Extraction and Structural Characterization of Four Grape Polysaccharides and Their Protective Effects in Alcohol-Induced Gastric Mucosal Injury

Grapes, recognized as a nutritionally rich fruit, have been found through extensive research to contain various bioactive components. However, the roles of polysaccharides and their bioactive properties remain unclear. Based on this, in our research, four different grape polysaccharides were obtained using an enzymatic-assisted extraction method. We investigated and compared their physicochemical properties, antioxidant activities, and protective effects on gastric mucosa in mice. The results indicated that the monosaccharide compositions of these specific grape polysaccharides were similar; however, their molar ratios, molecular weights, and morphological characteristics varied. The results of radical scavenging tests revealed that red-fleshed grape polysaccharide (RFP) exhibited superior antioxidant properties. In vivo assessments demonstrated that RFP protects against gastric mucosal injury in mice by inhibiting inflammation and radical generation. Therefore, the polysaccharide from red-fleshed grape holds potential application value in the pharmaceutical and food industries.