Antihyperglycemic effect of water extract of dry fruits of<Emphasis Type="Italic">Terminalia chebula</Emphasis> in experimental diabetes mellitus

Water extract of dry fruits ofTerminalia chebula (Hindi-Harda, Telugu-Karakkaya) at a dose of 200 mg/kg body weight improved the glucose tolerance as indicated by 44% of reduction in the peak blood glucose at 2^nd hour in glucose tolerance test in diabetic (streptozotocin induced) rats. Treatment of diabetic rats with an initial fasting blood glucose of 253±9.4 mg/dl daily once with the water extract (200 mg/kg) for two weeks brought down the fasting blood glucose to 123±8.4 mg/dl which is only slightly above the normal value. These results indicate that water extract of Terminalia chebula improves glucose tolerance and brings down fasting blood glucose in diabetic rats.     

Preliminary studies on the hypoglycaemic effect ofAbroma augusta in alloxan diabetic rats

The hypoglycemic effect of the aqueous extract ofAbroma augusta (Family: Steculiceae) was studied in normal as well as alloxan diabetic rats. Treatement of diabetic rats with 4 ml (4gm dry weight) of agueous extract ofA. augusta for 16 weeks resulted in gradual but significant fall in fasting blood glucose and improvement in glucose tolerance. Serum total and LDL cholesterol and triacylglycerol which increased in diabetic rats showed improvement. These results show that the water extract ofA. augusta has both hypoglycemic and hypocholesterolemic effects.     

Attenuation of oxidative stress in streptozotocin-induced diabetic rats by <Emphasis Type="Italic">Eucalyptus globulus</Emphasis>

In traditional medicine, Eucalyptus globulus (eucalyptus) was used for the treatment of diabetes mellitus. Hyperglycemia in diabetes has been associated with increased formation of reactive oxygen species (ROS) and oxidative damage to tissue compounds. The aim of this study was to evaluate the effects of eucalyptus in the diet (20 g/Kg) and drinking water (2.5 g/L) on lipid peroxidation, protein oxidation and antioxidant power in plasma and liver homogenate, as well as glycated-Hb (HbA_1C) of blood in streptozotocin-induced diabetic rats for a period of 4 weeks. Diabetes induced in rats by a single intraperitoneal injection of streptozotocin (STZ, 65 mg/Kg). At the end of the treatment period, the level of plasma glucose, plasma and liver malondialdehyde (MDA, the main product of lipid peroxidation), protein carbonyl (PC, one of the protein oxidation products) and HbA_1C increased and ferric reducing antioxidant power (FRAP) decreased in diabetic rats compared to normal rats. Eucalyptus administration for 4 weeks caused a significant decrease in the plasma glucose levels, plasma and liver MDA, PC and HbA_1C, also a concomitant increase in the levels of FRAP in diabetic treated rats. In conclusion, the present study showed that eucalyptus posses antioxidant activities. Eucalyptus probably restores antioxidant power, due to the improved hyperglycemia in streptozotocin-induced diabetic rats.     

Experimental Validation of Antidiabetic Potential of <Emphasis Type="Italic">Cayratia trifolia</Emphasis> (L.) Domin: An Indigenous Medicinal Plant

The present study was undertaken to evaluate antidiabetic and antioxidant activities of Cayratia trifolia root extract against streptozotocin induced diabetes in experimental rats to scientifically validate its use against diabetes in some parts of India. Ethanolic extract, showing the highest activity in in vitro experiments, was prepared in saline and administered orally to streptozotocin induced albino Wistar diabetic rats for 21 days. Biochemical parameters liver and muscles glycogen and in vivo antioxidant activity in normal, diabetic control, standard (metformin) and treated animals were determined and compared. Attempt was made to isolate, purify and characterize one of the major secondary metabolites in extract by range of chromatographic and spectroscopic techniques. Treatment of streptozotocin induced diabetic rats with ethanolic root extract (500 mg/kg) caused significant (P < 0.01) reduction in blood glucose (312–178 mg/dL), increase in body weight (181–219 g) and serum insulin (1.28–2.26 IU/dL). It also maintained lipid profile and tests of liver and kidney functions within normal range as compared to diabetic control rats and almost at par with standard drug metformin. The oxidative stress induced decline in glutathione and catalase in liver and kidney tissues showed recovery nearly to normal level as a function of treatment. The GC–MS profile of the extract showed relatively high concentration of β-sitosterol which was characterized by different spectroscopic and chromatographic techniques. The result scientifically and comprehensively validate the reported use of roots of this indigenous plant against diabetes. A strong antioxidant activity of the ethanolic root extract suitably compliments the antidiabetic effect.     

Evaluation of hypoglycemic and antioxidant effect of<Emphasis Type="Italic">Ocimum sanctum</Emphasis>

Ocimum sanctum leaves have been traditionally used in treatment of diabetes mellitus. Dietary supplementation of fresh tulsi leaves in a dose of 2 gm/kg BW for 30 days led to significant lowering of blood glucose levels in test group. Intake ofOcimum sanctum also led to significant increase in levels of superoxide dismutase, reduced glutathione and total thiols, but marked reduction in peroxiodised lipid levels as compared to untreated control group. The leaves were found to possess both superoxide and hydroxyl free radical scavenging action. The present observations establish the efficacy ofOcimum sanctum leaves in lowering blood glucose levels and antioxidant property appears to be predominantly responsible for hypoglycemic effect.     

Suppression of Type-II Diabetes with Dyslipidemia and Nephropathy by Peels of <Emphasis Type="Italic">Musa cavendish</Emphasis> Fruit

Musa cavendish, peels has local and traditional use to promote wound healing, hyperglycemia, ulceration etc. The present work investigated the lipid lowering; nephroprotective and glucose lowering properties of ethanolic extract of peels of Musa cavendish (EMC) in alloxan-induced diabetic rats. The EMC 250, 500 and 1000 mg/kg/day and the vehicle were administered orally to alloxan-induced diabetic rats (n = 6) for 3 weeks. Changes in plasma glucose, lipid profile along with kidney function before and after treatment with EMC were recorded. The ethanolic extract of peels of Musa cavendish reduced blood glucose, serum triglyceride, cholesterol, LDL cholesterol and creatinine levels and improvement in body weight, liver glycogen, serum HDL cholesterol, serum albumin and total protein level when compared with untreated rats. Musa cavendish has lipid lowering, nephroprotective and antidiabetic property by regulating glucose uptake in the liver and muscles by restoring the intracellular energy balance.     

Antidiabetic and antioxidant effects of <Emphasis Type="Italic">Picrorhiza kurrooa</Emphasis> rhizome extracts in diabetic rats

Picrorhiza kurrooa is mentioned in Ayurveda for the treatment of many disorders, but it has not been subjected to systematic scientific investigations to assess its antidiabetic effect. The oral administration of aqueous and methanol extracts of P. kurrooa rhizomes (250 and 500 mg / kg body weight / day) for 15 days significantly reduced blood glucose, glycosylated haemoglobin and increased total hemoglobin, plasma insulin in alloxan-induced diabetes in albino rats. The treatment also showed significant correction in the level of nitric oxide radicals, superoxide radicals, peroxynitrite radical, lipid peroxidation, glutathione, glutathione reductase, glutathione-S-transferase, glutathione peroxidase, superoxide dismutase and catalase in the pancreas of alloxan diabetic rats.     

Effect of water extract of <Emphasis Type="Italic">Trichosanthes dioica</Emphasis> fruits in streptozotocin induced diabetic rats

In rats with streptozotocin induced severe diabetes mellitus, aqueous extract of Trichosanthes dioica fruits at a dose of 1000mg/kg body weight daily once for 28 days reduced the levels of fasting blood glucose, postprandial glucose, asparate amino transferase, alanine amino transferase, alkaline phosphatase, creatinine, urine sugar and urine protein where as total protein and body weight was increased. No toxic effect was observed during LD50. Our study suggests that further detailed toxicity studies and mechanism of action of T. dioica would be useful for undertaking human trials.     

Hypoglycemic, hypolipidemic and antioxidant properties of combination ofCurcumin fromCurcuma longa, Linn, and partially purified product fromAbroma augusta, Linn. in streptozotocin induced diabetes

Dietary spice components ofCurcuma longa andAbroma augusta have been screened for their protective effect against reactive oxygen species induced lipid peroxidation. They have been found to be efficient antioxidant when administered in combination. The purpose of the study was to investigate the effect of oral administration (300mg/Kg) of the aqueous extract of turmeric whose active ingredient isCurcumin andAbromine powder as a hypoglycemic agent mixed with diet. The effect of this aqueous extract on blood glucose, lipid peroxidation (LPO) and the antioxidant defense system in rat tissues like liver, lung, kidney and brain was studied for 8 weeks in streptozotocin induced diabetic rats. The administration of an aqueous extract of turmeric and abromine powder resulted in a significant reduction in blood glucose and an increase in total haemoglobin. The aqueous extract also resulted in decreased free radical formation in the tissues studied. The decrease in thiobarbituric acid reactive substances (TBARS) and increase in reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) clearly showed the antioxidant property of the mixture. It is suggested that these changes initially counteract the oxidative stress in diabetes however, a gradual decrease in the antioxidative process may be one of the factors which results in chronic diabetes. These results indicate that the mixture of the two plants have shown antidiabetic activity and also reduced oxidative stress in diabetes. A combination ofAbroma augusta and Curcuma longa also restored the other general parameters in diabetic animals. The results were statistically analyzed and indicated that combination of herbal extracts showed better efficacy as compared to individual herbal plant extracts used.     

Antidyslipidemic and antioxidant activities of different fractions of<Emphasis Type="Italic">Terminalia arjuna</Emphasis> stem bark

Terminalia arjuna (T. arjuna) stem bark was successively extracted with petroleum ether (A), solvent ether (B), ethanol (C) and water (D). The lipid lowering activity of these four fractions A, B, C, and D was evaluatedin vivo in two models viz., triton WR-1339 induced hyperlipemia in rats as well as fructose rich high fat diet (HFD) fed diabetic- dyslipidemic hamsters. Hyperlipidemia induced by triton caused marked increase in the plasma levels of total cholesterol (Tc), triglyceride (Tg) and phospholipids (PL) in rats. After treament withT. arjuna fractions A, B, C, and D at the doses of 250 mg/kg per oral (p.o.),only the ethanolic fraction (C) exerted significant lipid lowering effect as assessed by reversal of plasma levels of Tc, Tg and PL in hyperlipidemic rats. In another experiment, feeding with HFD produced marked dyslipidemia as observed by increased levels of plasma Tc, Tg, glucose (Glu), glycerol (Gly) and free fatty acids (FFA) in hamsters. After treatment withT. arjuna fractions at the doses of 250 mg/kg p.o. only two fraction (B and C) could exert significant lowering in the plasma levels of lipids and Glu. in dyslipidemic hamsters.In vitro experimentT. arjuna fractions at tested concentrations (50–500 μg/ml) inhibited the oxidative degradation of lipids in human low density lipoprotein and rat liver microsomes induced by metal ions. These fractions when tested against generation of oxygen free radicals at the concentrations (50–500 μg/ml), counteracted the formation of superoxide anions (O⁻²) and hydrodyl radicals (OH) in non enzymic test systems. The efficacy ofT. arjuna fractions as antidyslipidemic and antioxidant agents was found, fraction C> fraction B> fraction A.     

Reversal of diabetic retinopathy in streptozotocin induced diabetic rats using traditional Indian anti-diabetic plant,Azadirachta indica (L.)

This study was carried out to investigate the effect of oral feeding of water extract of fresh leaves ofAzadirachta indica (Fam:Meliaceae) in streptozotocin induced diabetes and its associated retinopathy in rats. Treatment of the diabetic rats with aqueous extract of leaves ofA. indica at a dose of 250 mg/kg body weight for 16 weeks resulted in gradual but significant fall in blood glucose and improvement in serum total, LDL and HDL cholesterol and triacylglycerol which increased in diabetic rats. It also showed improvement in body weight and reversed retinopathy.     

Antihyperglycemic,antihyperlipidemic and antioxidative potential of <Emphasis Type="Italic">Prosopis cineraria</Emphasis> bark

Alloxan administration in male Swiss albino mice, induced diabetes by increasing blood glucose concentration and reducing hepatic glycogen content as compared to normal control group. Besides, serum lipid profile parameters such as total-cholesterol, triglyceride, low-density lipoprotein and very low-density lipoprotein-cholesterol were also elevated, whereas, the level of high-density lipoprotein-cholesterol was reduced significantly (P<0.05) in diabetic mice. Treatment of diabetic animals with crude ethanolic extract of bark of Prosopis cineraria (P. cineraria) for 45 days, significantly lowered blood glucose level, elevated hepatic glycogen content and maintained body weight and lipid-profile parameters towards near normal range. Declined activity of antioxidant enzymes and concentration of non-enzymatic antioxidants were also normalized by drug treatment, thereby reducing the oxidative damage in the tissues of diabetic animals and hence indicating the anti-diabetic and antioxidant efficacy of the extract.     

Hypoglycaemic, hypolipidemic and antioxidant properties of tulsi (Ocimum sanctum linn) on streptozotocin induced diabetes in rats

Effect of oral administration of 200 mg/Kg body weight of the aqueous extract ofOcimum sanctum (Tulsi) mixed with diet for eight weeks to diabetic (streptozotocin induced) rats was studied. There was significant reduction in fasting blood glucose, serum lipid profile, lipid peroxidation products, (LPO) and improvement in glucose tolerance. The aqueous extract also decreased LPO formation (thiobarbituric acid reactive substances TBARS) and increased antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione transferase (GT) and one antioxidant reduced glutathione (GSH) in plasma and rat liver, lung, kidney and brain. The decrease in TBARS and increase in GSH, SOD, CAT, GPX, and GT clearly shows the antioxidant property ofOcimum sanctum.     

Curative effect of <Emphasis Type="Italic">Cynodon dactylon</Emphasis> against STZ induced hepatic injury in diabetic rats

The aim of the study was to ascertain the role of ethanolic extract of Cynodon dactylon against hepatic complications in streptozotocin (STZ) induced type 2 diabetic models. Effect of the pre identified most effective dose of 500 mg/kg body weight was studied on hepatic injury caused by chemically induced diabetes by 55 mg/kg body weight i.p. injection of STZ in male Wistar rats. The dose of 500mg/kg body weight given once daily for 14 days reduced the levels of serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, alkaline phosphatase, creatinine and urine sugar significantly (P<0.05) with increase in total protein, haemoglobin and body weight was increased. High LD₅₀ validates its high margin of safety.     

Preliminary studies on the hypoglycemic effect of <Emphasis Type="Italic">Peganum harmala</Emphasis> L. Seeds ethanol extract on normal and streptozotocin induced diabetic rats

Peganum harmala L. (Zygophyllaceae) is a traditional medicine used for the treatment of variety of human ailments, including antidepression, hallucination, antileishmaniasis etc. We report for first time the hypoglycemic activity of the ethanolic extract of this plant at two dose levels of 150 and 250mg/kg bw in sucrose challenged normal as well as in rats with streptozotocin induced diabetes. The oral administration of ethanolic extract causes maximum fall of blood glucose level to 22.9% (p<0.05) and 29.4% (p<0.01) respectively with the two doses in normal and 30.3% (p<0.01) and 48.4% (p<0.001) in diabetic rats. The standard drug metformin treated group showed 28.0% (p<0.01) and 45.5% (p<0.001) respectively in normal and diabetic rats. The above results show that the ethanolic extract of P. harmala is as effective as metformin in reducing the blood glucose levels of normoglycemic and streptozotocin-induced diabetic rats.     

Enhanced anti-proteases in<Emphasis Type="Italic">Labeo rohita</Emphasis> fed with diet containing herbal ingredients

Aqueous root extract ofAchyranthes aspera was incorporated in the experimental diet ofLabeo rohita (rohu). Control diet was prepared without root extract. Feeding of fishes with experimental diet has significantly (p<0.05) enhanced the serum anti-proteases level than fishes fed with control diet.     

Antidiabetic Effect of GII Compound Purified from Fenugreek (<Emphasis Type="Italic">Trigonella foenum graecum</Emphasis> Linn) Seeds in Diabetic Rabbits

Aim is to study the antidiabetic effect of a compound GII purified earlier from the water extract of fenugreek (Trigonella foenum graecum) seeds by Murthy and his colleagues (patented in India and USA) in diabetic rabbits. Diabetes was induced in rabbits by injecting 80 mg/kg bw of alloxan intravenously into rabiits. Rabbits were subdivided into subdiabetic [fasting blood sugar (FBG) up to 120 mg/dl with abnormal glucose tolerance in glucose tolerance test (GTT)], moderately diabetic (FBG below 250 mg/dl) and severely diabetic (FBG above 250 mg/dl). Blood glucose and glycosylated hemoglobin (HbA1C) were estimated by procedures in the kits of Stangen Immunodiagnostics, Mumbai using, respectively, glucose oxidase method and absorbance at 415 nm. Serum insulin was estimated by the ELISA method as described in the kit of Boehringer Mannheim Immunodiagnostics, Mumbai, India. GII was found to improve blood glucose utilization in GTT and reduced FBG and HbA1C. In the present communication detailed studies were carried out with GII in the subdiabetic, moderately diabetic and severely diabetic rabbits. GII at a dose of 50 mg/kg bw per day brought down the elevated FBG levels in the untreated subdiabetic (FBG 96.6 ± 7 mg/dl), moderately diabetic (150.1 ± 14 mg/dl) and severely diabetic rabbits (427 ± 46 mg/dl) to normal in 12, 15 and 28 days of treatment. It improved serum HbA1C and insulin levels also in these rabbits. Intermittent therapy once a week for 6 weeks with GII at the same dose brought down the FBG values to normal in the subdiabetic (FBG 96.0 ± 2 mg/dl) and in the moderately diabetic rabbits to 133.0 ± 12 mg/dl. After stopping therapy of the subdiabetic and moderately diabetic rabbits whose FBG values came to normal after treatment with GII 50 mg/kg bw, the values remained normal for 1 week and showed a tendency to increase only after 15 days. If these animal studies are applicable to humans these results indicate that a diabetic person need not take GII daily when once the FBG value comes to normal or near to normal. Patients might be able to take GII only when the FBG value shows tendency to increase. So, intermittent therapy is possible with the potent product GII of the fenugreek seeds which is of a great advantage.     

Effect of <Emphasis Type="Italic">Curcuma longa</Emphasis> freeze dried rhizome powder with milk in STZ induced diabetic rats

This study deals with the effects of freeze dried rhizome powder of Curcuma longa (C. longa) dissolved in milk on normal as well as diabetic models. Diabetes of type II and type I was within 3 days of a single administration of doses of 45 and 65 mg kg⁻¹ of streptozotocin respectively. Various parameters such as blood glucose levels, triglycerides, total cholesterol, high density lipoprotein, very low density lipoprotein, low density lipoprotein, serum glutamic oxaloacetic transaminase, serum glutamic pyruvate transaminase, alkaline phosphatase, creatinine, hemoglobin, urine protein and urine sugar in addition to body weight were taken in to consideration and were analyzed after administration of variable doses of rhizome powder. The dose of 200 mg kg⁻¹ was identified as the most effective dose as it increased HDL, Hb and bw (P<0.05) with significant decrease in the levels of blood glucose, lipid profile and hepatoprotective enzymes (P<0.001).     

Effect ofOcimum sanctum (Tulsi) and vitamin E on biochemical parameters and retinopathy in streptozotocin induced diabetic rats

This study was carried out to see the effect of the aqueous extract ofOcitum sanctum Linn (Tulsi) with Vitamin E on biochemical parameters and retinopathy in the streptozotocin-induced diabetic albino male rats. Adult albino male rats weighing 150–200 gm were made diabetic by intraperitoneal injection of streptozotocin in the dose 60 mg/kg in citrate buffer (pH 6.3). The diabetic animals were left for one month to develop retinopathy. Biochemical parameters like plasma glucose, oral glucose tolerance and glycosylated hemoglobin HbA_1c, were measured along with lipid profile, and enzymes like glutathione peroxidase (GPX), lipid peroxidase (LPO), superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) in normal, untreated diabetic rats and diabetic rats treated withOcimum sanctum L extracts and vitamin E. Fluorescein angiography test was done for assessing retinopathy. Results on biochemical parameters were analyzed statistically by using ANOVA followed by Dunnet's ‘t’-test. A p-value of <0.05 was considered as significant. Evaluation of biochemical profile in treated groups showed statistically significant reduction in plasma levels of glucose, HbA_1c, lipid profile and LPO, and elevation of GPX, SOD, CAT and GST. Treatment of the diabetic animals withOcimum sanctum and Vitamin E, alone and in combination for 16 weeks showed reversal of most of the parameters studied including plasma glucose levels. Angiography showed improvement in retinal changes following combined antidiabetic treatment.     

Antihyperglycemic and antilipidperoxidative effects of<Emphasis Type="Italic">Tephrosia purpurea</Emphasis> seed extract in streptozotocin induced diabetic rats

The aim of the present study was to evaluate the antihyperglycemic and antilipidperoxidative effects of ethanolic seed extract ofTephrosia purpurea (TpEt) in streptozotocin induced diabetic rats. Hyperglycemia associated with an altered hexokinase and glucose 6 phosphatase activities, elevated lipid peroxidation, disturbed enzymatic and non-enzymatic antioxidants status were observed in streptozotocin induced diabetic rats. Oral administration of “TpEt” at a dose of 300mg/kg bw showed significant antihyperglcemic and antilipidperoxidative effects as well as increased the activities of enzymatic antioxidants and levels of non enzymatic antioxidants. We also noticed that the antihyperglycemic effect of plant drug (TpEt) was comparable to that of the reference drug glibenclamide. Our results clearly indicate that “TpEt” has potent antihyperglycemic and antilipidperoxidative effects in streptozotocin induced diabetic rats and therefore further studies are warranted to isolate and characterize the bioactive antidiabetic principles from “TpEt”.