Development of solid lipid nanoparticles containing Spinacia oleracea extract and evaluation of their antioxidant potential

The development of nanoparticulate systems represents a promising strategy for incorporating plant extracts rich in bioactive compounds, aiming to explore their functional properties and expand their potential applications (WASEEM et al., 2021). In this context, the present study aimed to develop solid lipid nanoparticles (SLNs) containing Spinacia oleracea extract and evaluate their antioxidant potential, as well as determine the total polyphenol content of the plant extract. Antioxidant activity was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay at different sample concentrations, while total polyphenol content was determined using 5, 10, and 20 mg of the extract. The S. oleracea extract exhibited concentration-dependent antioxidant activity, with DPPH reduction percentages of 76.81%, 91.67%, and 94.86% at concentrations of 5, 10, and 20 mg, respectively. Gallic acid, used as a reference standard, exhibited antioxidant activity of 85.44%. The solid lipid nanoparticles containing the plant extract showed DPPH reduction percentages of 55.75%, 59.62%, and 60.25% at the evaluated concentrations of 5, 10, and 20 mg, respectively. Regarding total polyphenol content, values of 67.30 µg, 114.30 µg, and 175.30 µg were obtained for extract concentrations of 5, 10, and 20 mg, respectively, demonstrating a progressive increase in phenolic compound content as a function of concentration. The results showed that the S. oleracea extract exhibits high antioxidant activity and a substantial total polyphenol content. The solid lipid nanoparticles containing the extract also demonstrated DPPH radical scavenging capacity, although with lower percentages than those observed for the free extract. These findings indicate the potential of S. oleracea extract as a source of bioactive compounds with antioxidant properties and highlight the feasibility of investigating its incorporation into lipid-based nanoparticulate systems (HAO et al., 2026). In conclusion, this study contributes to research on strategies for encapsulating plant extracts and developing lipid-based systems with potential applications in the pharmaceutical, cosmetic, and biotechnological fields.

Funding: São Paulo Research Foundation (FAPESP), grant numbers 2024/18002-4 and 2025/11148-6.