MODULATION OF CARBOHYDRATE DIGESTION BY PLANT-DERIVED INHIBITORS OF MGAM AND SI SUBUNITS: A STRUCTURED NARRATIVE REVIEW APPLIED TO THREE BRAZILIAN CERRADO SPECIES

Abstract

Postprandial hyperglycemia is a well-established therapeutic target in diabetes mellitus, and the intestinal α-glucosidases maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI) catalyze the terminal step of starch digestion. As approved inhibitors have limited uptake due to gastrointestinal adverse effects, there remains a search for plant-based scaffolds. This structured narrative review articulates structural knowledge about MGAM and SI with evidence of inhibition by plant metabolites and applies this scaffold to three species from the Brazilian Cerrado, based on a survey of five databases. The four catalytic subunits differ in volume and polarity of the recognition subsite, which opens up a little-explored possibility of selective inhibition, and iminosugars have the greatest mechanistic plausibility. In Solanum lycocarpum, evidence about the human enzyme comes from isolated calystegin compounds, which preferentially inhibit sucrase; the crude fraction assay, although it surpassed acarbose, used yeast α-glucosidase. In Eugenia dysenterica, the ethanolic fruit peel extract surpassed acarbose on mammalian preparation. In Salacia crassifolia, there is no report of inhibitors associated with the genus. None of the three has established molecular attribution.