Lycium barbarum polysaccharides promote longevity and healthspan in Caenorhabditis elegans via insulin/IGF-1 signalling and lipid metabolic remodelling.

Lycium barbarum (goji berry) has long been consumed as a food, and its water-soluble polysaccharides (LBPs) are proposed as key bioactive constituents. Here, we evaluated three L. barbarum fractions in Caenorhabditis elegans and subsequently focused on purified LBPs, which showed the most consistent pro-longevity phenotype in preliminary screening. LBPs (700 μg/mL) increased mean lifespan by 20.67% (p < 0.01) and improved multiple healthspan-related outcomes, including locomotion, resistance to heat and oxidative stress, and reduced age-associated accumulation of lipofuscin and neutral lipids. Using mutant and transgenic strains, we found that these benefits depend on the transcription factors DAF-16/FOXO, SKN-1/Nrf2 and HSF-1, and are attenuated in an insulin/IGF-1 signalling (IIS) pathway mutant (age-1/PI3K). Consistent with altered lipid homeostasis, LBPs changed the expression of lipid metabolic genes, including Δ9 desaturases (fat-6/fat-7) and fat-5. Collectively, these findings indicate that LBPs can promote longevity and functional maintenance in C. elegans, with effects linked to IIS, stress-response regulation and lipid metabolic remodeling.