A study of the antidiabetic activity of Barleria prionitisLinn

Objectives:

To study the antidiabetic activity of Barleria prionitis Linn in normal and alloxan-induced diabetic rats.

Materials and Methods:

Alcoholic extract of leaf and root of B. prionitis was tested for their antidiabetic activity. Albino rats were divided into six groups of six animals each. In three groups, diabetes was induced using alloxan monohydrate (150 mg/kg b.w., i.p.) and all the rats were given different treatments consisting of vehicle, alcoholic extract of leaves, and alcoholic extract roots of B. prionitis Linn (200 mg/kg) for 14 days. The same treatment was given to the other three groups, comprising non-diabetic (normal) animals. Blood glucose level, glycosylated hemoglobin, liver glycogen, serum insulin, and body weight were estimated in normal and alloxan-induced diabetic rats, before and 2 weeks after administration of drugs.

Results:

Animals treated with the alcoholic extract of leaves of B. prionitis Linn showed a significant decrease in blood glucose level (P<0.01) and glycosylated hemoglobin (P<0.01). A significant increase was observed in serum insulin level (P<0.01) and liver glycogen level (P<0.05), whereas the decrease in the body weight was arrested by administration of leaf extract to the animals. The alcoholic extract of roots showed a moderate but non-significant antidiabetic activity in experimental animals.

Conclusion:

The study reveals that the alcoholic leaf extract of B. prionitis could be added in the list of herbal preparations beneficial in diabetes mellitus.     

Hypoglycemic effect of aqueous extract of Parthenium hysterophorus L. in normal and alloxan induced diabetic rats

Objectives:

To study the effects of Parthenium hysterophorus L. flower on serum glucose level in normal and alloxan induced diabetic rats.

Materials and Methods:

Albino rats were divided into six groups of six animals each, three groups of normal animals receiving different treatments consisting of vehicle, aqueous extract of Parthenium hysterophorus L. flower (100 mg/kg) and the standard antidiabetic drug, glibenclamide (0.5 mg/kg). The same treatment was given to the other three groups comprising alloxan induced diabetic animals. Fasting blood glucose level was estimated using the glucose oxidase method in normal and alloxan induced diabetic rats, before and 2 h after the administration of drugs.

Results:

Parthenium hysterophorus L. showed significant reduction in blood glucose level in the diabetic (P<0.01) rats. However, the reduction in blood glucose level with aqueous extract was less than with the standard drug glibenclamide. The extract showed less hypoglycemic effect in fasted normal rats, (P<0.05).

Conclusion:

The study reveals that the active fraction of Parthenium hysterophorus L. flower extract is very promising for developing standardized phytomedicine for diabetes mellitus.     

The study of aqueous extract of Pterocarpus marsupium Roxb. on cytokine TNF-α in type 2 diabetic rats

Objective:

This study was designed to investigate the effect of aqueous extract of Pterocarpus marsupium Roxb. on elevated inflammatory cytokine, tumor necrosis factor (TNF)-α in type 2 diabetic rats.

Materials and Methods:

Type 2 diabetes was induced by administering streptozotocin (90 mg/kg, i.p.) in a neonatal rat model. Aqueous extract of P. marsupium at a dose of 100 and 200 mg/kg was given orally to desired group of animals for a period of 4 weeks. After 4 weeks of drug treatment, parameters such as fasting blood glucose, postprandial blood glucose, and TNF-α in serum were analyzed.

Results:

Aqueous extract of P. marsupium at both doses, i.e., 100 and 200 mg/kg, decreased the fasting and postprandial blood glucose in type 2 diabetic rats. The 200 mg/kg had more pronounced effect on postprandial hyperglycemia. The drug also improved the body weight of diabetic animals. Cytokine TNF-α was found to be elevated in untreated diabetic rats due to chronic systemic inflammation. The aqueous extract at both doses significantly (P < 0.001) decreased the elevated TNF-α level in type 2 diabetic rats.

Conclusion:

Modulation of cytokine TNF-α by the rasayana drug P. marsupium is related with its potential anti-diabetic activity.     

An evaluation of the antidiabetic effects of Elaeocarpus ganitrus in experimental animals

Objective:

To evaluate the antidiabetic effects of the aqueous extract of Elaeocarpus ganitrus (EAG) in experimental animals.

Materials and Methods:

The hypoglycemic activity of the EGA was evaluated in normoglycemic rats by single dose at three graded dose levels, viz. 250, 500 and 1000 mg/kg of body weight. Antihyperglycemic activity of the extract was also evaluated at the same dose levels in streptozotocin (STZ) (60 mg/kg, i.p.)-induced diabetic rats during a 30-day treatment period. Metformin (500 mg/kg) was used as the reference drug. Fasting blood glucose and lipid parameters, viz. triglycerides, total cholesterol, high-density lipoprotein and low-density lipoprotein levels were measured. Acute oral toxicity of the EGA extract was carried out in Swiss albino mice.

Results:

In normoglycemic rats, EGA showed a significant (P < 0.01) hypoglycemic effect at 2 h. In STZ-induced diabetic rats, the EGA treatment significantly (P < 0.05) decreased the blood glucose level in a dose-dependent manner during the 30 days of treatment period. EGA modulated lipid profile changes in STZ-diabetic rats in a dose-dependant manner. In the acute oral toxicity study, EGA showed no mortality till the 5 g/kg dose in mice.

Conclusion:

The present investigation shows that EAG seeds has potential antidiabetic effects.     

Antidiabetic activity of Cassia occidentalis (Linn) in normal and alloxan-induced diabetic rats

Objective:

To evaluate the hypoglycemic activity of various extracts, petroleum ether, chloroform and aqueous extract of Cassia occidentalis in normal and alloxan-induced diabetic rats.

Materials and Methods:

Petroleum ether, chloroform and aqueous extract of whole plant of Cassia occidentalis were orally tested at the dose of 200 mg/kg for hypoglycemic effect in normal and alloxan-induced diabetic rats. In addition, changes in body weight, serum cholesterol, triglyceride and total protein levels, assessed in the ethanol extract-treated diabetic rats, were compared with diabetic control and normal animals. Histopathological observations during 21 days treatment were also evaluated.

Results:

Aqueous extract of C. occidentalis produced a significant reduction in fasting blood glucose levels in the normal and alloxan-induced diabetic rats. Apart from aqueous extract, petroleum ether extract showed activity from day 14 and chloroform extract showed activity from 7 days. Significant differences were observed in serum lipid profiles (cholesterol and triglyceride), serum protein, and changes in body weight by aqueous extract treated-diabetic animals, when compared with the diabetic control and normal animals. Concurrent histopathological studies of the pancreas of these animals showed comparable regeneration by extract which were earlier necrosed by alloxan.

Conclusion:

Aqueous extract of C. occidentalis exhibited significant antihyperglycemic activity in normal and alloxan-induced diabetic rats. They also showed improvement in parameters like body weight and serum lipid profiles as well as histopathological studies showed regeneration of β-cells of pancreas and so might be of value in diabetes treatment.     

Antidiabetic activity of aqueous root extract of Ichnocarpus frutescens in streptozotocin-nicotinamide induced type-II diabetes in rats

Objective:

To evaluate the antidiabetic activity of aqueous extract of roots of Ichnocarpus frutescens in streptozotocin-nicotinamide induced type-II diabetes in rats.

Materials and Methods:

Streptozotocin-nicotinamide induced type-II diabetic rats (n = 6) were administered aqueous root extract (250 and 500 mg/kg, p.o.) of Ichnocarpus frutescens or vehicle (gum acacia solution) or standard drug glibenclamide (0.25 mg/kg) for 15 days. Blood samples were collected by retro-orbital puncture and were analyzed for serum glucose on days 0, 5, 10, and 15 by using glucose oxidase-peroxidase reactive strips and a glucometer. For oral glucose tolerance test, glucose (2 g/kg, p.o.) was administered to nondiabetic control rats and the rats treated with glibenclamide (10 mg/kg, p.o.) and aqueous root extract of Ichnocarpus frutescens. The serum glucose levels were analyzed at 0, 30, 60, and 120 min after drug administration. The effect of the extract on the body weight of the diabetic rats was also observed.

Results:

The aqueous root extract of Ichnocarpus frutescens (250 and 500 mg/kg, p.o.) induced significant reduction (P < 0.05) of fasting blood glucose levels in streptozotocin-nicotinamide induced type-II diabetic rats on the 10^th and 15^th days. In the oral glucose tolerance test, the extract increased the glucose tolerance. It also brought about an increase in the body weight of diabetic rats.

Conclusion:

It is concluded that Ichnocarpus frutescens has significant antidiabetic activity as it lowers the fasting blood sugar level in diabetic rats and increases the glucose tolerance.     

Antidiabetic activity of ethanolic extract of tubers of Dioscorea alata in alloxan induced diabetic rats

Objective:

To evaluate the antidiabetic activity of ethanolic extract of Dioscorea alata in glucose loaded and alloxan induced diabetic rats.

Materials and Methods:

The authenticated tubers of D. alata (DA) (JSSCPDP/2008/157) were collected from Dharmapuri, Tamil Nadu. The ethanol extract was tested for hypoglycemic activity in normal rats. In oral glucose tolerance test, glucose (3 g/kg, p.o.) was administered to non diabetic control, metformin (250 mg/kg, p.o.) and DA extract (100 and 200 mg/kg, p.o.) to treat treated rats. Diabetes mellitus was induced by alloxan monohydrate (120 mg/kg, i.p.) in physiological saline after overnight fasting for 18 hours. DA extract (100 and 200 mg/kg, p.o.) and standard drug metformin (250 mg/kg, p.o.) were administered to diabetic rats for 21 days. Fasting blood glucose level and changes in body weight were measured on days 0, 7, 14, and 21. At the end of 21^st day, serum lipid profile, total protein, albumin, and creatinine were assessed.

Results:

In glucose loaded normal rats, the treatment with the extract of DA had shown a highly significant reduction (P < 0.001) in blood glucose levels at the doses of 100 and 200 mg/kg, respectively. The extract did not produce hypoglycemic activity at both the dose levels in normal, fasted rats. In alloxan induced diabetic rats, the body weight of the DA extract treated animals had shown a significant increase (P < 0.001) after 21 days treatment. The blood glucose level was reduced significantly by 47.48% and 52.09% after 21 days treatment at dose levels 100 and 200 mg/kg, respectively. Serum lipid levels, total protein, albumin, and creatinine were reversed toward near normal in treated rats as compared to diabetic control.

Conclusion:

The results indicate that ethanol extract of DA tubers possesses significant antidiabetic activity.     

In vivo antimalarial activity of ethanolic leaf extract of Stachytarpheta cayennensis

Objective:

To evaluate the in vivo antiplasmodial activity of the ethanol leaf extract of Stachytarpheta cayennensis in the treatment of various ailment in Niger Delta region of Nigeria, in Plasmodium berghei infected mice.

Materials and Methods:

The ethanolic leaf extract of Stachytarpheta cayennensis (90-270 mg/kg/day) was screened for blood schizonticidal activity against chloroquine sensitive Plasmodium berghei berghei in mice. The schizonticidal effect during early and established infections was investigated.

Result:

Stachytarpheta cayennensis (90-270 mg/kg/day) exhibited significant (P< 0.05) blood schizonticidal activity both in 4-day early infection test and in established infection with a considerable mean survival time comparable to that of the standard drug, chloroquine, 5 mg/kg/day.

Conclusion:

The leaf extract possesses significant (P< 0.05) antiplasmodial activity which confirms it''s use in folkloric medicine in the treatment of malaria.     

Effect of an isolated active compound (Cg-1) of Cassia glauca leaf on blood glucose, lipid profile, and atherogenic index in diabetic rats

Objectives:

The objective of present study was to evaluate the effect of active principle (Cg-1) from Cassia glauca leaf on serum glucose and lipid profile in normal and diabetic rats.

Materials and Methods:

Diabetes was induced by streptozotocin in neonates. Oral administration of petroleum ether, chloroform, acetone, and methanol of C. glauca leaf (100 mg/kg, p.o.) for 21 days caused a decrease in fasting blood glucose (FBG) in diabetic rats. Among all the extracts, acetone extract was found to lower the FBG level significantly in diabetic rats. Glibenclamide was used as standard antidiabetic drug (5 mg/kg, p.o). Acetone extract was subjected to column chromatography that led to isolation of an active principle, which was given trivial name Cg-1. Cg-1 (50 mg/kg, p.o.) was studied for its hypoglycemic and hypolipidemic potential. The unpaired t-test and analysis of variance (ANOVA) followed by post hoc test was used for statistical analysis.

Results:

Cg-1 caused a significant reduction in FBG level. It also caused reduction in cholesterol, triglycerides, and LDL levels and improvement in the atherogenic index and HDL level in diabetic rats.

Conclusion:

Improvement in the FBG and the atherogenic index by Cg-1 indicates that Cg-1 has cardioprotective potential along with antidiabetic activity and provides a scientific rationale for the use as an antidiabetic agent.     

Astragalus polysaccharides alleviates glucose toxicity and restores glucose homeostasis in diabetic states via activation of AM PK

Aim:

To establish the mechanism underlying the improvement of glucose toxicity by Astragalus polysaccharide (APS), which occurred via an AMP activated protein kinase (AMPK)-dependent pathway.

Methods:

In vivo and in vitro effects of APS on glucose homeostasis were examined in a type 2 diabetes mellitus (T2DM) rat model. The T2DM rat model was duplicated by a high-fat diet (58% fat, 25.6% carbohydrate, and 16.4% protein) and a small dose of streptozotocin (STZ, 25 mg/kg, ip). After APS therapy (700 mg·kg⁻¹·d⁻¹, ig) for 8 weeks, blood glucose, glycosylated hemoglobin, and serum insulin were measured. Insulin sensitivity was evaluated by the comprehensive analysis of oral glucose tolerance tests (OGTT) and HOMA IR index. Hepatic glycogen was observed by the PAS staining method. The expression and activity of skeletal muscle AMPKα and acetyl-CoA carboxylase (ACC), and the phosphorylation of hepatic glycogen synthase (GS), the glycogen synthase (GS),were measured by Western blotting. Glucose uptake was measured with the 2-deoxy-[³H]-D-glucose method in C2C12 cells.

Results:

The hyperglycemia status, insulin sensitivity, glucose uptake, and activation level of AMPK in diabetic rats were improved in response to APS administration. APS could also alleviate glucose toxicity in cultured mouse cells by the activation of AMPK.

Conclusion:

APS can alleviate glucose toxicity by increasing liver glycogen synthesis and skeletal muscle glucose translocation in the T2DM rat model, via activation of AMPK.     

Cleistanthus collinus induces type I distal renal tubular acidosis and type II respiratory failure in rats

Background and Purpose:

A water decoction of the poisonous shrub Cleistanthus collinus is used for suicidal purposes. The mortality rate is 28%. The clinical profile includes distal renal tubular acidosis (DRTA) and respiratory failure. The mechanism of toxicity is unclear.

Objectives:

To demonstrate features of C. collinus toxicity in a rat model and to identify its mechanism(s) of action.

Materials and Methods:

Rats were anesthetized and the carotid artery was cannulated. Electrocardiogram and respiratory movements were recorded. Either aqueous extract of C. collinus or control solution was administered intraperitoneally. Serial measurements of blood gases, electrolytes and urinary pH were made. Isolated brush border and basolateral membranes from rat kidney were incubated with C. collinus extract and reduction in ATPase activity was assessed. Venous blood samples from human volunteers and rats were incubated with an acetone extract of C. collinus and plasma potassium was estimated as an assay for sodium–potassium pump activity.

Results:

The mortality was 100% in tests and 17% in controls. Terminal event in test animals was respiratory arrest. Controls had metabolic acidosis, respiratory compensation acidic urine and hyperkalemia. Test animals showed respiratory acidosis, alkaline urine and low blood potassium as compared to controls. C. collinus extract inhibited ATPase activity in rat kidney. Plasma K⁺ did not increase in human blood incubated with C. collinus extract.

Conclusions and Implications:

Active principles of C. collinus inhibit proton pumps in the renal brush border, resulting in type I DRTA in rats. There is no inhibition of sodium–potassium pump activity. Test animals develop respiratory acidosis, and the immediate cause of death is respiratory arrest.     

Anticataleptic and antiepileptic activity of ethanolic extract of leaves of Mucuna pruriens: A study on role of dopaminergic system in epilepsy in albino rats

Objective:

To assess the anticataleptic and antiepileptic activity of leaves of Mucuna pruriens in albino rats.

Materials and Methods:

Haloperidol-induced catalepsy (HIC), maximum electro-shock (MES) method, pilocarpine-induced Status epilepticus (PISE) and single-dose effect of M. pruriens were employed.

Results:

M. pruriens (100 mg/kg) had significant anticataleptic and antiepileptic activity in HIC, MES, and PISE.

Conclusions:

M. pruriens extract has the potential to be an anticataleptic and antiepileptic drug. Dopamine and 5-HT may have a role in such activity.     

Evaluation of an oral insulin formulation in normal and diabetic rats

Aim:

As injection is not an ideal means for insulin delivery, various attempts have been made to administer insulin orally until now. The development of an oral dosage form of insulin would help diabetic patients and make the treatment more convenient. The aim of the present study is to evaluate the effectiveness of an oral insulin formulation containing polar and non-polar ingredients.

Materials and Methods:

New excipient for oral insulin administration in normal and diabetic rats was evaluated by measuring blood glucose concentrations in two groups (10 rats each) of normal and streptozotocin-induced diabetic rats. Oral insulin was administrated and blood glucose was measured by glucometer at 0, 1, 2, 3 and 4 h post-feeding. The data was compared by Student''s t test.

Results:

Oral insulin formulation significantly (P<0.05) reduced blood glucose from 100 mg/dl to 33.73 mg/dl and 451.66 mg/dl to 200.83 mg/dl at 4 h in normal and diabetic rats, respectively.

Conclusion:

The novel excipient used could protect insulin from gastric and pancreatic enzymes and reduce blood glucose concentration in both healthy and diabetic rats suggesting that oral delivery of insulin is feasible in a near future.KEY WORDS: Blood glucose, normal and diabetic rats, oral insulin     

The hypoglycemic effect of Juglans regia leaves aqueous extract in diabetic patients: A first human trial

Background

Juglans regia L. (J. regia ) is one of the medicinal plants traditionally used for treatment of diabetes in Iranian medicine. The effect of this plant has already been investigated on animal models; however, this is the first study conducted on human subjects. The aim of this study is to investigate the hypoglycemic effect of J. regia leaves aqueous extract in type 2 diabetes patients. Fifty eight Iranian male and female patients with type 2 diabetes were enrolled. The patients were randomly allocated into two groups. One group (n = 30) received J. regia leaves extract while the other group (n = 28) received placebo. Fasting blood samples were collected at the beginning of the study and after two months for determination of HbA1c and blood glucose level as a main outcome and insulin, SGOT, SGPT, and ALP level as secondary outcome.

Results

Our analysis showed that serum fasting HbA1C and blood glucose levels were significantly decreased and the insulin level was increased in patients in the J. regia arm.

Conclusions

The results indicate that J. regia aqueous extract favorably affects blood levels of glucose, insulin and HbA1C in type 2 diabetic patients.     

Alcoholic leaf extract of Plectranthus amboinicus regulates carbohydrate metabolism in alloxan-induced diabetic rats

Objective:

The present investigation was undertaken to explore the possible mechanisms of Plectranthus amboinicus leaf extract in alloxan-induced diabetic rats.

Materials and Methods:

Control and alloxan-induced diabetic albino rats received different treatments; orally control (vehicle), 200 mg/kg and 400 mg/kg of ethanol extract of Plectranthus amboinicus (PAEE) and 600 μg/kg of glibenclamide (standard) for 15 days. At the end of the experiment, the animals were sacrificed and enzyme activities of carbohydrate metabolism were measured in the liver.

Results:

Diabetic control rats showed a significant elevation (P < 0.001) in fasting blood glucose on successive days of the experiment as compared with their basal values, which was maintained over a period of 2 weeks. Daily oral treatment with PAEE showed a significant reduction (P < 0.001) in the blood glucose levels on successive days of the experiment as compared with their basal values. The most pronounced antihyperglycemic effect was obtained with the dose of 400 mg/kg. PAEE shows a dose-dependent reduction in gluconeogenic enzymes like glucose-6-phosphatase and fructose-1,6-disphosphatase. After 15 days of treatment with PAEE, glycolytic enzymes like phosphoglucoisomerase resulted in a significant increase with a concomitant significant decrease in the activities of aldolase. On the other hand, glucose-6-phosphate dehydrogenase was significantly improved in diabetic rats on administration of PAEE; the 400 mg/kg dose of PAEE elicited a more potent effect compared with the 200 mg/kg dose.

Conclusion:

The results obtained in this study provide evidence of the antidiabetic activity of PAEE, mediated through the regulation of carbohydrate metabolic enzyme activities.     

Evaluation of the in vivo antimalarial activity of ethanolic leaf and stembark extracts of Anthocleista djalonensis

Objective:

To evaluate the in vivo antimalarial activities of ethanolic leaf and stembark extracts of Anthocleista djalonensis used traditionally as malarial remedy in Southern Nigeria in mice infected with Plasmodium berghei berghei.

Methods:

The ethanolic extracts of the A. djalonensis leaf (1000 – 3000 mg/kg/day) and stembark (220 – 660 mg/kg/day) were screened for blood schizonticidal activity against chloroquine-sensitive P. berghei in mice. The schizonticidal effect during early and established infections was investigated.

Results:

The A. djalonensis leaf extract (1000 – 3000 mg/kg/day) exhibited a significant antiplasmodial activity both in the 4-day early infection test and in the established infection with a considerable mean survival time, which was incomparable to that of the standard drug, chloroquine (5 mg/kg/day). The stembark extract (220 – 660 mg/kg/day) also demonstrated a promising blood schizontocidal activity in early and established infections.

Conclusion:

These plant extracts possess considerable antiplasmodial activities, which justify their use in ethnomedicine and can be exploited in malaria therapy.     

Antioxidant potential of the methanol-methylene chloride extract of Terminalia glaucescens leaves on mice liver in streptozotocin-induced stress

Aim:

The antioxidant effect of the methanol–methylene chloride extract of Terminalia glaucescens (Combretaceae) leaves was investigated in streptozotocin (STZ)-induced oxidative stress.

Methods:

Oxidative stress was induced in mice by a daily dose of STZ (45 mg/kg body weight i.p.) for five days. From day one, before STZ injection, normal and diabetic-test mice received an oral dose of the extract (100 or 300 mg/kg b.w.) daily. Plasma metabolites, lipid peroxidation, and antioxidant enzymes in the liver were assessed and gain in body weight recorded.

Results:

In normal mice the plant extract reduced food and water intake, blood glucose and LDL-C level and body weight gain, did not affect the lipid peroxidation in the liver, while the antioxidant enzyme activities seemed increased. Blood glucose was decreased (P < 0.05) in normal mice treated with 300 mg/kg extract. Diabetic mice pretreated with 100 mg/kg extract as diabetic control mice (DC) showed significant (P < 0.001) body weight loss, polyphagia and polydipsia, high plasma glucose level, decrease in the liver catalase, peroxidase, and superoxide dismutase activities, and increase in lipid peroxidation. The HDL-C level was lowered (P < 0.05) whereas LDL-C increased. In 300 mg/kg extract-pretreated diabetic mice the extract prevented body weight loss, increase of blood glucose level, lipid peroxidation in liver, food and water intake, and lowering of plasma HDL-C level and liver antioxidants; this extract prevented LDL-C level increase.

Conclusion:

These results indicate that T. glaucescens protects against STZ-induced oxidative stress and could thus explain its traditional use for diabetes and obesity treatment or management.     

Antidiabetic activity of flower buds of Michelia champaca Linn

Objective:

To identify the antihyperglycemic activity of various extracts, petroleum ether (60-80°), chloroform, acetone, ethanol, aqueous and crude aqueous, of the flower buds of Michelia champaca, and to identify the antidiabetic activity of active antihyperglycemic extract.

Materials and Methods:

Plant extracts were tested for antihyperglycemic activity in glucose overloaded hyperglycemic rats. The effective antihyperglycemic extract was tested for its hypoglycemic activity at two-dose levels, 200 and 400 mg/kg respectively. To confirm its utility in the higher model, the effective extract of M. champaca was subjected to antidiabetic study in alloxan induced diabetic model at two dose levels, 200 and 400 mg/kg respectively. The biochemical parameters, glucose, urea, creatinine, serum cholesterol, serum triglyceride, high density lipoprotein, low density lipoprotein, hemoglobin and glycosylated hemoglobin were also assessed in the experimental animals.

Results:

The ethanolic extract of M. champaca exhibited significant antihyperglycemic activity but did not produce hypoglycemia in fasted normal rats. Apart from this extract, the crude aqueous and petroleum ether extracts were found active only at the end of the first hour. Treatment of diabetic rats with ethanolic extract of this plant restored the elevated biochemical parameters significantly (P<0.05) (P<0.01) and the activity was found dose dependent.

Conclusion:

This study supports the traditional claim and the ethanolic extract of this plant could be added in traditional preparations for the ailment of various diabetes-associated complications.     

Adaptogenic effect of Morus alba on chronic footshock-induced stress in rats

Objective:

The objective of the present study was to evaluate the adaptogenic property of the ethyl acetate-soluble fraction of methanol extract of Morus alba roots against a rat model of chronic stress (CS).

Materials and Methods:

Rats were exposed to stress procedure for 21 days. The stress procedure was mild, unpredictable footshock, administered for 1 h once daily for 21 days. Rats were administered with the ethyl acetate soluble fraction of methanol extract of M. alba roots (25, 50 and 100 mg/kg p.o) 1 h before footshock for 21 days and behavioral parameters were evaluated for cognitive dysfunction and depression using elevated plus maze and despair swim test, respectively. On day 21, rats were sacrificed immediately after stress and blood was collected for biochemical estimation. The adrenal gland and spleen were dissected for organ weight and the stomach was dissected for ulcer score.

Results:

CS significantly induced cognitive deficit, mental depression and hyperglycemia and increased blood corticosterone levels, gastric ulcerations and adrenal gland weight, but decreased the splenic weight. Pre-treatments with the ethyl acetate soluble fraction of methanol extract of M. alba roots (25, 50 and 100 mg/kg, p.o.) significantly attenuated the CS-induced perturbations. Diazepam (1 mg/kg, p.o.) was used as the standard antistress drug.

Conclusion:

The results indicate that M. alba possesses significant adaptogenic activity, indicating its possible clinical utility as an antistress agent.     

Antihyperglycemic effect of Annona squamosa hexane extract in type 2 diabetes animal model: PTP1B inhibition,a possible mechanism of action?

Aim:

The mechanism of action of Annona squamosa hexane extract in mediating antihyperglycemic and antitriglyceridimic effect were investigated in this study.

Materials and Methods:

The effects of extract on glucose uptake, insulin receptor-β (IR-β), insulin receptor substrate-1 (IRS-1) phosphorylation and glucose transporter type 4 (GLUT4) and phosphoinositide 3-kinase (PI3 kinase) mRNA expression were studied in L6 myotubes. The in vitro mechanism of action was tested in protein-tyrosine phosphatase 1B (PTP1B), G-protein-coupled receptor 40 (GPR40), silent mating type information regulation 2 homolog 1 (SIRT1) and dipeptidyl peptidase-IV (DPP-IV) assays. The in vivo efficacy was characterized in ob/ob mice after an oral administration of the extract for 21 days.

Results:

The effect of extract promoted glucose uptake, IR-β and IRS-1 phosphorylation and GLUT4 and PI3 kinase mRNA upregulation in L6 myotubes. The extract inhibited PTP1B with an IC₅₀ 17.4 μg/ml and did not modulate GPR40, SIRT1 or DPP-IV activities. An oral administration of extract in ob/ob mice for 21 days improved random blood glucose, triglyceride and oral glucose tolerance. Further, the extract did not result in body weight gain before and after treatment (29.3 vs. 33.6 g) compared to rosiglitazone where significant body weight gain was observed (28.4 vs. 44.5 g; *P<0.05 after treatment compared to before treatment).

Conclusion:

The results suggest that Annona squamosa hexane extract exerts its action by modulating insulin signaling through inhibition of PTP1B.KEY WORDS: Annona squamosa, type 2 diabetes mellitus, insulin mimetics, PTP1B inhibitor, OGTT, ob/ob mice