Effect of <Emphasis Type="Italic">Gymnema montanum</Emphasis> leaves on red blood cell resistance to oxidative stress in experimental diabetes

The aim of the present study was to evaluate the protective effect of Gymnema montanum on red blood cell (RBC) membrane in diabetic rats during lipid peroxidation. Ethanol extract of G. montanum leaves (GLEt) was administered orally to alloxan-induced diabetic rats for 3 weeks, and the effects on blood glucose, insulin, lipid peroxidation markers, thiobarbituric acid reactive substances, hydroperoxides in plasma and antioxidant enzymes including superoxide dismutase, catalase and glutathione peroxidase activities in erythrocytes were studied. Administration of GLEt to diabetic animals at doses of 50, 100, and 200 mg/kg body weight lowered elevated blood glucose levels by 24, 35, and 66%, respectively, relative to untreated diabetic rats. In comparison, treatment with the known antidiabetic drug, glibenclamide (600 μg/kg body weight) decreased blood glucose concentrations by 51%. Plasma insulin concentrations were increased in the diabetic rat by 73% with GLEt (200 mg/kg body weight) and 45% with glibenclamide (600 μg/kg body weight). Although a significant decrease in the lipid peroxidation markers was observed in plasma on treatment with GLEt and glibenclamide, the RBC antioxidant levels were increased significantly in diabetic rats. Furthermore, erythrocytes from the GLEt-treated animals were found to be more resistant to H₂O₂-induced peroxidation than that of untreated diabetic animals. The chemical characterization of the polyphenolics of the extract showed the presence of gallic acid (5.29% w/w), resveratrol (2.2% w/w), and quercetin (16.6% w/w). The results of this study suggest that G. montanum may be useful for the control, management, and prevention of oxidative stress associated with diabetes.     

Hypoglycemic activity of a polyphenolic oligomer-rich extract of Cinnamomum parthenoxylon bark in normal and streptozotocin-induced diabetic rats

Cinnamon bark has been reported to be effective in the alleviation of diabetes through its antioxidant and insulin-potentiating activities. The water-soluble polyphenolic oligomers found in cinnamon are thought to be responsible for this biological activity. In this study, the hypoglycemic activity of a polyphenolic oligomer-rich extract from the barks of Cinnamomum parthenoxylon (Jack) Nees was studied in normal, transiently hyperglycemic, and streptozotocin (STZ)-induced diabetic rats. Oral administration of the extract at doses of 100, 200, and 300 mg/kg body wt. caused significant changes in body weight loss and fasting blood glucose levels of normal rats. In STZ-induced diabetic rats, after administration of the extract at doses of 100, 200, and 300 mg/kg body wt. over 14 days, the blood glucose levels were decreased by 11.1%, 22.5%, and 38.7%, respectively, and the plasma insulin levels were significantly increased over pre-treatment levels. In an oral glucose tolerance test, the extract produced a significant decrease in glycemia 90 min after the glucose pulse. These results suggest that Cinnamomum parthenoxylon polyphenolic oligomer-rich extract could be potentially useful for post-prandial hyperglycemia treatment.     

Cytoprotective and anti-diabetic effects of Derris reticulata aqueous extract

The current study was aimed to investigate pancreatic protective and anti-diabetic activities of the aqueous extract of Derris reticulata stem. First, we evaluated a cytoprotective potential of D. reticulata extract on alloxan-induced damage in vitro. Treatment with D. reticulata extract at the doses of 250 and 500 μg/ml significantly increased cell viability of the pancreatic β-cell line RINm5F after exposure of alloxan. The anti-hyperglycemic activity of D. reticulata extract was further studied in alloxan-induced diabetic rats. A significant reduction in blood glucose level along with an increase in body weight was observed in diabetic rats treated with D. reticulata extract at 250 mg/kg body weight for 15 days. Serum aspartate transaminase and alanine transaminase levels were also significantly decreased compared to diabetic control rats. In accordance with in vitro cytoprotective effect, histopathological examination revealed that pancreatic islet cells of the extract-treated diabetic rat were less damage than those of the untreated diabetic group. In order to find another possible mechanism of action underling hypoglycemic activity, the effect on glucose absorption was examined using everted sac jejunum. The results showed that D. reticulata extract suppressed glucose absorption from small intestine. To corroborate safety use of D. reticulata extract, acute oral toxicity was also conducted in rats. Our results showed that none of the tested doses (250, 500, 1,000, and 2,000 mg/kg) induced signs of toxicity or mortality after administration of the extract. The results suggested that D. reticulata extract possess anti-diabetic activity, which resulting from its pancreatic cytoprotective effect and inhibition of intestinal glucose absorption.     

Hypoglycemic activity of leaf organic extracts from Smallanthus sonchifolius: Constituents of the most active fractions

The aim of the present study was to determine the in vivo hypoglycemic activity of five organic extracts and enhydrin obtained from yacon leaves. The main constituents of the most active fraction were identified. Five organic extracts and pure crystalline enhydrin were administered to normoglycemic, transiently hyperglycemic and streptozotocin (STZ)-diabetic rats. The fasting and post-prandial blood glucose, and serum insulin levels were estimated and an oral glucose tolerance test (OGTT) was performed for the evaluation of hypoglycemic activity and dose optimization of each extract.We found that the methanol, butanol and chloroform extracts showed effective hypoglycemic activity at minimum doses of 50, 10 and 20 mg/kg body weight, respectively, and were selected for further experiments. Oral administration of a single-dose of each extract produced a slight lowering effect in the fasting blood glucose level of normal healthy rats, whereas each extract tempered significantly the hyperglycemic peak after food ingestion. Daily administration of each extract for 8 weeks produced an effective glycemic control in diabetic animals with an increase in the plasma insulin level. Phytochemical analysis of the most active fraction, the butanol extract, showed that caffeic, chlorogenic and three dicaffeoilquinic acids were significant components. Additionally, enhydrin, the major sesquiterpene lactone of yacon leaves, was also effective to reduce post-prandial glucose and useful in the treatment of diabetic animals (minimum dose: 0.8 mg/kg body weight).The results presented here strongly support the notion that the phenolic compounds above as well as enhydrin are important hypoglycemic principles of yacon leaves that could ameliorate the diabetic state.     

Effects of Canarium odontophyllum leaves on plasma glucose and T lymphocyte population in streptozotocin-induced diabetic rats

Type 1 diabetes mellitus is a chronic disease characterized by lack of insulin production. Immune mechanisms are implicated in the pathogenesis of Type 1 diabetes. Canarium odontophyllum (CO) fruits and leaves have been shown to possess high antioxidant activity. This study was conducted to evaluate the effects of CO leaves aqueous extract on the blood glucose and T lymphocyte population in the spleen of streptozotocin (STZ)-induced diabetic rats. Nineteen male Sprague–Dawley rats were randomly divided into three groups: normal, diabetic control and CO treated diabetic groups. Diabetes was induced by a single intraperitoneal injection of 65 mg STZ/kg body weight. The extract of CO leaves was administered orally by force feeding daily at the dose of 300 mg/kg for 28 days. The rats were sacrificed at the end of the study and the spleen was harvested for flow cytometry analysis. The results showed a significant decrease in body weight of diabetic and CO treated diabetic groups compared with the normal group (p < 0.05). The fasting blood glucose level of CO treated diabetic group was significantly lower than the diabetic group (p < 0.05). Diabetic and CO treated diabetic groups showed a significant increase in the percentage of spleen CD3⁺ CD4⁺ T lymphocytes (p < 0.05) when compared with the normal group. However, there was no significant difference in the percentage of spleen CD3⁺ CD8⁺ T lymphocytes among all experimental groups. The finding suggested that an aqueous extract of CO leaves has the ability to reduce blood glucose levels in diabetic rats.     

Antidiabetic potential of Caralluma europaea against alloxan-induced diabetes in mice

Medicinal plants play an important role in the management of diabetes mellitus especially in developing countries where resources are lacking. Herbal of natural origin, unlike the synthetic compounds, are more effective, safer and have less side effects. For continuing research on biological properties of Moroccan medicinal plants, the present work was undertaken to evaluate the potential and mechanism of the antidiabetic activity of the Caralluma europaea methanolic extract in alloxan-induced diabetic mice. A high-performance liquid chromatography technique (HPLC) was used to identify and quantify the major phenolic compounds in the methanolic extract. The in vitro antioxidant property was evaluated using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging method, reducing power and ß-carotene-linoleic acid assays. The acute toxicity of the extract was evaluated by giving it orally to mice at single doses of 200, 500, 1000, 2000 mg/kg body weight. The antidiabetic effect was conducted on Swiss albino mice. Diabetes was induced with single intraperitonial injection of alloxan monohydrate (200 mg/kg body weight) and animals were treated with methanol extract at a dose of 250 mg/kg and 500 mg/kg body weight. The blood glucose levels were measured and histopathological analysis of pancreas was performed to evaluate alloxan-induced tissue injuries. The main phenols identified and quantified in the extract were ferulic acid, quercetine, 3,4 dihydroxybenzoic acid, rutin, epigallocatechin, and catechin. Ferulic acid was found to be the main phenolic compound ant its proportion was up to 52% of total phenolic compounds, followed by quercetin (36%). The result showed that methanol extract exhibited an antioxidant effect. Acute toxicity studies revealed that C. europaea extract was safe up 2000 mg/kg body weight and approximate LD₅₀ is more than 2000 mg/kg. Moreover, the methanol extract prevented the diabetogenic effect of alloxan and decreased significantly the blood glucose level (P < 0.001) in treated mice. Morphometric study of pancreas revealed that C. europaea extract protected significantly the islets of Langerhans against alloxan-induced tissue alterations.     

Protective effect of Morus rubra L. leaf extract on diet-induced atherosclerosis in diabetic rats

The antiatherosclerotic effect of aqueous leaves extract of Morus rubra was studied in streptozotocin-induced diabetic rats fed with atherosclerotic (Ath) diet [1.5 ml olive oil containing 8 mg (3, 20,000 IU) vitamin D2 and 40 mg cholesterol] for 5 consecutive days. A short-term toxicity assessment was also conducted in healthy rats to examine toxic effects of the extract. Oral administration of extract to diabetic rats (100, 200 and 400 mg/kg body weight per day for a period of 30 days) produced significant (p<0.001) fall in fasting blood glucose (FBG) in a dose-dependent manner. Treatment with the extract (400 mg/kg) showed significant (p<0.001) improvement in body weight and serum lipid profile i.e., total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol and VLDL-cholesterol, when compared with diabetic control. Endothelial dysfunction parameters (sVCAM-1, Fibrinogen, total NO levels and oxidized LDL), apolipoprotein A and apolipoprotein B were significantly (p<0.001) reversed to near normal, following treatment with the extract. Thus, our study shows that aqueous leaf extract of Morus rubra (400 mg/kg) significantly improves the homeostasis of glucose and fat and possesses significant anti-atherosclerotic activity.     

Effect of Ethanolic Extract of Embelia Ribes on Dyslipidemia in Diabetic Rats

Diabetes mellitus has been treated orally with herbal remedies based on folk medicine since ancient times. Embelia ribes burm (Myrsinaceae), known commonly as vidanga, was used in Ayurveda for its anthelmintic activity. Ayurveda describes vidanga as pungent, causes increase in digestive fire, and cures flatulence and colic. A single study reported the antihyperglycemic activity of decoction of E. ribes in glucose-induced hyperglycemic albino rabbits. In the present study, the lipid-lowering and antioxidant potential of ethanolic extract of E. ribes burm was investigated in streptozotocin (40 mg/kg, IV, single injection)-induced diabetes in rats. Twenty days of orally feeding the extract (200 mg/kg) to diabetic rats resulted in significant (P < 0.01) decrease in blood glucose, serum total cholesterol, and triglycerides, and increase in HDLcholesterol levels when compared to pathogenic diabetic rats. Further, the extract also lowered the liver and pancreas thiobarbituric acid–reactive substances (TBARSs) values (P < 0.01) when compared to TBARS values of liver and pancreas of pathogenic diabetic rats. The results of test drug were comparable to gliclazide (25 mg/kg, orally), a standard antihyperglycemic agent. This is the first pilot study to provide biochemical evidence of potential of E. ribes in diabetic dyslipidemia.     

Modulatory effects of one polysaccharide from Acanthopanax senticosus in alloxan-induced diabetic mice

One water-soluble polysaccharide ASP was purified from Acanthopanax senticosus and its physicochemical properties were confirmed by the combination of chemical and instrumental analysis. ASP administered orally at three doses (100, 200 and 400 mg/kg body weight) could significantly decrease the concentration of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein (LDL) cholesterol levels except for high density lipoprotein (HDL) cholesterol level and the relative ratio (HDL/TC) in alloxan-induced diabetic mice, compared with the diabetic controls without drug treatment, comparable with that of diabetic mice treated with metformin. Furthermore, ASP could obviously increase the body weight and serum insulin level and reduce the fasting blood glucose (FBG) levels, especially at dose of 200 mg/kg. The data demonstrated ASP at the certain did often exhibit the optimal protective effect in alloxan-induced diabetic mice. It is promising that ASP may serve as a drug candidate or a healthcare food for diabetic therapy or protection.     

The hypoglycemic activity of Euclea undulata Thunb. var. myrtina (Ebenaceae) root bark evaluated in a streptozotocin–nicotinamide induced type 2 diabetes rat model

The hypoglycemic activity of a crude acetone extract of the root bark of Euclea undulata var. myrtina was evaluated in a streptozotocin–nicotinamide induced type 2 diabetes rat model after positive results were obtained by in vitro screening of glucose utilization by C2C12 myocytes, 3T3-L1 preadipocytes and Chang liver cells and alpha-glucosidase inhibition. Thirty male Wistar rats were used for the experiment. Type 2 diabetes was induced by a single intraperitoneal injection of streptozotocin and administration of nicotinamide 15 min after. Animals exhibiting fasting glucose levels of 140–200 mg/dl after 7 days were screened as type 2 diabetes. Extract was administered for 21 days orally at a concentration of 50 mg/kg and 100 mg/kg respectively. Glibenclamide (1 mg/kg) was used as positive control. On day 21, blood lipid profiles and body weight were determined by using standard enzymatic colorimetric kits before the rats were sacrificed by cervical decapitation. The crude acetone extract of E. undulata root bark at a concentration of 100 mg/kg body weight significantly lowered fasting blood glucose levels as well as elevated cholesterol and triglyceride levels to near normal without any weight gain. The results indicate that the crude acetone root bark extract of E. undulata exhibit antidiabetic activity in type 2 induced diabetic rats. It confirms the in vitro screening results as well as its use in the treatment of diabetes by traditional healers and herbalists in southern Africa.     

Panax ginseng improves glucose metabolism in streptozotocin-induced diabetic rats through 5′ adenosine monophosphate kinase up-regulation

5′ AMP-activated protein kinase (AMPK), insulin receptors and transporters are distorted in diabetes mellitus. In this study, the effect of Panax ginseng was assessed on glucose manipulating enzymes activities and gene expression of AMPK, IRA and GLUT2 in streptozotocin-induced diabetic male rats. Forty male albino rats were randomly divided to four groups 10 rats of each, group I, normal control group (received saline orally); group II, normal rats received 200 mg/kg of Panax ginseng orally; group III, Streptozotocin (STZ) –induced diabetic rats and group IV, STZ-induced diabetic rats received 200 mg/kg of Panax ginseng orally. The duration of experiment was 30 days. Results showed the ability of Panax ginseng to induce a significant decrease in the blood glucose and increase in the serum insulin levels, hepatic glucokinase (GK), and glycogen synthase (GS) activities with a modulation of lipid profile besides high expression levels of AMPK, insulin receptor A (IRA), glucose transporting protein-2 (GLUT-2) in liver of diabetic rats. In conclusion, the obtained results point to the ability of Panax ginseng to improve the glucose metabolism in diabetic models.     

Lowering of blood sugar by water extract of Azadirachta indica and Abroma augusta in diabetes rats

Combination (1:1 ) of water extract of dried powder of root and leaves (200 mg/kg body wt) of A. augusta and A. indica respectively was administered orally to alloxan diabetic rats once a day for 8 weeks. This treatment caused significant lowering of blood sugar in fasted as estimated by glucose tolerance test. The treatment resulted in a significant reduction in serum lipids. Aqueous extract also decreased the formation of lipid peroxides estimated as thiobarbituric acid reactive substance, (TBARS), and increased antioxidants (superoxide dismutase, catalase, glutathione peroxidase and glutathione transferase) in erythrocytes. There was reduction in LPO as TBARS in heart, liver, kidney, and muscles. It also prevented decrease in body weight. Present study showed that Abroma augusta roots and A. indica leaves when given together as water extract had hypoglycaemic action and had better effect than given alone.     

Hepatoprotective potential of flavonoid-rich extracts from Gongronema latifolium benth leaf in type 2 diabetic rats via fetuin-A and tumor necrosis factor-alpha

Background

This study assessed the hepatoprotective potential of flavonoid-rich extracts from Gongronema latifolium Benth on diabetes-induced type 2 rats via Fetuin-A and tumor necrosis factor-alpha (TnF-α).

Methods

In a standard procedure, the flavonoid-rich extract was prepared. For experimental rats, streptozotocin was injected intraperitoneally (45 mg/kg body weight) to induce diabetes mellitus. Following this, rats were given 5% of glucose water for 24 h. Hence, the animals were randomly divided into five groups of ten rats each, consisting of non-diabetic rats, diabetic controls, diabetic rats treated with low and high doses of flavonoid rich-extracts from Gongronema latifolium leaf (FREGL) (13 and 26 mg/kg, respectively), and diabetic rats treated with 200 mg/kg of metformin glibenclamide orally for 3 weeks. Afterwards, the animals were sacrificed, blood and liver were harvested to evaluate different biochemical parameters, hepatic gene expressions and histological examinations.

Results

The results revealed that FREGL (especially at the low dose) significantly (p?<?0.05) reduced alanine transaminase (ALT), aspartate aminotransferase (AST) and alkaline phosphate (ALP) activities, lipid peroxidation level, as well as relative gene expressions of fetuin-A and TNF-α in diabetic rats. Furthermore, diabetic rats given various doses of FREGL showed an increase in antioxidant enzymes and hexokinase activity, as well as glucose transporters (GLUT 2 and GLUT 4), and glycogen levels. In addition, histoarchitecture of the liver of diabetic rats administered FREGL (especially at the low dose) was also ameliorated.

Conclusion

Hence, FREGL (particularly at a low dose) may play a substantial role in mitigating the hepatopathy complication associated with diabetes mellitus.

     

In vitro toxicity and antidiabetic activity of a newly developed polyherbal formulation (MAC-ST/001) in streptozotocin-induced diabetic Wistar rats

The present study was designed to investigate the hypoglycemic effect of an aqueous extract of MAC-ST/001 (a new polyherbal formulation) which was given once daily to rats at different doses. The animals were divided into diabetic and nondiabetic control groups. The duration of each experiment lasted from 1 week to 1 month, and the results were compared with that of the standard hypoglycemic drug glibenclamide (10 mg/kg), which was given once daily. In this study, biochemical and histopathological parameters were studied in streptozotacin (STZ) (single intraperitoneal injection of 55 mg/kg)-induced diabetic rats. The diabetic rats showed a significant (p?<?0.05 and p?<?0.01) decrease in their body weight and serum amylase with marked elevation in blood glucose, serum cholesterol, blood urea nitrogen, creatinine, alkaline phosphatase, and serum transaminases (AST and ALT) after 1 week till the 28th day of diabetes. Cytotoxicity of MAC-ST/001 formulation was also studied on C2C12, 3T3-L1, and HepG2 cells through MTT assay. Histological examination of the liver and pancreas of normal control, diabetic control, and drug-treated rats revealed significant results. Finally, it was concluded that administration of this MAC-ST/001 extract reversed most blood and tissue changes caused by STZ-induced diabetes in rats.     

The Effect of Different Oral Doses of Hydroalcoholic Extract of Silymarin on the Blood Oxidative Stress Indicators in Streptozotocin Induced Diabetic Rats

The effect of oral administration of different doses of hydroalcoholic extract of silymarin on body weight, glucose concentration and indicators of oxidative stress superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT) and malondialdehyde (MDA) was investigated in the present study. Fifty adult male Wistar rats were used. The animals were divided into five groups and oral route of administration was used in control group (0.9 %, NaCl), control group patients (0.9 %, NaCl), diabetic group (100 mg/kg, silymarin), diabetic group (125 mg/kg, silymarin), diabetic group (250 mg/kg, silymarin) for 14 days with gavage. Diabetes was induced by a single injection of streptozotocin (45 mg/kg, i.p.). Before and 3 days after injection, and at 7 and 14 days of treatment, the fasting glucose level and weight were measured. At the end of 14 days, animals were anesthetized with ether and blood samples were taken by heart puncture and were analyzed for oxidative stress indicators. The results showed that hydroalcoholic extract of silymarin can increase the average body weight and decrease glucose and, at the end of 14 days, decrease MDA level and increase the level of antioxidant enzymes (SOD, GPX, CAT) in red blood cells in a dose-dependent manner (P < 0.05). In conclusion, the hydroalcoholic extract of silymarin has an overall beneficial effect on body weight, glucose level and oxidative stress. Therefore, silymarin may reduce oxidative stress via increasing antioxidant enzyme activity.     

Effects of Momordica charantia on pancreatic histopathological changes associated with streptozotocin-induced diabetes in neonatal rats

The aim of this research was to determine the effects of Momordica charantia (MC) fruit aqueous extract on pancreatic histopathological changes in neonatal STZ-induced type-II diabetic rats. Diabetes mellitus was induced in one day Sprague-Dawley neonatal rats using a single intrapretoneal injection of streptozotocin (STZ) (85 mg/kg body weight) and monitored for 12 weeks thereafter. The diabetic rats were separated into three groups, as follows: the diabetic control group (i.e. nSTZ), the diabetic group (i.e. nSTZ/M) - which was orally given 20 mg/kg of MC fruit extract, and the diabetic group (i.e. nSTZ/G) - that was treated with glibenclamide, 0.1 mg/kg for a period of four weeks. At the end of treatment, the animals were sacrificed and blood samples were collected from the saphenous vein to measure the blood glucose and serum insulin level. The pancreatic specimens were removed and processed for light microscopy, electron microscopy examination and immunohistochemical study. The results of this study showed that MC fruit aqueous extract reduced the blood glucose level as well as glibenclamide and increased the serum insulin level in the treated diabetic rats (P<0.05). The fruit extract of MC alleviated pancreatic damage and increased the number of β-cells in the diabetic treated rats (P<0.05). Our results suggest that oral feeding of MC fruit extract may have a significant role in the renewal of pancreatic β-cells in the nSTZ rats.     

The Glycemic Elemental Profile of <Emphasis Type="Italic">Trichosanthes dioica</Emphasis>: A LIBS-Based Study

The scientific evaluation of the antidiabetic efficacy of aqueous extract of Trichosanthes dioica fruits on streptozotocin-induced diabetic rats is being presented. The graded doses of the extract, viz., 500, 750, 1,000, and 1,250 mg/kg body weight (bw), were administered orally, and it was observed that the blood glucose concentration decreased in a dose-dependent manner. The dose of 1,000 mg/kg bw showed the maximum fall of 23.8% and 19.1% in blood glucose level (BGL) during fasting BGL and glucose tolerance test (GTT) studies, respectively, of nondiabetic rats. Whereas in the case of subdiabetic and mild diabetic models, the same dose showed reduction in BGL of 22.0% and 31.4% during GTT. The study also involves the first use of laser-induced breakdown spectroscopy as a sensitive analytical tool to detect the elemental profile responsible for the antidiabetic activity of aqueous extract of T. dioica fruits that exhibits the antidiabetic activity. High intensities of Ca, Mg, and Fe indicate large concentrations of these elements in the extract, since according to Boltzmann’s distribution law, intensities are directly proportional to concentrations. The higher concentrations of these glycemic elements, viz. Ca, Mg, and Fe, are responsible for the antidiabetic potential of T. dioica as well as other plant already reported by our research group.     

Beneficial effect of vitamin E on the metabolic parameters of diabetic rats

The role of vitamin E in the pathogenesis of diabetes mellitus is unknown. The purpose of this study was to examine the effect of oral administration of vitamin E on some of the metabolic parameters of experimental diabetic rats. Diabetes was induced by intraperitoneal injection of streptozotocin (60 mg/kg body weight at 12 weeks of age). Vitamin E (0.2, 0.4, 0.8 mg/kg body weight) was administered orally for a period of 3 weeks to normal and diabetic Wistar rats. In some experiments, Vitamin E was given either before or after the induction of diabetes mellitus. Blood glucose level and weight were recorded for each rat in different groups on a weekly basis. Oral glucose tolerance test (OGTT) was performed on fasted normal, diabetic and vitamin E treated rats at the end of the experiment. Vitamin E significantly (p < 0.01) reduced blood glucose levels in experimental diabetes mellitus at all doses as compared to untreated rats. Vitamin E induced weight loss in normal as well as in diabetic rats. The beneficial effect of vitamin E on the hyperglycaemia of diabetic rats was dose-dependent. Moreover, vitamin E also improved OGTT in diabetic rats compared to untreated diabetics. In conclusion, vitamin E may play a role in glucose metabolism and thus be a useful adjuvant therapy in type I diabetes. (Mol Cell Biochem 261: 35–42, 2004)     

Shorea roxburghii Leaf Extract Ameliorates Hyperglycemia Induced Abnormalities in High Fat/Fructose and Streptozotocin Induced Diabetic Rats

This study investigated the hypoglycemic effect of the methanol extract of Shorea roxburghii leaves (SRL) in high fat diet/high fructose solution (HFDHF) and streptozotocin (STZ) induced type 2 diabetes mellitus (T2DM) in rats as well as evaluating its ameliorative potentials in altered biochemical and hematological parameters in the treated rats. T2DM was induced in Sprague Dawley (SD) rats by feeding with HFDHF for 4 weeks and administering STZ (35 mg/kg, i. p.). Diabetic rats were given SRL extract at doses of 100 and 400 mg/kg for 30 days. The food and water intake were monitored on a daily basis, while the fasting blood glucose (FBG) levels and body weight were measured weekly. Biochemical and hematological parameters as well as histopathological studies of the pancreas were also evaluated. SRL significantly decreased FBG and improved the body weight, food and water intake of treated diabetic rats. Furthermore, biochemical and hematological parameters including liver and kidney function enzymes, lipid profiles, white blood and red blood cells parameters were markedly ameliorated by SRL. Histopathological analyses of the pancreas indicated reconstitution of β‐cells architecture in SRL treated rats. The results of this study suggest that SRL has antidiabetic potential and can be considered for the treatment of T2DM.     

Extract of Cassiae semen attenuates diabetic nephropathy via inhibition of advanced glycation end products accumulation in streptozotocin-induced diabetic rats

Chronic hyperglycemia leads to the formation of advanced glycation end products (AGEs), which accelerates the development of diabetic complications. Previous studies have shown that extract of Cassiae semen (CS), the seed of Cassia tora, has inhibitory activity on AGEs formation in vitro and reduces transforming growth factor-beta1 (TGF-β1) and extracellular matrix protein expression via inhibition of AGEs-mediated signaling in glomerular mesangial cells. In this study, to examine the preventive effects of CS extract on the development of diabetic nephropathy in vivo, streptozotocin (STZ)-injected diabetic rats were orally administered CS extract (200 mg/kg body weight/day) for 12 weeks. Serum glucose, triglycerides, and total cholesterol in diabetic rats were significantly higher compared to control rats. CS or aminoguanidine (AG) treatment significantly reduced these factors. Proteinuria and creatinine clearance were also significantly decreased in the CS-treated group compared with the untreated diabetic group. The CS-treated group had significantly inhibited COX-2 mRNA and protein, which mediates the symptoms of inflammation in the renal cortex of diabetic rats. Furthermore, histopathological studies of kidney tissue showed that in diabetic rats, AGEs, the receptor for AGEs, TGF-β1, and collagen IV were suppressed by CS treatment. Our data suggest that oral treatment of CS can inhibit the development of diabetic nephropathy via inhibition of AGEs accumulation in STZ-induced diabetic rats.