Chito-oligosaccharides (COS) with anti-aging effect from Flammulina velutipes

• Chitin, chitosan and chito-oligosaccharides from Flammulina velutipes were extracted . • Structure of chito-oligosaccharides from F. velutipes were characterized. • Antioxidant activity in vitro and anti-aging effects in vivo of COS were investigated. Chito-oligosaccharides (COS) with a degree of deacetylation (DD) of 67.85 % and a degree of polymerization (DP) ranging from 2 to 6 was prepared from Flammulina velutipes ( F. velutipes ). The COS was confirmed as α-form by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Nuclear magnetic resonance analysis (NMR). Furthermore, the in vitro antioxidant activity of COS was evaluated, along with its anti-aging effects in D-Galactose (D-gal)-induced aging BALB/c mice. COS treatment demonstrated a dose-dependent enhancement in the scavenging activities of DPPH, ABTS, and hydroxyl radicals. Additionally, COS treatment alleviated tissue injury in the liver and kidney of mice induced by D-gal. The antioxidative indices, including superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), glutathione (GSH), and glutathione peroxidase (GSH-Px), were improved in the liver of mice treated with COS. Moreover, the relative expressions of inflammatory factors Interleukin-1β (IL-1β) and Interleukin-6 (IL-6) were reduced in the COS treatment groups. These findings indicate that F. velutipes COS exhibits resistance to D-gal-induced aging, with mechanisms linked to its antioxidant and immunoregulatory activities. This suggests that F. velutipes COS may serve as a potential source of antioxidant and anti-aging agent.