Comparative effects of xylitol and erythritol on modulating blood glucose;inducing insulin secretion;reducing dyslipidemia and redox imbalance in a type 2 diabetes rat model

Xylitol and erythritol have been reported in numerous previous and recent studies as potential antidiabetic sweeteners,however,it is not certain which one is most effective in this regard.In the present study,the effects of xylitol and erythritol were comparatively investigated on blood glucose,insulin level,dyslipidemia,pancreatic islet morphology andβ-cell function,and redox imbalance in a type 2 diabetes(T2D)model of rats.Seven-week-old male Sprague-Dawley rats were randomly divided into 8 groups:Normal Control(NC),Diabetic Control(DC),Diabetic Xylitol 5%(DX5),Diabetic Xylitol 10%(DX10),Diabetic Xylitol 20%(DX20),Diabetic Erythritol 5%(DE5),Diabetic Erythritol 10%(DE10),and Diabetic Erythritol 20%(DE20).T2D was induced in the diabetic groups initially by feeding 10%fructose solution to induce insulin resistance followed by an intraperitoneal injection of streptozotocin(40 mg/kg body weight)dissolved in citrate buffer(pH 4.5)to induce partial pancreaticβ-cells dysfunctions.The animals in NC group were fed with normal drinking water and injected with citrate buffer only.After the confi rmation of diabetes,the xylitol and erythritol with above-mentioned concentrations were supplied to the respective animal groups when the animals in NC and DC groups were supplied with normal drinking water.After 8 weeks intervention period,the body weight,fl uid and water intake,blood glucose,serum alanine aminotransferase,aspartate aminotransferase,CK-MB and creatinine were signifi cantly decreased,while the serum insulin level,serum lipids,glucose tolerance ability,pancreatic islet morphology andβ-cell function,pancreatic and serum redox imbalance were improved in the most xylitol and erythritol fed groups compared to the DC group,when effects were better for xylitol compared to erythritol.The data of this study suggests that xylitol has better antioxidant and antidiabetic effects compared to erythritol.Therefore,xylitol can be used as a preferrable dietary anti-diabetic sweetener or supplement over erythritol for the management of diabetes and its associated complications.

Red honeybush(Cyclopia genistoides)tea mitigates oxidative imbalance and hyperlipidemia,while improving glucose homeostasis in type 2 diabetic rats

Red honeybush tea(RHT)is a tea product developed from Cyclopia spp.which is endemic to South Africa.Aside refreshment,RHT has over the years been used traditionally in the treatment of various diseases including type 2 diabetes.This study investigated the in vivo antioxidant and anti-diabetic activity of RHT concentrated hot water extract in type 2 diabetes(T2D)model of rats.T2D was induced starting with feeding 10%fructose solution ad libitum for 2 weeks followed by a single intraperitoneal injection of streptozotocin(40 mg/kg body weight(BW)).Five weeks of treatment of RHT led to significant(P<0.05)elevation in serum insulin,pancreaticβ-cell function,HDL-C levels with concomitant decrease in AST,ALT,ALP,urea,CK-MB,fructosamine,total cholesterol,triglycerides,LDL-C,and insulin resistance in diabetic rats.RHT also signifi cantly(P<0.05)decreased MDA levels and enhanced level of GSH,activity of SOD,catalase,GR in most of organs(pancreas,liver,kidneys,and heart).Signifi cantly(P<0.05)improved morphological changes in the islets andβ-cells were observed in rats treated with RHT.The data of this study suggest that RHT demonstrates an outstanding antioxidant and anti-diabetic effects in STZ-induced T2D model of rats.

Senna petersiana inhibits key digestive enzymes and modulates dysfunctional enzyme activities in oxidative pancreatic injury

Objective:To evaluate the effect of Senna petersiana leaf extracts on key digestive enzymes and FeSO_(4)-induced oxidative injury.Methods:Dried Senna petersiana leaf powder(60 g)was defatted in n-hexane and then extracted sequentially at room temperature with dichloromethane,methanol,and distilled water.The total phytochemical content of the extracts was estimated using established methods.The in vitro antioxidant,anti-lipase,and antidiabetic activities and the effect of the extracts on intestinal glucose absorption and FeSO_(4)-induced pancreatic oxidative injury were determined using different protocols.Moreover,GC-MS analysis was performed to identify the main compounds of the plant extract.Molecular docking analysis was also carried out to evaluate the binding energy of compounds with digestive enzymes.Results:Senna petersiana leaf extracts showed significant antioxidant activities in FRAP,DPPH,and hydroxyl radical scavenging assays.They also inhibited pancreatic lipase and lowered intestinal glucose absorption by suppressing activities ofα-amylase andα-glucosidase.Treatment with the extracts also lowered lipid peroxidation(malondialdehyde),nitric oxide level,acetylcholinesterase,and ATPase activities with simultaneous improvement of antioxidant(catalase,superoxide dismutase,glutathione)capacity in the type 2 diabetes model of oxidative pancreatic injury.GC-MS characterization of the extracts revealed the presence of stilbenoids,alkaloids,and other compounds.Molecular docking screening assay indicated the extract phytochemicals showed strong interaction with the active site amino acids of the targeted digestive enzymes.Among the Senna petersiana compounds,veratramine had the highest affinity forα-amylase and lipase,whereas dihydrostilbestrol was most attracted toα-glucosidase.Conclusions:Senna petersiana inhibits carbohydrate digestive enzymes,reduces intestinal glucose absorption,and exerts ameliorative effects on FeSO_(4)-induced oxidative pancreatic injury with significant antioxidant capabilities.Detailed in vivo studies are underway to understand the plant's therapeutic potential in diabetes management.

Rhus longipes (Engl.) infusions improve glucose metabolism and mitigate oxidative biomarkers in ferrous sulfate-induced renal injury

Objective:To explore the antioxidant and antidiabetic activities of Rhus longipes(R.longipes)leaf and stem bark aqueous infusions.Methods:R.longipes leaf and stem bark infusions were characterized via gas-chromatography mass-spectroscopy(GC-MS)analysis.In vitro antioxidant and carbohydrate and lipid digestive enzyme inhibitory activities of R.longipes infusions were determined.Additionally,the modulatory effects of R.longipes infusions on intestinal glucose absorption,muscle glucose uptake,and biomarkers of renal oxidative injury were evaluated.Molecular docking was performed to determine the binding affinities of the identified compounds from the leaf and stem bark infusions on carbohydrate and lipid digestive enzymes.Results:GC-MS analysis revealed the presence of several phytocompounds,including palmitoleic acid,octadecanamide,24,25-dihydroxyvitamin D and L-ascorbic acid.The bark infusion had significantly higher total phenolic contents compared with the leaf infusion,with better DPPH scavenging[IC_(50):(10.50±1.03)μg/mL]and ferric reducing[IC_(50):(9.85±0.32)μg/mL]activities(P<0.05).Both R.longipes infusions at their highest concentrations significantly increased glucose uptake in yeast suspension and rat psoas muscle with marked suppression of glucose absorption in the rat jejunum(P<0.05).With no cytotoxicity on Vero cells,the infusions lowered lipid peroxidation,increased cellular reduced glutathione concentration,and the activities of superoxide dismutase and catalase in renal homogenate treated with FeSO_(4).Conclusions:R.longipes shows antioxidant and antidiabetic activities and could be a potential therapeutic candidate for diabetes.

Harpephyllum caffrum stimulates glucose uptake,abates redox imbalance and modulates purinergic and glucogenic enzyme activities in oxidative hepatic injury

Objective:To investigate the antioxidative and antidiabetic effects of Harpephyllum caffrum bark infusion as well as its effects on glucogenic and nucleotide hydrolyzing enzyme activities in FeSO4-induced oxidative stress in rat hepatic tissue.Methods:Harpephyllum caffrum infusion was prepared from dried plant materials(40 g)infused in boiling water(400 mL)for 20 min at room temperature.The antioxidative and inhibitory activities against carbohydrate digestive enzymes of the infusion were determined using established protocols.The liver tissues of rats were used for glucose uptake assay and to evaluate the infusion’s effect on endogenous antioxidant,glucogenic,and nucleotide hydrolyzing enzyme activities in FeSO4-induced hepatic injury.Results:The Harpephyllum caffrum infusion significantly reduced ferric iron(FRAP)and free radicals(OH•and DPPH)in a dose-dependent manner.It inhibitedα-amylase andα-glucosidase activities and increased glucose uptake in hepatic tissues.FeSO4 significantly decreased glutathione concentration,catalase,and superoxide dismutase activities while increasing malondialdehyde level,glycogen phosphorylase,fructose-1,6-bisphosphatase,and adenosine triphosphatase activities.However,treatment with Harpephyllum caffrum infusion reversed FeSO4-induced changes.Characterization of the infusion revealed the presence of catechol,O-pyrocatechuic acid,mequinol,maltol,and glycoside derivatives.Conclusions:The Harpephyllum caffrum infusion demonstrates antidiabetic and antioxidative potentials in in vitro models of type 2 diabetes as depicted by its ability to inhibit carbohydrate digestive enzymes,mitigate oxidative imbalance,and regulate glucogenic and nucleotide hydrolyzing enzyme activities in oxidative hepatic injury.