A novel polysaccharide from Rubus chingii Hu unripe fruits: Extraction optimization, structural characterization and amelioration of colonic inflammation and oxidative stress

Raspberry is used as a medicine food homology species and its polysaccharides are worthy being investigated and developed. In the present study, a novel polysaccharide of unripe raspberry fruits (pRCP) was extracted and characterized. The results show that pRCP was an acidic heteropolysaccharide and its Mw value was 74.86 kDa with a high homogeneity. The main chain of pRCP consisted of -> 3,6)-beta-Galp(1 -> and -> 5)-alpha-Araf(1 ->, and its side chain was composed of alpha-Araf(1 -> linked to the C3 position of -> 3,6)-beta-Galp(1 ->. In addition, pRCP supplementation increased the gut microbial diversity and reduced harmful bacteria including Erysipelatoclostridium and Negativibacillus in high-fat diet (HFD)-fed mice. Treatment with pRCP also alleviated HFD-induced colonic inflammation and oxidative stress in mice. These beneficial effects can be transferred to recipient mice by faecal microbiota transplantation from pRCP-treated mice. Therefore, our study suggests that pRCP could be used as a potential prebiotics to improve intestinal health by modulating the gut microbiota.