Purple sweet potato polysaccharide alleviates intestinal inflammation by blocking NF‑κB and MAPK JNK/ERK pathway and regulating mitochondrial dynamics

In contemporary society, unhealthy dietary patterns increase the risk of intestinal inflammation. Regrettably, intestinal inflammation is also associated with an elevated risk of other inflammatory disorders and metabolic syndrome. Therefore, it is essential to alleviate intestinal inflammation. Natural plant polysaccharides are widely used to alleviate intestinal inflammation owing to their desirable anti-inflammatory properties. In this study, a water-soluble polysaccharide (WSP) is isolated and purified from purple sweet potato (variety of Xuzi 3). The in vivo anti-inflammatory effects of WSP are determined using dextran sulfate sodium (DSS)- and lipopolysaccharide (LPS)-treated mice. From a phenotypic perspective, WSP effectively alleviates DSS and LPS-induced colonic lesions and reduces disease activity index. WSP markedly reduces the levels of ROS, MDA, and pro‑inflammatory cytokines, and increases the activities of antioxidant enzymes in the serum and colonic tissues, thus mitigating oxidative stress and inflammatory response. WSP significantly upregulates the expression of tight junction protein ZO-1 in the colon and further strengthens intestinal physical barrier. At the molecular level, WSP blocks TLR-4/NF-κB and MAPK ERK/JNK signaling cascades. Protein analysis also confirms that WSP does not alleviate endoplasmic reticulum stress in the colon, and WSP promotes mitochondrial fusion and inhibits abnormal mitochondrial fission. In conclusion, WSP improves mitochondrial dynamics and decreases ROS production, which in turn suppresses TLR‑4/NF‑κB and MAPK ERK/JNK pathways and reduces the secretion of pro‑inflammatory cytokines.