Polysaccharide from Actinidia arguta leaves and its anti-aging mechanism using the Caenorhabditis elegans model

Abstract

This study examined the structural features and anti-aging mechanisms of a pectic polysaccharide (AAP) extracted from Actinidia arguta leaves. AAP was extracted via three-phase partitioning coupled with ammonium sulfate precipitation and subsequently purified on a DEAE-52 cellulose column. Structural characterization via FT-IR, GC‒MS, NMR, and SEC-MALLS-RI revealed that AAP is a rhamnogalacturonan I (RG-I)-type pectin, consisting of rhamnose, arabinose, galactose, and galacturonic acid with a molar ratio of 20.1:28.4:14.8:36.7, with a weight-average molecular weight (Mw) of 4.14 × 10⁵ g/mol and a random coil conformation in aqueous solution; the Congo red assay confirmed that it does not possess a stable triple-helical structure. In Caenorhabditis elegans models, AAP significantly prolonged lifespan and improved exercise capacity, accompanied by reduced accumulation of lipofuscin and reactive oxygen species. Transcriptome profiling revealed 334 differentially expressed genes (DEGs) in response to AAP treatment, with bioinformatics analysis indicating enrichment in metabolic pathways (e.g., lipid metabolism, amino acid metabolism, one-carbon metabolism), extracellular matrix homeostasis, and innate immunity. The key regulated genes included upregulated fat-7 (lipid desaturase), alh-2 (aldehyde dehydrogenase), and collagen-encoding genes (col-138, lon-3) and immune-related dod-17, as well as downregulated fmo-2 (involved in one-carbon metabolism). Protein‒protein interaction (PPI) network analysis revealed that collagen-encoding genes and other genes served as core regulatory nodes; qRT‒PCR validated the expression trends of key DEGs, such as fat-7, lon-3, and dod-17, which were consistent with the transcriptomic data. These findings demonstrate that AAP exerts antioxidant and anti-aging effects in C. elegans by coordinating multiple pathways, emphasizing its potential as a natural anti-aging ingredient for functional foods or pharmaceuticals.