Chlorogenic and phenolic acids are only very weak inhibitors of human salivary α-amylase and rat intestinal maltase activities.

There is increasing evidence that consumption of polyphenol and phenolic-rich foods and beverages have the potential to reduce the risk of developing diabetes type 2, with coffee a dominant example according to epidemiological evidence. One of the proposed mechanisms of action is the inhibition of carbohydrate-digesting enzymes leading to attenuated post-prandial blood glucose concentrations, as exemplified by the anti-diabetic drug, acarbose. We determined if the phenolic, 5-caffeoylquinic acid, present in coffee, apples, potatoes, artichokes and prunes, for example, and also selected free phenolic acids (ferulic acid, caffeic acid and 3,4-dimethoxycinnamic acid), could inhibit human salivary α-amylase and rat intestinal maltase activities, digestive enzymes involved in the degradation of starch and malto-oligosaccharides.

Nutritional implications of olives and sugar: attenuation of post-prandial glucose spikes in healthy volunteers by inhibition of sucrose hydrolysis and glucose transport by oleuropein.

Purpose: The secoiridoid oleuropein, as found in olives and olive leaves, modulates some biomarkers of diabetes risk in vivo. A possible mechanism may be to attenuate sugar digestion and absorption.

Methods: We explored the potential of oleuropein, prepared from olive leaves in a water soluble form (OLE), to inhibit digestive enzymes (α-amylase, maltase, sucrase), and lower [C(U)]-glucose uptake in Xenopus oocytes expressing human GLUT2 and [C(U)]-glucose transport across differentiated Caco-2 cell monolayers.

Pomegranate juice, but not an extract, confers a lower glycemic response on a high-glycemic index food: randomized, crossover, controlled trials in healthy subjects.

Low-glycemic index diets have demonstrated health benefits associated with a reduced risk of developing type 2 diabetes. We tested whether pomegranate polyphenols could lower the glycemic response of a high-glycemic index food when consumed together and the mechanism by which this might occur. We compared the acute effect of a pomegranate juice and a polyphenol-rich extract from pomegranate (supplement) on the bread-derived postprandial blood glucose concentration in 2 randomized, crossover, controlled studies (double-blinded for the supplements), each on 16 healthy volunteers.

Inhibition of Human and Rat Sucrase and Maltase Activities To Assess Antiglycemic Potential: Optimization of the Assay Using Acarbose and Polyphenols.

Unlabelled: We optimized the assays used to measure inhibition of rat and human α-glucosidases (sucrase and maltase activities), intestinal enzymes which catalyze the final steps of carbohydrate digestion. Cell-free extracts from fully differentiated intestinal Caco-2/TC7 monolayers were shown to be a suitable source of sucrase-isomaltase, with the same sequence as human small intestine, and were compared to a rat intestinal extract. The kinetic conditions of the assay were optimized, including comparison of enzymatic and chromatographic methods to detect the monosaccharide products.