Antidiabetic potential of Butea monosperma in rats

The antihyperglycemic activity of the ethanolic extract of Butea monosperma (BMEE) was studied in glucose-loaded and alloxan-induced diabetic rats. Single dose treatment of BMEE (200 mg/kg, p.o.) significantly improved glucose tolerance and caused reduction in blood glucose level in alloxan-induced diabetic rats. Repeated oral treatment with BMEE (200 mg/kg/day) for 2 weeks significantly reduced blood glucose, serum cholesterol and improved HDL-cholesterol and albumin as compared to diabetic control group.     

Hypoglycemic activity of Nymphaea stellata leaves ethanolic extract in alloxan induced diabetic rats

The ethanolic extract of leaves of Nymphaea stellata given by oral route to diabetic rats at dose of 100 and 200 mg/kg/day for seven days reduced significantly by 31.6 and 42.6 % the plasma glucose level increased by intraperitoneal injection of 120 mg/day of alloxan. Moreover, the treatment significantly affected the plasma level of cholesterol and triglyceride.     

Hypoglycemic and antidiabetic activities on the stem bark aqueous and ethanol extracts of Musanga cecropioides in normal and alloxan-induced diabetic rats

Daily oral administration of the aqueous and ethanolic extracts of Musanga cecropioides stem bark in normal and diabetic rats at doses of 250, 500 and 1000 mg/kg/day, for 14 days significantly lowered the fasting plasma glucose levels in normal and alloxan-induced diabetic rats in dose-dependent fashion. The ethanol extract induced more significant antidiabetic effect than the aqueous extract.     

Antidiabetic and antihyperlipemic effects of Clemeo felina

Petroleum ether and benzene extracts of Clemeo felina, given orally at doses of 300 mg kg(-1) day(-1) for 30 days, were found to be antidiabetic and antihyperlipemic on alloxan diabetic rats. Moreover, a significant decrease in the activities of serum enzymes like alkaline phosphatase, acid phosphatase and HMGCoA reductase activity in the liver was observed. However, treatment of rats with the extracts as well as standard antidiabetic drugs increased liver hexakinase activity and serum LDH activity.     

Antihyperglycemic and antioxidant activities of total alkaloids from Catharanthus roseus in streptozotocin-induced diabetic rats

We evaluated the hypoglycemic and antioxidant effects of the total alkaloids of leaves and twigs of Catharanthus roseus Linn.(CTA) in streptozotocin(STZ)-induced diabetic rats. The hypoglycemic effect was measured by blood glucose and plasma insulin level. Oxidative stress was measured in heart, liver and kidney by levels of antioxidant markers, free radical scavengers and lipid peroxides i.e. superoxide dismutase(SOD), catalase(CAT), glutathione(GSH) and thiobarbituric acid reactive substances(TBARS). Biochemical parameters, i.e. aspartate aminotransferase(AST), alanine aminotransferase(ALT), alkaline phosphate(ALP) were observed in diabetic control and treated rats. Oral administration of CTA for30 days was followed by a significant(P \ 0.05) decrease in fasting blood glucose and increase in insulin level as compared with untreated diabetic rats. Also it significantly(P \ 0.05) reduced ALT, AST and ALP. The treatment also resulted in significant(P \ 0.05) reductions in GSH,SOD, CAT, and decrease in TBARS in the heart, liver and kidney of diabetic rats. The results suggest that CTA can effectively normalize the impaired antioxidant status in STZ-induced diabetes in a dose-dependent manner.CTA exerted rapid protective effects against lipid peroxidation by scavenging of free radicals and reducing the risk of diabetic complications.     

Antidiabetic properties of aqueous barks extract of Parinari excelsa in alloxan-induced diabetic rats

The aqueous extract of the Parinari excelsa barks at doses of 100 and 300 mg/kg/day for 7 days has a significant antihyperglycemic effect on alloxan-induced diabetic rats. At the same dose the acute oral administration of aqueous extract of the P. excelsa barks (100 and 300 mg/kg) induced a significant decrease of blood glucose on glucose-loaded normoglycaemic rats. Our results seem to confirm the rational bases for its use in traditional medicine.     

Compositional analysis and in vivo anti-diabetic activity of wild Algerian Marrubium vulgare L. infusion

Marrubium vulgare (Lamiaceae) is a plant traditionally used for the treatment of diabetes in Algeria. Compositional analysis of the aqueous infusion revealed the presence of fifteen metabolites, all belonging to the class of polyphenols. Particularly, seven flavonoids have been detected, together with 5-caffeoylquinic (chlorogenic) acid in small amounts; the extract is dominated by the presence of a series of complex molecules, characterized as verbascoside (acteoside) derivatives. Concerning the anti-diabetic effectiveness a series of in vivo experiments were carried out on albinos Wistar rats. Diabetes was induced in the animals by intra-peritoneal injection of alloxane; they were treated twice a day with aqueous extract from aerial part infusion (100, 200 and 300 mg/kg body weight) and glibenclamide (5mg/kg body weight) for 15 days. Oral administration of 200 and 300 mg/kg body weight of aqueous extract the Marrubium vulgare induced an significant effect antidiabetic and antihyperlipidemic (dose-dependent effect). A decrease in blood glucose by 50% for the dose 100 mg/kg and more than 60% for doses 200 and 300 mg/kg, as well as a significant lowering of total lipids, triglycerides, and total cholesterol levels in treated animals, compared with diabetic controls group (p<0.001), have been observed. Glibenclamide was used as reference and showed similar effects.     

Swietenine: A potential oral hypoglycemic from Swietenia macrophylla seed

Swietenine, a tetranortriterpenoid, was isolated from the Swietenia macrophylla seeds. The in vivo hypoglycemic activity was evaluated against neonatal-streptozotocin induced type 2 diabetic rats. Oral administration of swietenine at 25 and 50 mg/kg body weight per day to diabetic rats was found to possess significant dose dependant hypoglycemic and hypolipidemic activity in type 2 diabetic rats.     

Pre-treatment of Syndrex® protects mice from becoming diabetic after streptozotocin injection

Diabetes mellitus is a metabolic disorder characterized by hyperglycemia due to either insufficiency of insulin or inability of cells to respond to insulin. Many clinical and experimental evidence have suggested the strong association between hyperglycemia, oxidative stress and diabetic complications. Therefore, the antidiabetic drugs with antioxidant potential would have a higher therapeutic value. To check its antidiabetic and antioxidant properties in vivo, experiments were done wherein mice were fed with Syndrex^® in different schedules and/or made diabetic by intraperitoneal injection of streptozotocin. Animals fed with Syndrex^® prior to the induction of diabetes by streptozotocin injection showed resistance to an increase in blood glucose levels. This treatment increased the activities of antioxidant enzymes namely, catalase, glutathione reductase and superoxide dismutase and reduced serum triglyceride and cholesterol levels as compared to those found in uncontrolled diabetic mice. Among the three different schedules used for Syndrex^® treatment, the best effect was seen in the case of mice pretreated with Syndrex^® prior to STZ injection. In our opinion, Syndrex^® given along with insulin may reduce the amount of insulin dose required and because of its strong antioxidant activity would certainly help to reduce the development of diabetic complications.     

4-Hydroxyisoleucine improves insulin resistance by promoting mitochondrial biogenesis and act through AMPK and Akt dependent pathway

4-Hydroxyisoleucine (4-HIL) is an unusual amino acid isolated from fenugreek seeds (Trigonella foenum graecum L). Various studies have shown that it acts as an antidiabetic agent yet its mechanism of action is not clear. We therefore investigated the effect 4-HIL on the high fructose diet fed streptozotocin induced diabetic rats and L6 myotubes. 4-HIL (50 mg/kg) has improved blood lipid profile, glucose tolerance and insulin sensitivity in a diabetic rat model. It has increased the glucose uptake in L6 myotubes in AMPK-dependent manner and upregulated the expression of genes (PGC-1α, PGC-1β, CPT 1 and CPT 2), which have role in mitochondrial biogenesis and energy metabolism in the liver, skeletal muscles as well as in L6 myotubes. Interestingly, it also increased the AMPK and Akt expression along with their phosphorylated forms in the liver and muscle tissues of treated animals. Altogether we concluded that 4-HIL acts to improve insulin resistance by promoting mitochondrial biogenesis in high fructose diet fed STZ induced diabetic rats.     

Antidiabetic potential of Phyllanthus reticulatus in alloxan-induced diabetic mice

The plant Phyllanthus reticulatus is claimed to have antidiabetic activity in tribal area. To validate the tribal claim, the petroleum ether and ethanolic extracts of leaves of the P. reticulatus were orally tested at 500 and 1000 mg/kg for hypoglycemic effect in alloxan induces diabetic mice. It shows antidiabetic activity at the dose of 1000 mg/kg. The phytochemical screening of the residues revealed the presence of terpenoids glycosides, protein, carbohydrates and absence of alkaloids and steroids.     

Antihyperglycemic activity of the aqueous extract of Urtica dioica

When administered 30 min before glucose loading, the aqueous extract of Urtica dioica (nettle) (250 mg/kg) showed a strong glucose lowering effect. The decrease of glycemia has reached to 33+/-3.4% of the control value 1 h after glucose loading. This effect was persistent during 3 h. In contrast, nettle did not show hypoglycemic effect in alloxan-induced diabetic rats. The amount of glucose absorbed in a segment jejunum in situ was 8.05+/-0.68 mg in presence of nettle extract vs. 11.11+/-0.75 mg in control rats during 2 h (P<0.05). The results indicate that nettle has a significant antihyperglycemic effect in OGTT model. This effect may be caused in part by the reduction of intestinal glucose absorption. LD(50) is 3.5 g/kg (i.p.).     

Hepatoprotective activity of Clerodendrum inerme against CCl4 induced hepatic injury in rats

The ethanolic extract of Clerodendrum inerme leaves were screened for its hepatoprotective activity in CCl(4) (0.5 ml/kg, i.p) induced liver damage in Swiss albino rats at a dose of 200 mg /kg bw. The ethanolic extract of C. inerme significantly (P<0.001) decreases the serum enzyme alanine amino transferase (ALT), asparate amino transferase (AST), alkaline phosphates (ALP), triglycerides (TGL), total cholesterol (TC) and significantly increased the glutathione level. Silymarin (25 mg/kg), a known hepatoprotective drug used for comparison exhibited significant activity (P<0.001). The extract did not shown any mortality up to a dose of 2000 g/kg bw.     

Effects of compound K on hyperglycemia and insulin resistance in rats with type 2 diabetes mellitus

Compound K (CK) is a final metabolite of panaxadiol ginsenosides from Panax ginseng. Although anti-diabetic activity of CK has been reported in recent years, the molecular mechanism of CK in the treatment of diabetes mellitus remains unclear. In the present investigation, we established a rat model of type 2 diabetes mellitus (T2DM) with insulin resistance using high-fat diet (HFD) and streptozotocin (STZ), and attempted to verify more details and exact mechanisms in the treatment of T2DM. CK was administered orally at three doses [300, 100 and 30 mg/kg bodyweight (b.w.)] to the diabetic rats. Bodyweight, food-intake, fasting blood glucose (FBG), fasting serum insulin (FINS), insulin sensitivity (ISI), total glycerin (TG), total cholesterol (TC), as well as oral glucose tolerance test (OGTT) were evaluated in normal and diabetic rats. According to our results, CK could improve bodyweight and food-intake of diabetic rats. CK exhibited dose-dependent reduction of FBG, TG and TC of diabetic rats. CK treatment also enhanced FINS and ISI. Meanwhile, the glucose tolerance observed in the present study was improved significantly by CK. It is concluded from the results that CK may have improving effects on hyperglycemia and insulin resistance of diabetic rats. Furthermore, research showed that CK could promote the expression of InsR, IRS1, PI3Kp85, pAkt and Glut4 in skeletal muscle tissue of diabetic rats. These results indicate that the hypoglycemic activity of CK is mediated by improvement of insulin sensitivity, which is closely related to PI3K/Akt signaling pathway.     

Neuroprotective effect of naringin by modulation of endogenous biomarkers in streptozotocin induced painful diabetic neuropathy

Diabetes mellitus is a serious debilitating epidemic affecting all social strata in developing as well as developed countries. Diabetic neuropathy is most common of secondary complications associated with diabetes mellitus and is characterized by slowing of nerve conduction velocity, elevated pain, sensory loss and nerve fiber degeneration. The aim of the present investigation was to evaluate the neuroprotective effect of naringin against streptozotocin (STZ) induced diabetic neuropathic pain in laboratory rats. Four weeks after intraperitoneal injection of STZ resulted in significant decrease in mechano-tactile allodynia, mechanical hyperalgesia, thermal hyperalgesia and motor nerve conduction velocity. Activity of endogenous antioxidant like superoxide dismutase as well as membrane bound inorganic phosphate enzyme was also found to be significantly decreased. It not only caused neural cell apoptosis but also enhanced lipid peroxide, nitrite, and inflammatory mediators' (TNF-α) level. Chronic treatment with naringin (40 and 80mg/kg) for 4 weeks significantly and dose dependently attenuated the decrease in level of nociceptive threshold, endogenous antioxidant and membrane bound inorganic phosphate enzyme. It also decreased the elevated levels of oxidative-nitrosative stress, inflammatory mediators as well as apoptosis in neural cells significantly and dose dependently. The important finding of the study is that, the naringin-insulin combination not only attenuated the diabetic condition but also reversed the neuropathic pain, whereas insulin or naringin alone only improved hyperglycemia but partially reversed the pain response in diabetic rats. Thus, naringin is a potential flavonone bearing antioxidant, antiapoptotic and disease modifying property acting via modulation of endogenous biomarker to inhibit diabetes induced neuropathic pain.     

Hypoglycemic effect of Bauhinia cheilandra in rats

The extract of the methanolic leaves of Bauhinia cheilandra (BC) was tested on glucose loaded and alloxan-induced diabetic rats. In both tests, the methanolic extract at doses of 300, 600, and 900 mg/kg, has shown a statistically significant and considerable hypoglycemic activity.     

Effects of treatment with St. John's Wort on blood glucose levels and pain perceptions of streptozotocin-diabetic rats

This present study was undertaken to examine treating effects of St. John's Wort (SJW) extract on nociceptive perception of STZ-diabetic animals based on its potential antidiabetic and antinociceptive activities. One week administrations of SJW extract (125 and 250 mg/kg) induced significant decrease in high blood glucose levels of three weeks STZ-diabetic rats and improved their dysregulated metabolic parameters. In addition, SJW extract treatment caused restoration in the mechanical hyperalgesia of diabetic animals. These findings provide a rationale for the traditional use of SJW against diabetes and display the potential of this plant as a new drug candidate/source for the treatment of diabetic pain.     

Anti-diabetic effect of American ginseng may not be linked to antioxidant activity: Comparison between American ginseng and Scutellaria baicalensis using an ob/ob mice model

Antioxidants have been considered as a useful remedy in diabetes therapeutics, and thus, herbal medicines with antioxidant properties may play major role in treating diabetes. In this report, we performed a comparative study using American ginseng and Scutellaria baicalensis to test whether the anti-diabetic effect of American ginseng is associated with its antioxidant activity. We used a simple water extraction procedure to prepare American ginseng root extract (AGE) and S. baicalensis extract (SbE), and utilized these two antioxidant herbs to evaluate their anti-diabetic effect in obese diabetic ob/ob mice. HPLC analysis was used to identify major constituents in the AGE and SbE. After 12 days of daily intraperitoneal injection, AGE at 300 mg/kg showed significant effects on fasting blood glucose levels (P < 0.01) and glucose tolerance test (P < 0.01) compared to vehicle-treated mice. Animal body weights also reduced significantly after 12-day treatment (P < 0.01). However, SbE, a very strong antioxidant extract, administered at 5–50 mg/kg (based on our previous studies without adverse events) for 12 days did not show any significant effects on blood glucose and body weight changes. No effects were shown when baicalein, an effective antioxidant constituent in SbE, was administered at 1–5 mg/kg. It appears that the anti-diabetic effect of American ginseng may not be linked to its antioxidant actions. The mechanisms of American ginseng's effects on reducing high blood glucose levels and body weight remain to be investigated in future experiments.     

Hypoglicemic effect of Leandra lacunosa in normal and alloxan-induced diabetic rats

Leandra lacunosa, popularly known as "erva-do-jabuti", is used in Brazilian folkloric medicine for the treatment of diabetes mellitus. Based on this traditional indication, the aim of this work was to evaluate the hypoglycemic activity of the hydroalcoholic extract of L. lacunosa aerial parts (LLH) in normal and alloxan-induced diabetic rats. Chromatographic fractionation of LLH was also carried out by several techniques, affording isolation of the following major compounds: ursolic acid (1), kaempferol (2), luteolin (3), and quercetin (4). The oral administration of LLH (500 mg/kg) in normal rats caused a significant reduction of 24.7% (P<0.05) in the blood glucose levels after 2 h of treatment, while the administration of chlorpropamide (20 mg/kg, p.o.) led to a reduction of 40.2% (P<0.01). After oral administration of glucose (10 g/kg, p.o.), LLH (500 mg/kg, p.o.) significantly inhibited the increase in blood glucose levels compared with the negative control group. The oral treatment with LLH (500 mg/kg) in alloxan-induced diabetic rats significantly reduced the blood glucose levels in 47.8% after 4 h of treatment, while chlorpropamide resulted in a significant reduction of 71.7% in the 4th hour. Our results showed that LLH, displays hypoglycemic activity, which may be related to the effect of the major compounds identified in the crude extract. This study seems to provide biological evidence for the folkloric use of L. lacunosa in the treatment of diabetes mellitus.