Status In Diabetic Rats Research Articles

Effects of grape seed extract on oxidative stress and antioxidant defense markers in streptozotocin-induced diabetic rats.

To evaluate the effects of grape seed extract (GSE) supplementation on oxidative stress and antioxidant markers in streptozotocin (STZ)-induced diabetic rats. Thirty-six male rats were divided into the following four groups: control, GSE-supplemented control, diabetic, and GSE-supplemented diabetic. Beginning on day 7 after STZ injection, the rats were administered GSE (100 mg kg(-1) day(-1) in drinking water for 6 weeks. At the end of week 6, rats were sacrificed by cardiac puncture. Plasma nitric oxide (NO) levels and xanthine oxidase (XO), adenosine deaminase (ADA), and glutathione peroxidase (GPx) activities were analyzed. Both XO and ADA activities increased and NO levels decreased in diabetic rats (P < 0.05). GSE supplementation normalized all of these changes. Antioxidant enzyme activities decreased in diabetic rats compared to the controls (P < 0.05). GSE supplementation increased antioxidant enzyme activities in both diabetic and healthy rats (P < 0.05). These findings suggest that 6 weeks of oral GSE supplementation may prevent oxidative stress and improve antioxidant status in diabetic rats.

Antihyperglycemic effect of syringic acid on attenuating the key enzymes of carbohydrate metabolism in experimental diabetic rats

Diabetes mellitus is one of the most common endocrine entities, which coexist with defect in carbohydrate metabolism. The Indian traditional system of medicine prescribed plant phytochemical therapies for diseases including diabetes mellitus. The present study was aimed to evaluate the therapeutic potential of syringic acid (SA) by assaying the activities of key enzymes of carbohydrate metabolism in experimental diabetic rats. Diabetes was induced into male albino Wistar rats by intraperitoneal administration of alloxan (150mg/kg). SA was administered to diabetic rats intragastrically at 25, 50 and 100mg/kg b.w daily once for 30days. The levels of plasma glucose, insulin, hemoglobin (Hb), glycated hemoglobin (HbA1c) and glycogen, levels of carbohydrate metabolic enzymes, liver and kidney markers were evaluated. Oral administration of SA (50mg/kg) for 30days, dose dependently improved the glycemic status in diabetic rats. The levels of insulin, Hb and glycogen increased with significant decrease in glucose and HbA1c levels in SA treated rats. The altered activities of carbohydrate metabolic enzymes, hepatic and renal marker were restored to near normal. Histopathological analysis of pancreas revealed that treatment with SA reduced the pancreatic damage induced by alloxan and stimulated β-cell regeneration in diabetic rats. The present findings suggest the antihyperglycemic effect of SA and its therapeutic potential for the management of diabetes.

Protective effect of chemically modified SOD on lipid peroxidation and antioxidant status in diabetic rats

Reactive oxygen species mediated oxidative stress play an important role on the injury of tissue damage and increased attention has been focused on the role of free radicals in diabetes mellitus (DM). In the present study firstly superoxide dismutase (SOD) enzyme was chemically modified with two different polymer and physicochemical properties of these conjugates clearly analyzed. Then, the stability of carboxymethylcellulose–SOD (CMC–SOD) and poly methyl vinyl ether-co-maleic anhydride–SOD (PMVE/MA–SOD) conjugates was investigated against temperature and externally added H2O2. Moreover, we investigated the effect of chemically modified SOD enzyme on lipid peroxidation and antioxidant status in streptozotocin (STZ)-induced diabetic rats. PMVE/MA–SOD conjugate treatment significantly reduced MDA level compared with the control groups, native and CMC–SOD conjugate treated groups in brain, kidney and liver tissue. GSH and SOD enzyme activity in diabetic groups was significantly increased by treatment of CMC–SOD and PMVE/MA–SOD conjugates. The protective effects on degenerative changes in diabetic rats were also further confirmed by histopathological examination. This study provides the preventative activity of SOD–polymer conjugates against complication of oxidative stress in experimentally induced diabetic rats. These results suggest that chemically modified SOD is effective on the oxidative stress-associated disease and offer a therapeutic advantage in clinical use.

Chemical characterization of Centaurium erythrea L. and its effects on carbohydrate and lipid metabolism in experimental diabetes

Ethnopharmacological relevanceCentaurium erythrea L. fam. Gentianaceae (CE) has been traditionally used for centuries in folk medicine of Balkans as a bitter medicinal herb for digestive complications and for treating febrile conditions and diabetes. The aim of this study was to gain insight into the chemical composition and underlying biochemical mechanism of action of the antihyperglycemic and antilipidemic activities of the dry extract of Centaurium erythrea L., wildly growing and traditionally used medicinal plant in the Republic of Macedonia. Materials and methodsAn ultrasonic methanol maceration of the aerial parts of the dried plant was performed and the extract was freeze-dried. HPLC–DAD–ESI–MSn was carried out on 150mm×4.6mm, 5μm RP-18 Eclipse XDB column, at 40°C. Mobile phase: water with 1% formic acid (A) and methanol (B) with linear gradient starting with 10% B was used to reach 15% at 5min, 40% B at 25min, 55% of B at 50min and 100% at 60min, with flow rate of 0.4mLmin−1. Normal and streptozotocin (STZ) hyperglycemic Wistar rats were used for assessment of the antihyperglycemic and antilipidemic activity by measurement of the key carbohydrate-related enzymes and substrates, as well as lipid state of the organism. ResultsHPLC–DAD–ESI–MSn analyses revealed presence of four different secoiridoids, seven flavonoid glycosides and seven xanthones in the freeze-dried extract of CE representing 53%, 25% and 22% of all compounds, respectively. The short-term (12 days) treatment of the STZ-diabetic rats with CE-extracts resulted in a 74% reduction of the produced hyperglycemia, which is only 6% less than the reduction caused by glibeclamide (GLB, positive control). The CE-extract had a significant impact on the hepatic carbohydrate metabolism enhancing the direct synthesis of glycogen, normalizing phosphorylase a activity and reducing the activity of glucose-6-phosphatase, which further causes reduction in production of blood glucose level. The long-term (45 days) treatment showed that the HbA1c in CE-treated group of animals was even lower than in the GLB-treated groups. The antilipidemic assessment of the CE-extract revealed decrease of total cholesterol, triglycerides, HDL and LDL level in the blood of the normal and STZ-hyperglycemic rats. ConclusionThe obtained results indicate that treatment with CE extract in STZ-diabetic rats regulates the elevated level of blood glucose and carbohydrate-related disturbances slightly better than the effect of glibenclamide. There was also regulation of the serum lipid status in diabetic rats. Identified groups of bitter compounds in the extract (flavonoides, iridoids and xanthones) probably have influence on the expressed antihyperglycaemic effect.

Effect of Green and Degree of Roasted Arabic Coffee on Hyperlipidemia and Antioxidant Status in Diabetic Rats

This study aims to examine the effects of green and different roasted degree of Arabic coffee on alloxan induced diabetes in rats. Animals were allocated into five groups of six rats each: a normal control group, diabetic group, diabetic rats fed with green Arabic coffee, diabetic rats fed with light roasted coffee and diabetic rats fed with dark roasted coffee group. The results showed increasing roasting degrees led to a decrease in moisture, radicalscavenging activity and total phenols. The diabetic rats presented a significant increase in blood glucose, plasma lipid profile compared to the control group. In addition, plasma malonaldialdehyde levels significantly increased compared to normal control group. Antioxidant enzymes activities such as superoxide dismutase and reduced Glutathione (GSH) levels significantly decreased in the plasma of diabetic rats compared to normal controls. The results showed that the experimental rats supplemented by green and roasted Arabic coffee significant increased feed efficiency ratio than diabetic control group. At the end of the study period, the experimental rats were showed significant improvement in blood glucose. It is noted that green coffee bean group has the best effect in decreasing glucose level followed by light coffee group followed by dark coffee group which recorded 95.46, 119.17 and 201.46 mg/dL, respectively. Experimental rats supplemented by green and light roasted Arabic coffee were similar insulin concentration normal control group. All treated groups showed a significant decrease in TC, TL, TG and LDL-C, while a significant increase HDL compared with diabetic control group with the highest value for green coffee. The diabetic rat supplemented by dark coffee was lower effective against lipids profile than green and light coffee. Diet supplemented with green and roasted Arabic coffee in the diabetic rats ameliorated antioxidant enzymes activities and level of GSH in diabetic rats and significantly decreased MDA levels. The administration of Arabic coffee attenuated the increased levels of the plasma enzymes produced by the induction of diabetes and caused a subsequent recovery towards normalization comparable to the control group animals. Our results thus suggest that green and light roasted Arabic coffee supplemented may be helpful in preventing diabetic complications in adult rats.

Asiatic acid prevents lipid peroxidation and improves antioxidant status in rats with streptozotocin-induced diabetes

Oxidative stress is a common pathogenesis of diabetes mellitus and asiatic acid (AA) plays an important role in ameliorating those difficulties. The present study was designed the protective effects of AA on altered lipid peroxidation products, enzymic and nonenzymic antioxidants in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in experimental rats by single dose STZ (40mg/kg b.w.) injection. Diabetic rats showed significantly increased levels of plasma glucose, thiobarbituric acid reactive substances, lipid hydroperoxides, aspartate aminotransferase, alanine aminotransferase, bilirubin, creatine kinase, urea, uric acid, creatinine and decreased levels of plasma insulin. The activities of enzymatic antioxidants such as superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase and the levels of non-enzymatic antioxidants such as vitamin C, vitamin E and reduced glutathione were decreased in diabetic rats. Oral treatment with AA (20mg/kg b.w.) showed near normalized levels of plasma glucose, insulin, lipid peroxidation products, enzymatic and nonenzymatic markers in diabetic rats. The results demonstrate that AA possesses potent antioxidant effect comparable with glibenclamide in improving antihyperglycemia and attenuating antioxidant status in diabetic rats.

Treatment with N-acetylcysteine does not alter blood glucose levels and the oxidative stress status in diabetic rats

Objectives: To verify the contribution of N-acetylcysteine (NAC) as an antioxidant drug in the therapy of diabetes, helping to reduce the deleterious effects resulting from oxidative stress associated with the hyperglycemic state. Materials and Methods: The animals were divided into normal (saline, 25 mg/kg NAC, and 75 mg/kg NAC) and diabetic rats (saline, 25 mg/kg NAC, and 75 mg/kg NAC) with five rats per group, and were treated or four weeks. Diabetes induction was performed by intraperitoneal injection of alloxan after fasting for 12 hours. Subsequently, glucose solution was used to promote wear of the pancreatic beta cells. Blood parameters such as glucose, glycated hemoglobin, hepatic and renal biomarkers, and butyrylcholinesterase activity were determined by commercial kits. Catalase, glutathione peroxidase, and superoxide dismutase activities were measured using spectrophotometric techniques, while glutathione and malondialdehyde levels were determined by chromatographic techniques. Results: NAC had no significant differences on glycemic, hepatic, renal, and oxidative stress biomarkers. Superoxide dismutase activity was significantly higher ( P P Conclusion: NAC supplementation did not re-establish the antioxidant system and consequently the deleterious effects of diabetes did not decrease. Diabetic groups that received NAC demonstrated that superoxide dismutase activity was indirectly linked to the levels of butyrylcholinesterase. More studies are necessary to investigate the action of NAC on superoxide dismutase and butyrylcholinesterase activities in the diabetic state.

Young inflorescence of Cocos nucifera contributes to improvement of glucose homeostasis and antioxidant status in diabetic rats

Enhanced oxidative stress and changes in oxidant capacity observed in clinical and experimental diabetes, are thought to be the aetiology of chronic diabetic complications. The aim of the study was to investigate whether Cocos nucifera inflorescence improves glucose homeostasis and antioxidant status, 20 % w/w of inflorescence containing diet were given to diabetic Sprague Dawley rats for 45 days. Diabetes was induced in rats by alloxan administration (150 mg/kg bodyweight) intraperitoneally. Treatment with inflorescence significantly lowered blood glucose levels thereby preventing steep onset of hyperglycemia which was observed after alloxan administration. It maintained glucose tolerance and glycosylated hemoglobin close to the values observed in normal control rats. In addition, the levels of serum total cholesterol and triglycerides were also lowered. Antioxidant enzymes registered a decline in their activity in diabetic rats, thus revealing the damaging effects of free radicals generated due to alloxan administration. But their activities were reverted towards near-normal range in inflorescence-supplemented animals. Histopathological analysis of pancreas of diabetic rats showed altered morphology, which was restored to near-normal in inflorescence-treated rats. Oxidative damage in various tissues of diabetic rats as evidenced by marked elevation in the levels of thiobarbituric acid reactive substances was nullified by inflorescence treatment, indicating its antioxidant efficacy in resisting oxidative damage.

Antioxidant enzymes effect and hormonal changes of leaf extracts of Gongronema latifolium and Nauclea latifolia in diabetic rats

The present study was carried out to evaluate the effects of ethanolic leaf extracts of Gongronema latifolium (G.L) and Nauclea latifolia (N.L) antioxidant enzymes activity and hormonal status in diabetic rats. Thirty six (36) albino Wistar rats of both sexes weighing 150–250g were divided into 6 parallel groups of 6 rats each and treated viz: Groups 1 and 2 served as controls (Normal and diabetic) and received placebo, groups 3, 4 and 5 received 200mg/kg b.w of G.L,N.L and 100mg/kg b.w each of G.L and N.L respectively while the group 6 received 5 iu/kg b.w of insulin subcutaneously daily for 21 days. Fasting blood glucose was determined using glucometer at the start of the experiment, and thereafter at 72 hours interval and at the end of experimental period. The animals were sacrificed using choloroform vapours and whole blood collected for sera preparation that were used to assay antioxidant enzymes and some hormones using standard kit methods of Agape diagnostics, Switzerland. A significant decrease (P<0.05) was observed from initial concentration by 66.34%, 18.12% and 67.73% respectively in fasting blood glucose upon treatment with extracts compared to diabetic control and N.L. Also a significant decrease (P<0.05) in insulin and T3 levels was observed in all treated groups compared to NC with an increase (P<0.05) when compared to diabetic group. Whereas a significant decrease (P<0.05) was observed in T4 level of all treated groups compared to the NC. A significant decrease (P<0.05) was observed in insulin and T3 level compared to DC. However, a significant decrease (P<0.05) was observed in T4 level of all treated groups compared to the NC.A significant decrease (P<0.05) in antioxidant concentrations viz SOD and CAT were observed in all treated groups compared to normal control. The result indicates that beside the antioxidant properties of these plants, they can also help in ameliorating the hormonal status of the diabetic rats.

Antioxidant enzymes activity and hormonal changes following administration of ethanolic leaf extract of Gongronema latifolium and Nauclea latifolia in streptozotocin induced diabetic rats

Aim of the work: The present study was carried out to evaluate the effects of ethanolic leaf extracts of Gongronema latifolium (G.L) and Nauclea latifolia (N.L) antioxidant enzymes activity and hormonal status in diabetic rats. Methods: Thirty six (36) albino Wistar rats of both sexes weighing 150–250g were divided into 6 parallel groups of 6 rats each and treated viz: Groups 1 and 2 served as controls (Normal and diabetic) and received placebo, groups 3, 4 and 5 received 200mg/kg b.w of G.L,N.L and 100mg/kg b.w each of G.L and N.L respectively while the group 6 received 5 iu/kg b.w of insulin subcutaneously daily for 21 days. Fasting blood glucose was determined using glucometer at the start of the experiment, and thereafter at 72 hours interval and at the end of experimental period. The animals were sacrificed using choloroform vapours and whole blood collected for sera preparation that were used to assay antioxidant enzymes and some hormones using standard kit methods of Agape diagnostics, Switzerland. Results: A significant decrease (P<0.05) was observed from initial concentration by 66.34%, 18.12% and 67.73% respectively in fasting blood glucose upon treatment with extracts compared to diabetic control and N.L. Also a significant decrease (P<0.05) in insulin and T3 levels was observed in all treated groups compared to NC with an increase (P<0.05) when compared to diabetic group. Whereas a significant decrease (P<0.05) was observed in T4 level of all treated groups compared to the NC. A significant decrease (P<0.05) was observed in insulin and T3 level compared to DC. However, a significant decrease (P<0.05) was observed in T4 level of all treated groups compared to the NC.A significant decrease (P<0.05) in antioxidant concentrations viz SOD and CAT were observed in all treated groups compared to normal control Conclusion: The result indicates that beside the antioxidant properties of these plants, they can also help in ameliorating the hormonal status of the diabetic rats.

Interaction of Barley β‐Glucan and Tea Polyphenols on Glucose Metabolism in Streptozotocin‐Induced Diabetic Rats

Soluble dietary fiber and antioxidants have received much attention as most important components of functional foods. However, few data are available on the effects of the combination of tea polyphenols (TP) and β-glucan (BG) on blood glucose in a diabetic rat. The effects of administration of barley BG and TP or their combination (TP + BG) on blood glucose, lipid profiles, and antioxidant parameters on streptozotocin-induced diabetic rats were investigated. Significant improvements on the blood glucose level, serum lipid parameters (decreases in triglyceride, total cholesterol, LDL-C, and increase in HDL-C), lipid peroxidation (decrease in malondiadehyde content), and serum antioxidant status (increases in superoxide dismutase, glutathione peroxidase, and total antioxidant capacity) resulted in diabetic rats after administering TP + BG. This study, therefore, demonstrated that the intake of TP + BG has beneficial effects on glucose tolerance, lipid metabolism, and serum antioxidant status. It also revealed that TP + BG is better than TP or BG alone in improving glucose metabolism and antioxidant status in diabetic rats. Practically, the present study suggested that polyphenols-rich cereal foods are help for type 2 diabetes. Although TP or BG was definitely helpful in the treatment and management of diabetes mellitus, synthetic anti-hyperglycemic effects were found between TP and BG. The fortification of a BG-rich cereal diet with TP could be used as a strategy to maintain health of diabetic subjects.

Antihyperglycemic, hypolipidemic and antioxidant activities of ethanolic extract of Commiphora mukul gum resin in fructose-fed male Wistar rats

High fructose feeding (66 % of fructose) induces type-2 diabetes in rats, which is associated with the insulin resistance, hyperinsulinemia, hypertriglyceridemia and oxidative stress. The present study was undertaken to evaluate the effect of ethanol extract of Commiphora mukul gum resin (CMEE) on blood glucose, plasma insulin, lipid profiles, reduced glutathione, lipid peroxidation, protein oxidation and enzymatic antioxidants like superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase, glutathione-S-transferase in fructose-induced type-2 diabetic rats. A significant gain in body weight, hyperglycemia, hyperinsulinemia, increased lipid profiles, lipid peroxidation, protein oxidation and decreased reduced glutathione, activities of enzymatic antioxidants and insulin sensitivity (increased homeostasis assessment assay) were observed in high-fructose-induced diabetic rats. The administration of CMEE (200 mg/kg/day) daily for 60 days in high-fructose-induced diabetic rats reversed the above parameters significantly. CMEE has the ability to improve insulin sensitivity and delay the development of insulin resistance, aggravate antioxidant status in diabetic rats and may be used as an adjuvant therapy for patients with insulin resistance.

Palladium-α-lipoic acid complex attenuates alloxan-induced hyperglycemia and enhances the declined blood antioxidant status in diabetic rats

Palladium α-lipoic acid (Pd-LA) complex has unique electronic and redox properties that appear to be the key to its physiological effectiveness. A proprietary liquid blend containing Pd-LA as the major component was demonstrated to be effective in improving the activities of mitochondrial enzymes in aged rats. The Pd-LA complex was evaluated for its hypoglycemic effect against the alloxan-induced diabetic model, as well as in the oral glucose tolerance test in rats. The in vitro free radical scavenging activity of Pd-LA was also determined. Administration of Pd-LA (0.5 mL/kg; equivalent to 3.8 mg complexed α-lipoic acid/kg, p.o.) daily for 5 days to alloxan-induced diabetic animals significantly reduced the blood glucose level (P < 0.05). The blood antioxidant status in the diabetic animals was significantly improved by the treatment of Pd-LA (P < 0.05). Similarly, Pd-LA showed significant in vitro antioxidant activity in a concentration-dependent manner. Results of the study conclude that the Pd-LA complex is effective in lowering the blood glucose level and enhancing the declined antioxidant status in diabetic animals. Significant finding(s) of the study include: (i) Pd-LA significantly increased the tolerance of glucose and was also effective in ameliorating hyperglycemia induced by alloxan; (ii) Pd-LA significantly enhanced the activities of blood superoxide dismutase, catalase, glutathione peroxidase and level of glutathione in diabetic animals; and (iii) Pd-LA showed significant in vitro antioxidant activity. This study adds: The therapeutic efficiency of Pd-LA is demonstrated against declined antioxidant status as well as hyperglycemia associated with diabetes.

Effect of protein and chromium intake on some nutritional and biochemical status in diabetic rats

ABSTRACT The present study was designed to investigate the effects of protein and chromium intake on some nutritional and biological status in streptozotocin induced diabetic rats. This study was conducted on forty -nine Sprague –Dawley adult male rats, weighting 190 ±15 g were classified into control and six treated groups with drug, chromium, high protein, low protein, high protein with chromium and low protein with chromium groups for ten weeks. The obtained results revealed that the drug, chromium, high protein, high protein with chromium and low protein with chromium groups rat group had a significant higher values of body weight gain, feed efficiency ratio, insulin, hemoglobin, packed cell volume, GPX, SOD and globulin and a significant lower value in ALT, AST, AP,γGT ,creatinine and urea when compared with control group but a significant decrease in the value of glucose and MDA compared with drug group . The high protein and high protein with chromium rat groups showed a significant increase in the value of total protein but high protein with chromium and low protein with chromium rat groups showed significant decrease in the value of albumin/ globulin ratio when compared with control group or with drug rat group. The chromium, high protein, high protein with chromium and low protein with chromium rat groups showed significant decrease in the value of total bilirubin while the chromium, low protein and low protein with chromium rat groups showed significant decrease in the value of uric acid when compared with control group. The low protein rat group showed a non significant difference in final weight, weight gain, feed intake, feed efficiency ratio, insulin, packed cell volume, SOD , MDA, ALT, AST, AP , γGT, total bilirubin and creatinine and a significant decrease in glucose and GPX but a significant increase in heamoglobin and globulin when compared with control group but showed a significant decrease in weight gain, feed efficiency ratio, insulin, packed cell volume, GPX, SOD and a significant increase in glucose, MDA, ALT, AST, AP ,γGT and creatinine when compared with drug group. Key wards :( protein - chromium - diabetic rat).

Quercitrin, a bioflavonoid improves glucose homeostasis in streptozotocin‐induced diabetic tissues by altering glycolytic and gluconeogenic enzymes

The present study is an investigation into the role of quercitrin on carbohydrate metabolism in normal and streptozotocin (STZ)-induced diabetic rats. Administration of STZ leads to a significant increase (P < 0.05) in fasting plasma glucose and a decrease in insulin levels. The content of glycogen is significantly decreased (P < 0.05) in liver and muscle, but increased in the kidney. The activity of hexokinase decreased whereas the activities of glucose 6-phosphatase and fructose 1,6-bisphosphatase significantly increased (P < 0.05) in the tissues. Oral administration of quercitrin (30 mg/kg) to diabetic rats for a period of 30 days resulted in significant (P < 0.05) alterations in the parameters studied but not in normal rats. A decrease of plasma glucose and increase in insulin levels were observed along with the restoration of glycogen content and the activities of carbohydrate metabolic enzymes in quercitrin-treated diabetic rats. The histopathological study of the pancreas revealed the protective role of quercitrin. There was an expansion of the islets and decreased fatty infiltrate of the islets in quercitrin treated diabetic rats. In normal rats treated with quercitrin, we could not observe any significant change in all the parameters studied. Combined, these results show that quercitrin plays a positive role in carbohydrate metabolism and antioxidant status in diabetic rats.

A high-resistance-starch rice diet reduces glycosylated hemoglobin levels and improves the antioxidant status in diabetic rats

Diabetes mellitus is a common problem in developed countries. An improved postprandial hyperglycemic peak is one of the main therapeutic targets in diabetic patients. The Wistar rats with streptozotocin (STZ)-induced diabetes were divided into cornstarch (control) and Japonica rice groups, which were fed 640 g starch/kg diets for 4 weeks. The area (means § SD) under the glucose curve of cornstarch was 173.8 § 6.9 and Japonica rice diet was 154.3 § 8.7 mmol £ min/L, and the area (means § SD) under the insulin curve of cornstarch was 12.9 § 0.1 and Japonica rice diet was 12.0 § 0.6 nmol £ min/L. The glycosylated hemoglobin levels, serum fructosamine and cholesterol concentrations in diabetic rats fed the Japonica rice diet were signiWcantly lower than the control group (P < 0.05). The decreased malondialdehyde levels and increased superoxide dismutase activity and total radical-trapping antioxidant parameter in plasma were also found in rat fed the Japonica rice diet compared to the control. These results suggested that the diet containing high-resistance-starch Japonica rice might reduce glycosylated hemoglobin levels, serum cholesterol concentrations and raised the antioxidant status in the blood.

N-3 Fatty acids modulate antioxidant status in diabetic rats and their macrosomic offspring

We investigated the role of dietary n-3 polyunsaturated fatty acids (n-3 PUFA) in the modulation of total antioxidant status in streptozotocin (STZ)-induced diabetic rats and their macrosomic offspring. Female wistar rats, fed on control diet or n-3 PUFA diet, were rendered diabetic by administration of five mild doses of STZ on day 5 and were killed on days 12 and 21 of gestation. The macrosomic (MAC) pups were killed at the age of 60 and 90 days. Lipid peroxidation was measured as the concentrations of plasma thiobarbituric acid reactive substances (TBARS), and the total antioxidant status was determined by measuring (i) plasma oxygen radical absorbance capacity (ORAC), (ii) plasma vitamin A, E and C concentrations, and (iii) antioxidant enzymes activities in erythrocytes. The plasma lipid concentrations and fatty acid composition were also determined. Diabetes increased plasma triglyceride and cholesterol concentrations, whereas macrosomia was associated with enhanced plasma cholesterol and triglyceride levels, which diminished by feeding n-3 PUFA diet. N-3 PUFA diet also reduced increased plasma TBARS and corrected the decreased ORAC values in diabetic rats and their macrosomic offspring. EPAX diet increased the diminished vitamin A levels in diabetic mothers and vitamin C concentrations in macrosomic pups. Also, this diet improved the decreased erythrocyte superoxide dismutase and glutathione peroxidase activities in diabetic and macrosomic animals. Diabetes and macrosomia were associated with altered lipid metabolism, antioxidant enzyme activities and vitamin concentrations. N-3 PUFA diet improved hyperlipidemia and restored antioxidant status in diabetic dams and MAC offspring.

Rutin improves glucose homeostasis in streptozotocin diabetic tissues by altering glycolytic and gluconeogenic enzymes

The role of rutin on carbohydrate metabolism in normal and streptozotocin (STZ)-induced diabetic rats was investigated in the present study. Administration of STZ led to a significant (p <0.05) increase in fasting plasma glucose and a decrease in insulin levels. The content of glycogen significantly (p <0.05) decreased in liver and muscle, but increased in kidney. The activity of hexokinase decreased whereas the activities of glucose-6-phosphatase and fructose-1,6-bisphosphatase significantly (p <0.05) increased in the tissues. Oral administration of rutin (100 mg/kg) to diabetic rats for a period of 45 days resulted in significant (p <0.05) alterations in the parameters studied but not in normal rats. A decrease of plasma glucose and increase in insulin levels were observed along with the restoration of glycogen content and the activities of carbohydrate metabolic enzymes in rutin-treated diabetic rats. The histopathological study of the pancreas revealed the protective role of rutin. There was an expansion of the islets and decreased fatty infiltrate of the islets in rutin-treated diabetic rats. In normal rats treated with rutin, we could not observe any significant change in all the parameters studied. Combined, these results show that rutin plays a positive role in carbohydrate metabolism and antioxidant status in diabetic rats.

Diabetic changes in the redox status of the microsomal protein folding machinery

Changes in assisted protein folding are largely unexplored in diabetes. In the present studies, we have identified a reductive shift in the redox status of rat liver microsomes after 4 weeks of streptozotocin-induced diabetes. This change was reflected by a significant increase in the total- and protein-sulfhydryl content, as well as in the free sulfhydryl groups of the major protein disulfide isomerases (PDIs), the 58 kDa PDI and the 57 kDa ERp57 but not other chaperones. A parallel decrease of the protein-disulfide oxidoreductase activity was detected in the microsomal fraction of diabetic livers. The oxidant of PDI, Ero1-Lα showed a more oxidized status in diabetic rats. Our results reveal major changes in the redox status of the endoplasmic reticulum and its redox chaperones in diabetic rats, which may contribute to the defective protein secretion of the diabetic liver.

Effect of herbal hypoglycemic agents on oxidative stress and antioxidant status in diabetic rats

In the present study the antioxidative potential ofMomordica charantia, Azadirachta indica, Allium sativum andOcimum sanctum was assessed in streptozotocin induced diabetic rats. Lipid peroxide levels were also measured in normal, diabetic and treated animals. Malondialdehyde (MDA) levels were significantly higher and antioxidant activity was found low in diabetic groups as compared to the control groups, and significant alteration in both the MDA levels and antioxidant activity was also observed when the above herbal hypoglycemic agents were given to diabetic rats. On the basis of our results we conclude thatM. charantia, A. indica, A. sativum andO. sanctum are not only useful in controlling the lipid peroxide levels but are also helpful in further strengthening the antioxidant potential.