Jinmei Zhao, Huan Miao, Fang Wu, Juan Wei
Oxidative stress is known to disrupt intestinal barrier integrity, whereas certain polysaccharides have demonstrated protective effects on intestinal function. This study aimed to isolate a polysaccharide from processed Hippophae rhamnoides subsp. sinensis pomace (remaining after oil and juice extraction) and evaluate its protective effect against H2O2-induced intestinal barrier dysfunction in Caco-2 cell monolayers. A polysaccharide fraction, designated SPP-0.2b, with a weight-average molecular weight (Mw) of 42.405 kDa, was successfully isolated by hot water extraction and purified using DEAE-52 cellulose and Sephadex G-100 gel chromatography. Monosaccharide composition analysis revealed that SPP-0.2b was mainly composed of rhamnose, arabinose, galactose, mannose, and galacturonic acid. Compared with the H2O2-treated group, SPP-0.2b (500 μg/mL) increased the transepithelial electrical resistance (TEER) by 76.67% and reduced basolateral FITC-dextran fluorescence intensity by 34.63% in Caco-2 monolayers. In addition, SPP-0.2b significantly increased the protein expression levels of Occludin and Zonula Occludens-1 by 79.49% and 66.75%, respectively. SPP-0.2b also reduced intracellular reactive oxygen species and malondialdehyde levels while enhancing the activities of superoxide dismutase and glutathione peroxidase. Collectively, these findings suggest that the protective effect of SPP-0.2b against H2O2-induced intestinal barrier dysfunction is associated with the maintenance of tight junction proteins and attenuation of oxidative stress. This study provides experimental evidence supporting the further investigation of SPP-0.2b as a potential functional food ingredient for intestinal health.