Structural characterizations and anti-aging activities of a homogeneous polysaccharide derived from Coix seed-lactic acid bacteria fermentation

Coix seed, a well-known traditional Chinese medicine, has been extensively used for its anti-aging properties. However, the biological mechanism of its polysaccharides remains unclear. This study systematically investigated the anti-aging effects and mechanism of purified Coix seed polysaccharide (CP1) for the first time. The structural analysis revealed that CP1 mainly consists of glucose linked by α-(1 → 4) and α-(1 → 6) glycosidic bonds and has an average molecular weight of 8.855 kDa. Further, CP1 exhibited strong scavenging activity of approximately 55.85 % against 1,1-diphenyl-2-trinitrobenzohydrazine, 71.30 % against 2,2′-bis-(3-ethylbenzothiazolin-6-sulfonic acid) diammonium salt, and 68.40 % against hydroxyl radicals. In Caenorhabditis elegans , CP1 significantly extended the lifespan by 3–5 days ( p  < 0.001) and increased the survival by 78 % under oxidative stress condition ( p  < 0.001). In addition, CP1 suppressed the activity of senescence-associated β-galactosidase in zebrafish ( p  < 0.001) and reduced DNA damage in human skin fibroblasts ( p  < 0.001). Mechanistically, CP1 mainly activates the p -AMPK/RICTOR/CREB3 pathway by interacting with PARP-1. Taken together, this study performs the structural characterization of a glucan polysaccharide from Coix seed and its anti-aging effects in different models. These findings can provide a theoretical basis and candidate molecule for anti-aging therapies.