Formulation of a sunscreen based on zinc oxide nanoparticles and (Daucus carrot.L) seeds

Abstract

The growing demand for natural and effective ultraviolet (UV) protective formulations has increased interest in the green synthesis of plant-based nanoparticles for cosmetic applications. This study aimed to synthesize zinc oxide nanoparticles (ZnO-NPs) through a green approach using the aqueous extract of Daucus carota L. seeds as both a reducing and stabilizing agent, and to evaluate their biological properties and UV-protective potential. Phytochemical analysis revealed a high content of phenolic compounds, followed by tannins and flavonoids, with an extraction yield of 9.99%. The successful synthesis of ZnO-NPs was confirmed by UV–Visible spectroscopy, which showed a characteristic absorption peak at 365 nm, while X-ray diffraction (XRD) analysis revealed a pure hexagonal wurtzite crystalline structure. FTIR spectroscopy further confirmed the interaction between the nanoparticle surface and the phytochemical compounds acting as capping agents. Antibacterial activity, evaluated using the agar well diffusion method, demonstrated that the biosynthesized ZnO-NPs exhibited broad-spectrum, concentration-dependent activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, with greater efficacy than the crude extract. Antioxidant activity assessed by the DPPH free radical scavenging assay showed a concentration-dependent increase in inhibition for both the extract and ZnO-NPs, with the nanoparticles displaying superior activity. A sunscreen cream containing the synthesized ZnO-NPs was successfully formulated and exhibited satisfactory sun protection factor (SPF) values and a stable pH compatible with skin physiology, supporting their potential application in the development of natural and effective sunscreen formulations.