Hypoglycemic effect of Cecropia obtusifolia on streptozotocin diabetic rats.

The hypoglycemic effects of water and butanolic extracts prepared from leaves of Cecropia obtusifolia (Cecropiaceae) were examined in streptozotocin induced diabetic rats. A single oral administration of a water extract at doses of 90 and 150 mg/kg and of a butanol extract at doses of 9 and 15 mg/kg significantly (P<0.05) lowered the plasma glucose levels in diabetic rats after 3 h administration. Glibenclamide was used as reference and showed similar hypoglycemic effect to the tested extracts at a dose of 3 mg/kg. The flavone, isoorientin and 3-caffeoylquinic acid (chlorogenic acid), were isolated as the important constituents of the plant and were identified as the main constituents in both extracts, too.     

Hypoglycemic effect of Tournefortia hirsutissima L., on n-streptozotocin diabetic rats

The hypoglycemic effect of aqueous and butanolic extracts from Tournefortia hirsutissima (Boraginaceae) was determined on neonatal induced streptozotocin diabetic rats (n-STZ). Oral administration of water extracts at doses of 20 and 80mg/kg, and butanolic extracts (8 and 80mg/kg) significantly lowered the plasma glucose levels in diabetic rats within 3h. Glibenclamide was used as reference and showed similar hypoglycemic effect. Our results support the traditional use of the plant as a hypoglycemic agent; we observe a dose-dependent action of the extracts. HPLC analysis confirmed that the aqueous and butanolic extracts had the same chemical composition.     

Hypoglycemic effect of Acosmium panamense bark on streptozotocin diabetic rats

The hypoglycemic effects of water and butanolic extracts prepared from the bark of Acosmium panamense (Fabaceae) were studied in diabetic rats (streptozotocin (STZ)-induced). Oral application of water extracts at doses of 20 and 200 mg/kg and of butanol extracts at doses of 20 and 100 mg/kg significantly lowered the plasma glucose levels in diabetic rats within 3 h. Glibenclamide was used as reference and showed similar hypoglycemic effect like the extracts.

Three structurally new compounds were isolated from the plant and shown to be the main constituents in both extracts.     

Assessment of antidiabetic potential of Cynodon dactylon extract in streptozotocin diabetic rats

This study was undertaken to investigate the hypoglycemic and antidiabetic effect of single and repeated oral administration of the aqueous extract of Cynodon dactylon (Family: Poaceae) in normal and streptozotocin induced diabetic rats, respectively. The effect of repeated oral administration of aqueous extract on serum lipid profile in diabetic rats was also examined. A range of doses, viz. 250, 500 and 1000mg/kg bw of aqueous extract of Cynodon dactylon were evaluated and the dose of 500mg/kg was identified as the most effective dose. It lowers blood glucose level around 31% after 4h of administration in normal rats. The same dose of 500mg/kg produced a fall of 23% in blood glucose level within 1h during glucose tolerance test (GTT) of mild diabetic rats. This dose has almost similar effect as that of standard drug tolbutamide (250mg/kg bw). Severely diabetic rats were also treated daily with 500mg/kg bw for 14 days and a significant reduction of 59% was observed in fasting blood glucose level. A reduction in the urine sugar level and increase in body weight of severe diabetic rats were additional corroborating factors for its antidiabetic potential. Total cholesterol (TC), low density lipoprotein (LDL) and triglyceride (TG) levels were decreased by 35, 77 and 29%, respectively, in severely diabetic rats whereas, cardioprotective, high density lipoprotein (HDL) was increased by 18%. These results clearly indicate that aqueous extract of Cynodon dactylon has high antidiabetic potential along with significant hypoglycemic and hypolipidemic effects.     

Tanshinone inhibits intimal hyperplasia in the ligated carotid artery in mice

The hypoglycemic effects of water, ethanolic and butanolic extracts prepared from the root of Malmea depressa (Baill) R.E. Fries. (Annonaceae) were studied in diabetic rats (streptozotocin induced). Oral application of water extracts at doses of 40 and 80 mg/kg, ethanolic (112 mg/kg) and butanolic (80 mg/kg) extracts significantly lowered the plasma glucose levels in diabetic rats within three hours. Glibenclamide and metformin were used as references and showed similar hypoglycemic effects like the extracts. The three extracts have a similar chemical composition (HPLC analysis).     

Oral hypoglycemic effect of Salacia reticulata in the streptozotocin induced diabetic rat

The oral hypoglycemic activity of Salacia reticulata extract was evaluated in streptozotocin induced diabetic rats. The diabetic rats were orally administered an aqueous extract of Salacia reticulata and the plasma glucose concentration was determined at regular intervals following administration. The drug was effective as a hypoglycemic agent at all the doses tested (0.5 g/kg, 1.0 g/kg and 5.0 g/kg). The maximum percentage decrease in plasma glucose was observed between 1–5h following administration of the drug.     

Acute and chronic hypoglycemic effect of Ibervillea sonorae root extracts-II

Ibervillea sonorae's root, or "wareque" (Cucurbitaceae), is widely used in Mexican traditional medicine for the control of diabetes mellitus. In the present study, the hypoglycemic effects produced by the acute and chronic administration of various extracts of Ibervillea sonorae were investigated. Both the traditional preparation (aqueous decoction) and the raw extract (juice) from the root resulted in significant reductions of glycemia in healthy mice after intraperitoneal administration at a dose of 600 mg/kg. Additionally, ground dried root was used to obtain a dichloromethane (DCM) extract and a methanol (MeOH) extract. The DCM extract induced a clear reduction of glycemia in healthy (P < 0.05) and in alloxan-diabetic mice. The intraperitoneally administered DCM extract caused a severe hypoglycemia that produced lethality in all the treated animals when doses of 300 and 600 mg/kg body weight were used. Since the DCM extract showed a marked hypoglycemic activity, it was administered daily per os to alloxan diabetic rats, employing corn oil and tolbutamide as controls. After 41 days of DCM extract administration at a dose of 300 mg/kg/day, diabetic rats showed improvement in glycemia, body weight, triglycerides, and GPT in comparison with the diabetic control group. Total cholesterol, GOT, and uric acid blood levels were not affected.     

Hypoglycemic activity of Ailanthus excelsa leaves in normal and streptozotocin-induced diabetic rats

The hypoglycemic activity of a 70% methanol extract from the leaves of Ailanthus excelsa Roxb. (Simaroubaceae) was studied in normal, transiently hyperglycemic and streptozotocin (STZ)-induced diabetic rats. Oral administration of the extract at doses of 14, 70 and 350 mg/kg body weight caused no significant changes in fasting blood glucose levels of normal rats. In an oral glucose tolerance test, the extract produced a significant decrease in glycemia 90 min after the glucose pulse. Daily administration of A. excelsa extract for 60 days produced a significant hypoglycemic effect in diabetic animals. In addition, this treatment improved the altered renal function observed in diabetic control rats. This study suggests that Ailanthus leaf extract could be potentially useful for post-prandial hyperglycemia treatment.     

Effect of crude extract and fractions from Vitex megapotamica leaves on hyperglycemia in alloxan-diabetic rats

The effect of the crude extract, ethyl acetate and n-butanol fractions from Vitex megapotamica (Spreng) Moldenke on glycemia was investigated in diabetic rats. Oral administration of crude extract significantly reduced serum glucose levels in both normal and diabetic animals. In normal rats, serum glucose lowering was observed with 400 and 800 mg/kg at 2 and 2-3h, respectively after oral crude extract treatment. Nevertheless, the hypoglycemic effect of Vitex megapotamica in diabetic rats was evident at 1 and 2h and from 1 to 3h after treatment with 400 and 800 mg/kg, respectively. The ethyl acetate as well as n-butanol fractions were able to diminish glycemia in diabetic animals. The ethyl acetate fraction (400 and 800 mg/kg) produced the maximum hypoglycemic effect (28 and 20%, respectively) in diabetic rats and the same dose of the n-butanol fraction reduced the hyperglycemia only by 11% at 1h after treatment. Additionally, in hyperglycemic normal rats neither crude extract nor ethyl acetate fraction modified the glucose tolerance and the known tolbutamide effect on insulin release was clearly observed in this group. Thus, this study shows that Vitex megapotamica has an anti-hyperglycemic action, is able to ameliorate the diabetic state and, probably, is a source of hypoglycemic compounds.     

Effect of oral administration of bark extracts of Pterocarpus santalinus L. on blood glucose level in experimental animals

The effect of administration of different doses of Pterocarpus santalinus L. bark extracts in normal and diabetic rats, on blood glucose levels was evaluated in this study. Among the three fractions (aqueous, ethanol and hexane), ethanolic fraction at the dose of 0.25 g/kg body weight showed maximum antihyperglycemic activity. The same dose did not cause any hypoglycemic activity in normal rats. The results were compared with the diabetic rats treated with glibenclamide and the antihyperglycemic activity of ethanolic extract of PS bark at the dose of 0.25 g/kg b.w. was found to be more effective than that of glibenclamide.     

Antihyperglycemic and hypoglycemic effect of Aporosa lindleyana in normal and alloxan induced diabetic rats

The hypoglycemic effect of aqueous and alcoholic extracts of root of Aporosa lindleyana was investigated in both normal and alloxan induced diabetic rats. The blood glucose levels were measured at 0, 1, 2 and 3 h after the treatment. The aqueous and alcoholic extracts of A. lindleyana (100 mg/kg) reduced the blood glucose of normal rat from 80.4+/-2.7 to 69.8+/-2.0 mg% and 82.6+/-1.9 to 70.8+/-3.2 mg%, respectively 3 h after oral administration of the extract (P < 0.001) and also significantly lowered blood glucose level in alloxan induced diabetic rat from 306+/-3.37 to 160+/-2.46 and 328+/-4.15 to 152+/-3.86 mg%, respectively 3 h after oral administration of the extract (P < 0.001). The antihyperglycemic activity of A. lindleyana was compared with tolbutamide, an oral hypoglycemic agent.     

Hypoglycemic effect of aqueous extract of seabuckthorn (Hippophae rhamnoides L.) seed residues in streptozotocin‐induced diabetic rats

An extract of seabuckthorn (Hippophae rhamnoides L.) seed residues has been shown to possess hypoglycemic and hypolipidemic properties in normal mice. The present study investigated the effects of an aqueous extract of seabuckthorn seed residues (ASSR) on serum glucose, lipid profiles and antioxidant parameters in streptozotocin‐induced diabetic rats. Male Sprague‐Dawley rats were divided into four groups: a normal control group; diabetic control group; diabetic groups supplemented with 5 mg/kg body weight glibenclamide (reference drug) and 400 mg/kg body weight ASSR. Diabetes in rats was induced by intraperitoneal injection of streptozotocin (45 mg/kg body weight). Vehicle (distilled water), glibenclamide and ASSR were administered orally to normal and diabetic rats once a day lasting for 4 weeks. The data showed that administration of ASSR significantly lowered the serum glucose, triglyceride and nitric oxide levels in diabetic rats. Moreover, ASSR treatment also increased serum superoxide dismutase activity and glutathione level markedly. These results show that ASSR has hypoglycemic, hypotriglyceridemic and antioxidant effects in streptozotocin‐induced diabetic rats, suggesting that ASSR supplementation can be useful in preventing diabetic complications associated with hyperlipidemia and oxidative stress. Copyright © 2009 John Wiley & Sons, Ltd.     

Acute effect of Bauhinia forficata on serum glucose levels in normal and alloxan-induced diabetic rats

Experimental diabetes was used to study the acute effect of the n-butanol fraction of Bauhinia forficata Link (Leguminosae) (BF) leaves on the serum glucose levels of rats. Body weight was measured on the day of diabetes induction and on the day of the experiment. Levels of glucose were determined at different doses and times following treatment with BF or with vehicle in normal, diabetic and hyperglycemic normal rats. Oral administration of n-BuOH fraction led to a significant blood glucose-lowering effect in normal and diabetic rats. However, in glucose-fed hyperglycemic normal rats, the maximum dose of this fraction failed to decrease blood glucose levels. The hypoglycemic effect was observed at doses of 500 and 600 mg/kg after 1 and 2 h treatment respectively, in normal rats. The maximum effect of BF was detected at 1 h with 800 mg/kg in diabetic animals and this profile was maintained for the next 3 h. Treatment of normal and alloxan-induced diabetic rats with BF decreased glucose levels, while this fraction was devoid of hypoglycemic effect in glucose-fed hyperglycemic normal rats.     

Hypoglycaemic effect of spergularia purpurea in normal and streptozotocin-induced diabetic rats

Single and repeated oral administration of the water extracts of Spergularia purpurea (SP) at a dose of 10 mg/kg were tested on hypoglycaemic activity in normal and streptozotocin-induced diabetic rats. In normal rats, the water extract of SP decreased significantly the plasma glucose levels 4 h after single oral administration (P<0.01), and one week after repeated oral administration (P<0.05). A significant decrease of plasma glucose levels was observed 6 h after a single oral administration of the water extract of S. purpurea in severe hyperglycaemic rats (n=6) from 22.78+/-0.60 to 11.21+/-0.49 mmol/l (P<0.001). On other hand, water extract of S. purpurea normalised plasma glucose levels after two weeks of repeated oral administration in diabetic rats; 24.05+/-1.16 versus 7.18+/-0.51 mmol/l (P<0.001) at the start and 2 weeks after water extract administration, respectively. We conclude that the water extract of SP induces hypoglycaemic activity when administered orally in normal and STZ diabetic rats. In order to determine the active principle (s) responsible of the hypoglycaemic effect, preliminary phytochemical analysis of the water extract has been investigated.     

Antidiabetic activity of Terminalia pallida fruit in alloxan induced diabetic rats

Different doses of ethanolic fraction of fruits of Terminalia pallida were evaluated for hypoglycemic and antihyperglycemic activity in normal and alloxan diabetic rats. The oral administration of ethanolic extract at a dosage of 0.5 g/kg body weight exhibited a significant antihyperglycemic activity in alloxan diabetic rats, whereas in normal rats no hypoglycemic activity was observed.     

In vivo antidiabetic and antioxidant potential of Helichrysum plicatum ssp. plicatum capitulums in streptozotocin-induced-diabetic rats

Helichrysum species (Asteraceae) are widely found in Anatolia. Decoction prepared from the capitulums of Helichrysum plicatum ssp. plicatum is used to alleviate the symptoms of diabetes mellitus in folk medicine. In the present study, the hypoglycaemic and antioxidant potential of Helichrysum plicatum ssp. plicatum was evaluated by using in vivo methods in normal and streptozotocin-induced-diabetic rats. After the oral administration of water and ethanolic extracts at doses of 500mg/kg body weight prepared from the capitulums of plant, blood glucose levels were monitored at specific intervals. Tolbutamide was used as a reference drug at a dose of 100mg/kg. The experimental data indicated that water and ethanol extracts of capitulums demonstrate significant antihyperglycaemic and antioxidant activity in streptozotocin-induced rats which confirmed the folkloric utilization. In order to assess the role of polyphenolic components in the relevant activity, phenolic and flavonoid contents of each extract were also determined in terms of total phenols: 113.5+/-8.6mg (gallic acid equivalent/1g extract) and total flavanoids 50.5+/-1.9mg (quercetin equivalent/1g extract) for ethanol extract, total phenols: 75.9+/-3.7, flavonoids: 31.5+/-2.3 for water extract using Folin-Ciocalteu reagent.     

Anti-diabetes and hypoglycaemic properties of Hemionitis arifolia (Burm.) Moore in rats

Hemionitis arifolia, a folklore anti-diabetes fern, was evaluated for its hypoglycaemic and anti-diabetic properties using rats. Glucose lowering effect and anti-diabetes activity were studied using glucose tolerance test in normal rats and alloxan diabetic rats, respectively. When different extracts were tested, the ethanol and, to some extent, the water extracts were found to lower the levels of blood glucose in glucose fed rats. The ethanol extract showed optimum activity at 200 mg/kg. The extract exhibited only marginal hypoglycaemic activity in overnight fasted normal rats and it was devoid of conspicuous toxic symptoms in sub-acute toxicity evaluation in mice. When the alcohol extract was fractionated by sequential solvent extraction, the activity was found in ethyl acetate fraction (50 mg/kg). This fraction containing steroids and coumarins showed anti-diabetes activity in alloxan diabetic rats as judged from serum glucose levels, liver glycogen content and body weight. This fraction is an attractive material for further research vis-à-vis drug development.     

Anti-hyperglycaemic activity of the aqueous extract of Origanum vulgare growing wild in Tafilalet region

The effect of an aqueous extract of Origanum vulgare (OV) leaves on blood glucose levels was investigated in normal and streptozotocin (STZ) diabetic rats. In normal rats, the blood glucose levels were slightly decreased 6 h after a single oral administration (P<0.05) as well as 15 days after once daily repeated oral administration of aqueous OV extract (P<0.05) (20 mg/kg). After a single dose or 15 daily doses, oral administration of the aqueous extract (20 mg/kg) produced a significant decrease on blood glucose levels in STZ diabetic rats (P<0.001). In STZ rats, the blood glucose levels were normalised from the fourth day after daily repeated oral administration of aqueous OV extract (20 mg/kg) (P<0.001). However, this effect was less pronounced 2 weeks after daily repeated oral administration of OV extract. In addition, no changes were observed in basal plasma insulin concentrations after treatment in either normal or STZ diabetic rats indicating that the aqueous OV extract acted without changing insulin secretion. We conclude that an aqueous extract of OV exhibits an anti-hyperglycaemic activity in STZ rats without affecting basal plasma insulin concentrations.     

Antidiabetic activity of Ficus amplissima Smith. bark extract in streptozotocin induced diabetic rats

Ethnopharmacological relevance

Ficus amplissima commonly known as kal-itchchi have a long history of use in Ayurveda, Siddha and Unani herbal preparations in Indian traditional system of medicine. It has been used in folklore medicine for the treatment of diabetes.

Aim

The aim of the present study was to evaluate the effect of methanolic extract of the bark of Ficus amplissima (FAB) in streptozotocin-induced diabetic rats.

Materials and methods

Oral administration of FAB bark at the doses of 50 mg/kg, 100 mg/kg and 150 mg/kg was studied in normal, glucose-loaded and STZ—induced diabetic rats.

Results

The three doses caused significant reduction in blood glucose levels in all the models. The effect was more pronounced in 50 mg/kg and 100 mg/kg than 150 mg/kg. FAB also showed significant increase in serum insulin and body weight. The glycogen content in liver, skeletal muscle, total protein contents were markedly increased and marker enzymes of hepatic function of STZ-induced diabetic rats while there was significant reduction in the levels of serum triglyceride and total cholesterol. FAB also showed significant anti-lipid peroxidative effect in the pancreas of STZ-induced diabetic rats. The anti-diabetic effect of FAB was compared with glibenclamide, a well known hypoglycemic drug. Histological analysis showed the regenerative effect of FAB on the β-cells of diabetic rats.

Conclusion

Results of this experimental study indicated that FAB possessed anti-diabetic and antioxidant activities. Hence it could be used as a natural source of antidiabetic (Type-I) and antioxidant drug.     

In-vivo assessment of antidiabetic and antioxidant activities of grapevine leaves (Vitis vinifera) in diabetic rats

The acute and the subacute (15 days) hypoglycaemic and antihyperglycaemic effect of the two different doses (250, 500 mg/kg) of the aqueous extract from the leaves of Vitis vinifera L. were evaluated in this study. The aqueous extract was further fractionated through successive solvent extractions and the acute effect of different doses of its subfractions, 25 mg/kg for ethylacetate fraction, 80 mg/kg for n-butanol fraction and 375 mg/kg for remaining aqueous fraction were investigated using normal, glucose-hyperglycaemic and streptozotocin-induced diabetic rats. Blood glucose levels were measured according to the glucose oxidase method. Tolbutamide was used as a reference drug at a dose of 100 mg/kg. The antioxidant activity of the test samples was studied in the liver, kidney and heart tissues of diabetic rats by measuring malondialdehyde (MDA) and glutathion (GSH) levels. All results were compared to the diabetic control groups. The results showed that EtOAc Fr. was rich in polyphenolics and possessed a significant antihyperglycaemic and antioxidant activity equipotent with the reference hypoglycaemic agent (tolbutamide), when evaluated in diabetic rats.