Anti-diabetic effects of the soluble dietary fiber from tartary buckwheat bran in diabetic mice and their potential mechanisms

Abstract

Background: Tartary buckwheat has beneficial effects on glucose and lipid metabolism of patients with type 2 diabetes mellitus. However, the physiological effects of a soluble dietary fiber (SDF) from tartary buckwheat have rarely been studied, especially in vivo. Objective: This study aimed to examine the hypoglycemic and hypolipidemic effects of SDF from tartary buckwheat bran on high-fat diet/streptozotocin-induced diabetic mice. Design: The SDF of tartary buckwheat bran was collected according to the Association of Official Analytical Chemists method 991.43. Diabetic mice were treated with high-fat diets supplemented with 0.5, 1, and 2% SDF for 8 weeks. Parameters related to glucose and lipid metabolism and relevant mechanisms, including the excretion of short-chain fatty acids and the glycemic signaling pathway in the liver, were investigated. In addition, the structural characterization of a purified polysaccharide from SDF of tartary buckwheat bran was illustrated. Result: Supplementation with SDF in the diet resulted in reduced levels of fasting blood glucose, improved oral glucose tolerance, increased levels of liver glycogen and insulin, as well as improved lipid profiles in both the serum and liver, in diabetic mice. The amelioration of glucose and lipid metabolism by SDF was accompanied by an increase in the short-chain fatty acid levels in the cecum and co-regulated by hepatic adenosine-5′-monophosphate-activated protein kinase (AMPK) phosphorylation. A neutral tartary buckwheat polysaccharide with an average molecular weight of 19.6 kDa was purified from the SDF, which consisted mainly of glucose with α-glycosidic bonds. Conclusions: The SDF of tartary buckwheat bran exhibits hypoglycemic and hypolipidemic effects in diabetic mice, contributing to the anti-diabetic mechanisms of tartary buckwheat.

Effect of Tartary Buckwheat Bran Substitution on the Quality, Bioactive Compounds Content, and In Vitro Starch Digestibility of Tartary Buckwheat Dried Noodles

“…With the increase of TBBF, the TDF contents ranged from 3.47 to 9.92 g per 100 g, the IDF contents ranged from 2.55 to 8.48 g per 100 g, and the SDF contents ranged from 0.7 to 1.37 g per 100 g. The increase of dietary fiber in TBDNs was related to the higher dietary fiber content of Tartary buckwheat bran compared to Tartary buckwheat flour [ 36 ]. In addition, the dietary fiber of Tartary buckwheat bran was dominated by insoluble dietary fiber [ 37 ]. Combined with the results for quality, although the addition of TBBF weakened the tenacity of the TBDNs, there was little change in the hardness and resilience, and the bioactive compound (phenolic, flavonoids and dietary fiber) content of the TBDNs was increased significantly ( p < 0.05).…”

Systematic Review of Human and Animal Evidence on the Role of Buckwheat Consumption on Gastrointestinal Health

“…Nine studies applied Tartary buckwheat and reported differences in the animal fecal microbiome in comparison to a high-fat diet [ 7 , 34 , 44 , 45 , 46 , 48 , 49 , 50 ] and basal diet [ 53 ]. In Supplemental Figure S2 , we summarized the findings on differences in GI microbiota from animal studies using Tartary buckwheat as an intervention.…”

“…Tartary buckwheat powder supplementation had no effect on the fecal SCFAs concentration. Wu et al [ 48 ] studied the antidiabetic effect of the soluble dietary fibers from Tartary buckwheat brans using mice with induced diabetes by feeding with a high-fat diet for five weeks. The diabetic groups were then given a varying (low, moderate, and high) dose of buckwheat fibers for eight weeks.…”

Tartary Buckwheat Bran: A Review of Its Chemical Composition, Processing Methods and Food Uses

“…Moreover, the polysaccharide fraction displayed α-glucosidase inhibitory activity. Wu et al [ 44 ] found that the SDF of Tartary buckwheat bran improved glucose and lipid metabolism in diabetic mice. Next to carbohydrates, proteins are the most abundant macronutrient of Tartary buckwheat bran.…”