A new colorimetric method for the estimation of glycosylated hemoglobin

Biochanin A, a soy isoflavone, diminishes insulin resistance by modulating insulin-signalling pathway in high-fat diet-induced diabetic mice

AIM

The objective of this study was to evaluate the probable mechanism of action of Biochanin A (BCA) on high-fat diet-induced insulin resistance mice.

METHODS

Twenty-four male C57/BL/6J mice were divided into two and fed either control diet or a high fat-high diet (HFD). After 6 weeks, mice were grouped into: Control, Control + BCA, HFD and HFD + BCA (n = 6). Mice were made diabetic by feeding them an HFD.

RESULTS

Body weight, plasma glucose, insulin, leptin levels and HOMA values were significantly lower in the BCA supplemented HFD group when related to the HFD group. Furthermore, BCA supplementation significantly increased Insulin receptor substrate 1 (IRS 1), PI3K, Akt and Glucose transporter type 4 (GLUT-4) protein abundance in skeletal muscle when equated with HFD.

CONCLUSION

This study demonstrates that BCA can improve insulin sensitivity by activating insulin signalling, suggesting that it may possess antidiabetic activities.

Senna petersiana (Bolle) leaf extract modulates glycemic homeostasis and improves dysregulated enzyme activities in fructose-fed streptozotocin-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Senna petersiana (Bolle) is a native South African medicinal shrub combined locally with other plant products to manage diabetes or used as a single therapy for several other ailing conditions.

AIM OF THE STUDY

This study evaluated the antidiabetic and antilipidemic effects of S. petersiana leaf ethanol extract and its modulatory effects on dysregulated enzyme activities in fructose-fed streptozotocin-induced diabetic rats.

MATERIALS AND METHODS

Six groups of 6-weeks old male Sprague Dawley rats were used in this study. Diabetes was induced in four of the groups by injecting (i.p.) 40 mg/kg of streptozotocin after a two-weeks feeding of 10% fructose via drinking water, while animals in the two normal groups were given similar volume of vehicle buffer and normal drinking water, respectively. After the confirmation of diabetes, treatment with 150 and 300 mg/kg body weight of the ethanolic leaf extract of S. petersiana proceeded for a period of 6 weeks.

RESULTS

Oral administration of S. petersiana leaf extract significantly lowered blood glucose, food and liquid intake, glycosylhaemoglobin in blood, liver and cardiac biomarkers, and lipid profile in serum and atherogenic index (AIP) in both the low and high-dose treated animal groups. This was accompanied by a simultaneous increase in Homeostatic Model Assessment-beta (HOMA-β) score, serum high-density lipoproteins cholesterol (HDL-c), and insulin levels. It also improved pancreatic and serum-reduced glutathione (GSH) levels, catalase, and superoxide dismutase (SOD) enzymes activities with a simultaneous reduction in malondialdehyde (MDA) and nitric oxide (NO) concentrations. Moreover, the extract modulated dysregulated α-amylase, lipase, cholinesterase, and 5' nucleotidase enzyme activities in pancreatic tissue as well as glycogen metabolism in the liver. Analysis of the phytochemicals in the S. petersiana extract showed the presence of phytol, 4a,7,7,10a-tetramethyldodecahydrobenzo[f]-chromen-3-ol, phytol acetate, solasodine glucoside, cassine, veratramine and solasodine acetate. Amongst these compounds, solasodine glucoside had the best binding energy (ΔG) with the selected diabetes-linked enzymes via molecular docking simulation.

CONCLUSION

Data from this study demonstrate the antidiabetic effects of S. petersiana leaf extract via the modulation of the dysregulated indices involved in type 2 diabetes and its associated complications. Although it has been shown safe in animals, further toxicological studies are required to ensure its safety for diabetes management in humans.

Vulgarin, a Sesquiterpene Lactone from Artemisia judaica, Improves the Antidiabetic Effectiveness of Glibenclamide in Streptozotocin-Induced Diabetic Rats via Modulation of PEPCK and G6Pase Genes Expression

The current investigation assessed the effect of the eudesmanolid, Vulgarin (VGN), obtained from Artemisia judaica (A. judaica), on the antidiabetic potential of glibenclamide (GLB) using streptozotocin (STZ) to induce diabetes. Seven groups of rats were used in the study; the first group received the vehicle and served as normal control. The diabetic rats of the second to the fifth groups were treated with the vehicle (negative control), GLB at 5 mg/kg (positive control), VGN at 10 mg/kg (VGN-10) and VGN at 20 mg/kg (VGN-20), respectively. The diabetic rats of the sixth and seventh groups were administered combinations of GLB plus VGN-10 and GLB plus VGN-20, respectively. The diabetic rats treated with GLB plus VGN-20 combination showed marked improvement in the fasting blood glucose (FBG), insulin and glycated hemoglobin (HbA1c), as well as the lipid profile, compared with those treated with GLB alone. Further, the pancreatic tissues of the diabetic rats that received the GLB+VGN-20 combination showed superior improvements in lipid peroxidation and antioxidant parameters than those of GLB monotherapy. The insulin content of the β-cells was restored in all treatments, while the levels of glucagon and somatostatin of the α- and δ-endocrine cells were reduced in the pancreatic islets. In addition, the concurrent administration of GLB+VGN-20 was the most effective in restoring PEPCK and G6Pase mRNA expression in the liver. In conclusion, the results demonstrated that the GLB+VGN-20 combination led to greater glycemic improvement in diabetic rats compared with GLB monotherapy through its antioxidant effect and capability to modulate PEPCK and G6Pase gene expression in their livers.

Protective Effects of the Bilobalide on Retinal Oxidative Stress and Inflammation in Streptozotocin-Induced Diabetic Rats

Diabetic retinopathy (DR) is a diabetes mellitus (DM) complication that causes visual acuity impairment and loss of sight in the working population, mainly in developed countries. According to the WHO, DR accounts for 5% of the world's 37 million blind people. The prevalence of diabetic retinopathy was highest in Africa, followed by North America and the Caribbean and South and Central America. Hyperglycemia can generate excessive ROS that activates multiple pathways, which can damage the cells. Oxidative stress and inflammatory process are intricate in the DR pathological mechanism. Bilobalide is the main bioactive compound isolated from the Ginkgo biloba, a plant utilized in folklore medicine. Bilobalide, a sesquiterpene trilactone, exhibits excellent antioxidant activity. But the molecular mechanisms associated with such effects, especially the antioxidant-related mechanism, have not been documented. Hence, this investigation explored whether bilobalide may attenuate DR in streptozotocin (STZ)-prompted diabetic rats. The effects of bilobalide on parameters of antioxidant content, oxidative stress, and inflammatory factors in the retinal tissues were evaluated by ELISA, RT-PCR, and immunohistochemistry methods. Bilobalide improved caloric management by reducing food consumption and increasing body weight. Furthermore, the administration of bilobalide decreases the blood glucose level and glycosylated (HbA1c) hemoglobin. The anti-retinopathy activity of bilobalide was established by the increase in the total retina thickness (TRT), inner nuclear layer (INL), and outer nuclear layer (ONL) in diabetic rats. Additionally, the serum level of MDA was decreased. In contrast, the antioxidant enzyme (SOD and CAT) levels were increased with TAC plus lower Keap1 and higher Nrf2 expression in the retina when associated with the DM rats. Moreover, bilobalide increased the nuclear factor erythroid 2-related factor 2 (Nrf2) and Heme oxygenase-1 (HO-1) expression level and inflammatory mediators (NF-κβ p65, TNF-α, IL-1β, and VEGF), thus inhibiting oxidative stress. Bilobalide can be effective against DR, and the possible mechanism may be relatively elucidated by decreasing oxidative stress and anti-inflammatory activities. But the further investigation should be directed to expose the precise mechanism.

Mesenchymal Stem Cells Ameliorate Hyperglycemia in Type I Diabetic Developing Male Rats

One of the most promising treatments for diabetes mellitus (DM) is stem cell therapy. This study is aimed at elucidating the antidiabetic effect of mesenchymal stem cells (MSCs) on streptozotocin- (STZ-) induced DM in developing male rats. Twenty-four male albino rats (4 weeks old) were divided into control, diabetic, diabetic+MSCs1 (received MSCs one week after STZ treatment), and diabetic+MSCs2 (received MSCs 4 weeks after STZ treatment). Diabetic rats showed marked impairment ( $p<0.05$ ) in serum levels of glucose, insulin, C-peptide, glycosylated hemoglobin (HbA1c), malondialdehyde (MDA), total antioxidant status (TAS), and total oxidant status (TOS) in addition to disruption of the calculated values of homeostatic model assessment of insulin resistance (HOMA-IR), pancreatic β cell function (HOMA-β), and oxidative stress index (OSI). These biochemical alterations were confirmed by the histopathological and ultrastructural assessments which showed marked destructive effect on pancreatic islet cells. MSC therapy in an early stage reversed most of the biochemical, histological, and ultrastructural alterations in the STZ-induced diabetic model and restored the normal cellular population of most acinar cells and islet of Langerhans. These results indicate that MSC therapy of STZ-induced diabetic developing rats during an early stage has the capacity of β cell restoration and the control of blood glycemic homeostasis.

Methanolic Extract of Myrsine africana Leaf Ameliorates Hyperglycemia and Dyslipidemia in Alloxan-Induced Diabetic Albino Mice

Background. Diabetes mellitus is one of the leading public health problems globally, and its prevalence is increasing in Ethiopia. The current drugs for people with diabetes are costly, less effective, and less safe with a challenging administration method. Thus, globally, the need for alternative herbal antidiabetic medicines is increasing. In the previous studies, antioxidant activities have been seen in crude extracts of M. africana leaves, which is an auspicious sign of antidiabetic property. Accordingly, this study has evaluated the antidiabetic and antidyslipidemic activities of methanolic extract of M. africana leaves. Methods. Hypoglycemic and antihyperglycemic activities of the three doses (250 mg/kg, 500 mg/kg, and 1000 mg/kg) of crude methanolic extract of M. africana leaf were studied on normoglycemic, oral glucose-loaded, and alloxan-induced diabetic mice models. The effect of the extract on diabetic dyslipidemia, insulin and glycated hemoglobin levels, carbohydrate-metabolizing enzymes, and body weight was also studied in alloxan-induced diabetic mice. Glibenclamide (5 mg/kg) was used as a standard drug in all cases. Data analysis was carried out using mixed-design ANOVA. A $P$ value of ≤0.05 was considered a statistically significant difference. Results. The methanolic extract of M. africana leaf did not show acute toxicity up to the dose of 5000 mg/kg and showed better glucose utilization in the oral glucose tolerance test. After 14 days of treatment, M. africana leaf extract decreased the blood glucose level, glycated hemoglobin, glucose-6-phosphatase, and fructose-1-6-bisphosphatase in diabetic mice. In contrast, it increased hexokinase and insulin levels in diabetic mice. Moreover, weight loss and dyslipidemia profiles have been corrected significantly in diabetic mice. Conclusion. M. africana leaves showed antihyperglycemic and antidyslipidemic effects in alloxan-induced diabetic mice. That suggests M. africana may be a potential treatment option for diabetes in the future. However, further molecular studies are required to analyze the mechanisms.

Biochemical characterization of high fat diet fed and low dose streptozotocin induced diabetic Wistar rat model

The development of a stable disease model with an adequate biochemical profile is crucial for the preclinical investigation of new antidiabetic agents. This study aimed at optimization and characterization of high fat diet (HFD) fed streptozotocin (STZ) induced type 2 diabetes mellitus (type 2 DM) Wistar rat model. Wistar rats fed with HFD for four weeks received STZ (30, 40, and 50 mg/kg, intraperitoneal). Diabetic rats were observed for four more weeks and sacrificed. Non- injected healthy Wistar rats and HFD-fed rats were used as control groups. The glucose status and the lipid profile of the model were assessed. STZ-induced rats showed significant dose-dependent alterations in fasting serum insulin and glucose, homeostatic model assessment- insulin resistance (HOMA-IR), HOMA- β cell function (HOMA- β), quantitative insulin sensitivity check index (QUICKI), total cholesterol (TC), triglycerides (TG) and atherogenic index (AI). STZ 50 mg/kg group rats showed significant increase in glycated hemoglobin (HbA_1c), low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (VLDL-C) levels compared to healthy rats. The atherogenic risk index (ARI), the Castelli risk index-I (CRII), and CRI-II were significantly (p < 0.05) high in the STZ 40 mg/kg and 50 mg/kg group rats. Results suggest that the Wistar rats fed with HFD rich in saturated fat for four weeks followed by a single intraperitoneal dose of 50 mg/kg of STZ would produce a stable diabetic model which closely mimic biochemical features of type 2 DM. Key messages: Wistar rats fed with HFD rich in saturated fat for four weeks followed by a single intraperitoneal dose of 50 mg/kg STZ would produce a stable diabetic model that closely mimics the biochemical characteristics of type 2 DM characterized by insulin resistance, relative insulin deficiency and impaired β cell function.

Antidiabetic Potential of Sinigrin Against Streptozotocin-Induced Diabetes via Modulating Inflammation and Oxidative Stress

Diabetes mellitus (DM) is a common metabolic disorder which arises due to the improper carbohydrate metabolism, decreased secretion/activity of insulin, and genetic abnormalities, which result in the increased blood glucose level generally known as hyperglycemia. Diabetes holds an increased global prevalence in each year and is responsible for increased morbidity and mortality rates. Hence, the current investigation focusses to assess the antidiabetic potential of sinigrin on diabetic animal model through the suppression of inflammation. Diabetes was initiated to the animals via administering streptozotocin (STZ) and supplemented with the sinigrin at 25- and 50-mg/kg dose via oral route. The diabetic rats demonstrated the elevated glucose, food and water intake, kidney and liver weights, and reduced bodyweight and depleted insulin status. The sinigrin treatment remarkably improved and modulated these changes in diabetic animals. Additionally, the sinigrin supplementation also modulated the changes in glucose-6-phosphatase; fructose 1,6-bisphosphatase; AST; ALT; creatinine; and inflammatory mediators in the STZ-provoked diabetic animals. The levels of hexokinase, protein, and antioxidants also improved by the sinigrin treatment. The histological investigations of pancreas also witnessed the therapeutic actions of sinigrin, which is supported by the findings of biochemical examinations. Therefore, it was clear that the sinigrin supplementation displayed remarkable antidiabetic effect on STZ-initiated diabetic animals via modulating inflammation and other biochemical changes, which recommends that sinigrin could be a talented candidate for diabetes management in the future.

Modulatory effect of isopulegol on hepatic key enzymes of glucose metabolism in high-fat diet/streptozotocin-induced diabetic rats

To investigate the antidiabetic effect of isopulegol in high-fat diet (HFD)/streptozotocin (STZ)-induced diabetic rats. Animals were made diabetic by feeding HFD for 4 weeks followed by single intraperitoneal injection of STZ (35 mg/kg b.w.; 0.1 M citrate buffer; pH 4.0). Plasma insulin, haemoglobin and glycogen content were decreased while increased glucose and glycated haemoglobin were observed in diabetic rats. An increase in glucose-6-phosphatase, fructose-1,6-bisphosphatase, phosphoenol pyruvate carboxykinase with a decrease in hexokinase, glucose-6-phosphate dehydrogenase and glycogen synthase activities was observed in diabetic rats. The expression of cyclic response element binding protein (CREB) was increased in the hepatic tissue of diabetic rats. Isopulegol dose dependently (50, 100 and 200 mg/kg b.w.) improved insulin secretion, glucose tolerance and decreased glucose levels in diabetic-treated rats. At the effective dose of 100 mg/kg b.w., isopulegol restored the activities of metabolic enzymes and down-regulated CREB expression. Thus, isopulegol restored glucose homeostasis through its insulinotrophic property.

Ameliorative property of Sesbania grandiflora on carbohydrate metabolic enzymes in the liver and kidney of streptozotocin-induced diabetic rats

In diabetic condition, endogenous glucose synthesis will be elevated due to defect in the action of vital enzymes involved in carbohydrate metabolism, which is the main cause for hyperglycemia. The current study was designed to explore the anti-hyperglycemic efficacy of Sesbania grandiflora flower (SGF) extract by evaluating the concentration of C-peptide, insulin, glucose, glycosylated hemoglobin (HbA1C), hemoglobin (Hb), glycogen and carbohydrate metabolic enzymes activities in diabetic rats. The study found to lower the level of glucose, HbA1C and simultaneously ameliorated concentrations of C-peptide, insulin, hemoglobin (Hb), glycogen and carbohydrate metabolic enzymes activities in SGF treated (250 mg/kg body weight for 45 days) diabetic rats. Moreover, SGF administered diabetic rats showed diminished consumption of food and water at the same time improved body weight. The results obtained from the present study were compared with glibenclamide treated (600 µg/kg body weight) diabetic rats. SGF were supplemented to normal rats to rule out toxic effect of SGF, to explore any significant alteration in the above parameters. Hence, the results depict that SGF modulated the carbohydrate metabolic enzymes activities through ameliorating the secretion of insulin and diminishing the level of glucose concentration in STZ-induced diabetic rats by its bioactive compounds.

Impact of Dairy Intake on Plasma F2-IsoProstane Profiles in Overweight Subjects with Hyperinsulinemia: A Randomized Crossover Trial

F₂-IsoProstanes (F₂-IsoPs) are major biomarkers of oxidative stress and are associated with type 2 diabetes (T2D). Further, plasma levels of F₂-IsoPs may be modified by dairy products. The aim is to investigate the effect of high dairy product (HD) consumption compared to an adequate dairy product (AD) consumption on the level of F₂-IsoPs among hyperinsulinemic subjects. In this crossover study, participants were randomized in two groups: HD (≥4 servings/day), or AD (≤2 servings/day) for six weeks. Fasting blood glucose and insulin were measured. The homeostatic model assessment of insulin resistance (HOMA-IR) was calculated. Six isomers of F₂-IsoPs were quantified by HPLC-MS/MS. Twenty-seven subjects with hyperinsulinemia (mean age; 55 ± 13 years, BMI; 31.4 ± 3.3 kg/m2) were included. Fasting glucose, insulin and HOMA-IR were unchanged after HD or AD intervention. After HD intake, the total level of F₂-IsoPs (p = 0.03), 5-F_2t-IsoP (p = 0.002), and 8-F_2t-IsoP (p = 0.004) decreased compared to AD. The 15-F_2t-IsoP tended to be positively correlated with fasting blood glucose (r = 0.39, p = 0.08). Generally, F₂-IsoPs levels were higher among men compared to women regardless of the dairy intake. Overall, intake of HD decreased plasma levels of F₂-IsoPs compared to AD without modifying glycemic parameters.

Antioxidant potential of biflavonoid attenuates hyperglycemia by modulating the carbohydrate metabolic enzymes in high fat diet/streptozotocin induced diabetic rats

Objectives: The present study was to isolate the biflavonoid (a bimolecular kaemferol structured molecule) and test its efficacy on oxidative stress and carbohydrate metabolic key enzymes in control and high fat diet and streptozotocin -induced diabetic rats.

Methods: Type 2 diabetes was induced in male albino wistar rats by feeding them with high fat diet comprising of 84.3% standard laboratory chow, 5% lard, 10% yolk powder, cholesterol 0.2%, and 0.5% bile salt for 2 weeks. After 2 weeks, the animals were kept in an overnight fast and injected with low dose of streptozotocin (35 mg/kg, dissolved in 0.1 M sodium citrate buffer, pH 4.5).

Results: At the end of the experimental period, diabetic control rats showed significant increase in plasma glucose, homeostatic model assessment of insulin resistance (HOMA-IR), glycosylated hemoglobin (HbA1c) with concomitant decrease in plasma insulin, total hemoglobin and body weight. The activities of key enzymes of carbohydrate metabolism, lipid peroxidation markers, antioxidant enzymes, glycogen content and glycogen synthase and glycogen phosphorylase were also altered in diabetic rats.

Discussion: Oral administration of biflavonoid to diabetic rats significantly ameliorated all the biochemical alterations to near normal levels. The effect produced by the biflavonoid on various parameters was comparable to that of metformin.

Triphenylphosphonium functionalized Ficus religiosa L. extract loaded nanoparticles improve the mitochondrial function in oxidative stress induced diabetes

The present study was aimed to enhance the mitochondrial function in oxidative stress-induced diabetes. To achieve this, Ficus religiosa L. extract loaded solid lipid nanoparticles (ETNPs) were prepared and functionalized by using triphenylphosphonium. Developed nanoparticles demonstrated desired quality attributes with sustained release for up to 24 h and excellent storage stability for up to 180 days at 40 ± 2°C and 75 ± 5% relative humidity. In vitro cytotoxicity assessment showed no toxicity of ETNPs. Interestingly, oral administration of ETNPs to diabetic rats demonstrated improved mitochondrial function by normalizing the mitochondrial morphology, intracellular calcium ion concentration, complexes I, II, IV, and V activity, mitochondrial membrane potential, and antioxidant levels. Further, reduction in apoptotic markers viz. cytochrome-C, caspase-3, and caspase-9 was observed following the ETNP treatment. Moreover, significant reduction in blood glucose and glycosylated hemoglobin while significant improvement in plasma insulin was observed as compared to the diabetic group following the treatment with developed formulation. Furthermore, histopathology studies confirmed the safety of the developed formulation and thus, data in hand collectively suggest that proposed strategy can be effectively used to improve the mitochondrial function in oxidative stress-induced diabetes along with better control over blood glucose and glycosylated hemoglobin.

Thymoquinone, the Most Prominent Constituent of Nigella Sativa, Attenuates Liver Damage in Streptozotocin-Induced Diabetic Rats via Regulation of Oxidative Stress, Inflammation and Cyclooxygenase-2 Protein Expression

Diabetes mellitus (DM) is a multifaceted metabolic disorder that results in dysfunction and failure of various organs. The present study aimed to evaluate the role of Thymoquinone (TQ), on antidiabetic, oxidative stress, and anti-inflammatory activities in streptozotocin (STZ)-induced (55 mg/kg b.w) diabetic rats. TQ was orally given for 8 consecutive weeks at dose of 150 mg/kg b.w. The blood glucose, insulin, total cholesterol, triglycerides, liver function enzymes, high density lipoprotein (HDL)-cholesterol, and low-density lipoprotein (LDL)-cholesterol levels were measured accordingly in control, diabetes control (DC), and TQ-treatment groups. These experiments confirmed that TQ conserves the insulin level (0.4 ng/mL vs. 0.23 ng/mL), fasting blood glucose (146 ± 7 mg/dL vs. 225 ± 5 mg/dL), and HbA1c (7.5% vs. 10.6%) quite considerably as compared to DC animals. Our results also confirmed that TQ treatment conserves the body weight and lipid profile significantly in STZ-treated animals as compared to the DC group. Moreover, the antioxidant enzymes (GSH, SOD, GST, and CAT) levels decreased, liver function enzymes (ALT, AST, and ALP), lipid peroxidation and inflammatory markers (TNF-α, CRP, IL-1β, IL-6) increased by STZ treatment, that is significantly restored after TQ treatment. As compared to untreated animals, TQ restored the hepatocytes architectural changes and collagen fibers and cox-2 protein expression in liver tissues as evaluated by hematoxylin and eosin, Masson’s trichrome, and immunohistochemistry staining. Taken together, all these findings indicated that TQ ameliorates glucose level and lipid metabolism. It restores liver function, antioxidant enzymes, anti-inflammatory markers, and maintains hepatocytes architecture in STZ-induced diabetes mellitus rats. Here, in this study, we have demonstrated for the first time the role of TQ in the reduction of the expression of cyclooxygenase-2 and fibrosis formation in diabetic rats. Based on the findings, the study suggests that TQ is a novel natural drug with a wide range of clinical applications including the management of diabetes mellitus.

Myricitrin, a Glycosyloxyflavone in Myrica esculenta Bark Ameliorates Diabetic Nephropathy via Improving Glycemic Status, Reducing Oxidative Stress, and Suppressing Inflammation

The present study evaluated the therapeutic potential of myricitrin (Myr), a glycosyloxyflavone extracted from Myrica esculenta bark, against diabetic nephropathy. Myr exhibited a significant hypoglycemic effect in high fat-fed and a single low-dose streptozotocin-induced type 2 diabetic (T2D) rats. Myr was found to improve glucose uptake by the skeletal muscle via activating IRS-1/PI3K/Akt/GLUT4 signaling in vitro and in vivo. Myr significantly attenuated high glucose (HG)-induced toxicity in NRK cells and in the kidneys of T2D rats. In this study, hyperglycemia caused nephrotoxicity via endorsing oxidative stress and inflammation resulting in the induction of apoptosis, fibrosis, and inflammatory damages. Myr was found to attenuate oxidative stress via scavenging/neutralizing oxidative radicals and improving endogenous redox defense through Nrf-2 activation in both in vitro and in vivo systems. Myr was also found to attenuate diabetes-triggered renal inflammation via suppressing NF-κB activation. Myr inhibited hyperglycemia-induced apoptosis and fibrosis in renal cells evidenced by the changes in the expressions of the apoptotic and fibrotic factors. The molecular docking predicted the interactions between Myr and different signal proteins. An in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) study predicted the drug-likeness character of Myr. Results suggested the possibility of Myr to be a potential therapeutic agent for diabetic nephropathy in the future.

Safely effective hypoglycemic action of stevia and turmeric extracts on diabetic Albino rats

The potentiality of Stevia leaves and turmeric roots as remedies against diabetes mellitus type 2 was tested in this study. Stevia leaves and turmeric roots were extracted with ethanol:water (80:20 v/v) and analyzed by HPLC. Turmeric extract (TUE) was rich in; curcumin, gallic acid, and eugenol. Stevia extract (STE) contained 28 known compounds, including glycosides, aromatic organic acids, and catechin. Fifty rats were divided into five groups (10 rats each); the control group were fed with feed and water ad libitum. Forty rats were injected a single dose of alloxan, then treated with either 10 mg/kg glibenclamide (GLI), 300 mg/kg STE, or 200 mg/kg TUE or water (positive control) through daily gastric oral gavages for 56 days. Treating diabetic rats with TUE significantly reduced serum glucose and glycated hemoglobin down to the negative control levels. Both GLI and STE produced similar but less effective actions. Animals treated with either STE or TUE exhibited reduced levels of liver and kidney markers compared to the negative control, while GLI increased them significantly. It could be concluded that turmeric roots and stevia leaves extracts can be used treatment for type 2 diabetes. PRACTICAL APPLICATIONS: Turmeric roots and stevia leaves extracts may be used as a remedy for type 2 diabetic patients as aiding substituting treatments under medical supervision. The two plant sources can be used as raw materials for the extracts, which can be used under medical supervision as a gradual replacement of the synthetic antidiabetic drugs. These extracts can be used after a preliminary clinical study to determine the dose and frequency of administration. Stevia extract can be incorporated in drinks as a sweetener and drug. Turmeric extract has a bitter taste, so it may be incorporated in some foods such as bread, which is a traditional practice in some kinds of bread in Egypt. But its content in the bread and the acceptability of the taste should be adjusted. Alternatively, this food can incorporate both TUE and STE to get the best biological action and to conceal the bitter taste of turmeric.

Antihyperglycemic and antihyperlipidemic activities of wild musk melon (Cucumis melo var. agrestis) in streptozotocin-nicotinamide induced diabetic rats

Objective

Wild musk melon (Cucumis melo var. agrestis, CMA) is one of the edible plants form Tamil Nadu. Traditionally, this plant was used as diabetic diet (leaves of CMA with Momordica charantia leaves), but there is no scientific report on antidiabetic action of this plant material. Hence, the current research work was designed to evaluate the antihyperglycemic and antihyperlipidemic effect of hydroalcoholic extract of CMA leaves (HALEC) in streptozotocin (STZ)-nicotinamide (NIC)-induced diabetic rats.

Methods

Diabetes was induced by administration of STZ (60 mg/kg, i.p.) after 15 min of NIC (120 mg/kg i.p.) administration. The diabetic rats were treated with HALEC (300 and 600 mg/kg, p.o., respectively) for 21 d.

Results

After the management with HALEC, blood glucose, HbA1c levels, total cholesterol, LDL cholesterol, triglycerides levels, glycogen phosphorylase and glucose-6-phosphatase levels were significantly diminished in diabetic rats. However, haemoglobin level, HDL cholesterol, liver glycogen, total protein, hexokinase, glucose-6-phosphate dehydrogenase levels were significantly increased in HALEC treated diabetic rats. The histopathological studies of the pancreas in HALEC-treated diabetic rats showed almost normal appearance. L6 cell line study revealed the increased glucose uptake activity of HALEC. High performance thin layer chromatography (HPTLC) analysis confirms the presence of active principles such as rutin, gallic acid and quercetin in HALEC.

Conclusion

The results indicated that HALEC possess significant antihyperglycemic and antihyperlipidemic activity in STZ-NIC-induced type II diabetic rats with protective effect. This research work will be useful for the isolation of active principles and development of herbal formulation in phytopharmaceuticals.

Sciatic Nerve Structural and Functional Recovery with Extract of Phyllanthus amarus and Esculetin in STZ-Induced Hyperglycemic Rats

Background: Diabetes-instigated nerve damage is a chronic complication including impaired peripheral nerve function with lowered nerve conduction velocity (NCV), demyelination of nerve fibres and alterations in the behaviour. Many clinical and experimental studies have proved that Phyllanthus amarus and esculetin have potential effects against various diseases.

Purpose: The aim of this study is to assess the neuroprotective role of hydro-ethanolic extract of Phyllanthus amaras (PAE) and esculetin (ESC) on NCV, metabolism, behavioural and structural changes in diabetic rats.

Methods: The extent of protection using PAE and ESC in diabetic rats was determined by checking the HbA₁c, NO, myeloperoxidase (MPO), total calcium, protein content, Na⁺-K⁺ ATPase activity, acetylcholine content and behavioural alterations using rotarod and maze learning tests on 7, 14 and 21 days. NCV was measured on the 21st day.

Results: The diabetic rats showed increased HbA1c, nitrite, MPO, calcium and decreased protein, Na⁺-K⁺ ATPase activity, NCV, acetylcholine, behavioural alterations and morphological changes of sciatic nerve so that diabetic peripheral neuropathy (DPN) is manifested. Continuous treatment for three weeks with Phyllanthus amarus and esculetin significantly minimized the damage to axons and myelin sheath and enhanced the sciatic NCV by reversing all the mentioned parameters.

Conclusion: Phyllanthus amarus and esculetin showed the anti-diabetic as well as anti-inflammatory characteristics by prevention of initiation of adverse processes of the sciatic nerve morphology, internal cell functions leading to improved coordination, behavioural and physiological functions in STZ-induced diabetic rats. PAE has shown similar effects with the ESC. However, further studies are essential to confirm their detailed therapeutic effects.

Galangin controls streptozotocin-caused glucose homeostasis and reverses glycolytic and gluconeogenic enzyme changes in rats

Galangin is a natural compound with anticancer, anti-inflammatory, and antioxidant properties. However, the ameliorating effect of streptozotocin (STZ)-induced glucose homeostasis has not yet been evaluated. Hence, this study was aimed at exploring the role of galangin in STZ-induced glucose homeostasis, glycolytic and gluconeogenic enzyme changes in rats. STZ-treated rats were characterised by increased plasma glucose and glycosylated haemoglobin and decreased plasma insulin and haemoglobin compared with the normal cage. Administration of galangin to STZ-treated rats effectively reversed the adverse biochemical and haematological changes. Significant alterations in glycogen levels as well as glycolytic and gluconeogenic enzyme activities were witnessed in STZ-treated rats, and these changes were reversed upon treatment with galangin. The compound exerts potent anti-hyperglycemic effects by regulating the glucose homeostasis and reversing the glycolytic and gluconeogenic enzyme changes in rats. However, the exact mechanism through which galangin prevents diabetic complications needs to be studied in detail.

Antioxidant potential of theaflavin ameliorates the activities of key enzymes of glucose metabolism in high fat diet and streptozotocin - induced diabetic rats

Objectives: The present study was to evaluate the effect of theaflavin on the activities of key enzymes of carbohydrate metabolism in high fat diet and streptozotocin – induced diabetic rats.

Methods: Diabetes was induced in male albino Wistar rats by feeding them with high fat diet comprising of standard laboratory rat chow 84.3%, lard 5%, egg yolk powder 10%, cholesterol 0.2% and bile salt 0.5% for 2 weeks. After 2 weeks, the animals were kept in an overnight fast and injected with low dose of streptozotocin (40 mg/kg b.w).

Results: Theaflavin (100 mg/kg b.w /day) was administered orally to diabetic rats for 30 days. At the end of the experimental period, diabetic control rats showed significant increase in plasma glucose, homeostatic model assessment of insulin resistance (HOMA-IR), glycosylated hemoglobin (HbA1c) with concomitant decrease in plasma insulin, total hemoglobin and body weight. The activities of key enzymes of carbohydrate metabolism, lipid peroxidation markers, antioxidant enzymes, glycogen content and glycogen synthase and glycogen phosphorylase were also altered in diabetic rats.

Discussion: Oral administration of theaflavin to diabetic rats significantly ameliorated all the biochemical alterations to near normal levels. The results of the present study suggest that theaflavin exhibits antidiabetic effect through its antioxidant activity.

Effect of β-sitosterol on glucose homeostasis by sensitization of insulin resistance via enhanced protein expression of PPRγ and glucose transporter 4 in high fat diet and streptozotocin-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

β-Sitosterol is a plant derived compound similar to cholesterol structure and used in the treatment of hypercholesterolemia, prostate cancer, breast cancer and coronary artery disease. But no studies have been reported the effect of β-sitosterol on glucose homeostasis by sensitization of insulin resistance via enhanced protein expression of peroxisome proliferator-activated receptor γ (PPARγ) and glucose transporter 4 (GLUT4) in insulin dependent tissues of high fat diet and streptozotocin-induced diabetic rats.

MATERIALS AND METHODS

Type 2 diabetes was induced in male albino Wistar rats by feeding them with high fat diet comprising of 84.3% standard laboratory chow, 5% lard, 10% yolk powder, 0.2% cholesterol and 0.5% bile salt for 2 weeks. After 2 weeks, the animals were kept in an overnight fast and injected with low dose of streptozotocin (35 mg/kg, dissolved in 0.1 M sodium citrate buffer, pH 4.5). Analysis of blood glucose, insulin, hemoglobin and glycated hemoglobin were done by commercially available diagnostic kits. The PPARγ and GLUT4 were analyzed by western blotting using respective primary and secondary antibodies.

RESULTS

Upon administration of β-sitosterol at a dose of 15 mg/kg body weight per day to high fat diet and streptozotocin induced diabetic rats for 30 days significantly decreased the levels of plasma glucose, homeostatic model assessment of insulin resistance and glycosylated hemoglobin and increased the levels of insulin, hemoglobin and protein expression of PPARγ and GLUT4 in insulin dependent tissues. Furthermore, β-sitosterol administration prevented the body weight loss and excessive intake of food and water.

CONCLUSION

These finding suggest that β-sitosterol can replace the commercial drugs which could lead to reduction in toxicity and side effect caused by the later as well as reduce the secondary complications.

Almond-supplemented diet improves sexual functions beyond Phosphodiesterase-5 inhibition in diabetic male rats

Hyperglycemia, an important feature of diabetes, can cause oxidative stress, which is associated with varieties of diabetic complications including erectile dysfunction. Therefore, this study sought to investigate the effect of almond-supplemented diet on some biochemical indices relevant to erection in diabetic male rats. Forty-two male rats were divided into two groups: A (n = 6) and B (n = 36). Diabetes was induced in Group B via injection of a single dose of STZ (50 mg/kg) intraperitoneally and confirmed 72 h after induction. Diabetic rats (blood glucose ≥250 mg/dL) were subsequently divided into six groups (n = 6). Fourteen days after confirmation of diabetes, rats were fed with diets containing almond drupe and seeds (10 and 20% inclusion) for fourteen days. The effects of the diets on blood glucose, sexual behavior, sexual hormones, phosphodiesterase-5 activity, nitric oxide, H₂S, and AGEs levels were evaluated. Significant increase in blood glucose level, phosphodiesterase-5 activity, and glycated hemoglobin was observed in diabetic rats. Furthermore, diabetes caused a significant decrease in nitric oxide, H₂S, sexual hormones (testosterone, follicle-stimulating hormone and luteinizing hormone) levels, and sexual behavioral indices. However, treatment with diets supplemented with almond drupe and seeds significantly reversed these effects in diabetic rats. Findings in this study revealed that almond-supplemented diets enhance some important biomarkers relevant to erection in diabetic rats. Thus, dietary inclusion of almond (drupe and seeds) could serve as a cheap and readily available nutraceutical in the management of erectile dysfunction associated with diabetes.

Antidiabetic property of miracle fruit plant (Synsepalum dulcificum Shumach. & Thonn. Daniell) leaf extracts in fructose-fed streptozotocin-injected rats via anti-inflammatory activity and inhibition of carbohydrate metabolizing enzymes

ETHNOPHARMACOLOGICAL RELEVANCE

Miracle fruit plant (Synsepalum dulcificum) has many applications in folk medicine. The leaves are used traditionally to treat diabetes and other diseases. The antidiabetic potential of Synsepalum dulcificum leaves in rats has been studied but the mechanisms involved are yet to be elucidated.

AIM

The present study aimed to provide insight into the antidiabetic mechanisms of methanol and flavonoid-rich leaf extracts of Synsepalum dulcificum (MSD and FSD, respectively).

METHODS

In vivo effects of administering 30 mg/kg or 60 mg/kg MSD and FSD for 21 consecutive days to rats after type II diabetes was induced through 14 days of fructose feeding and injection of one dose of streptozotocin, were assessed. Glibenclamide (5 mg/kg) served as the reference drug. In addition, in vitro inhibitory activity of MSD and FSD on the carbohydrate metabolizing enzymes, α-amylase and glucokinase, were evaluated, with acarbose as the reference drug. Moreover, in silico analyses to elucidate the contribution of key polyphenolics to the antidiabetic activity of the extracts through docking with glucokinase were performed.

RESULTS

MSD and FSD significantly reduced HbA1c and serum levels of interleukin-6 and TNF-α (p < 0.05) in diabetic animals. Conversely, serum level of insulin and hepatic hexokinase activity were increased (p < 0.05) in extract treated groups. Both extracts showed α-amylase and α-glucosidase inhibitory activities. Quercetin, caffeic acid and chlorogenic acid in extracts showed strong binding affinities with glucokinase in the molecular docking analyses.

CONCLUSION

Results from this study indicate that increased insulin synthesis, reduction of inflammation and inhibition of carbohydrate metabolizing enzymes are likely mechanisms by which MSD and FSD exert antidiabetic action in type II diabetic rats.

Tetramethylpyrazine alleviates diabetic nephropathy through the activation of Akt signalling pathway in rats

In the whole world, the principal cause of end-stage renal disease is diabetic nephropathy (DN), which is one of the most relentless complications of diabetes. However, there is a shortfall of compelling DN treatments and the mechanism potentially able to alleviate renal injury remains ambiguous. In this experiment, we estimated the preventive actions of tetramethylpyrazine (TMP) on DN in rats and further investigated the underlying mechanism. The different doses of TMP (100 mg/kg, 150 mg/kg and 200 mg/kg) were orally given each day for 8 weeks in streptozotocin (STZ) - nicotinamide (NCT) - induced type-2 diabetic (T2D) rats. The metabolic parameters of diabetes, blood urea nitrogen (BUN), serum creatinine (SCR), urinary protein and oxidative stress parameters were assessed. Microstructural changes in kidney were observed, and the expression of Akt signalling pathway proteins was measured by western blotting. TMP administration in T2D rats improved diabetic condition, as demonstrated by significant (P < 0.05) increase of body weight and fasting serum insulin (FSI) level, reduction of fasting blood glucose (FBG) and glycosylated haemoglobin (HbA1c) level and regulation of lipid profile and oral glucose tolerance in a dose-dependent manner. TMP treatment also reduced BUN, SCR, urinary protein and oxidative stress and prevented renal injury in diabetic rats. TMP activated Akt signalling pathway, increased the levels of p-Akt and Bcl-2, and diminished the expressions of p-GSK-3β, Bax and cleaved caspase-3. In conclusion, TMP ameliorates diabetic nephropathy in T2D rats by initiating the Akt signalling, improving the metabolic markers of diabetes and suppressing oxidative stress.

Antidiabetic and hypolipidemic efficacy of skin and seed extracts of Momordica cymbalaria on alloxan induced diabetic model in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Momordica cymbalaria, a wild vegetable belongs to the Cucurbitaceae family, has long been used as a food and a remedy for diabetes mellitus in the Asian native medicinal system.

AIM OF THE STUDY

This study aims to evaluate the efficacy of ethanolic extract of skin (EESK) and methanolic extract of seed (MESE) of M. cymbalaria (MC), for their hypoglycemic and hypolipidemic effects in alloxan induced diabetic rats.

MATERIALS AND METHODS

The diabetes induced rats were given skin and seed extracts at doses 250 and 500 mg/kg b.w. p.o. for 28 days. Alloxan monohydrate (120 mg/kg) was used to induce diabetes mellitus. Daily food and water intake were assessed. Blood glucose levels and body weights were measured every 7 days throughout the experiment. Antioxidant assays, different biochemical and glycemic parameters were evaluated. Histopathological studies on pancreas, liver and kidney were also studied.

RESULTS

Treatment of EESK and MESE showed dose significant decrease in fasting blood glucose level (FBG) in experimental diabetic animals with significant reduction in food and water intake and increase in body weight. Findings confirmed the hypoglycemic and hypolipidemic effects of EESK and MESE in the experimental groups. The impaired glucose tolerance and altered activities of the hepatic enzymes such as AST, ALT and ALP levels of diabetic rats were significantly improved by the administration of EESK and MESE. Oral treatment with MC extract for 28 days demonstrated significant protective effects on the lipid profile, biochemical parameters and antioxidant levels. Besides, biochemical findings were supported by histopathological investigations.

CONCLUSION

These results suggest that the treatment with EESK and MESE of MC at a dose of 500 mg/kg b.w. have better protective effects against hyperglycemia, hyperlipidemia and oxidative stress generated during diabetes justifying the use of the plant in traditional systems of medicine.

Evaluation of in-vitro and in-vivo antidiabetic, antilipidemic and antioxidant potentials of aqueous root extract of Strophanthus hispidus DC (Apocynaceae)

Background

Antidiabetic activity of aqueous root extract of Strophanthus hispidus (SHP) was evaluated based on its folklore used in traditional medicine for the treatment of diabetes. Objectives: This study aimed to investigate the in-vitro and in-vivo antidiabetic potential of the aqueous root extract of SHP.

Methods

SHP (50, 100 and 200 mg/kg p.o.), glibenclamide (5 mg/kg p.o.), normal saline (10 mL/kg; diabetic control) and distilled water (10 mL/kg; normal control) were administered once daily for 28 days, with the measurement of fasting blood glucose level at 7 days interval. Blood samples were collected on day 28 for serum biochemical (albumin, total protein [TP], creatinine, alanine transaminase [ALT], aspartate transaminase [AST], alkaline phosphatase [ALP], triglycerides [TG], total cholesterol [TC], high-density lipoprotein [HDL], low-density lipoprotein [LDL], bilirubin and urea) and hematological assays. The in-vitro antidiabetic activity was investigated using α-amylase and α-glucosidase enzymes inhibitory assays.

Results

SHP produced a day-dependent reduction in glucose level. Peak reduction (82.94 %; p < 0.05) was produced at the dose of 100 mg/kg. SHP significantly (p < 0.05) increased the level of HDL and TP but significantly (p < 0.05) reduced the levels of TG, LDL, TC, AST, ALT, ALP, bilirubin, creatinine and urea compared with diabetic control rats. Furthermore, SHP significantly (p < 0.05) increased the level of catalase, superoxide dismutase and reduced glutathione compared to diabetic control rats. SHP significantly (p < 0.05) inhibited α-amylase and α-glucosidase enzymes compared with acarbose.

Conclusion

The findings in this study showed that SHP possesses beneficial antidiabetic activity.

Effect of cisplatin on pancreas and testies in Wistar rats: biochemical parameters and histology

Objective

To investigate effect of cisplatin on biochemical parameter and histology of pancreas and testis in Wistar rats.

Material and methods

Single dose cisplatin (10 mg/kg) was injected by intraperitoneal route in Wistar rats. Blood was withdrawn on 7^th day from cisplatin treated rats by retro-orbital sinus for biochemical estimation. Further rats were scarified and dissected out their pancreases and testes for estimation of antioxidant enzymes and histopathological study.

Results

The cisplatin-treated group showed a significantly (P < 0.01) increased blood glucose level, Glycosylated hemoglobin in blood on the 7^th day as compared to the control group. Whereas cisplatin-treated group showed significantly (p < 0.001) increased lipid peroxidation and decreased reduced glutathione, superoxide dismutase, catalase in pancreatic and testicular tissue as compared to the control group. Histopathological sections of the pancreatic tissue showed marked vasoconstriction and micro infiltration were observed however testicular tissue showed degeneration in some somniferous tubules and also greatly depleted of germ cells in cisplatin treated group.

Conclusion

These findings demonstrated that the cisplatin could be induced diabetes and testicular toxicity due to their free radical mediated oxidative stress.

Impact of a High Intake of Dairy Product on Insulin Sensitivity in Hyperinsulinemic Adults: A Crossover Randomized Controlled Trial

BACKGROUND

Dairy product intake has been associated with decreased risk of type 2 diabetes (T2D) in cohort studies. However, results from clinical trials on T2D-related risk factors remain inconclusive.

OBJECTIVE

The aim of this clinical trial was to evaluate the impact of high dairy product intake (HD) (≥4 servings/d) for 6 wk, compared with an adequate dairy product intake (AD) (≤2 servings/d), on glycemic and insulinemic parameters, insulin sensitivity, insulin secretion, and β-cell function in hyperinsulinemic adults.

METHODS

In this crossover clinical trial, hyperinsulinemic adults were randomly assigned to HD or AD for 6 wk, then crossed over after a 6-wk washout period. Serum glucose, insulin, C-peptide, HOMA-IR, Matsuda index, insulinogenic index, and disposition index were measured and analyzed using a repeated-measures mixed model adjusted for age, sex, and BMI. Anthropometric measures were collected and food intake was evaluated using a validated FFQ.

RESULTS

Nineteen men and 8 women completed the study (mean ± SD age: 55 ± 14 y; BMI: 31.3 ± 3.3 kg/m2. Dairy product intake was 5.8 servings/d in the HD condition and 2.3 servings/d in the AD condition after 6 wk. No difference was observed between HD and AD after 6 wk for all outcomes.

CONCLUSIONS

HD does not affect glycemic and insulinemic parameters, insulin sensitivity, insulin secretion, and β-cell function over AD in hyperinsulinemic adults. Additional larger and longer studies assessing T2D-related risk factors are required. This trial was registered at clinicaltrials.gov as NCT02961179.

Phytotherapeutic efficacy of the medicinal plant Terminalia catappa L

Diabetes is a chronic, lifelong condition due to inadequate production of insulin or the cells does not properly respond it. Recently, the significance and effectiveness of herbal drugs associated with diabetes has emerged. The aim of the present study was to determine the anti-diabetic effects of Terminalia catappa L. leaves on streptozotocin (STZ)-treated rats. Two different concentrations of ethanolic leaf extract (300 and 500 mg/kg) of T. catappa were used to treat diabetic rats, and biochemical parameters were analyzed in blood samples. The results of herbal treatments were compared with the standard drug, glibenclamide. The ethanol extract (500 mg/kg) had significant anti-diabetic activity by altering blood glucose, glycosylated hemoglobin, liver glycogen, glucose 6-phosphatase, fructose 1,6-bisphosphatase, glucokinase, aspartate transaminase, alanine transaminase, alkaline phosphatase, urea, uric acid and creatinine levels while increasing insulin levels. Thus, the present study suggests that the supplementation of the diabetic patients with T. catappa leaves can lead to recovery from diabetic effects.

Protective effect of theaflavin on glycoprotein components and TCA cycle enzymes in high-fat diet and streptozotocin-induced diabetic rats

BACKGROUND

Theaflavins are major polyphenols in black tea which is the most widely consumed tea in the world. They possess a broad spectrum of biological activities, such as antioxidant, anti-tumor, anti-inflammatory, and cardio-protective effects. The present study was aimed to evaluate the protective effect of theaflavin on glycoprotein content and tricorboxylic acid cycle enzymes in high-fat diet and streptozotocin-induced diabetic rats as there was no study on this aspect. Diabetes was induced in male albino Wistar rats by feeding them with high-fat diet and injecting them intraperitoneally with streptozotocin (40 mg/kg b.wt).

RESULTS

Different doses of theaflavin (25, 50, and 100 mg/kg b.wt /day) were administered orally to high-fat diet and streptozotocin-induced diabetic rats for 30 days for fixing the glucose lowering dose. However, the dose at 100 mg/kg b.wt showed a significant reduction in the levels of plasma glucose and Homeostatic Model Assessment of Insulin Resistance with concomitant elevation of insulin when compared to the other two doses (25 and 50 mg/kg b.wt). Hence, 100 mg/kg b.wt was fixed as an effective dose and used for further analysis. Theaflavin administration restored the altered glycosylated hemoglobin, hemoglobin and glycoproteins (Hexose, hexosamine, fucose, and sialic acid) and TCA cycle enzymes (isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase) near the normal levels by correcting hyperglycemia. Improved histological changes were observed in the pancreas of diabetic rats upon treatment with theaflavin which supported the biochemicals investigated.

CONCLUSION

The effect produced by the theaflavin on various parameters was comparable to that of metformin-a reference antidiabetic drug. These findings suggest that theaflavin can replace the commercial drugs which could lead to reduction in toxicity and side effect caused by the later as well as reduce the secondary completions.

Antihyperglycemic Potential of Back Tea Extract Attenuates Tricarboxylic Acid Cycle Enzymes by Modulating Carbohydrate Metabolic Enzymes in Streptozotocin-Induced Diabetic Rats

The present study was aimed to investigate the effect of black tea extract on blood glucose, plasma insulin, Hemoglobin, carbohydrate metabolic enzymes and tricarboxylic enzymes in streptozotocin (STZ) induced diabetic rats. Diabetes was induced in male albino Wistar rats by intraperitoneal administration of STZ (40 mg/kg b wt). Black tea extract was administered to diabetic rats at a dose of 25, 50 and 100 mg/kg body weight for 30 days. The effects of black tea extract on glucose, insulin and HbA1c levels were analyzed to confirm the effective dose. Administration of black tea extract to diabetic rats was significantly decreased the level of glucose, glycated hemoglobin and increased the levels of insulin in a dose dependent manner. The black tea extracts at a dose of 100 mg/kg b wt showed a highly significant effect compared to other two doses (25 and 50 mg/kg b wt). The effect produced by black tea extract (100 mg/kg b wt) was comparable to that of glibenclamide (5 mg/kg b wt) a reference anti diabetic drug. Therefore, 100 mg/kg b wt was fixed as an effective dose and used for further analyses. Black tea extract was administered to diabetic rats at a dose of 100 mg/kg b wt for 30 days reinstated the altered levels of the plasma glucose, insulin, hemoglobin, glycosylated hemoglobin, carbohydrate metabolizing enzymes and tricarboxylic cycle enzymes in diabetic rats. Black tea extract administered to diabetic rats at a dose of 100 mg/kg b wt for 30 days reinstated the altered levels of the plasma glucose, insulin, hemoglobin, glycosylated hemoglobin, carbohydrate metabolizing enzymes and tricarboxylic cycle enzymes in diabetic rats. The effect produced by black tea extract of all the biochemical parameters were comparable with glibenclamide-used as a reference drug.

Myostatin alters with exercise training in diabetic rats; possible interaction with glycosylated hemoglobin and inflammatory cytokines

The role of myostatin (MSTN) in the regulation of energy homeostasis has been known and that MSTN inhibition can attenuate the development of diabetes. However, the response of MSTN to exercise in type 1 diabetes (T1DM) is unknown. This study aimed to investigate the alteration of MSTN following aerobic exercise training in diabetic rats and its possible interaction with glycosylated hemoglobin (HbA1c) and inflammatory cytokines. Forty-eight male Wistar rats were divided into non-diabetic untrained, non-diabetic trained, diabetic untrained and diabetic trained groups. To induce T1DM, rats received an intraperitoneal injection of STZ (60 mg·kg^-1). Treadmill exercise was performed for six weeks, five days/week. HbA1c was estimated, MSTN mRNA expression in skeletal muscle was measured, and plasma MSTN and inflammatory cytokines including interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) were determined. Results revealed a significant decrease of HbA1c and plasma inflammatory cytokines (IL-6, TNF-α and IL-1β) followed by a significant decrease of plasma and skeletal muscle MSTN in diabetic trained rats versus non-diabetic untrained and diabetic untrained rats after the experimental period. Moreover, in diabetic untrained and diabetic trained rats, a significantly positive correlation (change versus change) of plasma MSTN with HbA1c and plasma IL-6, TNF-α and IL-1β was found. In conclusion, this study indicated that aerobic exercise training by a decrease of HbA1c and plasma IL-6, TNF-α and IL-1β could decrease MSTN levels in plasma and skeletal muscle in T1DM. Furthermore, the effective influence of exercise may be reflected by changes of MSTN in diabetic rats.

Phenolic profiles, antihyperglycemic, antihyperlipidemic, and antioxidant properties of pomegranate (Punica granatum) peel extract

This work is aimed to evaluate phenolics composition, and in vitro antioxidant activities of hydro-methanol pomegranate (Punica granatum L.) peel extract (MPE). In addition, the antihyperglycemic, hypolipidemic, and hepatoprotective effect of MPE in Wister albino rats was compared with standard drugs (glibenclamide and atorvastatin). Total phenolic content and total flavonoid contents in MPE (mg g^-1 ) accounted for 188.9 as GAE and 13.95 as QE, respectively. Phenolic and flavonoids compounds in MPE analyzed by HPLC and revealed the presence of 23 phenolic compounds and 20 flavonoid compounds. For in vivo experiment, 56 rats were distributed into 8 groups. Group 1 was the normal control, while group 2 contained rats orally administrated with 200 mg kg^-1 MPE daily. Group 3 contained diabetic rats (induced with a single dose of 100 mg/kg b.w. alloxan). Group 4 contained diabetic rats administered daily with 200 mg/kg MPE. Group 5 contained diabetic rats administered orally with a glibenclamide (standard drug for diabetic) at 10 mg/kg daily. Group 6 fed with high fat diet (HFD). Group 7 contained HFD-rats administered orally with 200 mg/kg MPE daily. Group 8 contained HFD-rats administered orally with atorvastatin (used to lower LDL-cholesterol (LDL-C) and fats and to raise HDL-cholesterol (HDL-C) in the blood) at 10 mg/kg daily. The study lasted for 56 days. Administration with MPE 200 mg/kg to both diabetic and hyperlipidemic rats significantly decreased blood glucose, HbA_1c , total lipid, total cholesterol, LDL-C, and very low density lipoprotein cholesterol levels, while increased high density lipoprotein cholesterol levels, as well as improved liver and kidney functions, compared with glibenclamide and atorvastatin effects. PRACTICAL APPLICATIONS: Pomegranate peel, constituted about 50% of fruit fresh weight, is rich in bioactive compounds with potent health-promoting activities. The results of the current study stated that MPE is rich in phenolics and flavonoids with powerful antioxidant potential. In addition, MPE showed antihyperglycemic and antihyperlipidemic activities due to the strong antiradical action via its antioxidant compounds. MPE enhanced liver and kidney functions when compared to standard drugs in diabetic and hyperlipidemic rats. MPC could be used as a natural material to develop diabetic and hyperlipidemic drugs.

Ferulic Acid Protects Hyperglycemia-Induced Kidney Damage by Regulating Oxidative Insult, Inflammation and Autophagy

Oxidative insult, inflammation, apoptosis and autophagy play a pivotal role in the etiology of diabetic nephropathy, a global health concern. Ferulic acid, a phytochemical, is reported to protect against varied diseased conditions. However, the ameliorative role and mechanisms of ferulic acid in averting STZ-mediated nephrotoxicity largely remains unknown. For in vivo study, a single intraperitoneal injection of streptozotocin (50 mg kg^-1 body wt.) was administered in experimental rats to induce diabetes. The diabetic rats exhibited a rise in blood glucose level as well as kidney to body weight ratio, a decrease in serum insulin level, severe kidney tissue damage and dysfunction. Elevation of intracellular ROS level, altered mitochondrial membrane potential and cellular redox balance impairment shown the participation of oxidative stress in hyperglycemia-triggered renal injury. Treatment with ferulic acid (50 mg kg^-1 body wt., orally for 8 weeks), post-diabetic induction, could markedly ameliorate kidney injury, renal cell apoptosis, inflammation and defective autophagy in the kidneys. The underlying mechanism for such protection involved the modulation of AGEs, MAPKs (p38, JNK, and ERK 1/2), NF-κB mediated inflammatory pathways, mitochondria-dependent and -independent apoptosis as well as autophagy induction. In cultured NRK-52E cells, ferulic acid (at an optimum dose of 75 μM) could counter excessive ROS generation, induce autophagy and inhibit apoptotic death of cells under high glucose environment. Blockade of autophagy could significantly eradicate the protective effect of ferulic acid in high glucose-mediated cell death. Together, the study confirmed that ferulic acid, exhibiting hypoglycemic, antioxidant, anti-inflammatory, anti-apoptotic activities and role in autophagy, could circumvent oxidative stress-mediated renal cell damage.

Enhanced lipid and starch productivity of microalga (Chlorococcum sp. TISTR 8583) with nitrogen limitation following effective pretreatments for biofuel production

•

To enhance the lipid and starch productivity of Chlorococcum sp. TISTR 8583 for biofuel productions.

•

To identify suitable pretreatment strategy for release of fermentable sugars and lipids extraction from algal biomass.

•

To convert the released fermentable sugars and lipids into bioethanol and biodiesel respectively.

The study was conducted to evaluate the conditions to enhance the accumulation of lipids and starch in Chlorococcum sp. TISTR 8583 for the production of biofuel. The Chlorococcum sp. TISTR 8583 was cultivated on BG-11 medium under optimized light intensity. The nitrogen limitation (NL) enhanced the accumulation of both starch and lipids and resulted in 34.02% total sugars as compared to 22.57% on nitrogen supplemented (NS) media only. Similarly, the nitrogen supplemented (NS) media produced 17.05% lipids as compared to 29.59% lipids by NL media. The biomass was investigated for biodiesel and bioethanol production by adopting different pretreatment strategies, such as enzyme, acid and alkaline pretreatments. The alkaline pretreatment was found to be efficient strategy (23.67 wt% sugars/g algal biomass: 1.2% (w/v) at 140 ⁰C for 30 min) while the acid pretreatment (1%: v/v; 140 °C) was least effective pretreatment strategy with the yield of 14.83 wt% sugars/g algal biomass.

In vitro and in vivo antidiabetic activity of isolated fraction of Prosopis cineraria against streptozotocin-induced experimental diabetes: A mechanistic study

A rapidly increasing incidence of Diabetes mellitus throughout the world is a major concern in both developed and developing countries and the drawbacks associated with currently available treatments led to switching researcher's attention towards naturopathy. Since ancient time, herbal plants have been traditionally used for the treatment of diabetes as they consider to be less toxic and free from side effects than synthetic ones. In our previous studies, we had isolated two new compounds (Methyl 5-tridecyloctadec-4-enoate and Nonacosan-8-one), together with three known compounds (Lupeol, β-sitosterol and Stigmasterol) from chloroform fraction of stem bark of P. cineraria (CfPc). The present study aimed to determine the in vivo and in vivo antidiabetic activity of CfPc in streptozotocin induced experimental diabetes and also evaluated their possible mode of action. CfPc was orally administrated to STZ (55 mg/kg b.wt) induced diabetic rats at the doses of 50 and 100 mg/kg b.wt for 21 days. Treatment of CfPc significantly (p < 0.05) lowered the level of blood glucose, glycosylated hemoglobin and also restored body weight, liver glycogen content and serum insulin level in diabetic rats in a dose-dependent manner. A significant (p < 0.05) reduction in serum lipid profile markers and elevation in HDL-C after treatment with CfPc, also signifying the protective effects of CfPc in diabetes-associated complications. In addition, CfPc also promoted a significant inhibition of α-amylase enzyme activity with an IC₅₀ value of 40.29 μg/ml. Results indicate that CfPc possess a potential in vitro and in vivo antidiabetic activity and this effect could be due to multitarget mode of action that includes antihyperglycemic, postprandial hypoglycemic, hypolipidemic and insulin secretory actions. Therefore, it could be used as a safer complementary drug in the management of diabetes and associated complications.

Antidiabetic potential of active fraction obtained from methanolic extract of Ichnocarpus frutescens: A possible herbal remedy

OBJECTIVES

Ichnocarpus frutescens is a common plant used by tribal people and in Ayurveda for its high medicinal value. The purpose of the study was to investigate whether I. frutescens has any persuasive medicinal property to manage diabetes mellitus.

MATERIALS AND METHODS

Initially, male albino Wistar rats were given intraperitoneal injection of streptozotocin-nicotinamide to induce diabetes, followed with the administration of active fraction obtained from the methanolic extract of I. frutescens for the next 28 consecutive days. Glibenclamide (25 mg/kg) was used as positive control.

RESULTS

According to the results obtained, active fraction at a dose of 50 mg/kg body weight exhibited significant antihyperglycemic activity, which was evident with reduced blood glucose level up to 58.84%. The active fraction also showed improvement in serum lipid profile as well as regeneration of pancreatic β-cells in diabetic rats. Concurrent histopathological studies reinforce the effect of active fraction in healing pancreas, thus justifying the possible mechanism of its antidiabetic activity.

CONCLUSION

The results of the present investigation lead credence to the use of I. frutescens in ameliorating the diabetic condition.

Anti diabetic property of aqueous extract of Stevia rebaudiana Bertoni leaves in Streptozotocin-induced diabetes in albino rats

BACKGROUND

Stevia (Stevia rebaudiana) natural, non-caloric sugar substitute is rich source of pharmacologically important glycoside stevioside that is linked to the pathology and complications of diabetes.

METHODS

The current research was carried out to explore the anti-diabetic effect of aqueous extract of Stevia rebaudiana leaves in albino rats. For this purpose, diabetes was induced by administration of streptozotocin (40 mg/kg body weight, intraperitoneally). The diabetic rats were administered with aqueous stevia extract at different dose levels (200, 300, 400 and 500 ppm/kg b.w) for 8 weeks; the control rats were fed basal diet during this period.

RESULTS

Stevia aqueous extract improved caloric management and weight control by decreasing the feed intake and body weight gain. Furthermore, intake of stevia extract resulted in significant (P < 0.05) decrease in the random blood glucose level (- 73.24%) and fasting blood glucose (- 66.09%) and glycosylated (HbA1c) hemoglobin (5.32%) while insulin (17.82 μIU/mL) and liver glycogen (45.02 mg/g) levels significantly improved in the diabetic rats, compared with the diabetic and non-diabetic control rats after 8 weeks study period.

CONCLUSIONS

It is concluded that aqueous extact of stevia has anti-diabetic effects in albino rats, and therefore could be promising nutraceutical therapy for the management of diabetes and its associated complications.