Formulation and Evaluation of Hydrogel Incorporated With Zinc Oxide Nanoparticles Mediated By Cassia Fistula L.Flower Extract For Anti-Aging Property

Abstract

Green synthesis of metal oxide nanoparticles using plant-derived materials has attracted increasing interest as an alternative approach to conventional nanoparticle preparation. The present study investigated the plant-mediated synthesis and physicochemical characterization of zinc oxide nanoparticles (ZnO NPs) using Cassia fistula L. flower extract. The synthesized nanoparticles were characterized using UV–Visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray (EDX) analysis. The synthesized material showed a reported UV–Visible absorption maximum at 370 nm. FTIR analysis exhibited characteristic absorption bands at approximately 3360, 1633, 1384, and 474 cm⁻¹, with the band at 474 cm⁻¹ attributed to Zn–O stretching. XRD analysis showed principal reflections at 2θ values of 31.7°, 34.4°, and 36.2°, corresponding to the (100), (002), and (101) planes of hexagonal wurtzite ZnO, respectively. The average crystallite size was reported as approximately 28 nm based on the Debye–Scherrer equation. SEM examination revealed predominantly spherical and hexagonal morphological features with relatively uniform distribution and some aggregation, while the thesis-reported TEM analysis indicated nanoparticle dimensions below 30 nm. EDX analysis demonstrated the presence of zinc and oxygen together with carbon and nitrogen, with Zn and O accounting for 29.16 wt% and 46.08 wt%, respectively. Overall, the characterization findings document the formation of a ZnO-containing nanoscale material obtained using C. fistula flower extract and provide physicochemical information relevant to its further investigation in topical formulation development.