Insights on the Hypoglycemic Potential of Crocus sativus Tepal Polyphenols: An In Vitro and In Silico Study.

Post-prandial hyperglycemia typical of diabetes mellitus could be alleviated using plant-derived compounds such as polyphenols, which could influence the activities of enzymes involved in carbohydrate digestion and of intestinal glucose transporters. Here, we report on the potential anti-hyperglycemic effect of Crocus sativus tepals compared to stigmas, within the framework of valorizing these by-products of the saffron industry, since the anti-diabetic properties of saffron are well-known, but not those of its tepals. In vitro assays showed that tepal extracts (TE) had a greater inhibitory action than stigma extracts (SE) on α-amylase activity (IC50: TE = 0.60 ± 0.09 mg/mL; SE = 1.10 ± 0.08 mg/mL; acarbose = 0.051 ± 0.07) and on glucose absorption in Caco-2 differentiated cells (TE = 1.20 ± 0.02 mg/mL; SE = 2.30 ± 0.02 mg/mL; phlorizin = 0.23 ± 0.01). Virtual screening performed with principal compounds from stigma and tepals of C. sativus and human pancreatic α-amylase, glucose transporter 2 (GLUT2) and sodium glucose co-transporter-1 (SGLT1) were validated via molecular docking, e.g., for human pancreatic α-amylase, epicatechin 3-o-gallate and catechin-3-o-gallate were the best scored ligands from tepals (-9.5 kcal/mol and -9.4 kcal/mol, respectively), while sesamin and episesamin were the best scored ones from stigmas (-10.1 kcal/mol). Overall, the results point to the potential of C. sativus tepal extracts in the prevention/management of diabetes, likely due to the rich pool of phytocompounds characterized using high-resolution mass spectrometry, some of which are capable of binding and interacting with proteins involved in starch digestion and intestinal glucose transport.

A novel purgative mechanism of multiflorin A involves changing intestinal glucose absorption and permeability.

BACKGROUND: Multiflorin A (MA) is a potential active ingredient of traditional herbal laxative, Pruni semen, with unusual purgative activity and an unclear mechanism, and inhibiting intestinal glucose absorption is a promising mechanism of novel laxatives. However, this mechanism still lacks support and a description of basic research. PURPOSE: This study aimed to determine the main contribution of MA to the purgative activity of Pruni semen and elucidate the effect intensity, characteristics, site, and mechanism of MA in mice, and determine the novel mechanism of traditional herbal laxatives from the perspective of intestinal glucose absorption. METHODS: We induced diarrhoea in mice by administering Pruni semen and MA, and the defecation behaviour, glucose tolerance, and intestinal metabolism were analysed. The effects of MA and its metabolite on peristalsis of the intestinal smooth muscle were evaluated using an intestinal motility assay in vitro. Intestinal tight junction proteins, aquaporins, and glucose transporters expression were analysed using immunofluorescence; gut microbiota and faecal metabolites were analysed using 16S rRNA and liquid chromatography-mass spectrometry. RESULTS: MA administration (20 mg/kg) induced watery diarrhoea in over half of the experimental mice. The activity of MA in lowering peak postprandial glucose levels was synchronous with purgative action, with the acetyl group being the active moiety. MA was metabolised primarily in the small intestine, where it decreased sodium-glucose cotransporter-1, occludin, and claudin1 expression, then inhibited glucose absorption, resulting in a hyperosmotic environment. MA also increased the aquaporin3 expression to promote water secretion. Unabsorbed glucose reshapes the gut microbiota and their metabolism in the large intestine and the increasing gas and organic acid promoted defecation. After recovery, the intestinal permeability and glucose absorption function returned, and the abundance of probiotics such as Bifidobacterium increased. CONCLUSION: The purgative mechanism of MA involves inhibiting glucose absorption, altering permeability and water channels to promote water secretion in the small intestine, and regulating gut microbiota metabolism in the large intestine. This study is the first systematic experimental study on the purgative effect of MA. Our findings provide new insight into the study of novel purgative mechanisms.

Bridelia ferruginea inhibits key carbohydrate digesting enzyme and intestinal glucose absorption and modulates glucose metabolism in diabetic rats.

The antidiabetic potentials of the dichloromethene, ethyl acetate, butanol and aqueous fractions of Bridelia ferruginea leaves were investigated using in vitro, ex vivo and in vivo models. In vitro and ex vivo antidiabetic activities revealed the butanol (BFBF) to be the most active of the fractions, and thus selected for in vivo study. Diabetes was induced using the fructose-streptozotocin model. Treatments with BFBF significantly reduced blood glucose level and improved glucose tolerance, serum insulin level and sensitivity as well as suppressed hyperlipidaemia and serum nephropathy markers. Histopathological analysis revealed the ability of BFBF to protect and regenerate pancreatic ß-cells. BFBF significantly elevated glutathione level, catalase and superoxide dismutase activities, while depleting MDA level in serums and kidney of diabetic rats. Phenols, steroids, terpenoids, aliphatic and aromatic compounds were identified in the fractions following GC-MS analysis. Overall, results from this study propose that BFBF possess potent antidiabetic activity.

Dietary Epidermal Growth Factor Supplementation Alleviates Intestinal Injury in Piglets with Intrauterine Growth Retardation via Reducing Oxidative Stress and Enhancing Intestinal Glucose Transport and Barrier Function.

EGF plays an important role in the intestinal repair and nutrients transport of animals. However, the effect of EGF on the intestinal health of piglets with IUGR has not been reported. Thus, the present study was performed to investigate the effects of EGF on the intestinal morphology, glucose absorption, antioxidant capacity, and barrier function of piglets with IUGR. A total of 6 NBW piglets and 12 IUGR piglets were randomly divided into three treatments: NC group (NBW piglets fed with basal diet, n = 6), IC group (IUGR piglets fed with basal diet, n = 6), and IE group (IUGR piglets fed with basal diet supplemented with 2 mg/kg EGF, n = 6). Growth performance, serum biochemical profile, jejunum histomorphology, jejunum glucose absorption and antioxidant capacity, and jejunal barrier function were measured. The results showed that EGF supplementation significantly increased the final body weight (FBW), average daily gain (ADG), and average daily feed intake (ADFI) of piglets with IUGR; EGF supplementation significantly increased the total protein (TP), glucose (GLU), and immunoglobulin G (IgG) levels compared with the IUGR piglets in the IC group; EGF administration effectively exhibited an increased jejunum villus height (VH) and the villus-height-to-crypt-depth ratio (V/C) of IUGR piglets compared with the IC group; EGF supplementation significantly increased sodium/potassium-transporting adenosine triphosphatase (Na+/K+-ATPase) activity, intestinal alkaline phosphatase (AKP) activity, glucose transporter sodium/glucose cotransporter 1 (SGLT1), glucose transporter 2 (GLUT2), and AMP-activated protein kinase α1 (AMPK-α1) mRNA expressions in the jejunum of IUGR piglets compared with the IC group; EGF supplementation exhibited increased superoxide dismutase (SOD) activity and total antioxidant capacity (T-AOC) levels, tended to increase glutathione peroxidase (GSH-Px) and catalase (CAT) activities, and tended to decrease the malondialdehyde (MDA) level in the jejunum of IUGR piglets compared with the IC group; EGF supplementation significantly increased ZO-1, Claudin-1, Occludin, and MUC2 mRNA expressions and improved secreted immunoglobulin A (sIgA) secretion in the jejunum of IUGR piglets compared with the IC group and tended to decrease the interleukin 1ß (IL-1ß), IL-6, and tumor necrosis factor α (TNF-α) levels in the jejunum of IUGR piglets compared with the IC group. Pearson's correlation analysis further showed that EGF can promote intestinal development and nutrient absorption by promoting intestinal barrier function, thus improving the growth performance of IUGR piglets.

New insights into the in vitro, in situ and in vivo antihyperglycemic mechanisms of gallic acid and p-coumaric acid.

Objective: To explore the probable in vitro, in situ and in vivo mechanisms of gallic acid (GA) and p-coumaric acid (PCA) as anti-hyperglycemic agents.Animals and methods: Male albino rats were allocated into four groups, group1 was used as normal control. Group 2 was established as a diabetic control and group3 and 4 were treated with an oral dose of GA and PCA, respectively.Results: GA and PCA revealed a significant decrease in the activity of α-amylase, a noticeable rise in glucose induced-insulin secretion and glucose-uptake in peripheral glucose-uptake in vitro, increase also liver glycogen and serum insulin levels in vivo. Further, GA and PCA exhibited a significant reduction in intestinal glucose absorption in situ compared to blank.Conclusion: The antihyperglycemic activities of GA and PCA can be mediated through delaying intestinal glucose absorption, enhancing ß-cell activity and promoting glucose uptake by peripheral tissue via enhancing insulin sensitivity.

Acute and Subacute Toxicity and Cytotoxicity of Opuntia Dillenii (Ker-Gawl) Haw. Seed Oil and Its Impact on the Isolated Rat Diaphragm Glucose Absorption.

This study aims to assess the safety of the Opuntia dillenii (Ker-Gawl) haw. seed oil (ODSO) and its effect on the glucose absorption activity of the isolated rat hemidiaphragm. This oil's safety was studied by exploring its acute (doses 1, 3, 5, and 7 mL/kg) and subacute (doses 1 and 2 mL/kg) toxicities in albino mice and Wistar rats, respectively. The safety of the ODSO was also assessed by studying its effect on the HepG2 cell viability in vitro. The effect of ODSO, or combined with the insulin, on the glucose absorption activity of isolated rat hemidiaphragm was evaluated at the dose 1 g/L in vitro. The results demonstrated the safety of ODSO. Indeed, this study showed that this oil does not produce any mortality or signs of toxicity after the single-dose administration in mice. Additionally, the daily intake of the ODSO during four weeks does not induce a significant variation in the biochemical parameters and body weight of rats compared with the control group. Besides, the cell viability of HepG2 did not change in the presence of ODSO. On the other hand, the ODSO increased the glucose absorption activity of the isolated rat hemidiaphragm, and this activity was significantly enhanced when combined with insulin. This study confirms, on one side, the safety of this oil and its efficacy and, on the other side, encourages its potential use as a complement to treat diabetes.

Opuntia dillenii (Ker Gawl.) Haw., Seeds Oil Antidiabetic Potential Using In Vivo, In Vitro, In Situ, and Ex Vivo Approaches to Reveal Its Underlying Mechanism of Action.

Opuntia dillenii Ker Gawl. is one of the medicinal plants used for the prevention and treatment of diabetes mellitus (DM) in Morocco. This study aims to investigate the antihyperglycemic effect of Opuntia dillenii seed oil (ODSO), its mechanism of action, and any hypoglycemic risk and toxic effects. The antihyperglycemic effect was assessed using the OGTT test in normal and streptozotocin (STZ)-diabetic rats. The mechanisms of action were explored by studying the effect of ODSO on the intestinal absorption of d-glucose using the intestinal in situ single-pass perfusion technique. An Ussing chamber was used to explore the effects of ODSO on intestinal sodium-glucose cotransporter 1 (SGLT1). Additionally, ODSO's effect on carbohydrate degrading enzymes, pancreatic α-amylase, and intestinal α-glucosidase was evaluated in vitro and in vivo using STZ-diabetic rats. The acute toxicity test on mice was performed, along with a single-dose hypoglycemic effect test. The results showed that ODSO significantly attenuated the postprandial hyperglycemia in normal and STZ-diabetic rats. Indeed, ODSO significantly decreased the intestinal d-glucose absorption in situ. The ex vivo test (Ussing chamber) showed that the ODSO significantly blocks the SGLT1 (IC50 = 60.24 µg/mL). Moreover, ODSO indu\ced a significant inhibition of intestinal α-glucosidase (IC50 = 278 ± 0.01 µg/mL) and pancreatic α-amylase (IC50 = 0.81 ± 0.09 mg/mL) in vitro. A significant decrease of postprandial hyperglycemia was observed in sucrose/starch-loaded normal and STZ-diabetic ODSO-treated rats. On the other hand, ODSO had no risk of hypoglycemia on the basal glucose levels in normal rats. Therefore, no toxic effect was observed in ODSO-treated mice up to 7 mL/kg. The results of this study suggest that ODSO could be suitable as an antidiabetic functional food.

Cassia Abbreviata Enhances Glucose Uptake and Glucose Transporter 4 Translocation in C2C12 Mouse Skeletal Muscle Cells.

BACKGROUND: This study aim at assessing C. abbreviata aqueous extracts for its potential to exhibit anti-diabetic activity in skeletal muscle cells. In addition to the toxicological and glucose absorption studies, the action of C. abbreviata extracts on some major genes involved in the insulin signaling pathway was established. METHODS: The in vitro cytotoxic effects C. abbreviata was evaluated on muscle cells using the MTT assay and the in vitro glucose uptake assay conducted using a modified glucose oxidase method described by Van de Venter et al. (2008). The amount of GLUT-4 on cell surfaces was estimated quantitatively using the flow cytometry technique. Real time quantitative PCR (RT-qPCR) was used to determine the expression of GLUT-4, IRS-1, PI3 K, Akt1, Akt2, PPAR-γ. RESULTS: Cytotoxicity tests revealed that all extracts tested at various concentrations were non-toxic (LC50 > 5000). Aqueous extracts of leaves, bark and seeds resulted in a dose-dependent increase in glucose absorption by cells, after 1 h, 3 h and 6 h incubation period. Extracts of all three plant parts had the best effect after 3 h incubation, with the leaf extract showing the best activity across time (Glucose uptake of 29%, 56% and 42% higher than untreated control cells after treatment with 1 mg/ml extract at 1 h, 3 h and 6 h, respectively). All extracts, with the exception 500 µg/ml seed extract, induced a two-fold increase in GLUT-4 translocation while marginally inducing GLUT-10 translocation in the muscle cells. The indirect immunofluorescence confirmed that GLUT-4 translocation indeed occurred. There was an increased expression of GLUT-4, IRS1 and PI3 K in cells treated with insulin and bark extract as determined by the RT-qPCR. CONCLUSION: The study reveals that glucose uptake involves GLUT-4 translocation through a mechanism that is likely to involve the upstream effectors of the PI3-K/Akt pathway.

Formulation of a Mixture of Plant Extracts for Attenuating Postprandial Glycemia and Diet-Induced Disorders in Rats.

The aim of this study was to design a mixture consisting of plant-derived preparations containing inhibitors of carbohydrate digestion and/or glucose absorption that could lower postprandial glycemia and attenuate dietary-induced disorders. The following standardized preparations were tested: white mulberry leaf extract, green coffee bean extract, white kidney bean extract, pomelo fruit extract, bitter melon fruit extract, and purified l-arabinose. The study design was composed of oral sucrose and starch tolerance tests in Wistar rats preceded by a single ingestion of the preparations or their mixtures. Then, a 20 week-long experiment was conducted on rats that were fed a high-fat diet and supplemented with the most effective mixture. Based on the results of the oral sucrose and starch tolerance tests, the mulberry leaf extract, l-arabinose, kidney bean extract, and coffee bean extract were selected for composing three mixtures. The most effective inhibition of postprandial glycemia in the oral tolerance tests was observed after the ingestion of a mixture of mulberry leaf, kidney bean, and coffee bean extract. The glucose-lowering effect of the mixture and its effective dosage was confirmed in the feeding experiment.

Boerhaavia diffusa inhibits key enzymes linked to type 2 diabetes in vitro and in silico; and modulates abdominal glucose absorption and muscle glucose uptake ex vivo.

The present study investigated the in vitro and ex vivo antioxidant, anti-diabetic and anti-obesogenic potentials of different solvent (ethyl acetate, ethanol and water) extracts from the aerial parts of Boerhaavia diffusa. The ferric reducing antioxidant power (FRAP), DPPH scavenging activity and the ameliorative effects of the extracts on Fe2+-induced oxidative injury was investigated both in vitro and ex vivo. Alpha glucosidase and pancreatic lipase inhibitory potentials of the extracts were examined in vitro, while the effects of the ethanol extract on abdominal glucose intake and muscle glucose uptake were determined in freshly harvested tissues ex vivo. The extracts were subjected to Gas Chromatography-Mass Spectrometry (GC-MS) analysis to identify their possible bioactive components. The ethanol extract showed the most potent FRAP and DPPH radical scavenging activities compared to other extracts. All extracts increased catalase and SOD activities, and GSH levels in oxidative pancreatic injury. Both ethanol and aqueous extracts exhibited remarkable enzyme inhibitory activities, which was significantly higher than ethyl acetate extract and acarbose but was not comparable to orlistat. The ethanol extract portrayed a dose-dependent inhibitory effect on jejunal glucose uptake and enhancement of muscle glucose uptake. 9-(4 methoxyphenyl) xanthene, xanthone and stigmasterol showed strong binding affinities for α-glucosidase and lipase enzymes tested. Data from this study suggest that aerial parts of B. diffusa (particularly the ethanol extract) may not only exhibit antioxidant potentials but may also mediate anti-lipidemic and anti-hyperglycemic effects via inhibiting fat and carbohydrate digestion as well as abdominal glucose intake and enhancing muscle glucose uptake.

Colectomy induces an aldosterone-mediated increase in jejunal glucose uptake in rats.

AIMS: The main function of the colon is water and electrolyte absorption. Total colectomy eliminates this colonic function and may alter the absorptive capacity of the small intestine for nutrients. This study examines the effect of total colectomy on jejunal glucose absorption and investigates the potential role of aldosterone in mediating the alterations in glucose uptake post-colectomy using the aldosterone antagonist spironolactone. MAIN METHODS: Total colectomy with ileo-rectal anastomosis was performed on anesthetized rats. Sham rats were identically handled without colon resection. Two days post-surgery, groups of colectomized rats were injected with either a daily subcutaneous dose of spironolactone or sesame oil for 12days. Body weight changes and food and water intake were measured in all experimental groups. Glucose absorption was measured by in-vivo single pass perfusion in the rat jejunum of control, sham, colectomized, colectomized with spironolactone, and colectomized with sesame oil treatment. Na/K ATPase, SGK1, SGLT1 and GLUT2 expressions were determined in jejunal mucosa in control, colectomized and colectomized/spironolactone injected rats by Western blot analysis. Histological assessment was performed on jejunal sections in control and colectomized groups. KEY FINDINGS: Glucose absorption significantly increased in colectomized rats with an observed increase in Na/K ATPase and SGK1 expression. No significant expression change in SGLT1 and GLUT2 was detected in the jejunum in colectomized rats. Spironolactone, however, significantly decreased the glucose uptake post-colectomy and normalized Na/K ATPase and SGK1 expression. SIGNIFICANCE: Our results suggest that jejunal glucose uptake increases post-colectomy as a possible consequence of an aldosterone-mediated function.

Maltitol inhibits small intestinal glucose absorption and increases insulin mediated muscle glucose uptake ex vivo but not in normal and type 2 diabetic rats.

This study investigated the effects of maltitol on intestinal glucose absorption and muscle glucose uptake using ex vivo and in vivo experimental models. The ex vivo experiment was conducted in isolated jejunum and psoas muscle from normal rats. The in vivo study investigated the effects of a single bolus dose of maltitol on gastric emptying, intestinal glucose absorption and digesta transit in normal and type 2 diabetic rats. Maltitol inhibited glucose absorption in isolated rat jejunum and increased glucose uptake in isolated rat psoas muscle in the presence of insulin but not in the absence of insulin. In contrast, maltitol did not significantly (p > 0.05) alter small intestinal glucose absorption or blood glucose levels as well as gastric emptying and digesta transit in normal or type 2 diabetic rats. The results suggest that maltitol may not be a suitable dietary supplement for anti-diabetic food and food products to improve glycemic control.

Myo-inositol inhibits intestinal glucose absorption and promotes muscle glucose uptake: a dual approach study.

The present study investigated the effects of myo-inositol on muscle glucose uptake and intestinal glucose absorption ex vivo as well as in normal and type 2 diabetes model of rats. In ex vivo study, both intestinal glucose absorption and muscle glucose uptake were studied in isolated rat jejunum and psoas muscle respectively in the presence of increasing concentrations (2.5 % to 20 %) of myo-inositol. In the in vivo study, the effect of a single bolus dose (1 g/kg bw) of oral myo-inositol on intestinal glucose absorption, blood glucose, gastric emptying and digesta transit was investigated in normal and type 2 diabetic rats after 1 h of co-administration with 2 g/kg bw glucose, when phenol red was used as a recovery marker. Myo-inositol inhibited intestinal glucose absorption (IC50 = 28.23 ± 6.01 %) and increased muscle glucose uptake, with (GU50 = 2.68 ± 0.75 %) or without (GU50 = 8.61 ± 0.55 %) insulin. Additionally, oral myo-inositol not only inhibited duodenal glucose absorption and reduced blood glucose increase, but also delayed gastric emptying and accelerated digesta transit in both normal and diabetic animals. Results of this study suggest that dietary myo-inositol inhibits intestinal glucose absorption both in ex vivo and in normal or diabetic rats and also promotes muscle glucose uptake in ex vivo condition. Hence, myo-inositol may be further investigated as a possible anti-hyperglycaemic dietary supplement for diabetic foods and food products.

Effects of intraduodenal hydroxycitrate on glucose absorption, incretin release, and glycemia in response to intraduodenal glucose infusion in health and type 2 diabetes: A randomised controlled trial.

OBJECTIVE: Hydroxycitric acid (HCA), derived from the fruit Garcinia cambogia, reduces the rate of glucose absorption and lowers postprandial glycemia in rodents, but its effect in humans is unknown. The aim of this study was to investigate the effects of small intestinal perfusion with HCA on glucose absorption, as well as the incretin and glycemic responses to a subsequent intraduodenal glucose infusion, in both healthy individuals and patients with type 2 diabetes. METHODS: Twelve healthy participants and 8 patients with type 2 diabetes received an intraduodenal infusion of HCA (2800 mg in water) or control (water) over 60 min, followed by an intraduodenal infusion of 60 g glucose over 120 min, in a double-blind, randomized crossover design. In healthy individuals, 5 g 3-O-methylglucose (3-OMG) was co-infused with glucose as a marker of glucose absorption. Blood was sampled frequently. RESULTS: In healthy individuals, blood glucose was lower with HCA than control, both before and during the intraduodenal glucose infusion (P < 0.05 for each). Plasma glucose-dependent insulinotropic polypeptide (GIP; P = 0.01) and glucagon (P = 0.06) were higher with HCA, but there were no differences in plasma glucagon-like peptide (GLP)-1, insulin, or serum 3-OMG concentrations. In patients with type 2 diabetes, blood glucose, and plasma GIP, GLP-1, and insulin did not differ between HCA and control either before or after intraduodenal glucose, but during glucose infusion, plasma glucagon was higher with HCA (P = 0.04). CONCLUSION: In healthy individuals, small intestinal exposure to HCA resulted in a modest reduction in glycemia and stimulation of plasma GIP and glucagon, but no effect on plasma GLP-1 or insulin, or on glucose absorption. HCA had no effect on glycemia in patients with type 2 diabetes.

Evaluation of antidiabetic properties of cactus pear seed oil in rats.

CONTEXT: Cactus pear (Opuntia ficus-indica (L.) Mill. (Cactaceae)) is a medicinal plant widely used to treat diabetes. OBJECTIVE: This work investigates the hypoglycemic and antihyperglycemic effect of cactus pear seed oil (CPSO), its mechanism of action, and any toxic effects. MATERIALS AND METHODS: The hypoglycemic effect of CPSO was evaluated in groups of six healthy Wistar rats given 1 or 2 ml kg(-1) orally and compared with groups receiving glibenclamide (2 mg kg(-1)) or water. Glycemia was determined after 30, 60, 120, 240, and 360 min. The antihyperglycemic effect of CPSO was determined in healthy rats and in streptozotocin-induced diabetic rats (STZ); normal rats received 0.8 ml kg(-1) CPSO, while diabetic rats received 1 ml kg(-1) CPSO, their controls received water or 2 mg kg(-1) glibenclamide. For the antihyperglycemic effect evaluation, all the animals were fasted for 16 h before treatment and received glucose orally at 1 g kg(-1) 30 min after treatment; blood was taken after 30, 90, 150, and 210 min. Intestinal glucose absorption was estimated in rat jejunum perfused with a solution containing 5.55 mmol l(-1) glucose. Acute toxicity was determined in albino mice that received oral or intraperitoneal doses of 1, 3, or 5 ml kg(-1) CPSO. RESULTS: CPSO (p.o.) decreased postprandial hyperglycemia (60 min after glucose loading), 40.33% and 16.01%, in healthy and STZ-diabetic glucose-loaded rats, respectively. CPSO, also, significantly decreased intestinal glucose absorption by 25.42%. No adverse effects were seen in mice administered CPSO at up to 5 ml kg(-1). CONCLUSION: CPSO is antihyperglycemic. The effect can be explained partly by inhibition of intestinal glucose absorption.

Inhibition of α-glucosidase and glucose intestinal absorption by Thymelaea hirsuta fractions.

BACKGROUND: Thymelaea hirsuta (L.) Endl. (Thymelaeaceae) is a medicinal plant used in Morocco to treat diabetes. In previous studies T. hirsuta has shown a potent antihyperglycemic effect. Our aim was to study the effect of the plant on α-glucosidase inhibition and intestinal glucose absorption. METHODS: Five fractions of T. hirsuta were tested, in vitro, in vivo and, in situ, to elucidate the inhibition of α-glucosidase and intestinal glucose uptake. RESULTS: The fractions induced, in vitro, a significant inhibition of α-glucosidase. The ethyl acetate fraction (EATh) had high activity and its inhibition mode was non-competitive. The EATh at 50 and 100 mg/kg doses, decreased significantly, in vivo, the postprandial hyperglycemia after sucrose loading in normal and diabetic mice. Moreover, 50 mg/kg of EATh significantly decreased intestinal glucose uptake, in situ, in rats. CONCLUSION: The antihyperglycemic effect of T. hirsuta can be explained, in part, by the inhibition of intestinal α-glucosidase and intestinal glucose absorption.

Purificación parcial de un compuesto presente en las hojas de bauhinia megalandra capaz de inhibir la absorción intestinal de glucosa / Partial purification of a compound present in the leaves of Bauhinia megalandra capable of inhibiting intestinal glucose absorption

En la actualidad muchas investigaciones se han volcado al estudio de la actividad biológica de varias plantas que se considera, en el saber de los pueblos, puedan aliviar los síntomas en pacientes con diabetes, tal es el caso de Bauhinia megalandra. El estudio fitoquímico de las hojas de dicha planta se realizó guiado por bioensayos, evaluando el efecto de cada fracción obtenida sobre la absorción intestinal de glucosa con la finalidad de encontrar aquella que presente el mayor efecto inhibitorio sobre dicha actividad biológica, utilizando para su medición segmentos de intestino de rata aislados in situ. Luego de una serie de extracciones secuenciales con diferentes solventes orgánicos y fraccionamiento por cromatografía de columna en silica gel 60, se logró aislar y caracterizar por métodos espectroscópicos una fracción altamente enriquecida con el flavonoide apigenina glucosilada en el carbono ocho. Dicha fracción fue capaz de inhibir la absorción intestinal de glucosa en un 47,34% con respecto al control, y de generar un efecto aditivo cuando se ensayo junto a la floricina

At present, it has been an increase in the research of the biological activity of plants used by the traditional medicine for the empirical treatment of the diabetes mellitus, such as Bauhinia megalandra. The phytochemical study of the leaves of these plants was done guided by bioassay, evaluating the effect of each fraction on the glucose intestinal absorption, using in situ rat intestinal segments. After a sequential series of extractions with organic solvents and fractionation by column chromatographic on silica gel 60, we isolated a fraction characterized by spectroscopic method to be highly enriched in the flavonoid apigenin glicolisated in the carbon eight. This fraction was able to inhibit in a 47,34% the intestinal glucose absorption compared to control, and showed an additive effect when used simultaneously with phloricin