Evaluation of Azadirachta indica leaf extract for hypoglycaemic activity in rats

Water soluble fractions separated from the crude leaf extract of Azadirachta indica A. Juss. lowered hyperglycaemia in streptozotocin diabetes. Systematic fractionation of the concentrates led to the isolation of flavonol glycosides, quercetin-3-O-β-D-glucoside, myricetin-3-O-rutinoside, quercetin-3-O-rutinoside, kaempferol-3-O-rutinoside, kaempferol-3-O-β-D-glucoside and quercetin-3-O-α-L-rhamnoside.     

Antidiabetic effect of aqueous extract of seed of Tamarindus indica in streptozotocin-induced diabetic rats

In Indian traditional system of medicine, herbal remedies are prescribed for the treatment of diseases including diabetes mellitus. In recent years, plants are being effectively tried in a variety of pathophysiological states. Tamarindus indica Linn. is one of them. In the present study, aqueous extract of seed of Tamarindus indica Linn. was found to have potent antidiabetogenic activity that reduces blood sugar level in streptozotocin (STZ)-induced diabetic male rat. Supplementation of this aqueous extract by gavage at the dose of 80 mg/0.5 ml distilled water/100 g body weight per day in STZ-induced diabetic rat resulted a significant diminution of fasting blood sugar level after 7 days. Continuous supplementation of this extract for 14 days resulted no significant difference in this parameter from control level. Moreover, this supplementation produced a significant elevation in liver and skeletal muscle glycogen content, activity of liver glucose-6-phosphate dehydrogenase in respect to diabetic group. Activities of liver glucose-6-phosphatase, liver and kidney glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) activities were decreased significantly in the aqueous extract supplemented group in respect to diabetic group. All these parameters were not resettled to the controlled level after 7 days of this extract supplementation but after 14 days of this supplementation, all the above mentioned parameters were restored to the control level.     

Effects of Azadirachta indica extract on gastric ulceration and acid secretion in rats

The effect of Azadirachta indica extract on gastric ulceration was studied in albino rats. Azadirachta indica extract (100-800 mg/kg p.o., 100-25 mg/kg i.p.) significantly inhibited gastric ulceration induced by indomethacin (40 mg/kg). Administration of 800 mg/kg p.o. and 250 mg/kg i.p. caused 100% cytoprotection against indomethacin (40mg/kg, i.p.)-induced gastric ulceration. This action was accompanied by a dose-dependent decrease in total gastric acidity. In order to investigate the probable mechanism of Azadirachta indica antiulcer activity, the effect of the extract alone and in combination with histamine (1mg/kg) and cimetidine (0.12 mg/kg) on gastric acid secretion in situ was studied. Azadirachta indica (250 mg/kg) significantly inhibited the basal and histamine-induced gastric acid secretion. Cimetidine seemed to augment Azadirachta indica inhibition of gastric acid secretion.The results suggest that the stem bark extract of Azadirachta indica possesses antiulcer agents, which probably act via histamine H(2) receptor.     

Possible mechanism of antihyperglycemic effect of Azadirachta indica leaf extract: part V

Effect of Azadirachta indica leaf extract on serotonin inhibition in glucose mediated insulin release in rat pancreas was studied in vitro to elucidate the possible mechanism of antihyperglycemic effect of A. indica leaf extract. A. indica leaf extract blocks significantly (P < 0.05) the inhibitory effect of serotonin on insulin secretion mediated by glucose.     

Possible mechanism of hepatoprotective activity of Azadirachta indica leaf extract: part II

Hepatoprotective activity of Azadirachta indica leaf extract against paracetamol induced hepatic damage in rats has already been reported. In the present investigation effects of Azadirachta indica leaf extract on blood and liver glutathione, Na+K(+)-ATPase activity and thiobarbutiric acid reactive substances against paracetamol induced hepatic damage in rats have been studied with a view to elucidate possible mechanism behind its hepatoprotective action. It was interesting to observe that Azadirachta indica leaf extract has reversal effects on the levels of above mentioned parameters in paracetamol hepatotoxicity. Possible mechanism behind the results are discussed.     

Effect of Coccinia indica leaves on antioxidant status in streptozotocin-induced diabetic rats

The antioxidant effect of an ethanolic extract of Coccinia indica leaves, an indigenous plant used in Ayurvedic medicine in India, was studied in Streptozotocin-diabetic rats. Oral administration of Coccinia indica leaf extract (CLEt) (200 mg/kg body weight) for 45 days resulted in a significant reduction in thiobarbituric acid reactive substances and hydroperoxides. The extract also causes a significant increase in reduced glutathione, superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase in liver and kidney of streptozotocin diabetic rats, which clearly shows the antioxidant property of CLEt. The effect of CLEt at 200 mg/kg body weight was more effective than glibenclamide     

Evaluation of antiplaque activity of Azadirachta indica leaf extract gel--a 6-week clinical study

Various chemical agents have been evaluated over the years with respect to their antimicrobial effects in the oral cavity; however, all are associated with side effects that prohibit regular long-term use. Therefore, the effectiveness of neem (Azadirachta indica A. Juss) leaf extract against plaque formation was assessed in males between the age group of 20-30 years over a period of 6 weeks. Present study includes formulation of mucoadhesive dental gel containing Azadirachta indica leaf extract (25 mg/g). A 6-week clinical study was conducted to evaluate the efficacy of neem extract dental gel with commercially available chlorhexidine gluconate (0.2% w/v) mouthwash as positive control. Microbial evaluation of Streptococcus mutans and Lactobacilli species was carried out to determine the total decrease in the salivary bacterial count over a period of treatment using a semi-quantitative four quadrant streaking method. The results of the study suggested that the dental gel containing neem extract has significantly (P<0.05) reduced the plaque index and bacterial count than that of the control group.     

Chemopreventive potential of Azadirachta indica (Neem) leaf extract in murine carcinogenesis model systems

Numerous laboratory studies reveal that various naturally occurring dietary substances can modify the patho-physiological process of various metabolic disorders and can be an effective preventive strategy for various diseases, including cancer. Indian Neem tree, Azadirachta indica A. Juss. (family: Meliaceae), contains at least 35 biologically active principles and is widely grown all over the tropics. The effect of two different doses (250 and 500 mg per kilogram body weight) of 80% ethanolic extract of the leaves of Azadirachta indica were examined on drug metabolizing Phase-I and Phase-II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase, and lipid peroxidation in the liver of 7-week-old Swiss albino mice. Also anticarcinogenic potential of Azadirachta indica leaf extract was studied adopting protocol of benzo(a)pyrene-induced fore-stomach and 7,12-dimethyl benz(a)anthracene (DMBA)-induced skin papillomagenesis. Our primary findings reveal its potential to induce only the Phase-II enzyme activity associated mainly with carcinogen detoxification in liver of mice. The hepatic glutathione S-transferase (P < 0.005) and DT-diaphorase specific activities (P < 0.01) were elevated above basal level. With reference to antioxidant enzymes the investigated doses were effective in increasing the hepatic glutathione reductase (GR), glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT) activities significantly (from P < 0.005 to P < 0.001). Reduced glutathione measured as non-protein sulphydryl was found to be significantly elevated in liver (P < 0.005) and in extrahepatic organs (from P < 0.005 to P < 0.001) examined in our study. Glutathione S-transferase (GST) and DT-diaphorase (DTD) showed a dose-dependent increase in extrahepatic organs. Chemopreventive response was measured by the average number of papillomas per mouse, as well as percentage of tumor-bearing animals. There was a significant inhibition of tumor burden, in both the tumor model system studied (from P < 0.005 to P < 0.001). Tumor incidence was also reduced by both the doses of Azadirachta indica extract.     

Effect of ethanolic extract of Zingiber officinale on dyslipidaemia in diabetic rats

The lipid lowering and antioxidant potential of ethanolic extract of Zingiber officinale Roscoe (family, Zingiberaceae) was evaluated in streptozotocin (STZ)-induced diabetes in rats. Ethanolic extract of Zingiber officinale (200 mg/kg) fed orally for 20 days produced, significant antihyperglycaemic effect (P < 0.01) in diabetic rats. Further, the extract treatment also lowered serum total cholesterol, triglycerides and increased the HDL-cholesterol levels when compared with pathogenic diabetic rats (P < 0.01). STZ-treatment also induced a statistically significant increase in liver and pancreas lipid peroxide levels (P < 0.01) as compared to normal healthy control rats. Zingiber officinale extract treatment lowered the liver and pancreas thiobarbituric acid reactive substances (TBARS) values (P < 0.01) as compared to pathogenic diabetic rats. The results of test drug were comparable to gliclazide (25 mg/kg, orally), a standard antihyperglycaemic agent. The results indicate that ethanolic extract of Zingiber officinale Roscoe can protect the tissues from lipid peroxidation. The extract also exhibit significant lipid lowering activity in diabetic rats. The present study is the first pilot study to assess the potential of Zingiber officinale in diabetic dyslipidaemia.     

Ameliorative effects of Anoectochilus formosanus extract on osteopenia in ovariectomized rats

The purpose of this study was to determine ameliorative effects of crude aqueous extract of Anoectochilus formosanus (AFE) on osteopenia in ovariectomized (OVX) rats. First, all of the rats were divided into sham and OVX groups. The OVX rats were allowed to lose bone for 6 weeks. At 6 weeks post-OVX, the OVX rats were divided into four groups treated with water, 17beta-estradiol (30 microg/kg, daily s.c. injection) or AFE (0.5, 2 g/kg, daily, orally) for 12 weeks. In OVX rats, the increases of body weight and serum total cholesterol were significantly decreased by AFE or 17beta-estradiol treatment. In OVX rats, atrophy of uterus and vagina was preserved by treatment with 17beta-estradiol, but not by AFE. The decreased weight of pituitary was increased by treatment with both 17beta-estradiol and AFE. There were decreases in bone density and calcium content including the right femur and the fourth lumbar vertebra, when compared with the sham control rats. Treatment with either 17beta-estradiol or AFE ameliorated these changes induced by OVX. In addition, ovariectomy increased serum alkaline phosphatase levels. The increases were suppressed by the treatment with 17beta-estradiol and AFE. Our results demonstrated that AEF could ameliorate ovariectomy-induced osteopenia.     

Efficacy of ginseng adventitious root extract on hyperglycemia in streptozotocin-induced diabetic rats

Ethnopharmacological relevance

Ginseng has various bioactive effects on human health including its potential activity of improving the glucose homeostasis and insulin sensitivity.

Materials and methods

Tissue culture raised mountain ginseng adventitious root (TCMGARs) extract enriched with ginsenosides was used as experimental material. Streptozotocin-induced diabetic ‘Sprague Dawley’ male rats were used as experimental systems and were fed with Tissue culture raised mountain ginseng adventitious root extract. Field cultivated Korean ginseng root extract fed rats were used as positive control and several indices such as body weight, blood glucose level and other serological indicators were tested.

Results

Chemical profile showed TCMGARs were rich in varied ginsenosides especially Rb1, Rb2, Rc, Rd, Rg3, and Rh2 when compared to field cultivated Korean ginseng. TCMGARs extract at dosage levels of 250 and 500 mg/kg body weight significantly lowered the blood glucose, total cholesterol and triglyceride content in streptozotocin-induced diabetic rats.

Conclusion

The data of in vivo experiments on anti-glycemic effects of TCMGARs proves their efficacy and also their use as dietary supplement.     

Hypoglycemic and antioxidant activities of Clerodendrum inerme leaf extract on streptozotocin-induced diabetic models in mice

Objective: Recently, much attention has been paid to natural product-derived compounds for antidiabetic drug discovery. More recent studies are being focused on clarifying the bioactivity of plants and derived products. The aim of the present study was to investigate the anti-oxidant and antidiabetic activities of Clerodendrum inerme leaf extract(CILE) in streptozotocin-induced diabetic mice.Methods: C. inerme leaves were analyzed for preliminary phytochemical properties and the content of total phenolic and flavonoid were determined. In vitro anti-oxidant activity was measured using DPPH assay. Streptozotocin-induced diabetic model in mice was applied for in vivo study by the effect of CILE at two dose levels(343 and 686 mg/kg b.w.).Results: The results showed that C. inerme leaves contained the major constituents of flavonoids, alkaloids, tannins, triterpenes, and saponins. CILE exhibited the total polyphenol and flavonoid content with 120.458 mg gallic acid equivalent/g dry weight and 4.494 mg hispidulin equivalent/g dry weight,respectively. The anti-oxidant activity of CILE was expressed with IC50= 25.28 μg/m L. CILE at the doses of343 mg/kg and 686 mg/kg after 7 d administration exerted a decrease in plasma glucose, protected the liver, kidneys against oxidation stress via increasing glutathione content in the liver, and reduced malondialdehyde content in the liver and kidneys. Pancreatic histological analysis in diabetic mice treated with CILE also showed the pancreatic β-cells regeneration via increasing the size and number of pancreatic islets.Conclusion: These findings suggested that C. inerme leaves had potent antidiabetic and anti-oxidant activities. The results provide reliable scientific base, which is the premise for further research and development of CILE as supplements.     

Anti-diabetic effects of Cichorium intybus in streptozotocin-induced diabetic rats

The present study was designed to investigate the hypoglycemic and hypolipidemic properties of an ethanolic extract of Cichorium intybus (CIE) which is widely used in India as a traditional treatment for diabetes mellitus. Male Sprague-Dawley rats aged 9 weeks (160-200 g) were administered with streptozotocin (STZ, 50mg/kg) intraperitoneally to induce experimental diabetes. The Cichorium intybus whole plant was exhaustively extracted with 80% ethanol, concentrated at 40 degrees C using a rotavapor and freeze dried to get powder. Hypoglycemic effects of CIE were observed in an oral glucose tolerance test (OGTT) in which, a dose of 125 mg of plant extract/kg body weight exhibited the most potent hypoglycemic effect. Moreover, daily administration of CIE (125 mg/kg) for 14 days to diabetic rats attenuated serum glucose by 20%, triglycerides by 91% and total cholesterol by 16%. However, there was no change in serum insulin levels, which ruled out the possibility that CIE induces insulin secretion from pancreatic beta-cells. In addition, hepatic glucose-6-phosphatase activity (Glc-6-Pase) was markedly reduced by CIE when compared to the control group. The reduction in the hepatic Glc-6-Pase activity could decrease hepatic glucose production, which in turn results in lower concentration of blood glucose in CIE-treated diabetic rats. In conclusion, our results support the traditional belief that Cichorium intybus could ameliorate diabetic state.     

藏药灰兜巴对糖尿病肾病大鼠足细胞损伤的改善作用

目的探讨藏药灰兜巴对糖尿病肾病大鼠足细胞损伤的改善作用。方法采取高脂高糖饮食喂养和腹腔注射65 mg/kg链脲佐菌素法诱导糖尿病肾病大鼠模型。大鼠随机分为对照组、模型组、二甲双胍组、灰兜巴组,每组8只,灌胃给药6周。分别于药物干预前后进行口服葡萄糖耐量实验(oral glucose tolerance test,OGTT),收集24小时尿液并检测mAlb与Ucr比值;PASM观察肾组织病理学改变情况;Western blot法和免疫荧光法检测足细胞标志蛋白Nephrin表达;透射电子显微镜观察足细胞和肾小球基底膜损伤。结果与对照组比较,模型组大鼠时间-血糖曲线下面积及mAlb/Ucr升高(P<0.01),足细胞标志蛋白Nephrin表达减少(P<0.01),透射电镜下可见肾小球基底膜明显增厚及广泛足突融合。与模型组比较,灰兜巴可改善糖尿病肾病大鼠空腹葡萄糖耐量受损,降低mAlb/Ucr(P<0.01),上调足细胞标志蛋白Nephrin表达(P<0.01),减少足细胞丢失,改善足细胞和肾小球基底膜超微结构改变情况。结论益气养阴藏药灰兜巴可减轻糖尿病肾病大鼠足细胞损...     

Antidiabetic effect of Ficus religiosa extract in streptozotocin-induced diabetic rats

Aims of study

In Indian traditional system of medicine, Ficus religiosa (Family Moraceae) is prescribed for the treatment of diabetes mellitus. In the present study, the antidiabetic effect of aqueous extract of Ficus religiosa bark (FRAE) was investigated in normal, glucose-loaded hyperglycemic and streptozotocin (STZ)-induced diabetic rats.

Materials and methods

Oral administration of FRAE at the doses of 25, 50 and 100 mg/kg was studied in normal, glucose-loaded and STZ-diabetic rats.

Results

The three doses caused significant reduction in blood glucose levels in all the models. The effect was more pronounced in 50 and 100 mg/kg than 25 mg/kg. FRAE also showed significant increase in serum insulin, body weight and glycogen content in liver and skeletal muscle of STZ-induced diabetic rats while there was significant reduction in the levels of serum triglyceride and total cholesterol. FRAE also showed significant antilipidperoxidative effect in the pancreas of STZ-induced diabetic rats. The antidiabetic effect of Ficus religiosa was compared with glibenclamide, a well-known hypoglycemic drug.

Conclusion

The results indicate that aqueous extract of Ficus religiosa bark possesses significant antidiabetic activity.     

Antidiabetic and antioxidant effects of Annona muricata (Annonaceae), aqueous extract on streptozotocin-induced diabetic rats

Ethnopharmacological relevance

The leaves of Annona muricata are used in Cameroon to manage diabetes and its complications. The aim of this study was to evaluate the antidiabetic, antioxidant activities and the potential toxicity of aqueous extract of Annona muricata in streptozotocin-induced diabetic rats.

Material and methods

Oral administration of Annona muricata aqueous extract (100 mg/kg or 200 mg/kg) was studied in normal and streptozotocin-induced diabetic rats. In long term treatment, 2 weeks after streptozotocin-induced diabetic rats, animals received plant extract during 28 consecutive days. For a protective effect, extract was administered 3 days prior to streptozotocin exposure and animals were observed 2 weeks without treatment.

Results

The plant extract was not effective in normal rats. In diabetic rats, single administration of the extract significantly reduced blood glucose levels by 75% and 58.22% respectively at the dose of 100 mg/kg and 200 mg/kg as compared to the initial value. Treatment of normal rats 3 days prior to diabetes induction showed that, Annona muricata extract has no effect within 72 h following STZ injection. However, after 14 days post-treatment, the extract at the dose of 100 mg/kg significantly reduced blood glucose levels as compared with initial value and diabetic control rats. Immunohistochemical staining of pancreatic β-cells of diabetic rats treated with the dose of 100 mg/kg expressed strong staining for β-cell compared to diabetic control. In a long-term study daily administration of Annona muricata aqueous extract for 28 days to diabetic rats, reduced blood glucose levels, serum creatinine, MDA, AST, ALT activity, and nitrite levels LDL-cholesterol. Total cholesterol, triglycerides, SOD, and CAT activity contents were restored.

Conclusion

These different results show that the antidiabetic activity of Annona muricata aqueous extract can be explained by its hypolipidaemic effect, its antioxidant and protective action on pancreatic β-cells, which in turn improve glucose metabolism.     

Immunomodulatory activity of an aqueous extract of Azadirachta indica stem bark

The interference of an aqueous extract of the stem bark of Azadirachta indica with different parts of the human immune system was investigated. The extract showed strong anticomplementary effects which were dose-and time-dependent and most pronounced in the classical complement pathway assay. Moreover, a dose-dependent decrease in the chemiluminescence of polymorphonuclear leukocytes was observed and a dose-dependent increase in the production of migration inhibition factor by lymphocytes.     

Effects of Syzygium cordatum (Hochst.) [Myrtaceae] leaf extract on plasma glucose and hepatic glycogen in streptozotocin-induced diabetic rats

The present study investigates the hypoglycaemic effect of Syzygium cordatum (Hochst.) [Myrtaceae] leaf extract in non-diabetic and streptozotocin (STZ)-induced diabetic rats. Oral glucose tolerance tests (OGGT) were conducted in non-diabetic and STZ-diabetic rats using orally administered glucose (1.4 g 100 g(-1) body weight) followed by either the leaf extract (6 mg 100 g(-1) body weight) or subcutaneous (sc) injection of metformin (50 mg 100 g(-1)). Weekly plasma glucose and terminal hepatic glycogen concentrations were recorded in control STZ-diabetic rats and diabetic rats orally treated with the leaf extract once every third day for 4 weeks. Administration of the leaf extract decreased plasma glucose from 7.7+/-0.9 mmol l(-1) to 3.7+/-0.6 mmol l(-1) (n = 6), and 21.1+/-2.2 mmol l(-1) to 12.5+/-1.8 mmol l(-1) (n = 7) by 2 1/2 h in non-diabetic and STZ-diabetic rats, respectively. OGTT data in metformin-treated rats were similar at the corresponding time in all groups, except for significant blood glucose reduction by the drug in non-diabetic rats between 1 and 1 1/2 h after treatment. Oral administration of the extract did not affect plasma glucose concentration in STZ-diabetic rats after 4 weeks, although it significantly increased hepatic glycogen content by comparison with untreated STZ-diabetic rats (28+/-5 mg 100 g(-1) body weight, n = 7, versus 16+/-3 mg 100 g(-1) body weight, n = 6). We conclude that Syzygium cordatum leaf extract contains compounds that could be effective in mild diabetes mellitus or in cases of glucose tolerance impairment. The possible mechanism(s) involved in the short-term hypoglycaemic effect of the extract could not be established by the current study.     

Hypoglycemic properties of aqueous bark extract of Ceiba pentandra in streptozotocin-induced diabetic rats

The claim by Nigerian traditional herbal medicine practitioners that the silk cotton tree, Ceiba pentandra L. Gaertn (Bombacaceae) barks extract has antidiabetic properties was investigated. Diabetes mellitus was induced with streptozotocin and graded doses of the aqueous bark extract were then administered ad libitum in drinking water to the experimentally diabetic rats for 28 days. Administration of the aqueous bark extract caused a statistically significant reduction in plasma glucose level in streptozotocin induced diabetic rats. The extract appeared non-toxic as evidenced by normal serum levels of AST, ALT, ALP and bilirubin. The data appear to support the hypoglycemic effects of C. pentandra.     

Beneficial effects of swertiamarin on dyslipidaemia in streptozotocin-induced type 2 diabetic rats

Dyslipidaemia is one of the major risk factors for cardiovascular disease in diabetes mellitus. Lipid changes associated with diabetes mellitus are attributed to increases in free fatty acid flux, secondary to insulin resistance. In the present study, we have investigated the beneficial effects of swertiamarin on dyslipidaemic conditions associated with type 2 diabetes in streptozotocin‐induced type 2 diabetic rats. Swertiamarin (50 mg/kg, i.p.) administered once a day for 6 weeks resulted in significant (p < 0.001) reductions in serum triglycerides, cholesterol and low‐density lipoprotein levels in diabetic animals as compared with diabetic control animals. Serum fasting glucose was significantly (p < 0.05) decreased, moreover, the insulin sensitivity index was significantly (p < 0.05) increased in swertiamarin treated animals. Overall the data suggest that swertiamarin has beneficial effects on diabetic associated complications such as dyslipidaemia. Copyright © 2012 John Wiley & Sons, Ltd.