Antiglycemic Effect of Water Extractable Arabinoxylan from Wheat Aleurone and Bran

Abstract

The studies on the effects of arabinoxylan (AX) polysaccharides on postprandial glucose response have resulted in contrasting results owing to the diversity in AX structures. Four water extractable AX (WEAX) extracts obtained from wheat aleurone and bran were used to investigate (a) the effect of AX on activities of α-amylase and α-glucosidase, (b) influence of AX chemical composition on their inhibition potency, and (c) kinetics of enzyme inhibition. α-Amylase activity was not significantly affected by the presence WEAX fractions regardless of type or concentration. WEAX inhibited α-glucosidase activity only when maltose was used as a substrate but not sucrose. The IC50 values of WEAX (4.88 ± 0.3–10.14 ± 0.5 mg/mL) were highly correlated to ferulic acid content (R = −0.89), arabinose to xylose ratio (R = −0.67), and relative proportions of xylose being unsubstituted (R = 0.69), disubstituted (R = −0.63), and monosubstituted (R = −0.76). The Lineweaver–Burk plot suggested an uncompetitive enzyme inhibition mode. Thus, our results suggest that antiglycemic properties of WEAX may be derived from direct inhibition of α-glucosidase activity.

Beta-Glucan From Barley Attenuates Post-prandial Glycemic Response by Inhibiting the Activities of Glucose Transporters but Not Intestinal Brush Border Enzymes and Amylolysis of Starch

“…The lack of significant difference in the in vitro digestibility profiles of waffles suggest that BG does not affect amylase activity in the gastrointestinal tract as hypothesized previously. This finding is consistent with a previous study with a different soluble fiber, arabinoxylan, where amylolysis of starch was not affected by addition of arabinoxylan in vitro (23).…”

“…The results indicated that brush border α-glucosidase activity was not affected by BG regardless of BG's molecular weight or concentration. Similarly, arabinoxylan obtained from wheat could only inhibit α-glucosidase activity when feruloylated (23). This further suggests that viscosity of digesta generated by soluble fiber may not influence the digestibility of carbohydrates.…”

“…The effect of BG on intestinal brush border α-glucosidase activity was determined according to Malunga et al (23). Briefly, intestinal α-glucosidase was extracted from rat intestinal acetone powder with sodium phosphate buffer (pH 6.9, 0.1 M).…”

Cereal‐derived phenolic acids and intestinal alpha glucosidase activity inhibition: Structural activity relationship

“…For example, the total phenolic acid content in cereal grains (a major source of dietary carbohydrates) varies from 520 to 2,792 µg/g (Ndolo & Beta, ). However, <10% of the total phenolic acids in cereals are bioaccessible and not all bound phenolic acid can inhibit intestinal α‐glucosidase activity (Malunga & Izydorczyk, ) making it hard to achieve potency levels through dietary intake. Hence, technologies that increase bioaccessibility of phenolic acids could play a major role in improving antidiabetic properties of cereal grains.…”

Extraction and characterisation of arabinoxylan from brewers spent grain and investigation of microbiome modulation potential

“…Alongside cellulose, arabinoxylan (AX) is an abundant fibre in BSG. Arabinoxylan and arabinoxylanoligosaccharides (AXOS) from other cereal sources, primarily wheat, have been shown to be linked to potential health benefits, such as modulation of glycaemic index and potential prebiotic capacity [8][9][10][11]. Both EFSA and the FDA allow claims on AX in relation to modulating the glycaemic response; EFSA restricts this claim to wheat AX while the FDA does not [12,13].…”