Cellulase-assisted extracted Dendrobium officinale polysaccharides enhancing lifespan and stress resistance in C. elegans through Skn-1 and Daf-16 pathways.

Dendrobium officinale is a traditional Chinese medicinal herb containing multiple active components. Among these, Dendrobium officinale polysaccharides are considered the primary substances underlying its pharmacological effects and have attracted attention for their antioxidant and anti-aging properties. This study employed cellulase-assisted extraction and separation to purify CDOP and investigated its structural characteristics and anti-aging mechanisms. The molecular weight of CDOP was determined to be 14,798 Da. The repeating structural unit of CDOP consists of nine mannose and three glucose residues and contains four acyl groups linked to mannose. Among these, two are monoacyl substitutions at positions 2 and 3, and one is a diacyl substitution at both positions 2 and 3. In Caenorhabditis elegans, CDOP extended mean lifespan by 24.33%, enhanced motility, and reduced lipofuscin and ROS levels. By activating stress-related genes and the antioxidant system, CDOP increased mean lifespan under oxidative stress and heat stress by 22.44% and 29.01%, respectively. CDOP also enhanced SOD activity, increased GSH-Px content, reduced MDA levels, and upregulated the antioxidant genes Sod-3, Daf-16, and Skn-1 in nematodes. These findings indicate that CDOP primarily enhances the antioxidant capacity and stress resistance of Caenorhabditis elegans by increasing expression of Sod-3, Daf-16, and Skn-1. This mechanism elevates the activity and levels of antioxidant enzymes in the nematode, thereby reducing oxidative damage and exerting an anti-aging effect.