Ultrasound-Assisted Natural Deep Eutectic Solvent Extraction of Millet Polyphenols: Alleviating Effects on Oxidative Stress in Caenorhabditis elegans and Omics Analysis

Millet polyphenols are rich in nutrients and possess antioxidant, antibacterial, and hypoglycemic activities, but their in vivo mechanism remains unclear. In this study, a ternary natural deep eutectic solvent (NADES) was used as a green alternative to traditional solvents, and ultrasound-assisted extraction was applied to optimize purified millet polyphenol extract. Caenorhabditis elegans was used as an in vivo model to evaluate antioxidant activity. Growth and development, exercise capacity, lifespan, and antioxidant enzyme activities were measured, combined with transcriptome RNA-seq, RT-qPCR, and untargeted metabolomics to explore potential regulatory mechanisms. Results showed that purified millet polyphenol extract improved growth, development, and exercise capacity, and prolonged lifespan in stressed nematodes. They increased superoxide dismutase (SOD) and catalase (CAT) activities and decreased malondialdehyde (MDA) levels. The transcriptomic and metabolomic results suggest that the antioxidant effects of the purified foxtail millet polyphenol extract may be associated with changes in the Wnt, PI3K-Akt, and P53/P21 signaling pathways. At the same time, the remodeling of metabolite levels (such as glycerophospholipid metabolism and purine metabolism) also suggests that it may exert protective effects through a multi-pathway network. However, whether these pathways are activated and causally involved in the protective effects still requires functional experimental validation.