectively. Moreover, the zeta potential values of the as-prepared PC1 and C1 are determined as -47 and -57 mV indicating their good colloidal stability in an aqueous suspension. In vitro study has been performed to show the α-amylase inhibition activity. Furthermore, the PC1/C1 are investigated for their antidiabetic efficacy in streptozotocin (STZ)-induced diabetes in the C57BL/6 male mice. Both the PC1/C1 displayed a significant antidiabetic potential; however, the blood glucose level has been significantly reduced ( p < 0.05) in the STZ-induced diabetic mice treated with PC1 as compared to the C1. Overall, PC1 and C1 are found to be very promising antidiabetic candidates for the in vivo antidiabetic treatment. Graphical abstract