Myrtenal attenuates oxidative stress and inflammation in a rat model of streptozotocin-induced diabetes

The present study was aimed to investigate the effect of myrtenal on diabetes-associated oxidative stress, lipid peroxidation (LPO), and inflammation using a rat model of streptozotocin (STZ)-induced diabetes. Following the induction of diabetes in male Wistar rats using STZ (40 mg/kg body weight), myrtenal (80 mg/kg body weight) was administered orally to diabetic rats for four weeks and then sacrificed to harvest tissues. We measured the levels of antioxidants, LPO, and proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6), and the p65 subunit of nuclear factor-kappa B (NF-kB p65). Diabetic rats revealed increased levels of LPO, proinflammatory cytokines, and NF-kB p65, and decreased levels of antioxidants in the liver and pancreas. Supplementation with myrtenal significantly attenuated the diabetes-induced changes in the liver and pancreas of diabetic rats. Our findings suggest that myrtenal may serve as an antioxidant and anti-inflammatory agent against diabetes-associated oxidative stress and inflammation.HighlightsOral administration of myrtenal improved the antioxidant status in the liver and pancreas of diabetic rats.Myrtenal treatment diminished inflammation in the liver and pancreas of diabetic rats.Myrtenal supplementation averts oxidative stress and inflammation in diabetic rats.Myrtenal could serve as a potent antioxidant and anti-inflammatory agent in the management of diabetes.

Antihyperlipidemic effect of tyrosol, a phenolic compound in streptozotocin-induced diabetic rats

We investigated the antihyperlipidemic effects of tyrosol in streptozotocin (STZ)-induced diabetic rats. Rats were injected intraperitoneally with STZ (40 mg/kg), and these established experimental rats were treated with tyrosol (20 mg/kg) and glibenclamide (600 µg/kg) for 45 days. The observed results revealed that tyrosol treatment significantly reduced plasma glucose, plasma, and liver total cholesterol, triglycerides, free fatty acids, phospholipids, plasma low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, atherogenic index, and significantly increased plasma insulin and high-density lipoprotein cholesterol in STZ-induced diabetic rats. The activity of 3-hydroxy 3-methylglutaryl coenzyme A reductase significantly reduced in the liver, whereas the activities of lipoprotein lipase and lecithin cholesterol acyltransferase were significantly increased in the plasma of tyrosol treated STZ-induced diabetic rats. Histological examination showed that tyrosol treatment remarkably reduced lipid accumulation in the liver of STZ-induced diabetic rats. The present study revealed that tyrosol exhibits potent antihyperlipidemic effects in STZ-induced diabetic rats.

In-vivo and In-vitro Antioxidant Activity of Troxerutin on Nickel Induced Toxicity in Experimental Rats

The aim of the present study was to evaluate the effect of troxerutin (TXN) on Nickel (Ni) toxicity by using rats and in-vitro model. Ni toxicity induced in male albino wistar rats (20 mg/kg body weight (b.w) was administered orally for 20 days). TXN was administered orally (100 mg/kg (b.w) for 20 days with administration of Ni. The toxic effect of Ni and the action of TXN was measure by determining the lipid peroxidation markers and antioxidant levels in plasma and various in-vitro antioxidant systems. TXN exhibited a significant (p < 0.05) antioxidant activity in Ni induced toxicity by reversing the changes observed in TBARS, HP, Vitamin C, E and GSH. The free radical scavenging properties of TXN at different concentrations (10-50ug/mL) were investigated with various in-vitro methods such as 2, 2'-diphenyl-1- picrylhydrazyl radical (DPPH), 2, 2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS•+), hydroxyl radical, superoxide anion scavenging activity and reducing power. Among the different concentrations, 50 μg/mL of TXN was more effective compared to other concentrations in all in-vitro assays. The above study conclude that TXN possesses potent in-vivo and in-vitro antioxidant activity with effective free radical scavenger for potential therapeutic value.

In-vivo and In-vitro Antioxidant Activity of Troxerutin on Nickel Induced Toxicity in Experimental Rats

The aim of the present study was to evaluate the effect of troxerutin (TXN) on Nickel (Ni) toxicity by using rats and in-vitro model. Ni toxicity induced in male albino wistar rats (20 mg/kg body weight (b.w) was administered orally for 20 days). TXN was administered orally (100 mg/kg (b.w) for 20 days with administration of Ni. The toxic effect of Ni and the action of TXN was measure by determining the lipid peroxidation markers and antioxidant levels in plasma and various in-vitro antioxidant systems. TXN exhibited a significant (p < 0.05) antioxidant activity in Ni induced toxicity by reversing the changes observed in TBARS, HP, Vitamin C, E and GSH. The free radical scavenging properties of TXN at different concentrations (10-50ug/mL) were investigated with various in-vitro methods such as 2, 2'-diphenyl-1- picrylhydrazyl radical (DPPH), 2, 2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS•+), hydroxyl radical, superoxide anion scavenging activity and reducing power. Among the different concentrations, 50 μg/mL of TXN was more effective compared to other concentrations in all in-vitro assays. The above study conclude that TXN possesses potent in-vivo and in-vitro antioxidant activity with effective free radical scavenger for potential therapeutic value.

Beneficial effects of tyrosol on altered glycoprotein components in streptozotocin-induced diabetic rats

CONTEXT

Olive oil is the major source of tyrosol which is a natural phenolic antioxidant. Olive oil constitutes a major component of the Mediterranean diet that is linked to a reduced incidence of chronic diseases.

OBJECTIVE

This study evaluates the effects of tyrosol on altered glycoprotein components in streptozotocin-induced diabetic rats.

MATERIALS AND METHODS

Diabetes mellitus was induced in male Wistar rats by streptozotocin (40 mg/kg body weight). These rats were administered tyrosol (20 mg/kg body weight) and glibenclamide (600 μg/kg body weight) orally daily for 45 days. Plasma glucose, plasma insulin, glycoprotein components such as hexose, hexosamine, sialic acid and fucose in the plasma, liver and kidney, and histopathogy of tissues were analyzed.

RESULTS

Diabetic rats revealed significant (p < 0.05) increase in the levels of glucose, hexose, hexosamine, sialic acid and fucose (277.17, 152.45, 100.43, 79.69 and 49.29 mg/dL) in the plasma; decrease in the levels of palsma insulin (6.12 μU/mL) and sialic acid (4.36 and 5.03 mg/g) in the liver and kidney; significant (p < 0.05) increase in hexose (49.33 and 46.82 mg/g), hexosamine (22.68 and 33.20 mg/g) and fucose (31.63 and 32.44 mg/g) in the liver and kidney. Further, periodic acid-Schiff staining of tissues revealed positive-stain accumulation in diabetic rats. Tyrosol treatment showed significant (p < 0.05) effects on all the biochemical parameters and histopathology studied in streptozotocin- nduced diabetic rats. Also, the in vitro study revealed the antioxidant effect of tyrosol.

DISCUSSION AND CONCLUSIONS

Thus, tyrosol protects streptozotocin-induced diabetic rats from the altered glycoprotein components. Further, this study can be extrapolated to humans.

Modulatory effects of naringin on hepatic key enzymes of carbohydrate metabolism in high-fat diet/low-dose streptozotocin-induced diabetes in rats

We evaluated the modulatory effects of naringin on altered hepatic key enzymes of carbohydrate metabolism in high-fat diet/low-dose streptozotocin-induced diabetic rats. Oral treatment of naringin at a doses of 20, 40 and 80 mg/kg body weight to diabetic rats for 30 days resulted in a significant reduction in the levels of plasma glucose, blood glycosylated hemoglobin and increase in the levels of plasma insulin and blood hemoglobin. The altered activities of the hepatic key enzymes of carbohydrate metabolism such as hexokinase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, glucose-6-phosphate dehydrogenase, glycogen synthase, glycogen phosphorylase and glycogen content of diabetic rats were significantly reverted to near normal levels by the treatment of naringin in a dose-dependent manner. Naringin at a dose of 80 mg/kg body weight showed the highest significant effect than the other two doses (20 and 40 mg/kg). Further, immunohistochemical observation of pancreas revealed that naringin-treated diabetic rats showed the increased number of insulin immunoreactive β-cells, which confirmed the biochemical findings. These findings revealed that naringin has potential antihyperglycemic activity in high-fat diet/low-dose streptozotocin-induced diabetic rats.

Protective Effect of Troxerutin on Nickel-Induced Testicular Toxicity in Wistar Rats

Nickel (Ni)-induced oxidative damage is a serious problem that leads to reproductive system failure through testicular damage. The present investigation was carried out to determine the effect of troxerutin (Txn) on testicular toxicity induced by Ni in experimental rat testes. The oral administration of Txn (100 mg/kg body weight [bw]) showed a significant (p < 0.01) increase in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PD), reduced glutathione, ascorbate, total sulphydryl groups, and testis-organ weight. Subsequently, the administration of Txn also significantly reduced the accumulation of Ni, lipid peroxidation products, and protein carbonyl levels in Txn-treated animals. Testicular protection in the experimental animals by Txn is further substantiated by a remarkable reduction of Ni, which was revealed through testicular tissue histopathology. These studies suggest that Txn could prevent oxidative damage and testicular toxicity induced by Ni in experimental animals.

Myrtenal ameliorates hyperglycemia by enhancing GLUT2 through Akt in the skeletal muscle and liver of diabetic rats

Insulin signaling pathway is an important role in glucose utilization in tissues. Our Previous study has established that myrtenal has antihyperglycemic effect against diabetic rats. The aim of this study was to explore the molecular mechanism of myrtenal in Streptozotocin-induced diabetic rats. Experimental diabetes was induced by single intraperitoneal injection of Streptozotocin (STZ) (40 mg/kg bw) in Wistar albino rats. Diabetic rats were administered myrtenal (80 mg/kg bw) for a period of 28 days. Diabetic rats showed an increased the levels of plasma glucose, decreased the levels of plasma insulin, down-regulation of insulin receptor substrate 2 (IRS2), Akt and glucose transporter 2 (GLUT2) in liver and insulin receptor substrate 2 (IRS2), Akt and glucose transporter 4 (GLUT4) protein expression in skeletal muscle. However, myrtenal treated diabetic rats revealed decreased the levels of plasma glucose, improved the plasma insulin levels, up-regulation of IRS2, Akt and GLUT2 in liver and IRS2, Akt and GLUT4 protein expression in skeletal muscle. The up-regulation of glucose transporters enhances the glucose uptake in liver and skeletal muscle. The histopathology and immunohistochemical analysis of the pancreas also corroborates with the above findings. Our findings suggest that myrtenal could be a potent phytochemical in the management of diabetes.

Effects of diallyl tetrasulfide on cadmium-induced oxidative damage in the liver of rats

The protective efficacy of diallyl tetrasulfide (DTS) from garlic on liver injury induced by cadmium (Cd) was investigated. In this study, Cd (3 mg/kg body weight) was administered subcutaneously for 3 weeks to induce toxicity. DTS was administered orally (10, 20 and 40 mg/kg body weight) for 3 weeks with subcutaneous (sc) injection of Cd. Cd-induced liver damage was evidenced from increased activities of serum hepatic enzymes, namely aspartate transaminase, alanine transaminase, alkaline phosphatase and lactate dehydrogenase, with significant elevation of lipid peroxidation indices (thiobarbituric acid reactive substances and hydroperoxides) and protein carbonyl groups in the liver. Rats subjected to Cd toxicity also showed a decline in the levels of total thiols, reduced glutathione (GSH), vitamin C and vitamin E, accompanied by an increased accumulation of Cd, and significantly decreased activities of superoxide dismutase, catalase (CAT), glutathione peroxidase, glutathione-S-transferase (GST), glutathione reductase, and glucose-6-phosphate dehydrogenase in the liver. Administration of DTS at 40 mg/kg body weight significantly normalised the activities of hepatic marker enzymes, compared to other doses of DTS (10 and 20 mg/kg body weight). In addition, DTS (40 mg/kg body weight) significantly reduced the accumulation of Cd and the level of lipid peroxidation, and restored the level of antioxidant defense in the liver. Histological studies also showed that administration of DTS to Cd-treated rats resulted in a marked improvement of hepatocytes morphology with mild portal inflammation. Our results suggest that DTS might play a vital role in protecting Cd-induced oxidative damage in the liver. Human & Experimental Toxicology(2007) 26, 527—534

Tyrosol, a phenolic compound, ameliorates hyperglycemia by regulating key enzymes of carbohydrate metabolism in streptozotocin induced diabetic rats

The present study was designed to evaluate the effects of tyrosol, a phenolic compound, on the activities of key enzymes of carbohydrate metabolism in the control and streptozotocin-induced diabetic rats. Diabetes mellitus was induced in rats by a single intraperitoneal injection of streptozotocin (40 mg/kg body weight). Experimental rats were administered tyrosol 1 ml intra gastrically at the doses of 5, 10 and 20mg/kg body weight and glibenclamide 1 ml at a dose of 600 μg/kg body weight once a day for 45 days. At the end of the experimental period, diabetic control rats exhibited significant (p<0.05) increase in plasma glucose, glycosylated hemoglobin with significant (p<0.05) decrease in plasma insulin, total hemoglobin and body weight. The activities of key enzymes of carbohydrate metabolism such as phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase and glucose-6-phosphatase were significantly (p<0.05) increased and the activities of hexokinase and glucose-6-phosphate dehydrogenase were significantly (p<0.05) decreased in the liver and kidney of diabetic control rats. Further, antioxidants were lowered in diabetic control rats. A significant (p<0.05) decline in glycogen level in the liver and muscle and glycogen synthase activity in the liver and a significant (p<0.05) increase in the activity of liver glycogen phosphorylase were observed in diabetic control rats compared to normal control rats. Oral administration of tyrosol to diabetic rats reversed all the above mentioned biochemical parameters to near normal in a dose dependent manner. Tyrosol at a dose of 20mg/kg body weight showed the highest significant effect than the other two doses. Immunohistochemical staining of pancreas revealed that tyrosol treated diabetic rats showed increased insulin immunoreactive β-cells, which confirmed the biochemical findings. The observed results were compared with glibenclamide, a standard oral hypoglycemic drug. The results of the present study suggest that tyrosol decreases hyperglycemia, by its antioxidant effect.

Protective effects of hesperidin on oxidative stress, dyslipidaemia and histological changes in iron-induced hepatic and renal toxicity in rats

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Evaluate the effects of hesperidin in iron induced hepatic and renal function.

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Hesperidin has significant antioxidant property.

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Hesperidin shows reduced lipid profile.

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Administration of hesperidin averts oxidative stress in liver and kidney tissues.

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Rescue the liver and kidney tissues from pathology.

The present study was to evaluate the protective role of hesperidin (HDN) against iron-induced hepatic and renal toxicity in rats. Administration of iron (30 mg/kg body weight) intraperitoneally for 10 days, the levels of serum hepatic markers, renal functional markers, lipid profile, lipid peroxidation markers and iron concentration in blood were significantly (p < 0.05) increased. The toxic effect of iron was also indicated by significant (p < 0.05) decrease in the levels of plasma, liver and kidney of enzymatic and non-enzymatic antioxidants. Administration of hesperidin at different doses (20, 40 and 80 mg/kg body weight) significantly (p < 0.05) reversed the levels of serum hepatic markers, renal functional markers, lipid profile, lipid peroxidation markers, restored the levels of hepatic, renal enzymatic antioxidants and non-enzymatic antioxidants with decrease in iron concentration in blood. Hesperidin at a dose of 80 mg/kg body weight exhibits significant protection on hepatic and renal when compared with other two doses (20 and 40 mg/kg body weight). All these changes were corroborating by histological observations of liver and kidney. This study demonstrated the protective role of hesperidin in reducing toxic effects of iron in experimental rats.

Ameliorating effects of troxerutin on nickel-induced oxidative stress in rats

OBJECTIVE

This study investigates the effects of troxerutin on nickel (Ni)-induced oxidative stress in rats.

METHODS

Nickel as nickel sulfate (20 mg/kg body weight (b.w.)) was administered intraperitoneally for 20 days to induce toxicity in the subject rats. The levels of stress markers AST, ALT, ALP, LDH, and GGT in the hepatic tissue were significantly increased while a decrease in the levels of enzymic and non-enzymic antioxidants was observed in Ni intoxicated rats.

RESULTS

Oral administration of troxerutin along with Ni for 20 days in a dose-dependent manner significantly reverted the stress markers in the liver tissue to near normal level. Troxerutin exhibited significant protection at 100 mg/kg b.w. Histopathological studies also supported the above findings.

CONCLUSIONS

Thus, we conclude that troxerutin preserved the histo-architecture and ameliorated stress markers in the liver tissue of Ni-intoxicated rats.

Beneficial effect of caffeic Acid on alcohol-induced alterations in lipid peroxidation and antioxidant defense in rats

ABSTRACT We studied the effect of caffeic acid on alcohol-induced oxidative stress in alcohol-induced toxicity in rats. The elevation in the levels of lipid peroxidation in alcohol administration was accompanied by a significant decrease in the levels of vitamins C and E, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), and glutathione S-transferase (GST) in the liver and kidney. Oral administration of caffeic acid at a dose of 12 mg/kg/body weight for 45 days significantly reduced the severe oxidative stress in alcohol toxicity as evidenced by the decrease in the levels of lipid peroxidation with a simultaneous increase in the level of enzymic and nonenzymic antioxidants in liver and kidney. Histological studies in the liver and kidney also showed that administration of caffeic acid to alcohol-treated rats resulted in a marked reduction in alcohol-induced pathological changes. These results suggest that administration of caffeic acid to alcohol-supplemented rats alleviates the alcohol-induced oxidative damage in the liver and kidney.

Antioxidant role of coumarin on streptozotocin-nicotinamide-induced type 2 diabetic rats

The purpose of this study was to investigate the antioxidant role of coumarin on streptozotocin-nicotinamide-induced Type 2 diabetic rats. In experimental rats, the levels of plasma glucose, insulin, and the levels of thiobarbituric acid reactive substances, lipid hydroperoxides, conjugated dienes, and the activities of superoxide dismutase, catalase, glutathione-S-transferase, and glutathione peroxidase were assayed in liver and kidney. Diabetic rats showed elevated levels of plasma glucose and lipid peroxidation markers and reduced plasma insulin and antioxidant enzymes. Oral administration of coumarin resulted in a significant reduction in the plasma glucose and lipid peroxides and a significant increase in the plasma insulin and antioxidant enzymes. Chronic treatment of coumarin remarkably restored the normal status of the histopathological changes observed in the selected tissues. It can be concluded that coumarin has antioxidant effect in Type 2 diabetic rats.

Ameliorative effect of diosmin, a citrus flavonoid against streptozotocin-nicotinamide generated oxidative stress induced diabetic rats

Oxidative stress has been suggested as a contributory factor in development and complication of diabetes. The aim of the study was to evaluate the effect of diosmin (DS) in oxidative stress in streptozotocin-nicotinamide (STZ-NA)-induced diabetic rats by measuring the lipid peroxidation (LPO) as well as the ameliorative properties. Experimental diabetes was induced by a single intraperitoneal (i.p) injection of STZ (45 mg/kg body weight (b.w.)) dissolved in 0.1 mol/L citrate buffer (pH 4.5), 15 min after the i.p administration of NA (110 mg/kg b.w.). Diabetic rats exhibited increased plasma glucose with significant decrease in plasma insulin levels. The activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and the levels of low-molecular weight antioxidants vitamin C, vitamin E and reduced glutathione (GSH) were decreased while increases in the levels of LPO markers were observed in liver and kidney tissues of diabetic control rats as compared to normal control rats. Oral treatment with DS (100mg/kg/day) for a period of 45 days showed significant ameliorative effects on all the biochemical parameters studied. Biochemical findings were supported by histological studies. These results indicated that DS has potential ameliorative effects in addition to its antidiabetic effect in type 2 diabetic rats.

Hesperetin, a citrus flavonone, protects potentially cadmium induced oxidative testicular dysfunction in rats

The present study was aimed to evaluate the protective effect of hesperetin (Hp) on cadmium (Cd) induced oxidative testicular toxicity in rats. Subcutaneous administration of Cd (3mg/kg body weight) for 21 days significantly elevated the levels of oxidative stress markers, Cd concentration in testis and lowered the levels of enzymatic, non-enzymatic antioxidants and membrane bound enzymes in the testicular tissue. Hp administrated orally along with Cd injection for 21 days, significantly revert back the status of oxidative stress markers, Cd concentration in testis, improved status of antioxidant markers and membrane bound enzymes in the testis to near normal level. The histopathological studies in the testis of rats also supported that Hp (40 mg/kg) markedly reduced the toxicity of Cd and preserved the normal histoarchitecture pattern of the testis. Thus, the results suggest that Hp acts as a potent antioxidative agent against Cd induced testicular toxicity in rats.

Protective role of sinapic acid against arsenic: induced toxicity in rats

Arsenic compounds are classified as toxicants and human carcinogens. Environmental exposure to arsenic imposes a big health issue worldwide. Sinapic acid is a phenylpropanoid compound and is found in various herbal materials and high-bran cereals. It has been reported that sinapic acid has antioxidant efficacy as metal chelators due to the orientation of functional groups. However, it has not yet been examined in experimental animals. In light of this fact, the purpose of this study was to characterize the protective role of sinapic acid against arsenic induced toxicity in rats. Rats were orally treated with arsenic alone (5mg/kg body weight (bw)/day) plus sinapic acid at different doses (10, 20 and 40mg/kg bw/day) for 30days. Hepatotoxicity was measured by the increased activities of serum hepatospecific enzymes namely aspartate transaminase, alanine transaminase, alkaline phosphatase, gamma glutamyl transferase, lactate dehydrogenase and total bilirubin along with increased elevation of lipid peroxidative markers, thiobarbituric acid reactive substances, lipid hydroperoxides, protein carbonyl content and conjugated dienes. The toxic effect of arsenic was also indicated by significantly decreased activities of enzymatic antioxidants like superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase and glucose-6-phosphate dehydrogenase along with non-enzymatic antioxidant like reduced glutathione. Administration of sinapic acid exhibited significant reversal of arsenic induced toxicity in hepatic tissue. The effect at a dose of 40mg/kgbw/day was more pronounced than the other two doses (10 and 20mg/kgbw/day). All these changes were supported by reduction of arsenic concentration and histopathological observations of the liver. These results suggest that sinapic acid has a protective effect over arsenic induced toxicity in rat.

Beneficial role of naringin, a flavanoid on nickel induced nephrotoxicity in rats

This study was conducted to investigate the beneficial role of naringin on nickel induced nephrotoxicity. Nickel (Ni) (20mg/kg body weight (b.w.) was administered intraperitoneally (i.p.) for 20 days. Naringin was administered orally (20, 40 and 80 mg/kg b.w.) with i.p. administration of Ni. Ni administration increased the levels of serum urea, uric acid and creatinine with a significant decrease in creatinine clearance and decreased levels of urea, uric acid and creatinine in urine. The levels of lipid peroxidation markers and nickel concentration in blood and kidney were also increased. While, the activities of enzymic and non-enzymic antioxidants were decreased. Treatment with naringin attenuated the alterations in the renal and urine markers, decreasing lipid peroxidation markers, increasing the antioxidant cascade and decreasing the nickel concentration in blood and kidney. All these changes were supported by histopathological observations. These findings demonstrate that naringin exerts a protective effect against nickel toxicity.

Thymoquinone ameliorates chemical induced oxidative stress and β-cell damage in experimental hyperglycemic rats

The present study was aimed to investigate the effect of thymoquinone (TQ) on pancreatic insulin levels, tissue antioxidant and lipid peroxidation (LPO) status in streptozotocin (STZ) nicotinamide (NA) induced diabetic rats. Diabetes was induced in experimental rats by a single intraperitoneal (i.p) injection of STZ (45 mg/kg b.w) dissolved in 0.1 mol/L citrate buffer (pH 4.5), 15 min after the i.p administration of NA (110 mg/kg b.w). Diabetic rats exhibited increased blood glucose with significant decrease in plasma insulin levels. The activities of antioxidant enzymes catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and the levels of low-molecular weight antioxidants Vitamin C, Vitamin E and reduced glutathione (GSH) were decreased while increases in the levels of lipid peroxidation markers were observed in liver and kidney tissues of diabetic control rats as compared to control rats. In addition, diabetic rats showed an obvious decrease in pancreatic insulin levels. Administration of TQ (80 mg/kg b.w) to diabetic rats for 45 days significantly reversed the damage associated with diabetes. Biochemical findings were supported by histological studies. These results indicated that TQ exerts a protective action on pancreatic beta cell function and overcomes oxidative stress through its antioxidant properties.

Protective role of diallyl tetrasulfide on cadmium-induced testicular damage in adult rats: A biochemical and histological study

Cadmium (Cd)-induced oxidative damage is the most serious problem that leads to reproductive system failure in both human and animals. Our previous studies indicate that diallyl tetrasulfide (DTS) from garlic has the cytoprotective and antioxidant activity against Cd-induced toxicity in vivo and in vitro. The present investigation was carried out to find the influence of DTS on peroxidative damage induced by Cd in rat testes. The Cd-exposed rat testis showed a significant (p < 0.05) decrease in testes to body weight ratio, along with a significant (p < 0.05) increase in Cd accumulation, lipid peroxidation and protein carbonyl levels. In Cd-exposed rats, we also observed a significant (p < 0.05) decrease in the activities of antioxidant (superoxide dismutase, catalase and glutathione peroxidase) and glutathione metabolizing (glutathione-S-transferase, glutathione reductase and glucose-6-phosphate dehydrogenase) enzymes as well as reduced levels of non-enzymic (reduced glutathione, ascorbate and total sulphydryl groups) antioxidants. In contrast, treatment with DTS (40 mg/kg body weight orally) significantly (p < 0.05) reduced the accumulation of Cd and lipid peroxidation markers and also significantly improved the activities of antioxidant defense system in testes. Testicular protection by DTS is further substantiated by remarkable reduction of Cd-induced pathological changes. Our study has revealed that DTS renders protection against Cd-induced testicular injury by reducing Cd-mediated oxidative damage.

Hepatoprotective role of naringin on nickel-induced toxicity in male Wistar rats

Aim of the present study was planned to determine the protective role of naringin in attenuating the toxicity induced by nickel sulfate in rat liver. In this investigation nickel sulfate (20mg/kg body weight) was administered intraperitoneally for 20days to induce toxicity. Naringin was administered orally (20, 40 and 80mg/kg body weight) for 20days with intraperitoneal administration of nickel sulfate. Liver injury was measured by the increased activities of serum hepatic enzymes namely aspartate transaminase, alanine transaminase, alkaline phosphatase, gamma glutamyl transferase, lactate dehydrogenase and total bilirubin along with increased elevation of lipid peroxidation markers, thiobarbituric reactive acid substances, lipid hydroperoxides, protein carbonyl content and conjugated dienes. The toxic effect of nickel was also indicated by significantly decreased activities of enzymatic antioxidants like superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase and glucose-6-phosphate dehydrogenase and non-enzymatic antioxidants like reduced glutathione, total sulfhydryl groups, vitamin C and vitamin E levels were significantly decreased. Naringin administered at a dose of 80mg/kg body weight significantly reversed the activities of hepatic marker enzymes, decreasing lipid peroxidative markers, increasing the antioxidant cascade and decreasing the nickel concentration in the liver. The effect at a dose of 80mg/kg body weight was more pronounced than that of other two doses (20 and 40mg/kg body weight). All these changes were supported by histopathological observations. These results clearly demonstrate that naringin has the potential in alleviating the toxic effects of nickel in rat liver.

Combined treatment of tetrahydrocurcumin and chlorogenic acid exerts potential antihyperglycemic effect on streptozotocin-nicotinamide-induced diabetic rats

We have shown that separate dose of tetrahydrocurcumin (THC) at a dose of 80 mg/kg body weight (b.w.) and chlorogenic acid (CGA) at a dose of 5 mg/kg b.w. exerts antidiabetic potential in streptozotocin (STZ) (45 mg/kg b.w.) nicotinamide induced diabetic rats. In the present study we have attempted to compare the antihyperglycemic activity exerted by the combined treatment of THC/CGA with THC and CGA alone treated diabetic rats. After the experimental period of 45 days we observed that supplementation with combined dose of THC/CGA significantly decreased glycosylated hemoglobin (HbA(1C)) and increased the levels of plasma insulin, C-peptide, hemoglobin and glycogen which were decreased upon STZ treatment and also significantly reversed the altered activities of gluconeogenic enzymes such as glucose-6-phosphatase, fructose-1,6-bisphosphatase, and of glycolytic enzymes such as glucokinase and hexokinase in the tissues of experimental rats as compared to their individual supplementation. Thus our results substantiate that though THC and CGA alone found to exert hypoglycemic activity the maximum hypoglycemic effect was always observed in diabetic rats treated THC/CGA and this summed effect seems to have a promising value for the development of a potent phytomedicine for diabetes.

Comparative and combined effect of chlorogenic acid and tetrahydrocurcumin on antioxidant disparities in chemical induced experimental diabetes

The present study evaluates the combined effect of tetrahydrocurcumin and chlorogenic acid on oxidative stress in streptozotocin-nicotinamide-induced diabetic rats. Rats were rendered diabetic by a single intraperitoneal injection (i.p) of streptozotocin (45 mg/kg BW), 15 min after an i.p injection of nicotinamide (110 mg/kg BW). The levels of fasting plasma glucose and insulin were estimated. As an index of oxidative stress, the levels of enzymic antioxidants and lipid peroxidation products were analyzed in liver and kidney. Diabetic rats showed an increase in the levels of fasting plasma glucose, lipid peroxidative products such as thiobarbituric acid reactive substances and lipid hydroperoxides and a decrease in plasma insulin, and enzymic antioxidants viz., superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase. Combined administration of tetrahydrocurcumin (80 mg/kg BW) and chlorogenic acid (5 mg/kg BW) to diabetic rats for 45 days, reversed the biochemical changes to near normal. The above findings were supported by histological observations of the liver and kidney. Together the present study clearly reflects that combined dosage of tetrahydrocurcumin and chlorogenic acid augments enzymic antioxidants with a concomitant decrease in lipid peroxidation and protects against streptozotocin-nicotinamide-induced type 2 diabetes in experimental rats.

Effect of N-benzoyl-d-phenylalanine on streptozotocin-induced changes in the lipid and lipoprotein profile in rats

The effect of N-benzoyl-d-phenylalanine (NBDP) and metformin combination treatment on circulatory lipids, lipoproteins and lipid peroxidation markers were studied in neonatal streptozotocin (nSTZ) non-insulin dependent diabetic rats. Non-insulin dependent diabetes mellitus (NIDDM) was induced by a single dose injection of streptozotocin (100 mg kg−1, i.p.) to two-day-old rats. After 10–12 weeks, rats weighing above 150g were selected for screening for the NIDDM model. The rats were checked for fasting blood glucose levels to confirm the status of NIDDM. NBDP (50,100 or 200 mg kg−1) was administered orally for six weeks to the confirmed diabetic rats (to evaluate the effective dose). The levels of serum lipids and lipid peroxidation markers were significantly increased, whilst the activity of glucose-6-phosphate dehydrogenase was significantly decreased in nSTZ diabetic rats. NBDP and metformin were able to restore the altered serum lipids, lipoproteins, lipid peroxidation marker levels and glucose-6-phosphate dehydrogenase activity to almost control levels. The results showed the antihyperlipidaemic properties of NBDP and metformin in addition to its antidiabetic action. Combination treatment was more effective then either drug alone. The results indicated that the coadministration of NBDP with metformin to nSTZ diabetic rats normalized blood glucose and caused marked improvement in altered serum lipids, lipoproteins and lipid peroxidation markers during diabetes. The data indicated that NBDP represented an effective antihyperglycaemic and antihyperlipidaemic adjunct for the treatment of diabetes, and may be a potential source of new orally active agents for future therapy.

Antidiabetic effects of scoparic acid D isolated from Scoparia dulcis in rats with streptozotocin-induced diabetes

We evaluated the antihyperglycaemic effect of scoparic acid D (SAD), a diterpenoid isolated from the ethanol extract of Scoparia dulcis in streptozotocin (STZ)-induced diabetic male Wistar rats. SAD was administered orally at a dose of 10, 20 and 40 mg kg(-1) bodyweight for 15 days. At the end of the experimental period, the SAD-treated STZ diabetic rats showed decreased levels of glucose as compared with diabetic control rats. The improvement in blood glucose levels of SAD-treated rats was associated with a significant increase in plasma insulin levels. SAD at a dose of 20 mg kg(-1) bodyweight exhibited a significant effect when compared with other doses. Further, the effect of SAD was tested on STZ-treated rat insulinoma cell lines (RINm5F cells) and isolated islets in vitro. SAD at a dose of 20 microg mL(-1) evoked two-fold stimulation of insulin secretion from isolated islets, indicating its insulin secretagogue activity. Further, SAD protected STZ-mediated cytotoxicity and nitric oxide (NO) production in RINm5F cells. The present study thus confirms the antihyperglycaemic effect of SAD and also demonstrated the consistently strong cytoprotective properties of SAD.

Impact of Naringenin on Oxytetracycline-Mediated Oxidative Damage in Kidney of Rats

The aim of this study was to investigate the effect of naringenin on oxytetracycline-induced nephrotoxicity in rats. Oxytetracycline (200 mg/kg body weight, ip) was administered in 0.5 ml of sterile physiological saline for 15 days, resulting in a significant increase in serum urea and creatinine and reduction in creatinine clearance. A significant increase in lipid peroxidation markers (TBARS and lipid hydroperoxide) and decrease in antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and low molecular weight antioxidants (vitamin C, vitamin E, and reduced glutathione) levels were also observed in oxytetracycline-treated rats. The oral administration of naringenin (50 mg/kg body weight) attenuated the oxytetracycline-induced nephrotoxicity by significantly decreased levels of serum urea and creatinine with the significant normalization of creatinine clearance. Upon the administration of naringenin, the depleted renal antioxidant defense system (enzymatic and non-enzymatic antioxidants) was significantly increased in rats treated with oxytetracycline. These biochemical observations were supplemented by histopathological examination of kidney section. The present results suggest that the supplementation of naringenin might be helpful to alleviate the oxytetracycline-induced oxidative injury in kidney.

Attenuation of Chloroquine‐Induced Renal Damage by α‐Lipoic Acid: Possible Antioxidant Mechanism

The toxic effect of chloroquine (CQ) has been attributed to oxidative stress with the consequences of lipid peroxidation. This study investigates the effects of alpha-lipoic acid (LA) on CQ-induced nephrotoxicity in rats. A single oral administration of CQ (970 mg/kg)-induced nephrotoxicity, manifested biochemically by a significant increase in serum creatinine and blood urea nitrogen concentrations. In addition, renal tissue from CQ-treated rats showed a significant increase in lipid peroxides measured as thiobarbituric acid reactive substances and hydroperoxides, along with significant decrease in nonenzymic antioxidants (vitamin C, vitamin E, and reduced glutathione) and enzymic antioxidants (superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase) levels. Oral administration of LA (10, 30, or 100 mg/kg) in different doses for 10 days produced a significant protection against nephrotoxicity induced by CQ. Treatment with LA markedly reduced the elevated lipid peroxidation, restored the depleted renal antioxidant defense system. LA at 100 mg/kg was effective when compared with other doses (10 and 30 mg/kg). This was accompanied by the histopathological observations in kidney tissue. The results suggest that LA ameliorate the lipid peroxidation and the loss of cellular antioxidants, thereby protecting the CQ-induced oxidative damage in kidney.

Caffeic acid alleviates the increased lipid levels of serum and tissues in alcohol-induced [hepatotoxicity in] rats

Ethanol is one of the most widely used and abused drugs that increases lipid levels in human and experimental animals. The objective of this study was to determine the effect of caffeic acid (CA) on alcohol-induced alterations of lipid levels in serum, liver and kindey of Wistar rats. The alcohol toxicity was induced by oral administration of ethanol (7.9 g/kg/bw) for 45 days through intragastric intubation. The elevation in the levels of lipids upon alcohol administration was accompanied by a significant increase in the levels of cholesterol, phospholipids (PL), free fatty acids (FFA) and triglycerides (TG) in serum, liver and kidney. Oral administration of CA (12 mg/kg/bw) to alcohol fed rats significantly decreased the serum and tissue lipid levels to near those of the control rats. In conclusion, our study suggests that oral administration of CA to alcohol fed rats markedly reduced the accumulation of cholesterol, TG, FFA and PL in circulation, liver and kidney.

Effect of tetrahydrocurcumin on insulin receptor status in type 2 diabetic rats: studies on insulin binding to erythrocytes

Curcumin is the most active component of turmeric. It is believed that curcumin is a potent antioxidant and anti-inflammatory agent. Tetrahydrocurcumin (THC) is one of the major metabolites of curcumin, and exhibits many of the same physiological and pharmacological activities as curcumin and, in some systems, may exert greater antioxidant activity than curcumin. Using circulating erythrocytes as the cellular mode, the insulin-binding effect of THC and curcumin was investigated. Streptozotocin (STZ)-nicotinamide-induced male Wistar rats were used as the experimental models. THC (80 mg/kg body weight) was administered orally for 45 days. The effect of THC on blood glucose, plasma insulin and insulin binding to its receptor on the cell membrane of erythrocytes were studied. Mean specific binding of insulin was significantly lowered in diabetic rats with a decrease in plasma insulin. This was due to a significant decrease in mean insulin receptors. Erythrocytes from diabetic rats showed a decreased ability for insulin-receptor binding when compared with THC-treated diabetic rats. Scatchard analysis demonstrated that the decrease in insulin binding was accounted for by a decrease in insulin receptor sites per cell, with erythrocytes of diabetic rats having less insulin receptor sites per cell than THC-treated rats. High affinity (K d1), low affinity (K d2) and kinetic analyses revealed an increase in the average receptor affinity of erythrocytes from THC-treated rats compared with those of diabetic rats. These results suggest that acute alteration of the insulin receptor on the membranes of erythrocytes occurred in diabetic rats. Treatment with THC significantly improved specific insulin binding to the receptors, with receptor numbers and affinity binding reaching near-normal levels. Our study suggests the mechanism by which THC increases the number of total cellular insulin binding sites resulting in a significant increase in plasma insulin. The effect of THC is more prominent than that of curcumin.

Role of curcumin in health and disease

Curcumin (diferuloylmethane) is an orange-yellow component of turmeric (Curcuma longa), a spice often found in curry powder. In recent years, considerable interest has been focused on curcumin due to its use to treat a wide variety of disorders without any side effects. It is one of the major curcuminoids of turmeric, which impart its characteristic yellow colour. It was used in ancient times on the Indian subcontinent to treat various illnesses such as rheumatism, body ache, skin diseases, intestinal worms, diarrhoea, intermittent fevers, hepatic disorders, biliousness, urinary discharges, dyspepsia, inflammations, constipation, leukoderma, amenorrhea, and colic. Curcumin has the potential to treat a wide variety of inflammatory diseases including cancer, diabetes, cardiovascular diseases, arthritis, Alzheimer's disease, psoriasis, etc, through modulation of numerous molecular targets. This article reviews the use of curcumin for the chemoprevention and treatment of various diseases.

Influence of tetrahydrocurcumin on tail tendon collagen contents and its properties in rats with streptozotocin-nicotinamide-induced type 2 diabetes

Changes in the structural and functional properties of collagen caused by advanced glycation might be of importance for the etiology of late-stage complications in diabetics. Curcumin is the most active component of turmeric. It is believed that curcumin is a potent antioxidant and anti-inflammatory agent. Tetrahydrocurcumin (THC) is one of the major metabolites of curcumin, exhibiting many of the same physiological and pharmacological activities of curcumin and in some systems may exert greater antioxidant activity than curcumin. In diabetic rats, hydroxyproline and collagen content as well as its degree of cross-linking were increased, as shown by increased extent of glycation, collagen-linked fluorescence, neutral salt collagen, and decreased acid and pepsin solubility. Administration of THC for 45 days to diabetic rats significantly reduced the accumulation and cross-linking of collagen. The effects of THC were comparable with those of curcumin. In conclusion, administration of THC had a positive influence on the content of collagen and its properties in streptozotocin- and nicotinamide-induced diabetic rats. THC was found to be more effective than curcumin.

Influence of tetrahydrocurcumin on hepatic and renal functional markers and protein levels in experimental type 2 diabetic rats

Curcumin is the most active component of turmeric. It is believed that curcumin is a potent antioxidant and anti-inflammatory agent. Tetrahydrocurcumin is one of the major metabolites of curcumin that exhibits many of the same physiologic and pharmacological activities as curcumin and in some systems may exert greater antioxidant activity than curcumin. Oral administration of tetrahydrocurcumin at 80 mg/kg body weight to diabetic rats for 45 days resulted in a significant reduction in blood glucose and significant increase in plasma insulin levels. In addition, the diabetic rats had decreased levels of plasma total protein, albumin, globulin and albumin/globulin ratio as compared to control rats. After treatment with tetrahydrocurcumin and curcumin total protein, albumin, globulin and albumin/globulin ratio were brought back to near normal. The activities of hepatic and renal markers were significantly elevated in diabetic rats as compared to control rats, and treatment with tetrahydrocurcumin and curcumin has reversed these parameters to near normal levels. In diabetic rats, the decreased levels of urea, uric acid and creatinine with increased levels of albumin and urine volume was observed, and treatment with tetrahydrocurcumin and curcumin reversed these parameters to near normal. Tetrahydrocurcumin appeared to have a better protective effect when compared to curcumin.