Antidiabetic and antioxidant activity of the methanol extract of Diospyros peregrina fruit on Type I diabetic rats

Chronic diabetes complications are mainly associated with augmented oxidative stress. Thus the present study evaluated the hypoglycemic, as well the antioxidant effect, of the methanol extract of Diospyros peregrina Gurke. (Ebenaceae) fruits on experimental diabetic rats. Oral administration of methanol extract at 150 and 300?mg/kg body weight per day to diabetic rats was found to have profound hypoglycemic activity in term of reduction of fasting blood glucose level. The diabetic rats showed lower activities of superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) content in hepatic and renal tissues as compared with normal rats. The activities of SOD, CAT, and GSH were found to be increased in extract-treated diabetic rats in selected tissues. The increased levels of lipid peroxidation (thiobarbituric acid reactive substances and hydroperoxides) in diabetic rats were also found to be reverted back to near-normal status in extract-treated groups. It was found that the extract is more effective at the dose of 300?mg/kg body weight and this effect is almost comparable to that of standard glibenclamide.     

Hypoglycemic and antioxidant effects of Rheum franzenbachii extract in streptozotocin-induced diabetic rats

The hypoglycemic and antioxidant effects of ethanol extract from the roots and rhizomes of Rheum franzenbachii Münt. (Polygonaceae) were evaluated in streptozotocin-induced diabetic rats. Effects of repeated oral administration of ethanol extract (125, 250, and 500?mg/kg body weight) on the plasma glucose level (PGL), oral glucose tolerance test (OGTT), malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) in diabetic rats were examined. It was found that administration of ethanol extract (125, 250, and 500?mg/kg) produced a significant fall in PGL, AUC, and MDA, while elevating the GSH levels and SOD and CAT activities in diabetic rats. The dose of 500?mg/kg was identified as the most effective dose, with a decrease of 65.8 and 44.0% in PGL and MDA, and elevation of 72.6, 75.0, and 51.5% in GSH level and SOD and CAT activities, respectively, after 14 days of ERF administration in diabetic rats. Moreover, the OGTT studies showed a maximum reduction in PGL and AUC. From the active extract of Rheum franzenbachii, two stilbenes, desoxyrhapontigenin (1) and desoxyrhaponticin (2), were isolated as major constituents. The present study concludes that the ethanol extract of roots and rhizomes from Rheum franzenbachii had significant hypoglycemic and antioxidant effects.     

Protective effects of Phyllanthus amarus aqueous extract against renal oxidative stress in Streptozotocin -induced diabetic rats

Aim and Objectives:

In the present study, we have evaluated the antihyperglycemic, hypolipidemic and antioxidant activities of aqueous extract of Phyllanthus amarus (PAAEt) in streptozotocin (STZ)-induced diabetic rats.

Materials and Methods:

PAAEt was administered at 200 mg/kg body weight/day to normal treated (NT-group) and STZ-induced diabetic treated rats (DT-group) by gavage for eight weeks. During the experimental period, blood was collected from fasted rats at 10 days intervals and plasma glucose level was estimated. The plasma lipid profile was estimated at the end of experimental period. After the treatment, period kidney lipid peroxidation (LPO), protein oxidation and reduced glutathione (GSH) were estimated and antioxidant enzymes viz., glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD) were also assayed.

Results:

The significant decrease in the body weight, hyperglycemia and hyperlipidemia observed in STZ-induced diabetic rats (D-group) were rectified with PAAEt treatment in diabetic treated group (DT-group). D-group rats showed increased renal oxidative stress with increased LPO and protein oxidation. DT-group showed a significant decrease in renal LPO, protein oxidation and a significant increase in GSH content and GR, GPx and GST activities when compared with D-group. The activities of SOD and CAT decreased significantly in D-group, but were normalized in DT-group. Normal rats treated with PAAEt (NT-rats) showed a significant decrease in lipid profile, renal LPO and protein oxidation, with significant increase in renal GSH and activities of antioxidant enzymes compared to normal rats (N-group).

Conclusion:

Our results demonstrated that PAAEt with its antidiabetic, hypolipidemic and antioxidant properties could be a potential herbal medicine in treating diabetes and renal problems.     

糖尿病大鼠肾脏抗氧化防御系统机能的改变

目的：探讨糖尿病对肾脏抗氧化防御机能的影响。方法：观察12周糖尿病大鼠肾皮质丙二醛(MDA)及谷胱甘肽(GSH)水平,以及超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)、谷胱甘肽S转移酶(GSH-ST)和过氧化氢酶(CAT)活性的变化。结果：糖尿病大鼠肾组织中SOD、CAT活性下降;GSH含量显著降低;MDA没有变化;GSH-PX活性却明显增强。结论：糖尿病大鼠肾组织抗氧化防御机能明显下降。     

Protective effect of Gymnema montanum against renal damage in experimental diabetic rats

Gymnema montanum Hook (Asclepiadaceae), is an endemic plant species of India, traditionally used for diabetes and its management. In this experiment, the ethanol extract of G. montanum (GLEt) at a dose of 200 mg/kg body weight was tested to evaluate its effect on renal damage in alloxan-induced diabetic rats and the efficacy was compared with standard hypoglycemic drug, glibenclamide (600 μg/kg body weight). The GLEt and glibenclamide were administered orally for 3 weeks and the effects on glucose, insulin, renal markers including urea, creatinine and uric acid, lipid peroxidation markers including thiobarbituric reactive substances (TBARS) and hydroperoxides and antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities in kidney were studied. In addition, the urinary protein profile was studied using SDS–PAGE. The results indicated that the GLEt significantly normalized the elevated blood glucose, renal markers and lipid peroxidation markers and increased antioxidant levels in diabetic kidney. The diabetic rats excreted large amount of proteins than untreated rats which was normalized during the treatment with GLEt. In conclusion, the GLEt was found to be more effective in reducing oxidative stress, thus confirming the ethnopharmacological use of G. montanum in protecting diabetes and its complications.     

Enicostemma littorale Blume aqueous extract improves the antioxidant status in alloxan-induced diabetic rat tissues

This study investigates the effect of oral administration of an aqueous Enicostemma littorale whole plant extract on antioxidant defense in alloxan-induced diabetes in rats. A significant increase in blood glucose and increased concentration of thiobarbituric acid reactive substances (TBARS) and hydroperoxides (HP) in liver, kidney and pancreas were observed in alloxan diabetic rats. Decreased concentration of reduced glutathione (GSH) and decreased activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) were also observed in these tissues of diabetic rats. Oral administration of aqueous E. littorale whole plant extract (1 and 2 g/kg) to diabetic rats daily for 45 days significantly decreased blood glucose, TBARS, HP and increased GSH, SOD, catalase and GPx. E. littorale extract at the dose of 2 g/kg was more effective than 1 g/kg. Insulin (6 units/kg) administration to diabetic rats for 45 days brought back all the parameters to near normal status.     

Protective effect of puerariae radix on oxidative stress induced by hydrogen peroxide and streptozotocin

This study evaluated the protective effect of Puerariae radix against the oxidative stress induced by hydrogen peroxide (H2O2) and streptozotocin in vitro and in vivo, respectively. The ethanol extract scavenged intracellular reactive oxygen species (ROS), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and prevented lipid peroxidation. This radical scavenging activity of the ethanol extract protected the cell viability of Chinese hamster lung fibroblast (V79-4) cells exposed to H2O2. Furthermore, this extract reduced the formation of apoptotic cells induced by H2O2, which was demonstrated by the decreased number of sub G(1) hypo-diploid cells and apoptotic cell body formation. The extract increased the activities of the cellular antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT). Administration of the extract to the streptozotocin induced diabetic rats decreased the blood glucose levels. The diabetic rats showed low activities of superoxide dismutase and catalase in the liver, and the ethanol extract increased the CAT activity. The increased level of lipid peroxidation in the diabetic rats reverted to near normal levels after being treated with the extract. This study showed that Puerariae radix was effective in the amelioration of diabetes, which may be a consequence of its antioxidant potential.     

Ameliorative effect of an ethanol extract of Embelia ribes fruits on isoproterenol-induced cardiotoxicity in diabetic rats

The present study explored the protective effect of Embelia ribes Burm. (Myrsinaceae) fruit ethanol extract on isoproterenol (ISO)-induced cardiomyopathy in streptozotocin (STZ)-induced diabetic rats. STZ (40?mg/kg, intravenously, single-injection)-induced diabetic rats had significantly (p?<?0.01) increased heart rate (HR), systolic blood pressure (SBP), blood glucose, HbA_1C, serum LDH, serum CK, and myocardial TBARS levels, and decreased blood glutathione and myocardial endogenous antioxidants, viz. SOD, CAT, and GSH levels in comparison to group I rats. ISO (5.25 and 8.?5?mg/kg, s.c., for two consecutive days) administration produced myocardial necrosis as evidenced by a significant (p?<?0.01) increase in HR, SBP, serum LDH, serum CK, and myocardial TBARS levels and a significant (p?<?0.01) decrease in blood glutathione, and myocardial endogenous antioxidant levels in comparison to group I rats. Further, ISO administration to diabetic rats showed a significant (p?<?0.01) increase in SBP, blood glucose, and HbA_1C levels along with a significant (p?<?0.01) decrease in HR, blood glutathione, serum LDH, serum CK, myocardial TBARS, SOD, CAT, and GSH levels as compared to ISO-only treated (i.e. group IV) rats. Forty days treatment of Embelia ribes ethanol extract (200?mg/kg) to pathogenic (STZ + ISO treated) rats resulted in a significant (p?<?0.01) increase in HR, blood glutathione, serum LDH, and myocardial endogenous antioxidant levels with a significant (p?<?0.01) decrease in SBP, blood glucose, HbA_1C, serum CK, and myocardial TBARS levels as compared to pathogenic (STZ + ISO treated) rats. The study demonstrates the ability of Embelia ribes extract to attenuate ISO-induced oxidative stress in diabetic rats, enhancing cellular antioxidant defense.     

Bacopa monnieri modulates antioxidant responses in brain and kidney of diabetic rats

Role of oxidative stress has been reported in various diabetic complications including neuropathy, nephropathy and cardiopathy. This study was undertaken to evaluate the protective effect of Bacopa monnieri, a medicinal plant, on tissue antioxidant defense system and lipid peroxidative status in streptozotocin-induced diabetic rats. Extract of B. monnieri was administered orally, once a day for 15 days (at doses 50, 125 and 250mg/(kgbw)) to diabetic rats. Activity of antioxidant enzymes (SOD, Catalase, and GPx), levels of GSH and lipid peroxidation were estimated in kidney, cerebrum, cerebellum and midbrain of diabetic rats and compared to reference drug, Glibenclamide. Administration of plant extract to diabetic rats showed significant reversal of disturbed antioxidant status and peroxidative damage. Significant increase in SOD, CAT, GPx activity and levels of GSH was observed in extract treated diabetic rats. The present study indicates that extract of B. monnieri modulates antioxidant activity, and enhances the defense against ROS generated damage in diabetic rats.     

Biochemical evaluation of antihyperglycemic and antioxidative effects of Morinda citrifolia fruit extract studied in streptozotocin-induced diabetic rats

The hypoglycemic and antioxidative effects of Morinda citrifolia fruit extract were evaluated in streptozotocin (STZ)-induced diabetic rats. The ethanolic extract of Morinda citrifolia fruit at a concentration of 300 mg/kg body weight/rat/day was orally administered to STZ-induced diabetic rats for a period of 30 days. The elevated levels of blood glucose, glycosylated hemoglobin, blood urea, and serum creatinine in the diabetic rats reverted back to near normal after treatment with the noni fruit extract. Similarly significant decrease in the levels of plasma insulin and hemoglobin were elevated to near normal after treatment with fruit extract, suggesting the antihyperglycemic effect of Morinda citrifolia fruit. Determination of thiobarbituric acid reactive substance (TBARS), hydroperoxides, and both enzymatic and nonenzymatic antioxidants evidenced the antioxidative potential of the extract of noni fruit, which in turn may be responsible for its hypoglycemic potential. Alterations observed in the activities of pathophysiological enzymes such as serum aspartate transaminase (AST), serum alanine transaminase (ALT), and serum alkaline phosphatase (ALP) in the serum of control and experimental groups of rats revealed the tissue protective nature of Morinda citrifolia fruits, and the results of all the biochemical parameters analyzed were comparable with glyclazide, the standard reference drug.     

EUK-8 and EUK-134 reduce serum glucose and lipids and ameliorate streptozotocin-induced oxidative damage in the pancreas, liver, kidneys, and brain tissues of diabetic rats

In this study, the effects of EUK-8 and EUK-134, as two newly classified antioxidants, on the sera levels of glucose, insulin, lipids, nitric oxide (NO) and also on the extent of lipid peroxidation (measured in term of thiobarbituric acid reactive substances, TBARS), reactive oxygen species (ROS) formation and the activities of antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT) as well as reduced glutathione (GSH)] in the liver, pancreas, brain and kidneys of streptozotocin (STZ)-induced diabetic rats were evaluated. Results indicated that oral daily administration of EUK-8, EUK-134 (each at 20?mg/kg), and glibenclamide (2.5?mg/kg), as the control drug, to the diabetic rats for 21 consecutive days improved the sera levels of lipids and glucose along with insulin level to varying extents. In addition, treatment of rats with EUK-8, EUK-134, and/or glibenclamide decreased the TBARS, NO, and ROS levels and increased the activities of SOD and CAT as well as the GSH content in various tissues compared to untreated diabetic rats. In conclusion, this study indicated that EUK-8 and Euk-134 compounds improved the antioxidant status by reducing lipid peroxidation and enhancing the antioxidant enzymes activities in various tissues of diabetic rats.     

Protection against cisplatin-induced nephrotoxicity in mice by <Emphasis Type="Italic">Curcuma comosa</Emphasis> Roxb. ethanol extract

The protective effect of an ethanol extract of Curcuma comosa against cisplatin-induced renal toxicity in mice was studied. Adult male mice were pretreated for 4 days with the ethanol extract of C. comosa [100–200 mg/kg body weight (BW), orally (p.o.)] before injection of cisplatin (12.5 mg/kg BW, intraperitoneally (i.p.)). Five days later the mice were killed, and blood samples were collected to determine blood urea nitrogen (BUN) and plasma creatinine levels. Kidneys were examined histopathologically and levels of lipid peroxidation, gluthathione (GSH) content, and superoxide dismutase (SOD), gluthathione peroxidase (GPx), and catalase (CAT) activities were determined. Histological examinations revealed degenerative changes and tubular necrosis in mice treated with cisplatin, which were improved by pretreatment with C. comosa ethanol extract. Cisplatin raised BUN, creatinine, and kidney lipid peroxidation levels, and lowered kidney GSH content and levels of GPx, SOD, and CAT activities, all of which (except SOD and CAT) could be restored to normal values by pretreatment with 200 mg/kg BW of C. comosa ethanol extract. In addition, the ethanol extract of C. comosa and its isolated diarylheptanoid compound also exhibited radical scavenging activities. The results suggest that the ethanol extract of C. comosa exhibits effective protection against cisplatin-induced nephrotoxicity mediated through its antioxidant activity.     

Delayed progression of diabetic cataractogenesis and retinopathy by Litchi chinensis in STZ-induced diabetic rats

Context: The study was carried out to evaluate the effect of the aqueous fruit pericarp extract of Litchi chinensis (APLC) on parameters which leads to diabetic cataractogenesis and retinopathy in the streptozotocin-induced diabetic rats.

Objective: The objective of the study is to evaluate the APLC for in vivo antioxidant activity and its role in inhibiting the polyol pathway and formation of advanced glycation end products (AGEs).

Materials and methods: The diabetic animals were treated with L. chinensis for a period of 12 weeks. At the end of 12 weeks, the animals were killed and the biochemical pathways involved in the pathogenesis of cataract such as oxidative stress by protein content, superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and polyolpathway by aldose reductase (AR) in lens homogenates, alterations in protein carbonyl content (PCO) and AGEs in both serum and lens the APLC-treated diabetic rats were compared against diabetic control rats. Cataract progression due to hyperglycemia was monitored by slit lamp bio microscope and classified into four stages. Fundoscope test and retinal histopathology were done for assessing retinopathy.

Results: Statistically significant reduction in glucose, and elevation of protein content, SOD, CAT, and GSH levels and decreased levels of AR and PCO in lens homogenate and significant reduction in AGEs serum and lens homogenate were observed. Slit lamp examination, fundoscope, and histopathology showed improvement in retinal changes in APLC-treated rats compared to diabetic control animals.

Conclusion: The treatment with APLC found to delay the progression of diabetic cataractogenesis and retinopathy, which might be due to its antioxidant activity, because of the presence of active phytochemicals in APLC.     

Antihyperglycaemic and anti-oxidant properties of Andrographis paniculata in normal and diabetic rats

1. Oxidative stress is believed to be a pathogenetic factor in the development of diabetic complications. In the present study, we investigated the ethanolic extract of the aerial parts of Andrographis paniculata for antihyperglycaemic and anti-oxidant effects in normal and streptozotocin-induced type I diabetic rats. 2. Normal and diabetic rats were randomly divided into groups and treated orally by gavage with vehicle (distilled water), metformin (500 mg/kg bodyweight) or the extract (400 mg/kg bodyweight), twice a day for 14 days. 3. At the end of the 14 day period, the extract, like metformin, significantly increased bodyweight (P < 0.01) and reduced fasting serum glucose in diabetic rats (P < 0.001) when compared with vehicle, but had no effect on bodyweight and serum glucose in normal rats. Levels of liver and kidney thiobarbituric acid-reactive substances (TBARS) were significantly increased (P < 0.0001, P < 0.01, respectively), while liver glutathione (GSH) concentrations were significantly decreased (P < 0.005) in vehicle-treated diabetic rats. Liver and kidney TBARS levels were significantly lower (P < 0.0001, P < 0.005, respectively), whereas liver GSH concentrations were significantly higher (P < 0.05) in extract- and metformin-treated diabetic rats compared with vehicle-treated diabetic rats. Andrographis paniculata significantly decreased kidney TBARS level (P < 0.005) in normal rats. Hepatic superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities were significantly lower in vehicle-treated diabetic rats compared with vehicle-treated normal rats. The extract, as well as metformin, significantly increased the activity of SOD and CAT, but had no significant effect on GSH-Px activity in diabetic rats. The extract and metformin did not produce significant changes in the activity of these anti-oxidant enzymes in normal rats. 4. Our results show that oxidative stress is evident in streptozotocin-diabetic rats and indicate that the ethanolic extract of A. paniculata not only possesses an antihyperglycaemic property, but may also reduce oxidative stress in diabetic rats.     

Erythrocyte redox status in streptozotocin diabetic rats: effect of Casearia esculenta root extract

The present study was aimed to investigate the effect of Casearia esculenta root extract on erythrocyte lipid peroxidation and to assess the status of antioxidants in red blood cells of streptozotocin (STZ) diabetic rats. The study showed a significant elevation (p < 0.05) of erythrocyte thiobarbituric acid reactive substances (TBARS), an index of lipid peroxidation and significant reduction (p < 0.05) in reduced glutathione (GSH), ascorbic acid (vitamin C), alpha-tocopherol (vitamin E), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in the STZ diabetic rats. The study also observed significant reduction in membrane cholesterol and phospholipid content in STZ diabetic rats. By oral administration of C. esculenta (200 and 300 mg/kg body wt.) for 45 days to the diabetic rats these values approached almost normal levels. A dose of 300 mg/kg body weight C. esculenta extract showed better antioxidant effects than 200 mg/kg body weight.     

Antidiabetic and antioxidant activity of Swietenia mahagoni in streptozotocin-induced diabetic rats

Context: Swietenia mahagoni L. Jacq. (Meliaceae) is a medium to large evergreen tree native to Southern Florida, Cuba, The Bahamas, Hispaniola, and Jamaica.

Objective: To evaluate the antidiabetic and antioxidant potential of S. mahagoni bark.

Materials and methods: In the present study, the antidiabetic activity of the methanol extract of S. mahagoni (MESM) bark in streptozotocin (STZ; 65?mg/kg body weight)-induced diabetic rats was evaluated. Glibenclamide (0.5?mg/kg; orally) was taken as the reference drug. The blood glucose levels and body weights were measured every 5th day over a period of 15 days. Antioxidant effects were assayed in diabetic rats by estimating thiobarbituric acid reactive substances (TBARS), glutathione (GSH), and catalase (CAT) levels.

Results and discussion: Oral administration of MESM at the doses of 25 and 50?mg/kg b.w. resulted in a significant (p?<?0.001) reduction in blood glucose levels in diabetic rats. Body weights were significantly (p?<?0.001) reduced in STZ-induced diabetic rats when compared to normal rats, while the extract significantly restored body weight. The present study was further undertaken to evaluate the antioxidant activity of MESM in STZ-induced diabetic rats. Decreased levels of TBARS and increased levels of GSH and CAT activity indicated a reduction in free radical formation in tissues such as the liver and kidney of diabetic rats.

Conclusion: These findings showed the significant hypoglycemic and antioxidant activity of the extract (MESM) in diabetic rats.     

Effect of an Ethanol Extract of Embelia ribes Fruits on Isoproterenol-Induced Myocardial Infarction in Albino Rats

The ethanol extract of dried fruits of Embelia ribes Burm (Myrsinaceae) was evaluated for protection against isoproterenol (ISO)-induced myocardial infarction in albino rats. The cardiotoxicity induced by ISO (5.25 and 8.5 mg/kg, s.c., for two consecutive days) was indicated by a significant increase (P < 0.01) in heart rate and systolic blood pressure, elevated levels of lactate dehydrogenase (LDH) and creatine kinase (CK) in serum, with increased thiobarbituric acid reactive substances (TBARS), and reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) levels in heart homogenates, as compared to normal healthy control rats. Microscopical examination (histopathology) was also performed on the myocardial tissue. Pretreatment with ethanol Embelia ribes extract (200 mg/kg, p.o., 40 days) significantly (P < 0.01) decreased the elevated levels of LDH and CK in serum and myocardial TBARS and increased the reduced levels of GSH, SOD and CAT in heart homogenates in ISO-induced myocardial infarction in albino rats. Histopathological observation revealed a marked protection by the extract in myocardial necrotic damage. The results of our study, for the first time, provide clear evidence that ethanol Embelia ribes extract treatment enhances the antioxidant defense against ISO-induced myocardial infarction in rats and exhibit cardioprotective properties.     

Protective effect of Cyclea peltata Lam on cisplatin-induced nephrotoxicity and oxidative damage

The aim of the present investigation was to evaluate the protective effect of a 70% methanolic leaf extract of Cyclea peltata Lam on cisplatin-induced renal toxicity. The concentration of creatinine, urea, sodium, and potassium in serum and levels of malonyldyaldehyde (MDA), glutathione (GSH), as well as gluathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) activities were determined in kidney tissue. The marked cisplatin-induced renal damage, characterized by a significant increase in creatinine and urea levels, decreased in extract-treated group, whereas sodium and potassium levels did not change significantly. C. peltata Lam extract significantly changed the increased MDA level and decreased GSH levels found in rats treated with cisplatin alone. The reduced activities of GSH-Px, SOD, and CAT in groups treated with cisplatin alone were significantly increased by the extract. The protective effect was greater in the post-treated than in the pre-treated group of animals. The results indicate that the post-treatment of C. peltata Lam extract might effectively ameliorate the oxidative stress parameters observed in cisplatin induced renal toxicity and could be used as a natural antioxidant against cisplatin-induced oxidative stress.     

Effect of Helicteres isora. Bark Extracts on Brain Antioxidant Status and Lipid Peroxidation in Streptozotocin Diabetic Rats

Abstract

The current study investigated the effect of the aqueous extract of Helicteres isora. L (Sterculiaceae) bark on oxidative stress in the brains of rats during diabetes. The aqueous extract of H. isora. bark was administered orally (100, 200 mg/kg b.w.) and the effect of the extract on blood glucose, plasma insulin, and the levels of thiobarbituric acid reactive substances (TBARS), hydroperoxides, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S.-transferase (GST), and reduced glutathione (GSH) were estimated in streptozotocin (STZ) diabetic rats. Tolbutamide was used as the standard reference drug. A significant increase in the activities of plasma insulin, SOD, CAT, GPx, GST, and GSH were observed in the brain on treatment with 100 and 200 mg/kg b.w. of H. isora. bark extract (HIBe) and tolbutamide for 5 weeks. Both treated groups (bark extract and drug) showed a significant decrease in TBARS and hydroperoxides formation in brain, suggesting its role in protection against lipid peroxidation–induced membrane damage. These findings suggest a possible antiperoxidative role of H. isora. bark extract that may be used for therapeutic purposes.     

Restoration of antioxidants by ethanolic Tinospora cordifolia in alloxan-induced diabetic Wistar rats

The present study investigates the effect of oral administration of an alcoholic extract of Tinospora cordifolia roots on antioxidant defence in alloxan-induced diabetes in rats. A significant increase in the concentration of thiobarbituric acid reactive substances (TBARS) in brain along with a decrease in heart was observed in diabetic rats. Decreased concentration of glutathione (GSH) and decreased activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) in heart and brain of diabetic rats were also noted. Alcoholic Tinospora cordifolia root extract (TCREt) administered at a dose of 100 mg/kg to diabetic rats orally for six weeks normalized the antioxidant status of heart and brain. The effect of T. cordifolia root extract was more prominent than glibenclamide (600 microg/kg). Insulin (6 units/kg) restored all the parameters to normal status.