Ameliorating effects of Tartary buckwheat sprout polysaccharides with different esterification degree and molecular weight on DSS-induced colitis in mice
As the number of patients with ulcerative colitis (UC) continues to increase, there is an acute need for new, safe and effective medications, as traditional medications have poor efficacy and serious side effects. Plant polysaccharides of natural origin are safe alternatives of therapeutic drugs, which have been a popular research topic for the treatment of UC in recent years. Tartary buckwheat sprout polysaccharides (TP) possess a variety of health benefits and have been proven to have Immunomodulatory properties in previous studies. In this work, TP with low esterification degree (TP-LDE) and molecular weight (TP-LMW) were successfully prepared by mild alkaline deesterification treatment and ultrasound-assisted non-metallic Fenton reaction. Subsequently, the ameliorative effects of different structural TPs on dextrose sodium sulfate (DSS)-induced UC in mice were investigated. The results showed that TP, TP-LDE, and TP-LMW all exhibited therapeutic effects on UC mice, alleviating body weight loss, colon atrophy, repairing colon tissue damage, up-regulating tight junction expression, and inhibiting pro-inflammatory cytokines in the DSS group of mice. And low esterification and molecular weight (TP-LDE, TP-LMW) showed better therapeutic effects on UC mice. In addition, the therapeutic effects of TP, TP-LDE, and TP-LMW in UC mice can be dependent on the modulation of the intestinal flora, which was promoted by inhibiting the growth of Escherichia-Shigella, Lachnospiraceae_NK4A136_group, Parasutterella, and some bacteria that produce short-chain fatty acids (SCFAs), such as Lactobacillus, Paraprevotella, Dubosiella, Bifidobacterium. Overall, TP is a promising therapeutic medicine for UC, and its esterification degree and molecular weight can affect its therapeutic effect on UC.