Hypoglycemic activity of Erythrina variegata leaf in streptozotocin-induced diabetic rats

Context: Erythrina variegata Linn. (Fabaceae), commonly known as Tiger’s Claw, is a thorny deciduous tree grown in tropical and subtropical regions of Eastern Africa, Southern Asia, and Northern Australia. In India, its leaves are traditionally used for diabetes mellitus.

Objective: To evaluate the hypoglycemic activity of methanol extract of E. variegata leaf (MEEV) in streptozotocin (STZ)-induced diabetic Wistar rats.

Materials and methods: Hyperglycemia was induced in rats by single intraperitoneal injection of STZ (55?mg/kg body weight). Three days after STZ induction, the hyperglycemic rats were treated with MEEV orally at the doses of 300, 600, and 900?mg/kg body weight daily for 21 days. Glibenclamide (1?mg/kg, orally) was used as reference drug. The fasting blood glucose levels were measured on every 7th day during the 21 days of treatment. Serum biochemical parameters including lipid content were estimated.

Results and discussion: MEEV at the doses of 300, 600, and 900?mg/kg orally significantly (P?<?0.01) and dose-dependently reduced and normalized blood glucose levels as compared to that of STZ control group; the dose 900?mg/kg being the most potent showing complete normalization of blood glucose levels. Serum biochemical parameters including lipid profile were significantly (P?<?0.01) restored toward normal levels in META-treated rats as compared to STZ control animals.

Conclusion: This study concludes that E. variegata leaf demonstrated promising hypoglycemic action in STZ-induced diabetic rats substantiating its ethnomedicinal use.     

Geraniol,a natural monoterpene,ameliorates hyperglycemia by attenuating the key enzymes of carbohydrate metabolism in streptozotocin-induced diabetic rats

Context: Geraniol, an acyclic monoterpene alcohol is found in medicinal plants, is used traditionally for several medical purposes including diabetes.

Objectives: The present study evaluates the antihyperglycemic potential of geraniol on key enzymes of carbohydrate metabolism in streptozotocin (STZ)-induced diabetic rats.

Materials and methods: Diabetes was induced in experimental rats, by a single intraperitoneal (i.p) injection of STZ [40?mg/kg body weight (b.w.)]. Different doses of geraniol (100, 200 and 400?mg/kg b.w.) and glyclazide (5?mg/kg b.w.) were administrated orally to diabetic rats for 45?days. Body weight, food intake, plasma glucose, insulin, blood haemoglobin (Hb), glycosylated haemoglobin (HbA_1c), hepatic glucose metabolic enzymes and glycogen were examined.

Results: The LD₅₀ value of geraniol is 3600?mg/kg b.w. at oral administration in rats. Administration of geraniol in a dose-dependent manner (100, 200, 400?mg/kg b.w.) and glyclazide (5?mg/kg b.w.) for 45?days significantly improved the levels of insulin, Hb and decreased plasma glucose, HbA_1C in diabetic-treated rats. Geraniol at its effective dose (200?mg/kg b.w.) ameliorated the altered activities of carbohydrate metabolic enzymes near normal effects compared with two other doses (100 and 400?mg/kg b.w.). Geraniol treatment to diabetic rats improved hepatic glycogen content suggesting its anti-hyperglycemic potential. Geraniol supplement was found to preserve the normal histological appearance of hepatic cells and pancreatic β-cells in diabetic rats.

Discussion and conclusions: The present findings suggest that geraniol can potentially ameliorate key enzymes of glucose metabolism in experimental diabetes even though clinical studies used to evaluate this possibility are warranted.     

Evaluation of antidiabetic properties of cactus pear seed oil in rats

Context: Cactus pear (Opuntia ficus-indica (L.) Mill. (Cactaceae)) is a medicinal plant widely used to treat diabetes.

Objective: This work investigates the hypoglycemic and antihyperglycemic effect of cactus pear seed oil (CPSO), its mechanism of action, and any toxic effects.

Materials and methods: The hypoglycemic effect of CPSO was evaluated in groups of six healthy Wistar rats given 1 or 2?ml?kg^?1 orally and compared with groups receiving glibenclamide (2?mg?kg^?1) or water. Glycemia was determined after 30, 60, 120, 240, and 360?min. The antihyperglycemic effect of CPSO was determined in healthy rats and in streptozotocin-induced diabetic rats (STZ); normal rats received 0.8?ml?kg^?1 CPSO, while diabetic rats received 1?ml?kg^?1 CPSO, their controls received water or 2?mg?kg^?1 glibenclamide. For the antihyperglycemic effect evaluation, all the animals were fasted for 16?h before treatment and received glucose orally at 1?g?kg^?1 30?min after treatment; blood was taken after 30, 90, 150, and 210?min. Intestinal glucose absorption was estimated in rat jejunum perfused with a solution containing 5.55?mmol?l^?1 glucose. Acute toxicity was determined in albino mice that received oral or intraperitoneal doses of 1, 3, or 5?ml?kg^?1 CPSO.

Results: CPSO (p.o.) decreased postprandial hyperglycemia (60?min after glucose loading), 40.33% and 16.01%, in healthy and STZ-diabetic glucose-loaded rats, respectively. CPSO, also, significantly decreased intestinal glucose absorption by 25.42%. No adverse effects were seen in mice administered CPSO at up to 5?ml?kg^?1.

Conclusion: CPSO is antihyperglycemic. The effect can be explained partly by inhibition of intestinal glucose absorption.     

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.     

Effect of mulberry leaf (Folium Mori) on insulin resistance via IRS-1/PI3K/Glut-4 signalling pathway in type 2 diabetes mellitus rats

Context: Folium Mori, the leaf of Morus alba L. (Moraceae), has been used in traditional Chinese medicine (TCM) for treating diabetes. However, it is unclear which components in the mulberry leaf are effective for the treatment of type 2 diabetes mellitus (T2DM).

Objective: To investigate the flavonoids and polyphenols in mulberry leaves and their antihyperglycemic and antihyperlipidemic effects in T2DM rats.

Materials and methods: Male Sprague-Dawley rats were divided into five groups: normal control (NC), diabetic control (DBC), diabetic group with 0.3?mg/kg b.w./day rosiglitazone (RSG), diabetic group with 7?g/kg b.w./day TCM formula and diabetic group with 2?g/kg b.w./day Folium Mori extract (FME). After 4 weeks, the rats were sacrificed; biochemical parameters, gene and protein expression were measured.

Results: The FBG level was significantly lower in the FME group than in the DBC group (p?<?0.05). In oral glucose tolerance test, the AUC was significantly lower in the FME group (p?<?0.05). The HOMA-IR level was significantly decreased in the FME group (p?<?0.05). FME decreased the total cholesterol (TC), triglyceride (TG) and low density lipoprotein (LDL) levels (p?<?0.05). FME increased the mRNA and protein expression of IRS-1, PI3K p85α and Glut-4 increased significantly (p?<?0.05). Histological analysis revealed amelioration of lipid accumulation following FME treatment. Additionally, immunohistochemical analysis displayed stronger staining of Glut-4 in the FME group compared to the DBC group.

Discussion and conclusion: FME could decrease the body weight, blood glucose, TG, TC and LDL levels, and improve insulin resistance. FME possessed significant antihyperglycemic and antihyperlipidemic activities via the IRS-1/PI3K/Glut-4 signalling pathway.     

Myrtenal alleviates hyperglycaemia,hyperlipidaemia and improves pancreatic insulin level in STZ-induced diabetic rats

Context: Myrtenal is monoterpene a constituent of essential oils found mainly in herbs such as mint, pepper, cumin, etc. It exerts admirable pharmacological activities against many diseases including diabetes. Hyperlipidaemia is a secondary complication of diabetes and also a major risk factor for cardiovascular diseases.

Objective: The present study investigated the possible antihyperlipidaemic efficacy of myrtenal on plasma glucose, pancreatic insulin, plasma and tissue lipid levels in streptozotocin (STZ) induced diabetic rats.

Materials and methods: Diabetes was induced in male Wistar rats by a single intraperitoneal injection of STZ (40?mg/kg b.w.). Myrtenal (80?mg/kg) was administered orally to diabetic rats for a period of 28 d. Plasma glucose, pancreatic insulin, TC, TGs, FFAs, PLs, LDL-C, HDL-C, VLDL, atherogenic index, (HMG-CoA) reductase, LPL, LCAT and liver histology were analyzed.

Results: Diabetic rats showed significantly (p?<?0.05) increased plasma glucose (273.18?mg/dL), total cholesterol (142?mg/dL), triglycerides (126?mg/dL), free fatty acids (118?mg/dL), phospholipids (153?mg/dL), low-density lipoprotein (88.07?mg/dL), very low-density lipoprotein (25.2?mg/dL), atherogenic index, whereas a decrease in the levels of pancreatic insulin (97.48?ng/mg) and high-density lipoprotein (29.12?mg/dL). In addition, the activity of 3-hydroxy 3-methylglutaryl coenzyme A (HMG-CoA) reductase (0.94 HMG-CoA ratio/(mevalonate) increased significantly in contrast to the activities of lipoprotein lipase (4.87 μmoles of glycerol liberated/h/L) and lecithin cholesterol acyltransferase (54.61 μmoles of cholesterol esterified/h/L) in diabetic rats. Treatment with myrtenal significantly (p?<?0.05) improved the levels of plasma glucose, pancreatic insulin and lipid profiles. Moreover, the histopathological analysis of liver was also in agreement with the biochemical findings.

Discussion and conclusions: The present study indicates that myrtenal possess antihyperglycaemic and antihyperlipidemic properties, and could potentially be a useful phytochemical in treating diabetes.     

Sulfonylurea induction of caffeine-enhanced insulin secretion and reduction of glycemic levels in diabetic rats

Context: Caffeine can stimulate insulin secretion by attenuating hyperglycemia in diabetes models with significant reduction of pancreatic functional β cells. Knowledge of these mechanisms could contribute to new strategies for treating diabetes.

Objective: This study evaluated the effects of caffeine and physical exercise on glycemic and insulin responses in diabetic rats.

Materials and methods: The diabetes model was induced by intraperitoneal administration of 60?mg/kg of streptozotocin (STZ). Animals were divided into six groups: control, caffeine, STZ control, STZ caffeine, STZ sulfonylurea, and STZ caffeine?+?sulfonylurea. Acutely, control animals received 6?mg of caffeine and 10?mg/kg sulfonylurea or 10?mg/kg saline. Animals were sacrificed after physical exercise; blood samples were collected for glucose, glycerol, lactate, and insulin analyses. Cardiovascular responses were recorded before and after treatments. A one-way ANOVA and the post hoc Student–Newman–Keuls test were used to analyze statistical differences between treatments (p?Results: About 6?mg/kg of caffeine did not alter cardiovascular responses, but promoted blood glucose reduction after 60?min of exercise when compared to animals in the control groups (387–187?mg/dL; p?p?Discussion and conclusion: Acute caffeine intake with exercise can increase glucose uptake enhancing insulin secretion stimulated by sulfonylurea in β cells-deficient pancreas. The results indicate the potential use of caffeine as a strategy for glycemic and insulin control in diabetes.     

Antidiabetic,antihyperlipidaemic, and antioxidant activity of Syzygium densiflorum fruits in streptozotocin and nicotinamide-induced diabetic rats

Context Syzygium densiflorum Wall. ex Wight & Arn (Myrtaceae) has been traditionally used by local tribes of the Nilgiris, Tamil Nadu, India, for the treatment of diabetes, however, no definitive experimental studies are available.

Objective This study investigates the antidiabetic, antihyperlipidaemic and antioxidant activities of ethanol extract of S. densiflorum (EFSD) fruits in streptozotocin (STZ) and nicotinamide (NA)-induced diabetic rats.

Materials and methods Acute oral toxicity and oral glucose tolerance were assessed in normal rats. The antidiabetic, antihyperlipidaemic and antioxidant activities were investigated in STZ???NA-induced diabetic rats. Diabetic rats were orally administered with glibenclamide (10?mg/kg b.wt), EFSD (200, 400 and 800?mg/kg b.wt) for 28 d. Further, changes in the blood glucose level (BGL), biochemical parameters, antioxidants were observed and histology of pancreas was performed.

Results No toxicity and lethality were observed. Results of the following parameters are represented by treated versus disease control (STZ?+?NA) groups. BGL (161.33?±?22.8 versus 476.17?±?56.58?mg/dl), glycosylated haemoglobin (5.285?±?0.19 versus 8.05?±?0.55%), urea (40.32?±?1.96 versus 75.37?±?2.91?mg/dl), uric acid (1.2?±?0.07 versus 2.16?±?0.05?mg/dl), total cholesterol (89.3?±?5.14 versus 139.7?±?5.95?mg/dl) and triglycerides (79.65?±?2.52 versus 108.9?±?3.61?mg/dl) were significantly decreased, whereas haemoglobin (11.75?±?0.73 versus 7.95?±?0.42?g/dl), high‐density lipoprotein cholesterol (14.2?±?1.11 versus 6.97?±?0.84?mg/dl), total protein (45%) and liver glycogen (87%) were significantly increased in EFSD-treated diabetic group. Significant changes were observed in the enzymatic and non-enzymatic antioxidants in EFSD-treated groups (p?<?0.001). Histopathological examination showed the regeneration of β-cells in Islets of Langerhans.

Conclusion This study confirms the antidiabetic, antihyperlipidaemic and antioxidant activities of S. densiflorum fruits.     

Antihyperglycemic and antihyperlipidemic effect of Santalum album in streptozotocin induced diabetic rats

Context: Santalum album Linn (Santalaceae), commonly known as Sandalwood is used traditionally for its antihyperlipidemic and diuretic activity.

Objective: This study investigated the antihyperglycemic and antihyperlipidemic effect of long-term oral administration of the Santalum album pet ether fraction in streptozotocin-induced diabetic rats.

Materials and methods: Diabetes was induced by a single intraperitoneal injection of streptozotocin at 70?mg/kg body weight. Rats were treated with Santalum album pet ether fraction orally at a dose of 10 µg/kg body weight twice daily for 60 days. Metformin (30?mg/kg body weight) was used as positive control. Lipid profile and glycated hemoglobin were estimated. HPLC profiling of Santalum album pet ether fraction was carried out.

Results and discussion: Treatment of diabetic rats for 60 days demonstrated reduction in blood glucose level by 140?mg/dl. Metformin treated group showed a decrease in blood glucose by 70?mg/dl, as against an increase in diabetic control group by 125?mg/dl. Total cholesterol (TC), low density lipoprotein (LDL) and triglyceride (TG) levels were decreased by 22, 31 and 44%, respectively, in treated diabetic rats whereas, cardioprotective, high density lipoprotein (HDL) increased by 46%. In case of metformin, the values were 11, 29 and 15% respectively, while HDL increased by 7%. Significant improvement in atherogenic index from 267 to 139% was observed in treated rats.

Conclusion: Santalum album pet ether fraction has potential antihyperlipidemic activity that can help in overcoming insulin resistance.     

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.     

Galangin,a dietary flavonoid,ameliorates hyperglycaemia and lipid abnormalities in rats with streptozotocin-induced hyperglycaemia

Context: Galangin, a natural flavonoid, is found in honey and Alpinia officinarum Hance (Zingiberaceae). Galangin has antiviral, antimicrobial, antidiabetic and anticancer properties, without side effects. The effects of galangin on hyperglycaemia and lipid abnormalities are not known.

Objective: To elucidate the effectiveness of galangin on hyperglycaemia-associated complications and lipid changes in rats with streptozotocin (STZ)-induced hyperglycaemia.

Materials and methods: Diabetes was induced in adult Wistar rats by administering 40?mg/kg of STZ. In our previous study, galangin had no toxicity at concentrations up to 320?mg/kg. Therefore three doses of galangin (4, 8 or 16?mg/kg BW) or glibenclamide (600 µg/kg BW) were administered daily to diabetic rats orally for 45 days.

Results: Diabetic rats showed a significant (p?p?p?Discussion and conclusions: Administration of galangin reduced hyperlipidaemia related to the risk of diabetic complications and could be beneficial for diabetic hyperlipidaemic patients. Further work detailing its mechanism-of-action for improving hyperglycaemic-associated lipid abnormalities is needed.     

Hesperidin,a flavanoglycone attenuates experimental diabetic neuropathy via modulation of cellular and biochemical marker to improve nerve functions

Aim: Diabetic neuropathy (DN) is one of the most common long-term complications of diabetes mellitus and clinically can be characterized by an elevated nociceptive response with electrophysiological conduction abnormalities. The present investigation was designed to evaluate the neuroprotective effect of hesperidin against STZ induced diabetic neuropathic pain in laboratory rats.

Materials and methods: DN was induced in Sprague–Dawley rats (150–200?g) by intraperitoneal administration of streptozotocin (STZ) (55?mg/kg, p.o.). Rats were divided into various groups, namely, STZ control (vehicle), hesperidin (25, 50, and 100?mg/kg, p.o.), insulin (10?IU/kg, s.c.), and combination of hesperidin (100?mg/kg, p.o.) with insulin (10?IU/kg, s.c.) for 4 weeks. Various behavioral (allodynia and hyperalgesia), biochemical parameters [oxido-nitosative stress, Na–K–ATPase, aldose reductase (AR)], and molecular changes (TNF-α and IL-1β) along with hemodynamic changes were determined.

Results: Rats treated with hesperidin (50 and 100?mg/kg, p.o., 4 weeks) significantly reduced (p?p?p?Conclusion: In combination with insulin, hesperidin not only attenuated the diabetic condition but also reversed neuropathic pain via control over hyperglycemia as well as hyperlipidemia to down-regulate generation of free radical, release of pro-inflammatory cytokines as well as elevation in membrane bound enzyme.     

Influence of kaempferol,a flavonoid compound,on membrane-bound ATPases in streptozotocin-induced diabetic rats

Abstract

Context: Kaempferol is a flavonoid found in many edible plants (e.g. tea, cabbage, beans, tomato, strawberries, and grapes) and in plants or botanical products commonly used in traditional medicine. Numerous preclinical studies have shown that kaempferol have a wide range of pharmacological activities, including antioxidant, anti-inflammatory, anticancer, cardioprotective, neuroprotective, and antidiabetic activities.

Objective: The present study investigates the effect of kaempferol on membrane-bound ATPases in erythrocytes and in liver, kidney, and heart of streptozotocin (STZ)-induced diabetic rats.

Materials and methods: Diabetes was induced into adult male albino rats of the Wistar strain, by intraperitoneal administration of STZ (40?mg/kg body weight (BW)). Kaempferol (100?mg/kg BW) or glibenclamide (600?µg/kg BW) was administered orally once daily for 45?d to normal and STZ-induced diabetic rats. The effects of kaempferol on membrane-bound ATPases (total ATPase, Na⁺/K⁺-ATPase, Ca²⁺-ATPase, and Mg²⁺-ATPase) activity in erythrocytes and in liver, kidney, and heart were determined.

Results: In our study, diabetic rats had significantly (p?<?0.05) decreased activities of total ATPases, Na⁺/K⁺-ATPase, Ca²⁺-ATPase, and Mg²⁺-ATPase in erythrocytes and tissues. Oral administration of kaempferol (100?mg/kg BW) or glibenclamide (600?µg/kg BW) for a period of 45?d resulted in significant (p?<?0.05) reversal of these enzymes' activities to near normal in erythrocytes and tissues when compared with diabetic control rats.

Discussion and conclusion: Thus, obtained results indicate that administration of kaempferol has the potential to restore deranged activity of membrane-bound ATPases in STZ-induced diabetic rats. Further detailed investigation is necessary to discover kaempferol’s action mechanism.     

Effects of garlic extract on TNF-α expression and oxidative stress status in the kidneys of rats with STZ + nicotinamide-induced diabetes

Context: Allium sativum L. (Liliaceae) (garlic) is a medicinal plant that is widely used in herbal medicine. Nephropathy is a complication of diabetes that is induced by long-term hyperglycaemia.

Objective: The effects of aqueous extract of garlic (AGE) on the expression of tumour necrosis factor-alpha (TNF-α) and oxidative stress status were studied in the kidneys of rats with streptozotocin (STZ)?+?nicotinamide-induced diabetes.

Materials and methods: Twenty-four Wistar rats were divided into four groups: control rats, rats with STZ?+?nicotinamide-induced diabetes that received a single dose of STZ (65?mg/kg) and nicotinamide (110?mg/kg) intraperitoneally, diabetic rats that were treated with garlic (2?g/kg/d, gavage), and normal rats that received garlic (2?g/kg/d, gavage). The glucose level was determined in the start of study, 7 d after induction of diabetes and 33 d after treatment with garlic. At the end of the treatment period, urea, uric acid and creatinine levels were estimated in sera. Malondialdehyde (MDA), total oxidant status (TOS), nitric oxide (NO) levels and TNF-α gene and protein expression were measured in the renal tissues of the rats.

Results: The glucose, uric acid, and urea levels increased in the serum of diabetic rats compared with control rats, and decreased in garlic-treated diabetic rats compared with diabetic rats (p?p?p?p?p?Discussion and conclusion: These results indicate that garlic extract has hypoglycaemic, antioxidant and anti-inflammatory properties; therefore, it can be useful for the alleviation of diabetic complications.     

Antihyperglycemic,antilipid peroxidation,and insulin secretory activities of Otostegia persica shoot extract in streptozotocin-induced diabetic rats and in vitro C187 pancreatic β-cells

Context: Otostegia persica Boiss (Lamiaceae) contains antioxidant agents and is used in traditional medicine for treatment of diabetes mellitus complications.

Objectives: The acute antihyperglycemic, antilipid peroxidation, and insulin secretory activities of methanol extract of O. persica aerial parts were investigated.

Materials and methods: The extract [200, 300, 400?mg/kg body weight (b.w.)] was given orally to rats and glucose (2?g/kg b.w. orally) was administered 30?min later. Glucose and insulin serum levels were measured before and 30, 60, 120, and 240?min after administration of the test samples in normal and diabetic rats. The in vitro insulin secretory activity of extract was evaluated in C187 pancreatic β-cells and its antilipid peroxidation effect was determined by measuring malondialdehyde (MDA) and glutathione (GSH) levels in rat livers after 240?min. The identification of the major phytoconstituents of the extract was carried out using gas chromatography-mass spectrometry.

Results: The extract (300?mg/kg b.w.) significantly decreased the serum glucose level in diabetic rats at 1 h (494?±?13.4 vs. 426?±?12.9), 2 h (472.8?±?17.8 vs. 396?±?22), and 4?h (438.8?±?25 vs. 346?±?19) after treatment. Accordingly, the serum insulin level increased at the same times. The extract significantly increased glucose-induced insulin secretion in C187 β-cells. Moreover, the extract significantly decreased MDA and increased GSH levels in the liver of diabetic rats. Phytochemical analysis revealed thymol as the major phytoconstituent in the extract.

Discussion and conclusion: O. persica shoot extract has antihyperglycemic, antilipid peroxidation, and insulin secretory properties.     

The association effect of insulin and clonazepam on oxidative stress in liver of an experimental animal model of diabetes and depression

Abstract

Context: It is known that oxidative stress occurs in peripheral blood in an experimental animal model of diabetes and depression, and acute treatment with insulin and clonazepam (CNZ) has a protective effect on oxidative stress in this model.

Objective: This study evaluated the effect of insulin plus CNZ on oxidative stress parameters in the liver of diabetic male rats induced with streptozotocin (STZ) and subjected to forced swimming test (FST).

Materials and methods: Diabetes was induced by a single intraperitoneal (i.p.) dose of STZ 60?mg/kg in male Wistar rats. Insulin (4?IU/kg) plus CNZ acute i.p. treatment (0.25?mg/kg) was administered 24, 5 and 1?h before the FST. Nondiabetic control rats received i.p. injections of saline (1?mL/kg). Protein oxidative damage was evaluated by carbonyl formation and the antioxidant redox parameters were analyzed by the measurements of enzymatic activities of the superoxide dismutase (SOD), catalase and glyoxalase I (GLO). Glycemia levels also were determined.

Results: Our present study has shown an increase in carbonyl content from diabetic rats subjected to FST (2.04?±?0.55), while the activity of catalase (51.83?±?19.02) and SOD (2.30?±?1.23) were significantly decreased in liver from these animals, which were reverted by the treatment. Also, the activity of GLO (0.15?±?0.02) in the liver of the animals was decreased.

Discussion and conclusion: Our findings showed that insulin plus CNZ acute treatment ameliorate the antioxidant redox parameters and protect against protein oxidative damage in the liver of diabetic rats subjected to FST.     

Protective effects of Ficus carica leaves on glucose and lipids levels,carbohydrate metabolism enzymes and β-cells in type 2 diabetic rats

Context: The decoctions of Ficus carica Linn. (Moraceae) leaves are used in the folklore treatment of diabetes.

Objective: To evaluate the effect of F. carica on glucose and lipids levels, carbohydrate metabolism enzymes and β-cells protective effects in type 2 diabetes.

Material and methods: Diabetes was induced in 15 days high-fat diet (HFD)-fed Wistar rats by intraperitoneal injection of streptozotocin (STZ) (40?mg/kg). The ethyl acetate extract (250 and 500?mg/kg) of F. carica leaves was administered for 28 days. Oral glucose tolerance (OGTT) and intraperitoneal insulin tolerance tests (ITT) were evaluated on 15th and 25th days, respectively.

Results: The ethyl acetate extract (250 and 500?mg/kg) of n F. carica leaves showed significant effect (p?F. carica (250 and 500?mg/kg) significantly (p?F. carica enhanced the glucose utilization significantly (p?<?0.005) over 30 and 60?min compared to diabetic control. Further, the altered activities of key carbohydrate metabolizing enzymes such as glucose-6-phosphatase, fructose-1,6-bisphosphatase and hexokinase in the liver tissue of diabetic rats were significantly (p?F. carica. Immumohistochemical studies of islets substantiated the cytoprotective effect on pancreatic β-cells.

Discussion and conclusions: F. carica leaves exerted significant effect on carbohydrate metabolism enzymes with promising hypoglycemic and hypolipidemic activities in type 2 diabetic rats.     

Therapeutic potential of octyl gallate isolated from fruits of Terminalia bellerica in streptozotocin-induced diabetic rats

Abstract

Context: Medicinal plants are a potential source of antidiabetic drugs. Terminalia bellerica Roxb. (Combretaceae) is used in Indian traditional systems of medicine to treat diabetes mellitus.

Objective: The aim of this study was to isolate and identify antihyperglycemic principle(s) from the fruits of T. bellerica and assess the bioactivity in streptozotocin (STZ)-induced diabetic rats.

Materials and methods: Bioassay-guided fractionation was followed to isolate the active compound(s), structure was elucidated using ¹H and ¹³C NMR, IR and mass spectrometry and administered intragastrically to diabetic Wistar rats at different doses (5, 10 and 20?mg/kg, body weight) for 28?d. Plasma glucose, insulin, C-peptide and other biochemical parameters were studied.

Results: Octyl gallate (OG) isolated first time from the fruit rind of T. bellerica significantly (p?<?0.05) reduced plasma glucose to near normal values (108.47?±?6.9?mg/dl) after 14?d at the dose of 20?mg/kg. In addition, OG significantly increased plasma insulin, C-peptide, total protein, albumin, tissue glycogen, body weight and markedly decreased serum total cholesterol, triglyceride, LDL-cholesterol, urea, uric acid and creatinine in diabetic rats. Also OG restored the altered regulatory enzymes of carbohydrate metabolism.

Discussion and conclusion: OG might have augmented the secretion of insulin by the modulation of cAMP and intracellular calcium levels in the β cells of the pancreas. Our findings indicate that OG isolated first time from the fruit rind of T. bellerica has potential antidiabetic effect as it augments insulin secretion and normalizes the altered biochemical parameters in experimental diabetic rat models.     

Studies on the antidiabetic activities of Momordica charantia fruit juice in streptozotocin-induced diabetic rats

Context: Momordica charantia Linn (Cucurbitaceae) (MC) is used in folk medicine to treat various diseases including diabetes mellitus.

Objective: This study investigates the antidiabetic activities of Momordica charantia (bitter gourd) on streptozotocin-induced type 2 diabetes mellitus in rats.

Materials and methods: Male Wister rats were randomly assigned to 4 groups. Group I, Normal control; Group II, STZ diabetic; Group III and IV, Momordica charantia fruit juice was orally administered to diabetic rats (10?mL/kg/day either as prophylaxis for 14 days before induction of diabetes then 21 days treatment, or as treatment given for 21 days after induction of diabetes). The effects of MC juice were studied both in vivo and in vitro by studying the glucose uptake of isolated rat diaphragm muscles in the presence and absence of insulin. Histopathological examination of pancreas was also performed.

Results: This study showed that MC caused a significant reduction of serum glucose (135.99?±?6.27 and 149.79?±?1.90 vs. 253.40*?±?8.18) for prophylaxis and treatment respectively, fructosamine (0.99?±?0.01 and 1.01?±?0.04 vs. 3.04?±?0.07), total cholesterol, triglycerides levels, insulin resistance index (1.13?±?0.08 and 1.19?±?0.05 vs. 1.48?±?1.47) and pancreatic malondialdehyde content (p?p?p?Conclusions: Momordica charantia presents excellent antidiabetic and antioxidant activities and thus has great potential as a new source for diabetes treatment whether it is used for prophylaxis or treatment.     

Comparison of protective and curative potential of Daucus carota root extract on renal ischemia reperfusion injury in rats

Abstract

Context: Daucus carota Linn (Apiaceae), a useful vegetable, is traditionally used in treating kidney and hepatic dysfunctions.

Objective: To evaluate the protective and curative potential of D. carota root extract on renal ischemia reperfusion injury in rats.

Materials and methods: Wistar rats were selected with 8?+?8 groups (n?=?6). Renal pedicles of rats were occluded for 45?min and allowed for reperfusion period. In protective and curative studies, 14 days prior and 14 days after the induction of ischemia/reperfusion (I/R), rats received petroleum ether extract (PEE 250 and 500?mg/kg), fractional methanol extract (FME 250 and 500?mg/kg) and direct methanol extract (DME 250 and 500?mg/kg) of Daucus carota root, orally, once daily.

Results: PEE at a dose of 500?mg/kg significantly (p?<?0.001) reduced the levels of serum creatinine (0.853–3.090?mg/dl), uric acid (1.300–3.500?mg/dl) and urea (58.26–132.00?mg/dl) compared to disease control. FME at a dose of 500?mg/kg body weight significantly (p?<?0.001) reduced the levels of serum creatinine (0.960–3.090?mg/dl), uric acid (1.700–3.500?mg/dl) and urea (77.17–132.00?mg/dl) compared to disease control. DME at a dose of 500?mg/kg body weight significantly (p?<?0.001) reduced the levels of serum creatinine (1.173–3.090?mg/dl), uric acid (2.267–3.500?mg/dl) and urea (84.75–132.00?mg/dl) compared to disease control.

Discussion and conclusion: Findings demonstrate that postconditioning with the D. carota root extract significantly improves kidney function in I/R rats.