Glucose Uptake In Caco-2 Cells Research Articles

Oral Glucose Tolerance Test (OGTT) Evidence for the Postprandial Anti-Hyperglycemic Property of Salacca zalacca (Gaertn.) Voss Seed Extract.

Salak seed extract (Salacca zalacca) is known for its high antioxidant content and low caffeine levels, making it a promising candidate for the development of value-added health products. However, there is a lack of scientific evidence for its anti-hyperglycemic effects. To address this, we investigated the in vitro and in vivo anti-hyperglycemic and antioxidant effects of salak seed extract. The HPLC chromatogram of salak seed extract shows a prominent peak that corresponds to chlorogenic acid. In vitro studies revealed that salak seeds inhibited α-glucosidase activity and glucose uptake in Caco-2 cells in a concentration-dependent manner, while also exhibiting antioxidant properties. The extract exhibits a non-competitive inhibition on α-glucosidase activity, with an IC50 and Ki of 16.28 ± 7.22 and 24.81 μg/mL, respectively. In vivo studies utilizing streptozotocin-nicotinamide-induced diabetic mice showed that the extract significantly reduced fasting blood glucose (FBG) levels in the oral glucose tolerance test. Continuous administration of the salak seed extract resulted in lower FBG levels by 13.8% as compared with untreated diabetic mice, although this change was not statistically significant. The estimated LD50 value of salak seed extract exceeds 2000 mg/kg, and no toxicity symptoms have been detected. Our research supports that salak seed extract has the potential to serve as a functional food or supplement that may be beneficial in reducing postprandial hyperglycemia among people with type 2 diabetes. This effect was explained by the salak's inhibitory mechanisms of glucose absorption due to inhibition of both α-glucosidase activity and intestinal glucose uptake, coupled with its antioxidant effects.

Antidiabetic potential of Lysiphyllum strychnifolium (Craib) A. Schmitz compounds in human intestinal epithelial Caco-2 cells and molecular docking-based approaches

BackgroundLysiphyllum strychnifolium (Craib) A. Schmitz, a traditional Thai medicinal plant, is mainly composed of polyphenols and flavonoids and exhibits several pharmacological activities, including antioxidant, anticancer, antimicrobial, and antidiabetic activities. However, the mechanism by which pure compounds from L. strychnifolium inhibit glucose catalysis in the small intestine and their effect on the glucose transporter remain unknown.MethodsThe objectives of this research were to examine the effect of 3,5,7-trihydroxychromone-3-O-\U0001d6fc-L-rhamnopyranoside (compound 1) and 3,5,7,3’,5’-pentahydroxy-flavanonol-3-O-\U0001d6fc-L-rhamnopyranoside (compound 2) on the inhibition of α-amylase and α-glucosidase, as well as glucose transporters, such as sodium-glucose cotransporter 1 (SGLT1), glucose transporter 2 (GLUT2), and glucose transporter 5 (GLUT5), using Caco-2 cells as a model of human intestinal epithelial cells. Additionally, the binding affinity and interaction patterns of compounds against two receptor proteins (SGLT1 and GLUT2) were determined for the first time utilizing a molecular docking approach.ResultsIn the α-amylase inhibition assay, a concentration-dependent inhibitory response was observed against the enzyme. The results indicated that compound 1 inhibited α-amylase activity in a manner similar to that of acarbose (which exhibit IC50 values of 3.32 ± 0.30 µg/mL and 2.86 ± 0.10 µg/mL, respectively) in addition to a moderate inhibitory effect for compound 2 (IC50 = 10.15 ± 0.53 µg/mL). Interestingly, compounds 1 and 2 significantly inhibited α-glucosidase and exhibited better inhibition than that of acarbose, with IC50 values of 5.35 ± 1.66 µg/mL, 510.15 ± 1.46 µg/mL, and 736.93 ± 7.02 µg/mL, respectively. Additionally, α-glucosidase activity in the supernatant of the Caco-2 cell monolayer was observed. In comparison to acarbose, compounds 1 and 2 inhibited α-glucosidase activity more effectively in Caco-2 cells without cytotoxicity at a concentration of 62.5 µg/mL. Furthermore, the glucose uptake pathways mediated by SGLT1, GLUT2, and GLUT5- were downregulated in Caco-2 cells treated with compounds 1 and 2. Additionally, molecular modeling studies revealed that compounds 1 and 2 presented high binding activity with SGLT1 and GLUT2.ConclusionIn summary, our present study was the first to perform molecular docking with compounds present in L. strychnifolium extracts. Our findings indicated that compounds 1 and 2 reduced glucose uptake in Caco-2 cells by decreasing the expression of glucose transporter genes and inhibiting the binding sites of SGLT1 and GLUT2. Therefore, compounds 1 and 2 may be used as functional foods in dietary therapy for postprandial hyperglycemia modulation of type 2 diabetes.

Iridoids and polyphenols from chilean Gaultheria spp. berries decrease the glucose uptake in Caco-2 cells after simulated gastrointestinal digestion

Berries are rich food sources of potentially health-beneficial (poly)phenols. However, they may undergo chemical modifications during gastrointestinal digestion. The effect of simulated gastrointestinal digestion on the content and composition of secondary metabolites from Gaultheria phillyreifolia and G. poeppigii berries was studied. The influence of the digested extracts on the in vitro metabolism and absorption of carbohydrates was evaluated. After simulated digestion, 31 compounds were detected by UHPLC-DAD-MS. The total content of anthocyanins decreased by 98–100%, flavonols by 44–56%, phenylpropanoids by 49–75% and iridoids by 33–45%, the latter showing the highest stability during digestion. Digested extracts inhibited α-glucosidase (IC50 2.8–24.9 μg/mL) and decreased the glucose uptake in Caco-2 cells by 17–28%. Moreover, a decrease in the mRNA expression of glucose transporters SGLT1 (38–92%), GLUT2 (45–96%), GLUT5 (28–89%) and the enzyme sucrase-isomaltase (82–97%) was observed. These results show the effect of simulated gastrointestinal digestion on the content and composition of Gaultheria berries.

Phenolic acids from Coffea arabica L. suppress intestinal uptake of glucose and cholesterol.

The This study assessed the hypoglycaemic and hypocholesterolaemic effects of coffee fruit extracts and their active compounds involved in cholesterol and glucose uptake, as well as the inhibitory activity of α-glucosidase and α-amylase, the physiochemical changes of cholesterol micelles, and the uptake of glucose and cholesterol in Caco-2 cells. The results revealed that coffee green dry (CGD) coffee yellow dry (CYD), and coffee red bean dry (CRBD) extracts inhibited α-amylase activity by approximately 49% whereas caffeine and caffeic acid, showed high potency to inhibit α-amylase activity by 94.49% and 93.35%, respectively. In addition, coffee red pulps dry (CRPD) and citric acid inhibited αglucosidase by 29% and 46%, respectively. The extracts (1 mg/mL) and their active compounds (200 µM) inhibited glucose uptake in Caco-2 cells. All coffee fruit extracts inhibited cholesterol uptake in Caco-2 cells by approximately 40%, and they decreased the micellar solubility of cholesterol, except for coffee red fresh (CRF) and coffee red dry (CRD). Moreover, CYD strongly increased the size of cholesterol micelles. These findings demonstrate the potential effect of coffee extracts on anti-diabetic activity and their cholesterol-lowering activity according to the inhibitory activity of α-glucosidase and α-amylase and the uptake of glucose and cholesterol in Caco-2 cells.

The new insight into the influence of fermentation temperature on quality and bioactivities of black tea

This study aimed to figure out the optimum fermentation temperature by analyzing the major chemical constituents of black tea and its antioxidant activities, inhibitory activities against α-amylase, α-glucosidase and glucose uptake. Sensory evaluation revealed 28°C-fermented black tea showed best sensory quality with highest scores for aroma (6.5) and taste (29.8). With increasing fermentation temperature, polyphenols, polysaccharides, (−)-epigallocatechin, (+)-catechin, theaflavins and thearubigins decreased significantly, while amino acids, soluble sugars and volatiles increased when temperature increased up to 31 °C. Furthermore, black tea fermented at 28 °C showed strongest DPPH radical scavenging ability, anti-lipid peroxidation and inhibitory effect on α-glucosidase activity with IC50 value of 17.72 μg/mL, 1.49 mg/mL and 21.69 μg/mL respectively. While 25°C-fermented black tea showed highest inhibition rate of glucose uptake in Caco-2 cells. The results demonstrate that appropriately lowering fermentation temperature could improve both sensory quality and bioactivity of black tea.

Effect of extracted malva nut gum on reducing high glucose levels by Caco-2 cells

Abstract Mucilage of malva nut seeds has been commercially produced as a functional beverage in many South East Asian countries. The purposes of this research were, first, to analyze chemical compositions of different layers of malva nut seeds. Second objective was to investigate the efficacy and dose response of malva nut gum (MNG) for the reduction of glucose uptake in Caco-2 cells. Third objective was to determine the effect of 30 min pre-incubation of Caco-2 cells with various MNG preparations on the uptake of glucose. Caco-2 cells were incubated in Dulbecco's Modified Eagle's Medium (DMEM) containing (i) different concentrations of glucose (i.e. 5.5, 25 mM), (ii) different sources of glucose (i.e. sucrose, starch), (iii) different types of dietary fiber contained in different preparations of gum extracted from malva nut seeds and guar nuts. The cells were incubated in glucose containing DMEM under two different conditions: simultaneous and 30 min pre-incubation conditions. Scanning electron microscopy showed porous surface of extracted MNG compared to malva nut seed. In 25 mM glucose concentrate containing DMEM, the optimal level of dietary fiber to significantly reduce glucose uptake was 0.25% for malva nut seed, extracted MNG and mixed gum, but 0.5% for guar gum. FT-IR showed additional bands in the mixture of each gum and glucose. The contents of glucose uptake for the cells pre-incubated for 30 min, were 50–85% lower than that of the control. These results demonstrate that MNG is effective in lowering glucose uptake by Caco-2 cells in both low and high carbohydrate concentrations.

Fractionation of Plant Bioactives from Black Carrots (Daucus carota subspecies sativus varietas atrorubens Alef.) by Adsorptive Membrane Chromatography and Analysis of Their Potential Anti-Diabetic Activity.

Black and purple carrots have attracted interest as colored extracts for coloring food due to their high content of anthocyanins. This study aimed to investigate the polyphenol composition of black carrots. Particularly, the identification and quantification of phenolic compounds of the variety Deep Purple carrot (DPC), which presents a very dark color, was performed by HPLC-PDA and HPLC-ESI-MS(n) analyses. The separation of polyphenols from a DPC XAD-7 extract into an anthocyanin fraction (AF) and co-pigment fraction (CF; primarily phenolic acids) was carried out by membrane chromatography. Furthermore, possible anti-diabetic effects of the DPC XAD-7 extract and its AF and CF were determined. DPC samples (XAD-7, CF, and AF) inhibited α-amylase and α-glucosidase in a dose-dependent manner. Moreover, DPC XAD-7 and chlorogenic acid, but not DPC CF and DPC AF, caused a moderate inhibition of intestinal glucose uptake in Caco-2 cells. However, DPC samples did not affect glucagon-like peptide-1 (GLP-1) secretion and dipeptidyl peptidase IV (DPP-4) activity. Overall, DPC exhibits an inhibitory effect on α-amylase and α-glucosidase activity and on cellular glucose uptake indicating potential anti-diabetic properties.

Inhibition of Intestinal α-Glucosidase and Glucose Absorption by Feruloylated Arabinoxylan Mono- and Oligosaccharides from Corn Bran and Wheat Aleurone.

The effect of feruloylated arabinoxylan mono- and oligosaccharides (FAXmo) on mammalian α-glucosidase and glucose transporters was investigated using human Caco-2 cells, rat intestinal acetone powder, and Xenopus laevis oocytes. The isolated FAXmo from wheat aleurone and corn bran were identified to have degree of polymerization (DP) of 4 and 1, respectively, by HPLC-MS. Both FAXmo extracts were effective inhibitors of sucrase and maltase functions of the α-glucosidase. The IC50 for FAXmo extracts on Caco-2 cells and rat intestinal α-glucosidase was 1.03–1.65 mg/mL and 2.6–6.5 mg/mL, respectively. Similarly, glucose uptake in Caco-2 cells was inhibited up to 40%. The inhibitory effect of FAXmo was dependent on their ferulic acid (FA) content (R = 0.95). Sodium independent glucose transporter 2 (GLUT2) activity was completely inhibited by FAXmo in oocytes injected to express GLUT2. Our results suggest that ferulic acid and feruloylated arabinoxylan mono-/oligosaccharides have potential for use in diabetes management.

Involvement of the Niacin Receptor GPR109a in the LocalControl of Glucose Uptake in Small Intestine of Type 2Diabetic Mice.

Niacin is a popular nutritional supplement known to reduce the risk of cardiovascular diseases by enhancing high-density lipoprotein levels. Despite such health benefits, niacin impairs fasting blood glucose. In type 2 diabetes (T2DM), an increase in jejunal glucose transport has been well documented; however, this is intriguingly decreased during niacin deficient state. In this regard, the role of the niacin receptor GPR109a in T2DM jejunal glucose transport remains unknown. Therefore, the effects of diabetes and high-glucose conditions on GPR109a expression were studied using jejunal enterocytes of 10-week-old m+/db and db/db mice, as well as Caco-2 cells cultured in 5.6 or 25.2 mM glucose concentrations. Expression of the target genes and proteins were quantified using real-time polymerase chain reaction (RT-PCR) and Western blotting. Glucose uptake in Caco-2 cells and everted mouse jejunum was measured using liquid scintillation counting. 10-week T2DM increased mRNA and protein expression levels of GPR109a in jejunum by 195.0% and 75.9%, respectively, as compared with the respective m+/db control; high-glucose concentrations increased mRNA and protein expression of GPR109a in Caco-2 cells by 130.2% and 69.0%, respectively, which was also confirmed by immunohistochemistry. In conclusion, the enhanced GPR109a expression in jejunal enterocytes of T2DM mice and high-glucose treated Caco-2 cells suggests that GPR109a is involved in elevating intestinal glucose transport observed in diabetes.

Effects of ursolic acid derivatives on Caco-2 cells and their alleviating role in streptozocin-induced type 2 diabetic rats.

In this study, the effect and mechanism of a series of ursolic acid (UA) derivatives on glucose uptake were investigated in a Caco-2 cells model. Their effect on hyperglycemia, hyperlipidemia and oxidative stress were also demonstrated in streptozocin (STZ)-induced diabetic rats. 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-glucose (2-NBDG) was used as a fluorescein in Caco-2 cells model to screen UA derivatives by glucose uptake and expression of glucose transporter protein (SGLT-1, GLUT-2). Moreover, STZ-induced diabetic rats were administered with these derivatives for 4 weeks of treatment. The fasting blood glucose (FBG), insulin levels, biochemical parameters, lipid levels, and oxidative stress markers were finally evaluated. The results of this study indicated that compounds 10 and 11 significantly inhibited 2-NBDG uptake under both Na+-dependent and Na+-independent conditions by decreasing SGLT-1 and GLUT-2 expression in the Caco-2 cells model. Further in vivo studies revealed that compound 10 significantly reduced hyperglycemia by increasing levels of serum insulin, total protein, and albumin, while the fasting blood glucose, body weight and food intake were restored much closer to those of normal rats. Compounds 10 and 11 showed hypolipidemic activity by decreasing the total amounts of cholesterol (TC) and triglycerides (TG). Furthermore, compound 10 showed antioxidant potential which was confirmed by elevation of glutathione (GSH) and superoxide dismutase (SOD) and reduction of malondialdehyde (MDA) levels in the liver and kidney of diabetic rats. It was concluded that compound 10 caused an apparent inhibition of intestinal glucose uptake in Caco-2 cells and hypoglycemia, hypolipidemia and augmented oxidative stress in STZ-induced diabetic rats. Thus, compound 10 could be developed as a potentially complementary therapeutic or prophylactic agent for diabetics mellitus and its complications.

Fundamental studies on the inhibitory action of Acanthopanax senticosus Harms on glucose absorption

Acanthopanax senticosus Harms extract (ASE) is used as an ingredient of over-the-counter drugs and functional foods, such as health supplements, in Japan. ASE exhibits a hypoglycemic effect; however, the mechanism of the hypoglycemic effect is not clear. In the present study, we investigated whether ASE has a glucose absorption inhibitory action. We examined the effects of ASE on α-amylase and α-glucosidase activities, and on glucose uptake in Caco-2 cells. We also examined the effects of ASE oral administration on glucose tolerance in type 2 diabetes mellitus model db/db mice. The addition of ASE inhibited α-glucosidase activity but not α-amylase activity. The α-glucosidase inhibitory activity of ASE was approximately 1/13 of that of acarbose. The addition of ASE inhibited 2'-deoxy-D-glucose (DG) uptake in human intestinal Caco-2 cells, and the inhibitory activity of ASE was approximately 1/40 of that of phloretin. Kinetic analysis of glucose uptake indicated that ASE has no effects on DG uptake through passive diffusion, but that ASE inhibits intracellular DG uptake chiefly by inhibiting transport via a glucose transporter. In the glucose tolerance study, db/db mice orally administered ASE for 3 days showed significantly lower plasma glucose level than the control group 30 min after sucrose loading, without affecting plasma insulin levels. In addition, ASE oral administration significantly inhibited α-glucosidase activity in the small intestine mucosa extirpated from the mice. These findings indicate that ASE may be useful as an ingredient of functional foods to improve postprandial hyperglycemia and prevent type II diabetes mellitus.