Caraway and caper: potential anti-hyperglycaemic plants in diabetic rats

The hypoglycaemic effect of aqueous extracts of Carum carvi (CC) and Capparis spinosa L. (CS) fruit were investigated in normal and streptozotocin (STZ) diabetic rats. After a single dose or 14 daily doses, oral administration of the aqueous CC and CS extracts (20 mg/kg) produced a significant decrease on blood glucose levels in STZ diabetic rats (P < 0.001); the blood glucose levels were nearly normalised 2 weeks after daily repeated oral administration of both aqueous CC and CS extracts (20 mg/kg) (P < 0.001). No highly significant changes on blood glucose levels were noticed in normal rats after both acute and chronic treatments with CS and CC. In addition, no changes were observed in basal plasma insulin concentrations after treatment with these plants in either normal or STZ diabetic rats indicating that the underlying mechanism of this pharmacological activity seems to be independent of insulin secretion. We conclude that aqueous extracts of CC and CS exhibit a potent anti-hyperglycaemic activity in STZ rats without affecting basal plasma insulin concentrations.     

人参二味胶囊对糖尿病大鼠血糖、血脂的影响

目的:探讨人参二味胶囊对糖尿病大鼠血糖、血脂的影响。方法:60只SPF级雄性Wistar大鼠,体重为(180±20)g,普通饲料适应性喂养7 d。按随机数字表从中随机抽取10只作为正常组。其余50只用高脂饲料喂养4周后,给予30mg.kg-1的链脲佐菌素(STZ)ip。将造模成功的大鼠按随机表分为4组,每组10只。其中3组分别ig人参二味胶囊、盐酸二甲双胍、参芪降糖颗粒共14 d,其余10只为模型组作为对照。ig前和ig 2周后各测1次空腹血糖和体重,最后从腹主动脉取血,化验各组大鼠的甘油三脂和胆固醇。评价人参二味胶囊对糖尿病大鼠血糖、血脂和体重的影响。结果:给药14 d后,人参二味胶囊能降低2型糖尿病大鼠的血糖和血脂,有效控制大鼠体重的降低,与模型组比较差异有统计学意义(P<0.05)。结论:人参二味胶囊能降低2型糖尿病模型大鼠的血糖和血脂,有效控制大鼠体重的下降,但其降糖作用较盐酸二甲双胍和参芪降糖颗粒弱。     

Hypoglycemic effects of malonyl‐ginsenosides extracted from roots of Panax ginseng on streptozotocin‐induced diabetic mice

Hypoglycemic effects of malonyl‐ginsenosides (MGR), extracted from roots of Panax ginseng, were examined in streptozotocin‐ (STZ‐) induced diabetic mice. Animals received daily intravenous injections of MGR in doses of 30, 60, 120 mg/kg. At a dose of 120 mg/kg, MGR reduced the fasting blood glucose level of diabetic mice by 77.8% (76.7 ± 8.5 mg/dl versus 345.2 ± 35.8 mg/dl, P < 0.01). The same dose also showed a marked improvement in glucose tolerance of 80% (75.3 ± 10.8 mg/dl versus 375.6 ± 43.3 mg/dl, P < 0.01) in diabetic mice after four days. The alkali hydrolysis productions of MGR, ginseng panaxadiol (PDS), malonic acid and a mixture of malonic acid with PDS, showed no effects on fasting blood glucose levels indicated the hypoglycemic effect of MGR relied on their unique esterified chemical structures. The findings from this study suggest that MGR extracted from Panax ginseng may be prescribed as adjunct to drug treatment for controlling diabetes mellitus. Copyright © 2009 John Wiley & Sons, Ltd.     

Evaluation of antidiabetic and antihyperlipidemic activity of Artemisia indica linn (aeriel parts) in Streptozotocin induced diabetic rats

Ethnopharmacological relevance

Diabetes mellitus is a major metabolic disorder affecting a huge population all over the world. Artemisia species have been extensively used for the management of diabetes in folkloric medicine. The present study is designed to investigate the antidiabetic and antihyperlipidemic effects of aeriel parts of Artemisia indica.

Materials and methods

Hydromethanolic crude extracts, chloroform, ethyl acetate and n-butanol fractions of aerial parts of Artemisia indica were tested for their antidiabetic potential in Streptozotocin (STZ) (50 mg/kg, i.p.) induced diabetic Sprague-Dawley rats. Blood glucose level, body weight, serum lipid profile and activities of liver enzymes were determined. The extracts were further subjected to preliminary phytochemical analysis.

Results

A daily oral dose of hydromethanolic crude extracts (200 and 400 mg/kg b.w.) and chloroform fraction (200 mg/kg b.w.) of Artemisia indica for 15 days showed a significant reduction in blood glucose level which was comparable to that of the standard antidiabetic drug, glibenclamide (500 μg/kg, p.o.). Artemisia indica extracts also showed reduction in total cholesterol, triglycerides and low density lipoproteins as well as serum creatinine level, serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT) and alkaline phosphatase (ALP) in diabetic rats.

Conclusion

According to the results Artemisia indica possesses hypoglycemic, antihyperlipidemic and valuable effects on liver and renal functions in diabetic rats, which seems to validate its traditional usage.     

Antidiabetic and antioxidant activities of Toddalia asiatica (L.) Lam. leaves in Streptozotocin induced diabetic rats

Ethnopharmacological relevance

The leaves of Toddalia asiatica (L.) Lam. have been utilized traditionally for the cure of diabetes.

Aim of the study

The present study was aimed to assess the antidiabetic and antioxidant effects of T. asiatica leaves in Streptozotocin (STZ) induced diabetic rats.

Materials and methods

The phytochemical screening, total phenolic content, HPLC analysis, acute toxicity study and oral glucose tolerance test were carried out. Glucose lowering effect of the hexane, ethyl acetate and methanol extracts of T. asiatica leaves was studied in STZ-induced diabetic rats. The antidiabetic and antioxidant activities were studied for the ethyl acetate extract. The effects of extracts on blood glucose, body weight, plasma insulin, total protein, liver glycogen, plasma enzymes (SGOT, SGPT and ALP) and activities of SOD, CAT and GPx were analyzed.

Results

T. asiatica leaves ethyl acetate extract (TALEe) showed highly significant blood glucose lowering effect. Phytochemical evaluation of TALEe showed the presence of alkaloids, terpenoids, cumarins, flavonoids and phenolic compounds. The total phenolic content of TALEe was 126 mg of gallic acid equivalents/g extract. HPLC analysis revealed the presence of flindersine and ulopterol. Acute toxicity study of TALEe revealed no death or toxicity. The oral glucose tolerance test showed lowered area under curve (AUC_glucose) values in TALEe treated rats. After treatment with TALEe (250 and 500 mg/kg) for 28 days there was a significant decrease in blood glucose, plasma enzymes (SGOT, SGPT and ALP) and significant increase in body weight, total protein, serum insulin and liver glycogen levels in treated diabetic rats. The activities of antioxidant enzymes SOD, CAT and GPx were reversed to near normal in treated diabetic rats. Histopathology of pancreas in TALEe treated groups showed regeneration of β-cells.

Conclusion

The results of the experiments showed that TALEe exerted significant antidiabetic and antioxidant effects in STZ-induced diabetic rats justifying its traditional use.     

Hypoglycaemic effects of Mammea africana (Guttiferae) in diabetic rats

Aim of the study

The stem bark of Mammea africana Sabine (Guttiferae) is used in African rain forest to treat various diseases, including diabetes mellitus. We investigated whether Mammea africana extract induced hypoglycaemic activity in rats.

Materials and methods

We tested the effects of acute (5 h) and sub-acute (21 days) oral administrations of the CH₂Cl₂–MeOH stem bark extract of Mammea africana (19–300 mg/kg body weight) on blood glucose levels of normal and streptozotocin (STZ)-induced type 1 diabetic rats. The effects were compared with those of glibenclamide.

Results

Acute administration reduced blood glucose in the diabetic rats only (33.87%, P < 0.01). Sub-acute treatment for 21 days also reduced blood glucose level in diabetic rats (73.29%, P < 0.01). A reduction or stabilization in total serum protein, triglyceride, cholesterol and alanine amino transferase levels was also observed. No effect was observed on body weight loss but food and water intakes were significantly reduced (P < 0.01) in diabetic rats. The maximal anti-diabetic effect was obtained with the dose of 75 mg/kg and was more important than that of glibenclamide.

Conclusion

It can be concluded that extracts of Mammea africana exhibited a significant anti-hyperglycaemic activity and improved the metabolic alterations in STZ-diabetic rats. These results provide a rationale for the use of Mammea africana to treat diabetes mellitus and hypercholesterolemia.     

龙须草水煎液对糖尿病大鼠血糖和胰岛素水平的影响

目的:探讨龙须草水煎液对糖尿病大鼠血糖和胰岛素水平的影响.方法:大鼠以高脂饲料喂养1个月诱导加1次性ip链脲佐菌素制造2型糖尿病模型,将Wistar雄性大鼠随机分成6组:正常对照组、模型组、二甲双胍(0.15 g·kg-1·d-1),龙须草水煎液低、中、高剂量组(2.5,5,10 g·kg-1·d-1),口服给药30 d,并在相应时间采血测定空腹血糖(FBG)、糖耐量2h血糖、空腹胰岛素(FINS).结果:龙须草水煎液中、高剂量给药30 d糖尿病大鼠FBG分别为(14.30 ±3.04),(13.25±3.81)mmol·L-1低于模型组(P＜0.01);大鼠糖耐量分别为(13.44 ±3.24),(13.03±4.72) mmol·L-1低于模型组(P＜0.05);血清胰岛素水平分别为(15.40±3.76),(16.39±4.75)mU·L-1高于模型组(P＜0.01).结论:龙须草水煎液对高血糖模型大鼠具降低血糖和升高胰岛素水平的作用.     

Antidiabetic effect of Symplocos cochinchinensis (Lour.) S. Moore. in type 2 diabetic rats

Aim

Symplocos cochinchinensis (Lour.) S. Moore. is used in Indian system of traditional medicine to treat diabetes mellitus. The present study aims to investigate the antidiabetic efficacy of the hexane extract of Symplocos cochinchinensis leaves in high fat diet-low streptozotocin (STZ) induced type 2 diabetic rats.

Materials and methods

The doses for the study were fixed based on Irwin test. The hypoglycemic effect of the hexane extract of Symplocos cochinchinensis leaves were studied in normal rats. Oral glucose and insulin tolerance tests were carried out. The antihyperglycemic effect of the hexane extract at 250 and 500 mg/kg was studied in high fat diet-low STZ induced type 2 diabetic rats for 28 days.

Results

The extracts showed no adverse effects up to 5 g/kg concentration. In hypoglycemic study, after treatment with hexane extract at 250 and 500 mg/kg the blood glucose was mildly reduced. In oral glucose tolerance test, the treatment with the hexane extract at 250 and 500 mg/kg showed a highly significant reduction of 12.07% and 23.58% in plasma glucose levels, respectively 30 min after glucose load. The insulin tolerance test also showed improved insulin sensitivity after 60 min of insulin treatment. In high fat diet-low STZ induced type 2 diabetic rats, after 28 days treatment with the hexane extract at 250 and 500 mg/kg reduced the plasma glucose level by 17.04% and 42.10%, respectively. A significant reduction in plasma insulin, plasma and hepatic total cholesterol (TC), triglycerides (TG) and free fatty acids (FFA) and a significant increase in liver glycogen were observed in treated diabetic rats.

Conclusion

This study demonstrated the potential antidiabetic property of hexane extract of Symplocos cochinchinensis leaves on type 2 diabetes mellitus, thus justifying its traditional usage.     

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.     

齿叶白鹃梅叶对小鼠糖耐量的影响及降糖作用研究

目的:探讨齿叶白鹃梅叶对正常和糖尿病小鼠糖耐量的影响以及对STZ诱导糖尿病小鼠的降糖作用.方法:采用腹腔注射链脲佐菌素(150 mg·kg-1)诱导小鼠造成糖尿病模型,先观察齿叶白鹃梅叶水提物和80%醇提物对正常和糖尿病小鼠糖耐量的改变;再观察齿叶白鹃梅叶的水提取物和80%醇提物物以及阳性药盐酸二甲双胍(333 mg·...     

Renoprotection of Danshen Injection on streptozotocin-induced diabetic rats,associated with tubular function and structure

Ethnopharmacological relevance

Danshen Injection, the aqueous extracts of Radix Salvia miltiorrhiza (S. miltiorrhiza), is one of the most commonly used traditional Chinese herbs in chronic renal failure treatment. In present study, the mechanism of the renoprotective effect of Danshen Injection was analyzed on streptozocin (STZ)-induced diabetic rats.

Materials and methods

Diabetic experimental model was established in male Sprague-Dawley (SD) rats by intraperitoneal injection of STZ. Rats with blood glucose concentration of higher than 300 mg/dl were intraperitoneally administered with Danshen Injection at a dose of 0.78 ml/kg day. The blood glucose, 24 h urinary protein excretion, serum creatinine (sCr), blood urea nitrogen (BUN), advanced glycation end products (AGEs), lipid peroxide (LPO), antioxidant enzyme of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), transforming growth factor-β1 (TGF-β1), and histomorphological changes in kidney of diabetic rats were analyzed during the course of Danshen Injection administration, as well as the tubular function index of albumin reabsorption of fluorescein isothiocyanate labeled bovine serum albumin (FITC-BSA).

Results

The intraperitoneal administration of Danshen Injection could ameliorate the physiological dysfunctions of increased 24 h urinary protein excretion((48.21±8.04)%), sCr((39.4±3.7)%), and BUN((43.37±6.74)%), alleviate the ultrastructural abnormalities of hypertrophy, matrix expansion, and fibrosis in glomerulus, decrease the TGF-β1 expression, AGEs and LPO accumulation, and increase the activity of SOD and GSH-Px in kidney of diabetic rats, but did not significantly influence the blood glucose. Besides these, the Danshen Injection administration also partly restored the decrease of megalin expression in tubules and reabsorptive function of FITC-BSA, in diabetic rats.

Conclusion

The renoprotection of Danshen Injection on diabetic rats was associated with the preservation of tubular function and structure from the hyperglycemia induced toxicities of inappropriate cytokines secretion, oxidative stress, advanced glycation stress, and megalin expression deletion.     

Anti-hyperglycemic activity of the leaves of Tetracera scandens Linn. Merr. (Dilleniaceae) in alloxan induced diabetic rats

Aim of the study

The present study was aimed to investigate the anti-diabetic potential of the leaves of Tetracera scandens Linn. Merr. (Dilleniaceae) in vivo with regard to prove its efficacy by local herbalists in the treatment of diabetes frailties.

Materials and methods

Crude aqueous (AQ) and methanol (MEOH) extracts of the leaves of T. scandens L. were administered to both normal and alloxan induced diabetic male albino rats (Wistar strain). The blood glucose levels were measured at 0, 2, 4, 6 and 8 h after oral administration of AQ and MEOH extracts.

Results

Significant reduction in glucose was observed in fasting blood glucose levels in the treated diabetic rats without causing any hypoglycemic effect compared to normal rats. Both polar extracts of the leaves of T. scandens L. exhibited significant anti-hyperglycemic activity at different doses and intervals. The highest anti-hyperglycemic effect (62.5%) was observed by the AQ extract at 0.25 g/kg body weight (b.w.) and MEOH extract (36.5%) at 0.5 g/kg b.w. after 8 h. The significant anti-hyperglycemic activity was found to be comparable with a known oral synthetic hypoglycemic drug, glibenclamide 0.25 mg/kg b.w.

Conclusion

This study provides scientific evidence that the leaves of T. scandens L. have anti-diabetic efficacy and justifies its utility by local herbalists. However, more experiments at the clinical levels are required to confirm the utility of this plant by traditional practitioners in the management of diabetes mellitus.     

Antihyperglycemic and hypolipidemic activity of aqueous extract of Cassia auriculata L. leaves in experimental diabetes

Ethnopharmacological relevance

Cassia auriculata L. (Caesalpiniaceae) is widely used from ancient period to treat diabetes mellitus. The leaves of Cassia auriculata are having potential in the development of drug for diabetes due to its antihyperglycemic and lipid-lowering activity.

Aim of the study

The present study was to evaluate antihyperglycemic and hypolipidemic activity of aqueous extract of Cassia auriculata leaves (CLEt) in streptozotocin (STZ)-induced mild diabetic (MD) and severe diabetic (SD) rats.

Materials and methods

Male Albino rats were rendered diabetic by STZ (45 mg/kg, intraperitoneally). CLEt was orally administered to MD and SD rats at 100, 200 and 400 mg/kg doses for 1 day to determine antihyperglycemic activity. The 400 mg/kg dose was administered daily for 3 weeks to assess glycemic control and hypolipidemic effect.

Results

CLEt showed dose dependant fall in fasting blood glucose (FBG). After 5 h of extract administration at 400 mg/kg dose, FBG was reduced by 13.9% and 17.4% in MD and SD rats respectively. After 3 weeks treatment, CLEt produced significant reduction in FBG and glycosylated haemoglobin (GHb) in both MD and SD rats. Serum lipid levels were reversed towards normal in extract fed MD and SD rats.

Conclusions

The results demonstrate that CLEt possesses potent antihyperglycemic and hypolipidemic activity in both MD and SD rats.     

Study of the hypoglycaemic activity of Fraxinus excelsior and Silybum marianum in an animal model of type 1 diabetes mellitus

The hypoglycaemic effect of the aqueous extracts of Fraxinus excelsior (FE) seed and Silybum marianum (SM) aerial part was investigated in normal and streptozotocin (STZ) diabetic rats. After a single dose or 15 daily doses, oral administration of the aqueous extracts (20 mg/kg) produced a significant decrease of blood glucose levels in both normal and STZ diabetic rats (P < 0.001). From the first week, the body weight was increased in normal rats (P < 0.05) and decreased in STZ rats (P < 0.01) after FE administration. In addition, no changes were observed in basal plasma insulin concentrations after both FE and SM treatments in either normal and STZ diabetic rats indicating that these plants exert their pharmacological activity without affecting insulin secretion. We conclude that the aqueous extracts of FE and SM exhibit potent hypoglycaemic and anti-hyperglycaemic activities in normal and STZ rats, respectively, without affecting basal plasma insulin concentrations.     

栝蒌根散对糖尿病模型大鼠血糖、血脂的影响

目的:探讨栝蒌根散对糖尿病大鼠血糖、血脂的影响,分析其降糖作用与剂量之间的关系。方法:SPF级雄性Wistar大鼠,给予36 mg.kg-1链脲佐菌素(STZ)ip建立2型糖尿病模型。将成模大鼠按随机表随机分为模型组、盐酸二甲双胍组、参芪降糖颗粒组和栝蒌根散低、中、高(2,4,6 g.kg-1)剂量组,每组10只,每天ig相应的药物。10只正常大鼠作为正常组,每天ig2 mL生理盐水。ig前和ig 8周后各测一次空腹血糖和体重,最后从腹主动脉采血,化验各组大鼠的甘油三脂和胆固醇。结果:栝蒌根散低、高剂量均能降低链脲佐菌素所致糖尿病大鼠血糖(P<0.01),低剂量作用最强,中剂量无效。栝蒌根散3个剂量均能降低2型糖尿病大鼠血脂(P<0.05),但不能控制大鼠体重的下降。结论:栝蒌根散能降低糖尿病模型大鼠的血糖,其作用与剂量之间不存在量效关系。其降脂作用明显,但不能改变糖尿病大鼠体重下降的趋势。     

Effects of Juniperus oxycedrus ssp. oxycedrus on tissue lipid peroxidation, trace elements (Cu, Zn, Fe) and blood glucose levels in experimental diabetes

Ethnopharmacological relevance

Juniperus oxycedrus L. (Cupressaceae) fruits and leaves are used internally and pounded fruits are eaten for diabetes in Turkey.

Aim of the study

To evaluate the interrelationships between the levels of chosen trace elements (copper, iron, and zinc) and hepatic, renal lipid peroxidation (TBARS) in streptozotocin-induced diabetic rats treated with Juniperus oxycedrus ssp. oxycedrus (J.o.s.o.) leaf and fruit extracts for 10 days.

Materials and methods

J.o.s.o. fruit and leaf extracts were administered in STZ-induced diabetic rats, at doses of 500 and 1000 mg/kg. The blood glucose levels were measured in the 1st, 4th, 7th and 10th day of experiment. Fe, Cu, and Zn contents and lipid peroxidation levels of liver and kidney tissues were determined by atomic absorption spectrophotometry and ultraviolet spectrophotometry, respectively.

Results

Treatment of diabetic rats with the J.o.s.o. fruit and leaf extracts decreased the blood glucose levels and both the levels of lipid peroxidation in liver and kidney tissues. J.o.s.o. extracts have augmented Zn concentrations in liver of STZ-induced diabetic rats.

Conclusions

Results indicated that J.o.s.o. fruit and leaf extracts might be beneficial for diabetes and its complications.     

Antihyperglycemic effects of total flavonoids from Polygonatum odoratum in STZ and alloxan-induced diabetic rats

Aim of the study

Total flavonids of Polygonatum(P) odoratum (TFP) were tested for anti-diabetic activity in streptozotocin (STZ)-induced diabetic mice and alloxan-induced diabetic rats.

Materials and methods

Rhizoma Polygonati Odorati, well-known Chinese traditional medicine, is widely used for treatment of diverse diseases for example diabetes. In our study, TFP was extracted by 70% ethanol and purified by macroreticular resin. The experiments were designed to detect the anti-diabetic activity of TFP by determination of blood glucose (BG) using one touch gluco-meter and insulin levels by using a radioimmunoassay kit in streptozotocin (STZ)-induced diabetic mice and alloxan-induced diabetic rats and alpha-amylase inhibitory activity by alpha-amylase inhibition assay in vitro.

Results

TFP had beneficial effects on regulation of blood glucose. Daily administration with 50–200 mg/kg body weight of TFP for 9 days can reduce significantly hyperglycemia in STZ-induced diabetic mice. Thirtieth day administration with TFP (50–200 mg/kg body weight) also decreased significantly fasting blood glucose in alloxan-induced diabetic rats. The hypoglycemic effect of TFP at 50 and 100 mg/kg is less than that of acarbose 20 mg/kg and gliclazide 15 mg/kg. The hypoglycemic effects of TFP at 200 mg/kg is similar to that of acarbose 20 mg/kg and gliclazide 15 mg/kg. TFP also could increase significantly the insulin level in alloxan-induced type 2 diabetic rats (P < 0.05) compared with control. Alpha-amylase inhibition assay in vitro showed that TFP inhibited significantly alpha-amylase activity in a dose-dependent manner.

Conclusions

TFP possess significant dose-dependent anti-diabetic activity. TFP is one of the primary hypoglycemic active compounds of Polygonatum odoratum which would worth further study and development.     

Anti-hyperglycemic effect,inhibition of inflammatory cytokines expression,and histopathology profile in streptozotocin-induced diabetic rats treated with Arracacia tolucensis aerial-parts extracts

Ethopharmacological relevance

Arracacia tolucensis is a medicinal plant used in northeast of Mexico as a remedy to treat people with Diabetes mellitus (DM); however, there are no scientific studies that support this information. Thus, we evaluated the anti-hyperglycemic effect of the hexane, ethyl acetate and ethanol extracts from aerial parts in streptozotocin-induced diabetic rats.

Materials and methods

DM was induced in Wistar male rats by single intraperitoneal injection of streptozotocin (STZ 50 mg/kg). After STZ-induction, hyperglycemic rats were treated with all three extracts orally at a single dose (250 mg/kg) each 48 h for 21 days. Glibenclamide (1 mg/kg) was used as a reference drug. The fasting blood glucose levels, the hematic biometry and biochemical profiles, and the inhibition of inflammatory cytokines expression were estimated. Histopathology analysis of pancreas, liver, spleen, and kidney tissue was carried out.

Results

Ours results showed that ethyl acetate extract decreased blood glucose levels significantly (75%, p< 0.05) when compared to diabetic rats and controlled the body weight loss; the lipids level did not change, but the enzyme levels of aspartate aminotransferase and alanine aminotransferase decreased significantly (60.83% and 66.16%, respectively, p< 0.05) and inhibited the expression of inflammatory cytokines,with respect to diabetic rats. Histopathology injury was not observed; by contrast repair of islet of Langerhans was exhibited.

Conclusion

These results validate the use of Arracacia tolucensis as a treatment against DM and suggests it is suitable to continue studies for its safe therapeutic use.     

香椿子多酚对糖尿病大鼠早期肝损伤保护作用

目的:观察香椿子多酚(TSTP)对链脲佐菌素(STZ)诱导的大鼠糖尿病早期肝损伤的保护作用。方法:一次性ip链脲佐菌素(55 mg·kg-1),造模72 h后禁食不禁水,用血糖仪检测,空腹血糖大于11.1 mmol·L-1为造模成功大鼠。将造模成功大鼠随机分为模型组、香椿子多酚高、低剂量组(75,45 mg·kg-1)、格列本脲组(10 mg·kg-1),另取8只作为正常组,每天ig1次,连续14 d。第15 d处死后取其血清和肝脏。血清测空腹血糖(FBG),谷丙转氨酶(ALT),谷草转氨酶(AST);取肝脏测定脏器指数,肝脏石蜡切片,做HE染色。结果:香椿子多酚能降低大鼠空腹血糖,高、低剂量组7 d血糖分别为(11.79±2.75),(12.55±3.35)mmol·L-1,与模型组(15.53±2.33)mmol·L-1比较血糖降低(P<0.05),14 d血糖分别为(10.18±2.34),(11.80±2.74)mmol·L-1,与模型组(15.57±2.69)mmol·L-1比较差异有显著性(P<0.01);不能降低血清ALT及AST含量;香椿子多酚高剂量组大鼠肝脏脏器指数为(3.616±0.358),与模型组比较显著降低(P<0.05),改善大鼠肝脏形态。结论:香椿子多酚对糖尿病大鼠早期肝脏损伤具有一定的保护作用。     

Natural product vindoline stimulates insulin secretion and efficiently ameliorates glucose homeostasis in diabetic murine models

Ethnopharmacological relevance

Catharanthus roseus (L). Don (Catharanthus roseus) is a traditional anti-diabetic herb widely used in many countries, and the alkaloids of Catharanthus roseus are considered to possess hypoglycemic ability.

Aim of the study

To systematically investigate the potential anti-diabetic effects and the underlying anti-diabetic mechanisms of vindoline, one of the alkaloids in Catharanthus roseus.

Materials and methods

The regulation of vindoline against the glucose-stimulated insulin secretion (GSIS) was examined in insulinoma MIN6 cells and primary pancreatic islets. Insulin concentration was detected by Elisa assay. Diabetic models of db/db mice and type 2 diabetic rats induced by high-fat diet combining with streptozotocin (STZ/HFD-induced type 2 diabetic rats) were used to evaluate the anti-diabetic effect of vindoline in vivo. Daily oral treatment with vindoline (20 mg/kg) to diabetic mice/rats for 4 weeks, body weight and blood glucose were determined every week, oral glucose tolerance test (OGTT) was performed after 4 weeks.

Results

Vindoline enhanced GSIS in both glucose- and dose-dependent manners (EC₅₀=50 μM). It was determined that vindoline acted as a Kv2.1 inhibitor able to reduce the voltage-dependent outward potassium currents finally enhancing insulin secretion. It protected β-cells from the cytokines-induced apoptosis following its inhibitory role in Kv2.1. Moreover, vindoline (20 mg/kg) treatment significantly improved glucose homeostasis in db/db mice and STZ/HFD-induced type 2 diabetic rats, as reflected by its functions in increasing plasma insulin concentration, protecting the pancreatic β-cells from damage, decreasing fasting blood glucose and glycated hemoglobin (HbA_1c), improving OGTT and reducing plasma triglyceride (TG).

Conclusion

Our findings suggested that vindoline might contribute to the anti-diabetic effects of Catharanthus roseus, and this natural product may find its more applications in the improvement of β-cell dysfunction and further the potential treatment of type 2 diabetes.