Selenium Nanoparticles Derived from Moringa oleifera Lam. Polysaccharides: Construction, Stability, and In Vitro Antioxidant Activity

Selenium nanoparticles (SeNPs) have drawn considerable attention to biomedicine, the food industry, and cosmetics due to their strong antioxidant potential and low toxicity. However, their poor stability limits broader applications. A promising strategy to overcome this limitation involves combining SeNPs with polysaccharides. In this study, selenium nanoparticles (MOLP-SeNPs) were synthesized using Moringa oleifera Lam. polysaccharide (MOLP) as a stabilizer and dispersant within a redox system comprising sodium selenite and ascorbic acid. The structural characteristics of the synthesized MOLP-SeNPs were analyzed using spectroscopy. Additionally, their thermal and storage stability was evaluated, and their antioxidant activity was explored through simulated digestion in vitro and a HepG2 cell oxidative stress model. The results demonstrated that well-dispersed, zero-valent MOLP-SeNPs showing a mean particle size of 166.58 nm were synthesized successfully through an MOLP-to-sodium selenite ratio of 2.8:3 at pH 7.3 and 35 °C. The MOLP-SeNPs exhibited excellent stability during preparation. In simulated in vitro digestion and H 2 O 2 -induced oxidative stress experiments on HepG2 cells, MOLP-SeNPs displayed strong free radical scavenging capacity while improving antioxidant activity. Cellular experiments deeply revealed that pretreatment with MOLP-SeNPs significantly improved cell viability and provided a pronounced protective effect against oxidative damage. In conclusion, MOLP-SeNPs represent a novel antioxidant with promising applications in food and biomedicine.