Comparison of edible brown algae extracts for the inhibition of intestinal carbohydrate digestive enzymes involved in glucose release from the diet

Abstract

Type II diabetes is considered the most common metabolic disorder in the developed world and currently affects about one in ten globally. A therapeutic target for the management of type II diabetes is the inhibition of α- glucosidase, an essential enzyme located at the brush border of the small intestinal epithelium. The inhibition of α-glucosidase results in reduced digestion of carbohydrates and a decrease in postprandial blood glucose. Although pharmaceutical synthetic inhibitors are available, these are usually associated with significant gastrointestinal side effects. In the present study, the impact of inhibitors derived from edible brown algae is being investigated and compared for their effect on glycaemic control. Carbohydrate- and polyphenolic-enriched extracts derived from Ascophyllum nodosum, Fucus vesiculosus and Undaria pinnatifida were characterised and screened for their inhibitory effects on maltase and sucrase enzymes. Furthermore, enzyme kinetics and the mechanism of inhibition of maltase and sucrase were determined using linear and nonlinear regression methods. All tested extracts showed a dose-dependent inhibitory effect of α-glucosidase with IC50 values ranging from 0⋅26 to 0⋅47 mg/ml for maltase; however, the only extract that was able to inhibit sucrase activity was A. nodosum, with an IC50 value of 0⋅83 mg/ml. The present study demonstrates the mechanisms in which different brown seaweed extracts with varying composition and molecular weight distribution differentially inhibit α-glucosidase activities. The data highlight that all brown seaweed extracts are not equal in the inhibition of carbohydrate digestive enzymes involved in postprandial glycaemia.

Undaria Pinnatifida (Wakame) Moderates Postprandial Glycaemia in Healthy Young Japanese Women

“…Phenolic compounds and fucoidans are characterised as α-glucosidase inhibitors. 6,12,19 However, compared with other seaweeds, wakame has low polyphenols and fucoidans; therefore, its α-glucosidase inhibitory activity is likely weak.…”

“…Someof these inhibitors are derived from seaweeds. 5,6 One meta-analysis reported that dietary fiber improved Undaria Pinnatifida (Wakame) Moderates Postprandial Glycaemia in Healthy Young Japanese Women fasting blood glucose concentrations in patients with type 2 diabetes. 7 However, the reported effects on fasting blood glucose concentrations have differed depending on the type of dietary fiber.…”

Seaweed Exhibits Therapeutic Properties against Chronic Diseases: An Overview

“…Many seaweeds also exhibit inhibitory effects on α-glucosidase and α-amylase, such as Ascophyllum nodosum, Fucus vesiculosus, and Undaria pinnatifida [168,169]. Bioactive compounds from Ecklonia stolonifera and Eisenia bicyclis, including phlorotannin, showed inhibitory effects on protein tyrosine phosphatase 1 B (PTP1B) and α-glucosidase [174], whereas phlorotannin showed moderate inhibitory effects on rat lens aldose reductase (RLAR), human recombinant aldose reductase (HRAR), and PTP1B [10].…”

Citrus Flavanone Narirutin, In Vitro and In Silico Mechanistic Antidiabetic Potential

“…Alpha-glucosidase is one of the digestive enzymes, its main function is to accelerate the hydrolysis of polysaccharides (starch) to glucose (acts on (14) bonds) in order to promote glucose absorption and, therefore, raise blood glucose levels [58]. This helps to prevent hyperglycemia and maintain normal blood sugar levels by slowing down the digestion of starch and extra dietary carbohydrates [58].…”