Synergistic anti-aging effect of Dendrobium officinale polysaccharide and spermidine: A metabolomics analysis focusing on the regulation of lipid, nucleotide and energy metabolism.

The importance of synergy has been underscored in recent medical research for augmenting the efficacy of therapeutic interventions, targeting multiple biological pathways simultaneously. Our prior research elucidated that Dendrobium officinale polysaccharide (DOP) has the potential to prolong the lifespan of Caenorhabditis elegans (C. elegans) via regulating gut microbiota. Concurrently, spermidine (Spd), as a mimicking caloric restriction, facilitates autophagy and exerts a pronounced anti-aging effect. To enhance the anti-aging capabilities of DOP, we conducted a comprehensive study examining the combined effects of DOP and Spd in C. elegans, incorporating metabolomics analysis to investigate the underlying mechanisms. A combination of 250 mg/L DOP and 29.0 mg/L Spd yielded the most favorable outcomes in lifespan extension, evidencing a synergistic effect with a combination index (CI) of 0.65. In oxidative and heat stress tolerance assays, the observed CIs were 0.50 and 0.33, respectively. Metabolomic analysis highlighted significant alterations in metabolites related to lipid, nucleotide and energy metabolism, notably regulating glycerol 3-phosphate, linoleoyl glycerol, docosapentaenoic acid and β-nicotinamide mononucleotide, nicotinamide adenine dinucleotide. The effects of DS on lipid metabolism were further validated using Oil Red O staining and triglyceride level in C. elegans. The results indicated that DS may primarily be via modulating lipid metabolism. To further confirm these findings, a high-fat diet-induced mouse model was employed. Consequently, it can be inferred that the synergistic anti-aging impact of DOP and Spd is likely mediated primarily through alterations in lipid metabolic processes.