Selenium-Rich Ricegrass Juice Improves Antioxidant Properties and Nitric Oxide Inhibition in Macrophage Cells

Ricegrass juice (Oryza sativa L.) was introduced as a functional food as the consumption of sprouts or seedlings has been claimed to provide high nutritive value. Selenium (Se) is a trace mineral that plays a key role in the human antioxidation scheme. Supplementation of Se into plants is one strategy to enhance plant bioactivities, and the consumption of Se plant foods may confer superior health benefits. In this study, ricegrass juice extract was analyzed for its major phenolic components. The effect of ricegrass juice extracts bio-fortified with 0, 10 and 40 mg Se/L named as RG0, RG10, and RG40, respectively, were investigated for a percentage of cell viability, changes of endogenous antioxidant enzymes, lipid peroxidation, and nitric oxide inhibition in RAW264.7 macrophage cells. Flavone glycosides, namely chrysoeriol arabinosyl arabinoside derivatives, were found to be the foremost bioactive components in ricegrass juice extract indicated by UHPLC-MS. The results of cell culture assessment revealed that RG40 showed an ability to promote macrophage cell proliferation at low concentration. Ricegrass juice extract in all treatments possessed the ability to reduce malondialdehyde content, which may be regarded as the bioactivity of phenolic compounds. Moreover, Se also played a role in this effect since RG40 showed the greatest ability via increasing the level of GPx enzyme. It was also discovered that phenolic compounds in the extracts played a role in inhibiting nitric oxide in LPS-induced RAW264.7 cells. Furthermore, RG40 expressed significantly higher NO inhibition properties at IC₅₀ 118.76 µg/mL compared to RG0 and RG10, at 147.02 and 147.73 µg/mL, respectively. Se bio-fortified ricegrass juice could be considered as a new potent functional food that can lower the risk of oxidative stress and chronic inflammation diseases.