Physical processing treatments modified chemical composition and enhanced protective effects of Bangia fusco-purpurea polysaccharides against AGEs-induced intestinal injury.

In this study, Bangia fusco-purpurea was pretreated using physical processing techniques, including high-pressure homogenization, steam explosion, and twin-screw extrusion. Then, polysaccharides of B. fusco-purpurea (BFPs) were extracted and their chemical composition were analyzed. We found that physical processing treatments significantly altered the chemical composition of BFPs and reduced their molecular weight (Mw). Using an AGEs-induced Caco-2 cell injury model, the protective effects of different BFPs against this damage were compared. The results demonstrated that physical processing treatments significantly improved the protective effects of BFPs against AGEs-induced damage. Particularly, polysaccharide extracted from steam exploded B. fusco-purpurea (SBFP), which exhibited a higher sulfate content (11.43%) and lower Mw (463 kDa), exhibited superior efficacy in inhibiting AGEs-induced damage. Specifically, SBFP enhanced the inhibition of ROS and NO production by 8.65% and 24.79%, respectively, compared with BFP. Additionally, SBFP suppressed the upregulation of inflammatory factors induced by AGEs. Further proteomics and Western blot analysis indicated that the protective effects of SBFP were mediated through inhibition of the MAPK inflammatory pathway and activation of the PI3K/AKT anti-apoptotic pathway. In conclusion, steam explosion was identified as the optimal processing method for B. fusco-purpurea by significantly enhancing the protective effects of its polysaccharides against AGEs-induced damage. This study provides new insights into the high-value processing of seaweeds and elucidates the mechanistic basis of polysaccharide-mediated protection against AGEs-induced injury.