Hypoglycaemic effect of the lyophilised aqueous extract of Ajuga iva in normal and streptozotocin diabetic rats

The purpose of this study was to examine the hypoglycaemic effect of the lyophilised aqueous extract of the whole plant of Ajuga iva (L.) Schreber (Labiatae) in normal and streptozotocin-induced diabetic rats. Single and repeated oral administration of the extract of Ajuga iva L (AI) at a dose of 10 mg/kg produced a slight and significant decrease in plasma glucose levels in normal rats 6 h after administration and after 3 weeks of treatment. AI reduced plasma glucose levels of streptozotocin diabetic rats from 337±9.3 to 102.2±17.7 mg/dl after 6 h of oral administration (P<0.001). Repeated oral administration of AI to streptozotocin diabetic rats significantly decreased the plasma glucose levels after 1 week of treatment (112±14.4 mg/dl at 1 week vs 337±9.3 mg/dl at the baseline values, (P<0.001). It continuously decreased thereafter and showed a rapid normalisation after 1 week of AI treatment. It is concluded that these results demonstrated that the water extract of the whole plant of AI possess a strong hypoglycaemic effect in diabetic rats, and support therefore, its traditional use in diabetes mellitus control.     

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.     

Hypoglycaemic effect of Musa sapientum L. in alloxan-induced diabetic rats

Musa sapientum L. ('Ney Poovan') commonly known as 'banana' is mainly used in Indian folk medicine for the treatment of diabetes mellitus. Oral administration of 0.15, 0.20 and 0.25 g/kg of chloroform extract of the Musa sapientum flowers (MSFEt) for 30 days resulted in a significant reduction in blood glucose, glycosylated haemoglobin and an increase in total haemoglobin, but in the case of 0.25 g/kg the effect was highly significant. It also prevents decrease in body weight. Oral glucose tolerance test was also performed in experimental diabetic rats in which there was a significant improvement in glucose tolerance in animals treated with MSFEt and the effect was compared with glibenclamide. Thus the study shows that MSFEt has hypoglycaemic action.     

Cholesterol and triglycerides lowering activities of caraway fruits in normal and streptozotocin diabetic rats

The purpose of this study was to examine the effect of single and repeated oral administration of the aqueous extract of Carum carvi L. fruits at a dose of (20mg/kg) on lipid metabolism in normal and streptozotocin-induced diabetic rats (STZ). After a single oral administration, Carum carvi extract produced a significant decrease on triglycerides levels in normal rats (p<0.05). In STZ diabetic rats, cholesterol levels were decreased significantly 6h after Carum carvi treatment (p<0.05). On the other hand, repeated oral administration of Carum carvi extract exhibited a significant hypotriglyceridemic and hypocholesterolemic activities in both normal (p<0.01 and <0.001 respectively) and STZ diabetic rats (p<0.001) 15 days after Carum carvi treatment. We conclude that the aqueous extract of Carum carvi (20mg/kg) exhibits a potent lipid lowering activity in both normal and severe hyperglycemic rats after repeated oral administration of Carum carvi aqueous extract.     

Hypolipidaemic activity of Helicteres isora L. bark extracts in streptozotocin induced diabetic rats

In this study, the hypolipidaemic effect of an aqueous extract of the bark of Helicteres isora was investigated in streptozotocin (STZ)-induced diabetic rats. Administration of the bark extract of Helicteres isora (100 and 200 mg/kgb.w.) for 21 days resulted in significant reduction in serum and tissue cholesterol, phospholipids, free fatty acids and triglycerides in STZ diabetic rats. In addition to that, significant (p<0.05) decrease in high-density lipoprotein (HDL) whereas significant increase (p<0.05) low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) were observed in STZ diabetic rats, which were normalized after 21 days of bark extract treatment. The bark extract at a dose of 200 mg/kgb.w. showed much significant hypolipidaemic effect than at the dose of 100 mg/kgb.w.     

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 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.     

Hypoglycaemic effect of Triticum repens P. Beauv. in normal and diabetic rats

The hypoglycaemic effect of an aqueous extract of Triticum repens (TR) rhizomes was investigated in normal and streptozotocin (STZ) diabetic rats. After a single oral administration of the aqueous extract (20mg/kg) a significant decrease on blood glucose levels in STZ diabetic rats (p<0.001) was observed; the blood glucose levels were normalized after 2 weeks of daily oral administration of TR aqueous extract (20mg/kg) (p<0.001). Significant reduction on blood glucose levels were noticed in normal rats after both acute (p<0.001) and chronic treatment (p<0.001). In addition, no changes were observed in basal plasma insulin concentrations after treatment 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 the aqueous extract of TR exhibits a potent hypoglycaemic activity in STZ rats without affecting basal plasma insulin concentrations.     

Hypoglycemic effect of Equisetum myriochaetum aerial parts on streptozotocin diabetic rats

The hypoglycemic effect of water as well as butanolic extracts prepared from aerial parts of Equisetum myriochaetum (Equisetaceae) was examined in streptozotocin induced diabetic rats. A single oral administration of the water extract (WE) at doses of 7 and 13 mg/kg and of the butanol extract (BE) at doses of 8 and 16 mg/kg significantly (P<0.001) lowered the plasma glucose levels in diabetic rats after three hours of the administration. As a reference drug glibenclamide was used and showed, at a dose of 3 mg/kg, similar hypoglycemic effect like the tested extracts. Three kaempferol glucosides and one caffeoyl glucoside were isolated from the drug and were shown to be the main constituents in both extracts.     

Evaluation of the antithyroid, antioxidative and antihyperglycemic activity of scopoletin from Aegle marmelos leaves in hyperthyroid rats

Scopoletin (7-hydroxy-6-methoxy coumarin) was isolated from the leaves of Aegle marmelos and evaluated for its potential to regulate hyperthyroidism, lipid peroxidation and hyperglycemia in levo-thyroxine-induced hyperthyroid rats. Scopoletin (1.00 mg/kg, p.o.) administered daily for 7 days to levo-thyroxine-treated animals decreased the levels of serum thyroid hormones and glucose as well as hepatic glucose-6-phosphatase activity, demonstrating its potential to regulate hyperthyroidism and hyperglycemia. Scopoletin also inhibited hepatic lipid peroxidation and increased the activity of antioxidants, superoxide dismutase and catalase. Compared with the standard antithyroid drug, propylthiouracil, scopoletin exhibited a superior therapeutic activity, since unlike propylthiouracil, it also inhibited hepatic lipid peroxidation. These findings indicate that scopoletin has the potential to inhibit thyroid function and hyperglycemia without hepatotoxicity.     

Hypoglycaemic activity of Leucas lavandulaefolia Rees. in streptozotocin-induced diabetic rats

The antidiabetic activity of Leucas lavandulaefolia Rees (Family - Labiatae) extract on streptozotocin (STZ) induced diabetic rats has been investigated. A methanol extract of the herb at doses of 200 and 400 mg/kg, and glybenclamide (1 mg/kg) were administered concurrently to STZ-diabetic rats. The extract caused a significant reduction of blood glucose levels in streptozotocin-induced diabetic rats by 29.8% (p <0.001) compared with control groups. © 1997 John Wiley & Sons, Ltd.     

茶多酚对链脲菌素诱导糖尿病大鼠肾损伤的防治作用

目的 :研究茶多酚对糖尿病 (DM)大鼠肾损伤的防治作用。方法 :采用链脲菌素 (STZ)腹腔注射致大鼠 DM模型 ,通过茶多酚及苯那普利治疗 ,对比观察尿蛋白排泄 ,内生肌酐清除率 (Ccr) ,血、尿内皮素- 1 (ET- 1 ) ,肿瘤坏死因子 -α(TNF-α)及肾病理。结果 :茶多酚有类似苯那普利减轻 DM大鼠尿量增多及Ccr增高的幅度 (P<0 .0 0 1 ) ,减少尿蛋白排泄 (P<0 .0 1 ) ,降低尿 ET- 1 (P<0 .0 1 )水平的作用 ,并能降低DM大鼠血甘油三脂水平。肾病理损害较模型组明显减轻 (P<0 .0 0 2 )。结论 :茶多酚对 STZ诱导 DM大鼠肾损伤具有防治作用     

Hypoglycaemic effect of Helicteres isora bark extract in rats

The hypoglycaemic effect of the aqueous extract of the bark of Helicteres isora L. (Sterculiaceae) was investigated in normal, glucose load conditions and streptozotocin (STZ)-induced diabetic rats. In normal rats, the aqueous extract of the bark of Helicteres isora L. (100 and 200 mg/kg/p.o.) significantly (P<0.001) reduced the blood glucose levels from 64.5-48.5 and 67-47 mg% 2h after oral administration of bark extract and also significantly lowered the blood glucose in STZ diabetic rats from 68-105 and 66-85.5 mg% 21 days after daily oral administration of the extract (P<0.001). The results suggested that the aqueous extract of bark of Helicteres isora L. possesses a potential hypoglycaemic effect in diabetic rats.     

柿叶提取物对小鼠链脲佐菌素糖尿病的影响

目的:观察柿叶各提取物对链脲佐菌素(STZ)所致糖尿病小鼠的血糖、胰岛素及血脂的影响。方法:将实验小鼠随机分为13组:正常对照组,模型组,二甲双胍组,乙醇总提物高、低剂量组,氯仿萃取部位高、低剂量组,乙酸乙酯萃取部位高、低剂量组,正丁醇萃取部位高、低剂量组,水提醇沉部位高、低剂量组。除正常对照组外其它组均以腹腔注射STZ(150mg/kg)建立Ⅱ型糖尿病小鼠模型。连续给药15d后,分别测定各小鼠空腹血糖(FBG)、空腹胰岛素(FINS)和血脂。结果:与模型组比较,乙醇总提物、氯仿萃取部位、乙酸乙酯萃取部位、正丁醇萃取部位和水提醇沉部位对STZ所致糖尿病小鼠有显著降低血糖的作用,降低胰岛素抵抗指数(IR)及甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C),显著提高胰岛素敏感指数(ISI)和高密度脂蛋白胆固醇(HDL-C)。结论:柿叶提取物有降低STZ致糖尿病小鼠模型的血糖水平,改善胰岛素抵抗,调节脂代谢紊乱的作用,其作用有效成分主要存在于氯仿萃取部位、乙酸乙酯萃取部位、正丁醇萃取部位和水提醇沉部位。     

Hypoglycaemic effect of Opuntia lindheimeri Englem in a diabetic pig model

The hypoglycaemic activity of Opuntia lindheimeri Englem. was investigated in non-diabetic (control pigs) and streptozotocin-induced diabetic pigs using an enteral (oral) route of administration. Following the administration of O. lindheimeri extract (0, 250 or 500 mg/kg body weight), blood glucose concentrations in control pigs fluctuated around initial baseline concentrations, but were not consistently affected by either the dose of O. lindheimeri or by the time following administration. In contrast, administration of O. lindheimeri extract to STZ-treated pigs resulted in both a dose- (p < 0.001) and time-dependent (p < 0.001) decrease in blood glucose concentrations. The hypoglycaemic effect of the extract was apparent within 1 h of administration, with maximal effects occurring at 4 h after administration. These results confirm the hypoglycaemic effect of O. lindheimeri extract in a diabetic pig model. In addition, given the physiological similarities of the pig to humans, this model will be of tremendous use in assessing the long-term effects of Opuntia administration on the secondary problems associated with diabetes.     

黄芪皂苷提取物对糖尿病大鼠肾脏的保护作用

为研究黄芪皂苷提取物对糖尿病大鼠肾脏的保护作用,将经链脲佐菌素诱导成功的32只糖尿病大鼠随机分为黄芪皂苷高、低剂量组、阳性对照组、模型组,分别以黄芪皂苷提取物200,50 mg·kg^-1·d^-1、缬沙坦25 mg·kg^-1·d^-1、生理盐水10 mL·kg^-1·d^-1灌胃,另取8只正常大鼠作为正常对照组(生理盐水10 mL·kg^-1·d^-1),连续给药6周。给药后每周称量大鼠体重,第2,4,6周检测空腹血糖;第6周代谢笼法检测24 h尿量及尿蛋白总量(U-TP);第6周末处死大鼠,心脏取血,检测血清中血尿素氮(BUN)、血肌酐(Scr)、尿酸(UA)、总胆固醇(CH)、甘油三酯(TG)等指标的含量;取双肾,计算肾肥大指数,观察肾脏病理切片。实验结果显示,模型组大鼠的血糖,24 h代谢值,肾肥大指数,U-TP,BUN,Scr,UA,TG较正常组均有显著性升高(P < 0.01,P < 0.05),病理改变明显加重;经黄芪皂苷提取物治疗后,高剂量组大鼠的24 h代谢值,肾肥大指数,U-TP,BUN,Scr,UA,TG均有明显下降(P < 0.01,P < 0.05),低剂量组大鼠的肾肥大指数,BUN,Scr,UA,TG亦下降明显(P < 0.05),2组大鼠的肾脏病理改变均有所减轻。本实验结果说明黄芪皂苷提取物对糖尿病大鼠具有一定的肾脏保护作用。     

芪灯明目胶囊及有效组分对糖尿病视网膜病变大鼠的影响及机制研究

目的:研究芪灯明目胶囊对糖尿病视网膜病变大鼠新生血管形成、炎症反应及氧化应激的影响,探讨芪灯明目胶囊治疗糖尿病视网膜病变可能的作用机制。方法:采用高脂饲料喂养合并腹腔注射链脲佐菌素(STZ)40 mg/kg诱导糖尿病视网膜病变大鼠模型,模型大鼠随机分为模型对照组、羟苯磺酸钙组(150 mg/kg)、芪灯明目胶囊组(600 mg/kg)、葛根总异黄酮组(421 mg/kg)、灯盏细辛总黄酮组(136 mg/kg)、黄芪总皂苷组(43 mg/kg),另设正常对照组。进行体重及血糖的常规监测;造模成功后,连续灌胃给药10周后酶联免疫法测定血清缺氧诱导因子1α(HIF-1α)、血管内皮生长因子(VEGF)、血管紧张素Ⅱ(ANGⅡ)、细胞间黏附分子-1(ICAM-1)、肿瘤坏死因子-α(TNF-α)和血浆超氧化物歧化酶1(SOD1)含量;硝酸盐还原酶法测定血清一氧化氮(NO)含量,竞争性酶联免疫法测定血浆丙二醛(MDA)含量。结果:芪灯明目胶囊及各有效组分对糖尿病视网膜病变模型大鼠体重、血糖均无明显影响。与正常对照组比较,模型大鼠HIF-1α、VEGF、ANGⅡ、ICAM-1、MDA含量显著增加,SOD1含量显著降低;与模型组比较,芪灯明目胶囊组HIF-1α、VEGF、ANGⅡ、MDA含量显著降低,SOD1含量显著升高;葛根总异黄酮组VEGF、MDA含量显著降低,SOD1含量显著升高;灯盏细辛总黄酮组VEGF、ANGⅡ含量显著降低;黄芪总皂苷组MDA含量显著降低;各给药组对炎症因子均无明显影响。主成分分析表明,模型组与正常对照组有较明显区别,阳性药及复方对疾病均有明显的回调作用,单味药中以葛根总异黄酮疗效最强。结论:芪灯明目胶囊对糖尿病视网膜病变大鼠的保护作用可能主要与抑制氧化应激损伤及新生血管的形成有关。     

Antihyperglycaemic and Insulin Release Effects of Aegle marmelos Leaves in Streptozotocin–Diabetic Rats

An aqueous extract of Aegle marmelos leaves exhibited significant hypoglycaemic and antihyperglycaemic effects in normoglycaemic and streptozotocin-diabetic rats, respectively. It also significantly ( p <0.05) increased the plasma insulin levels of diabetic rats. The extract did not show any signs of toxicity and the LD₅₀ was greater than 10.0 g/kg when given orally in rats.     

Hypoglycaemic effect of Rubus fructicosis L. and Globularia alypum L. in normal and streptozotocin-induced diabetic rats

The present study investigates the effect of oral administration of the aqueous extract of Rubus fructicosis L. (RF) and Globularia alypum L. (GA) leaves on blood glucose levels in normal and streptozotocin (STZ) diabetic rats. In normal rats, single and repeated oral administration of RF lowered significantly the blood glucose levels, while, GA treatment did not change blood glucose levels. In STZ rats, single and repeated oral administration of both RF and GA produced significant decrease of blood glucose levels. RF and GA treatments did not affect insulin secretion both in normal and STZ rats, indicating that mechanism(s) by which these plants decrease blood glucose levels is extra-pancreatic at least, for the doses used. In addition, the acute toxicity study revealed that the aqueous extracts may be considered relatively safe since that the LD(50) value was over 8.1 and 14.5 g/kg for RF and GA respectively. These findings indicate that RF and GA represent an effective blood glucose lowering and a potential source for discovery of new orally active component(s) for future therapy.     

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.