Antioxidant and anti-aging effects of purified Rehmannia glutinosa polysaccharide in Caenorhabditis elegans

Oxidative stress has been linked to the onset and progression of aging. Natural polysaccharides have attracted considerable attention in the field of antioxidants and anti-aging products owing to their exceptional biological activity and low toxicity. In this study, a homogeneous (glucogalactan-structured) polysaccharide (RGP70–1) was purified from the roots of Rehmannia glutinosa Libosch. The matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), monosaccharide composition, methylation, and nuclear magnetic resonance analyses were employed to characterize structure. RGP70–1 (3.6 kDa) was composed of glucose, galactose. RGP70–1's primary chain consisted of α-D-Galp connected by 1,4-linkages, α-D-Galp connected by 1,6-linkages, and β-D-Galp connected by 1,3,4,6-linkages.The side branches included α-D-Galp linked in a 1,4 position, α-D-Galp linked in a 1,6 position, and α-D-Glcp linked at the terminal end. In vivo, the effects of RGP70–1 on aging were examined using a Caenorhabditis elegans model. The findings demonstrated that RGP70–1 enhanced the performance of antioxidant enzymes, decreased reactive oxygen species levels, and prolonged the lifespan of Caenorhabditis elegans. The results of the quantitative real-time polymerase chain reaction indicated that RGP70–1 might demonstrate anti-aging properties by influencing insulin/insulin-like signaling pathway. In general, these findings highlight the possibility of RGP70–1 being utilized in dietary supplements for its anti-aging properties.