Characterization of carboxymethyl cellulose-based antimicrobial films incorporated with plant essential oils.

The aim of this study was to investigate the effect of essential oil (EO) addition (1, 2, and 3% v/v) obtained from different plants (Santolina chamaecyparissus (SC), Schinus molle (SM), and Eucalyptus globulus (EG) on the antimicrobial, physical, water vapor permeability, mechanical, optical and microstructural properties of the carboxymethyl cellulose (CMC) films. The films containing EO at the concentration of 3% showed the highest antimicrobial activity on tested microorganisms. The EO content increase from 1% to 3% in films decreased the moisture content and water solubility of all films. The water vapor permeability also decreased in films with EGEO but it increased in films with SCEO and SMEO. While the tensile strength (TS) of films containing EO (29.43 ± 3.28-77.05 ± 0.02 MPa) was determined higher than the TS of the control (24.60 ± 0.54 MPa), the elongation at break (E%) of films (14.41 ± 0.02-33.01 ± 0.01%) were lower than E% of the control (37.06 ± 0.85%). The microstructures of films were homogeneous in the films containing 1% and 2% EOs. CMC films gained a significant antimicrobial property and improved its characteristic properties with the incorporation of EOs presenting a good potential for applying to foods.

Phenolic compounds increase the transcription of mouse intestinal maltase-glucoamylase and sucrase-isomaltase.

Diverse natural phenolic compounds show inhibition activity of intestinal α-glucosidases, which may constitute the molecular basis for their ability to control systemic glycemia. Additionally, phenolics can modify mRNA expression for proteins involved in nutritional, metabolic or immune processes. To explore the possibility that phenolics can regulate the mRNA expression, enzymatic activity, and protein synthesis/processing of intestinal Maltase-Glucoamylase (MGAM) and Sucrase-Isomaltase (SI), small intestinal explants from Balb/c mice were cultured for 24 h in the presence or absence of gallic acid, caffeic acid, and (+)-catechin at 0.1, 0.5, and 1 mM. We measured the levels of MGAM and SI mRNA expression by qRT-PCR, maltase and sucrase activities by a standard colorimetric method and the molecular size distribution of MGAM and SI proteins by western blotting. mRNA expression for MGAM was induced by the three phenolic compounds at 0.1 mM. mRNA expression for SI was induced by caffeic and gallic acids, but not by (+)-catechin. Caffeic acid was the most effective inducer of mRNA expression of these enzymes. Total maltase and sucrase activities were not affected by treatment with phenolics. The proportion of high molecular size forms of MGAM was significantly increased by two of the three phenolic compounds, but little effect was observed on SI proteins. Thus, changes in the protein synthesis/processing, affecting the proportions of the different molecular forms of MGAM, may account for the lack of correlation between mRNA expression and enzymatic activity.

Dietary phenolic compounds selectively inhibit the individual subunits of maltase-glucoamylase and sucrase-isomaltase with the potential of modulating glucose release.

In this study, it was hypothesized that dietary phenolic compounds selectively inhibit the individual C- and N-terminal (Ct, Nt) subunits of the two small intestinal α-glucosidases, maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI), for a modulated glycemic carbohydrate digestion. The inhibition by chlorogenic acid, caffeic acid, gallic acid, (+)-catechin, and (-)-epigallocatechin gallate (EGCG) on individual recombinant human Nt-MGAM and Nt-SI and on mouse Ct-MGAM and Ct-SI was assayed using maltose as the substrate. Inhibition constants, inhibition mechanisms, and IC50 values for each combination of phenolic compound and enzymatic subunit were determined. EGCG and chlorogenic acid were found to be more potent inhibitors for selectively inhibiting the two subunits with highest activity, Ct-MGAM and Ct-SI. All compounds displayed noncompetitive type inhibition. Inhibition of fast-digesting Ct-MGAM and Ct-SI by EGCG and chlorogenic acid could lead to a slow, but complete, digestion of starch for improved glycemic response of starchy foods with potential health benefit.