Biphasic effects of Morus alba leaves green tea extract on mice in chronic forced swimming model

In this study, the effects of an aqueous extract of Morus alba leaves green tea (ME) on mouse behaviors (depression, anxiety, climbing activity and thermal response), muscle coordination and muscle strength were studied. Male IRC mice received a single intraperitoneal injection of either the ME, desipramine or diazepam. Thirty minutes after injection, the mice were tested in all experimental models. A significant antidepressant-like effect could be detected in the animals receiving either 100 or 200 mg/kg ME. The effect of 200 mg/kg ME in decreasing the immobility time was comparable to 10 mg/kg desipramine. With higher dose (1000 mg/kg), a significant increase in immobility time could be observed. In the elevated plus maze, no increase in time in the open arm could be observed in mice treated with ME at either 100 or 200 mg/kg. However, high doses of ME (500 or 1000 mg/kg) decreased both time in the open arm and the number of entries in the maze. No change in thermal response could be seen in mice treated with ME at doses up to 500 mg/kg, however, at 1000 mg/kg, the response time to heat was increased significantly. The ME at either 500 or 1000 mg/kg also decreased muscle coordination, strength and climbing activity significantly when compared with the control. This study suggests that ME possesses an antidepressant- without an anxiolytic-like effect, however, at high doses, the extract might show the sedative effect and alter other functions such as muscle strength, animal activity in the maze and pain response.     

The antioxidant activity of standardized extract of Ginkgo biloba (EGb 761) in rats

The standardized extract of Ginkgo biloba (EGb 761) has been widely employed for its significant benefit in neurodegenerative disorders. Although antioxidative actions have been attributed to this extract, the mechanisms of the multiple principles involved in this pharmacological activity are not completely established. Parkinson's and Alzheimer's diseases are frequently associated with oxidative stress and defects in the cellular protective mechanisms. In this study, the lipid peroxidation (LPO) and the activity of the antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD) were evaluated in the hippocampus, striatum and substantia nigra (SN) of rats treated with EGb 761. An increase in the CAT and SOD activities in the hippocampus, striatum and SN, and a decrease of the LPO in the hippocampus were observed. These data are additional to the antioxidant properties of EGb 761 reported in the literature and indicate a possible role for the extract in the treatment of diseases involving free radicals and oxidative damage.     

Glabridin, a phytoestrogen from licorice root, up-regulates manganese superoxide dismutase, catalase and paraoxonase 2 under glucose stress

The risk of death from cardiovascular diseases (CVDs), which are exacerbated by oxidative stress, is higher in diabetic women. This phenomenon has been attributed to the loss of estradiol-vascular protection. Such knowledge led us to examine the potential of glabridin, a phytoestrogen, to substitute estradiol up-regulation of antioxidant enzymes under high glucose conditions. Chronic glucose stress was found to down-regulate catalase (CAT) and paraoxonase 2 (PON2) mRNA expression by 20% and 17%, respectively, and to decrease PON2 activity by 83% in macrophages. Inflammatory conditions had an additive effect on PON2 expression in a time-dependent manner. Treatment with glabridin, under high glucose stress, increased PON2 activity by 60% and up-regulated its mRNA expression by 3.5 fold. Furthermore, glabridin up-regulated the expression of manganese superoxide dismutase (Mn-SOD) and CAT in monocytes. In conclusion, glabridin has the potential of strengthening the antioxidant defense mechanism and may serve as an antiatherogenic agent in diabetes.     

桑叶多糖的提取纯化及其含量测定

目的：纯化桑叶多糖并测定其含量。方法：采用10％三氯乙酸、大孔树脂初步纯化桑叶多糖，采用硫酸-蒽酮法对其含量进行测定。结果：用三氯乙酸除蛋白的方法是可行的；桑叶中多糖的平均含量为2．62％，平均回收率为98．81％，RSD为2．08％。结论：该法可作为桑叶中多糖的含量测定方法。     

Curcumin and a Morus alba extract reduce pro-inflammatory effects of resistin in human endothelial cells

Resistin is a cytokine which plays an important role in cardiovascular disease by influencing systemic inflammation and endothelial activation. In human endothelial cells (HEC) it increases the expression of P‐selectin and fractalkine, and enhances monocyte adhesion by antioxidant mechanisms. This study investigated whether the natural antioxidants curcumin (CC) and an extract of Morus alba leaves (MA) have protective effects in resistin‐activated HEC. HEC were exposed to 100 ng/mL resistin for 6 and 18 h in the absence or presence of MA or CC and the expression of fractalkine and P‐selectin was determined by RT‐PCR and western blot. Intracellular accumulation of reactive oxygen species (ROS) was monitored by fluorimetry and NADPH oxidase activity by a lucigenin‐enhanced chemiluminescence assay. In addition, adhesion assays using the monocytic U937 cells were performed. The results showed that treatment of HEC exposed to resistin with MA and CC: (1) inhibited significantly P‐selectin and fractalkine expression, (2) inhibited the increase in the intracellular ROS level, (3) reduced NADPH activation and (4) reduced monocytes adhesion to HEC. The results indicate that MA and curcumin target resistin‐induced human endothelial activation partly via antioxidant mechanisms and suggest that they may represent therapeutic agents in vascular disease mediated by resistin. Copyright © 2011 John Wiley & Sons, Ltd.     

银杏叶提取物对大鼠血流动力学的影响

目的银杏叶提取物(GBE)对正常麻醉大鼠血流动力学影响进行实验研究.方法采用多道生理记录仪记录iv给药后大鼠血流动力学的改变及对由血小板活化因子(PAF)诱导大鼠血流动力学改变的影响.结果ivGBE100,200mg/kg仅引起大鼠血压的轻度升高,分别为(1.2±0.6)和(1.3±0.9)kPa,且30min后即可恢复至正常对照水平,对其余血流动力学参数无影响;大鼠ivPAF90ng/kg可引起大鼠血压显著下降、心律不齐、心肌收缩力减弱,预先给100mg/kgGBE可完全取消上述PAF效应.结论GBE能引起大鼠血压的短暂轻度升高,并能拮抗PAF引起的心血管功能改变,是一种有效的抗PAF活性药物.     

Aqueous garlic extract attenuates hepatitis and oxidative stress induced by galactosamine/lipoploysaccharide in rats

Injection of D-galactosamine and lipopolysaccharide (DGaIN/LPS) is useful as an experimental model of acute hepatic damage. Juvenile rats were used for investigation. The hepatoprotective activity of aqueous garlic (Allium sativum) extract (AGE) at a dose of 300 mg/kg body weight for 14 days, intraperitoneal (i.p.) prior to the induction of DGalN/LPS, was investigated against DGalN/LPS-induced hepatitis in rats. DGalN/LPS (300 mg/kg body weight/30 microg/kg body weight, i.p.), induced hepatic damage that was manifested by a significant increase in the activities of marker enzymes [alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and gamma glutamyl transferase (gamma GT)], bilirubin, lipid peroxides (LPO), tumor necrosis factor (TNF-alpha) and myeloperoxidase (MPO) activity level in serum. Also, the lipid profile in serum and liver homogenate including total cholesterol, triglycerides, free fatty acids and phospholipids were significantly deteriorated. The antioxidant enzyme activities (superoxide dismutase, SOD; reduced glutathione, GSH; catalase, CAT and glutathione peroxidase, GPX) in liver homogenate were significantly decreased in the DGalN/LPS. Pretreatment of rats with AGE reversed these altered parameters near to normal control values. Results of this study revealed that AGE could afford a significant protection in the alleviation of DGalN/LPS-induced hepatic damage.     

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.     

2种采血方法大鼠应激神经内分泌反应的比较研究

目的探讨眼眶静脉丛和舌下静脉2种采血方法中,可作为大鼠较大剂量采血的较优方法。方法选择眼眶静脉丛和舌下静脉2种采血方法,分别在0、20、60 min时间点对Wistar大鼠进行3次采血,测定各组血糖(GLU)、皮质酮(CORT)及β-内啡肽(β-EP)水平,分析不同采血方法对大鼠的影响。结果眼眶静脉丛采血组在第1次采血后GLU有显著升高,在第2次采血后有显著降低;舌下静脉采血组GLU在第1次采血后有极显著降低,第2次采血后仍保持较低水平。与对照组相比,3次采血后2个采血组的血清CORT均有显著升高,β-EP均无显著性变化。结论舌下静脉采血可替代眼眶静脉丛采血作为优化的大鼠较大剂量采血方法。     

Protective effects of Phellinus linteus extract against iron overload-mediated oxidative stress in cultured rat hepatocytes

Phellinus linteus (PL) mushroom has been reported to possess antioxidant activity. The present study was designed to investigate whether an ethanol extract obtained from PL might ameliorate oxidative stress and enhance antioxidant enzyme activities in primary rat hepatocytes, which were overloaded with iron using ferric nitrilotriacetate (FeNTA) complex. FeNTA enables hepatocytes to accumulate substantially redox-active iron and stimulates the production of injurious hydroxyl radicals, which in turn, initiate oxidative stress-mediated cytotoxicity. The results showed that pretreatment of hepatocytes with PL extract (50, 100 and 200 microg/mL) for 24 h significantly reversed FeNTA-induced cell viability loss, lactate dehydrogenase leakage (LDH), lipid peroxidation (LPO) and protein carbonyl formation in a dose-dependent manner. It was further observed that PL extract produced an inhibitory effect on intracellular reactive oxygen species (ROS) formation caused by FeNTA. Concomitantly, the amount of GSH content and the activities of glutathione reductase (GSH Rd) and glutathione peroxidase (GSH Px) in hepatocytes pretreated with PL extract increased substantially compared with those treated with FeNTA alone. These results suggest that PL may be useful in protecting against FeNTA-induced oxidative damage and also be capable of attenuating cytotoxicity of other oxidants.     

大豆胚轴提取物对人餐后高血糖的抑制作用

目的　观察大豆胚轴提取物对人餐后血糖和糖耐量的影响。方法　健康受试者进餐或食用蔗糖时 ,同时服用大豆胚轴提取物 ,检测餐后血糖和糖耐量。结果　餐后血糖水平明显降低 ,糖耐量显著改善。结论　大豆胚轴提取物具有抗餐后高血糖作用 ,长期服用有助于抑制糖尿病患者餐后血糖的持续升高。     

Endothelium-independent relaxation and contraction of rat aorta induced by ethyl acetate extract from leaves of Morus alba (L.)

Aim of the study

Based on screening for vasoactive traditional Chinese medicinal herbs, the present study was performed to investigate the vasoactive effects of an ethyl acetate extract from leaves of Morus alba (L.) (ELM) on rat thoracic aorta and the mechanisms underlying these effects.

Materials and methods

Isolated rat thoracic rings were mounted in an organ bath system and the effects of ELM on their responses were evaluated.

Results

ELM (0.125–32.000 g/l) induced a concentration-dependent relaxation (P < 0.01 vs. control) both in endothelium-intact and -denuded aortas precontracted by high K⁺ (6 × 10⁻² M) or 10⁻⁶ M phenylephrine (PE). In endothelium-denuded aortas, ELM at the EC₅₀ concentration reduced Ca²⁺-induced contraction (P < 0.01 vs. control) after PE or KCl had generated a stable contraction in Ca²⁺-free solution. And after incubation with verapamil, ELM induced contraction in endothelium-denuded aortas precontracted by PE (P < 0.01 vs. control); this was abolished by ruthenium red (P < 0.01 vs. ELM-treated endothelium-denuded group; P > 0.05 vs. control), but not by heparin (P > 0.01 vs. ELM-treated endothelium-denuded group; P < 0.01 vs. control).

Conclusions

The results showed that ELM had dual vasoactive effects, and the relaxation was greater than the contraction. The relaxation was mediated by inhibition of voltage- and receptor-dependent Ca²⁺ channels in vascular smooth muscle cells, while the contraction occurred via activation of ryanodine receptors in the sarcoplasmic reticulum.     

芪龙胶囊对急性应激血瘀大鼠血液流变学的影响

目的 :研究芪龙胶囊对急性应激血瘀大鼠血液流变学的改善作用。方法 :急性应激血瘀大鼠模型采用在两次皮下注射肾上腺素 1mg·kg^-1之间将大鼠置于冰水中 5mim的方法建立。利用此模型观察芪龙胶囊对模型大鼠全血黏度、全血还原黏度、血浆黏度、红细胞压积、红细胞变形性、红细胞聚集性等血液流变学指标的作用。结果 :芪龙胶囊 0.6 ,0.3,0.15g·kg^-1均能明显降低高、中、低切变率下全血黏度 ,降低中、低切变率下全血还原黏度和红细胞压积 ,降低红细胞聚集性 ,并能够显著升高红细胞变形性 (与模型组比较P <0.05 ,P <0.01)。芪龙胶囊 0.6 ,0.3g·kg^-1还可降低模型大鼠血浆黏度 (P <0.05 ,P <0.0 1)。结论 :芪龙胶囊可明显改善急性应激血瘀大鼠多项血液流变学指标。     

番石榴叶调节小鼠血糖血脂作用的研究

目的:研究番石榴叶对实验性糖尿病小鼠和高脂血症小鼠的影响。方法:采用链脲佐菌素复制糖尿病小鼠模型,观察番石榴叶对小鼠空腹血糖和糖耐量的影响;采用脂肪乳剂灌胃建立高血脂小鼠模型,观察番石榴叶对小鼠血脂水平及肝脏指数的影响。结果:番石榴叶高、低剂量(10g/kg、5g/kg)均能明显降低糖尿病小鼠空腹血糖,改善其糖耐量,也能明显调节高脂血症小鼠的血脂水平,高剂量还能降低高脂血症小鼠的肝脏指数。结论:番石榴叶有明显的降糖和调脂作用,为其临床应用和研究开发提供实验依据。     

Effect of the alcohol extract of the seeds of Mucuna pruriens on free radicals and oxidative stress in albino rats

In vitro and in vivo studies were made with an alcohol extract of the seeds of Mucuna pruriens (Fabaceae) to investigate its antioxidant property. In vitro studies were carried out in rat liver homogenate to investigate the chemical interaction of various phytochemicals with different species of free radicals. The effect was also checked on iron-induced lipid peroxidation, oxidation of GSH content, and its interaction with hydroxyl and superoxide radicals. There was no change on the rate of aerial oxidation of GSH content but it significantly inhibited FeSO(4) induced lipid peroxidation. It also inhibited the specific chemical reactions induced by superoxides and hydroxyl radicals. The removal of these species was through direct chemical interaction. An in vivo study on albino rats for 30 days showed no toxic effect up to a dose of 600 mg/kg body weight, on oral administration. There was no change in the level of TBA-reactive substances, reduced glutathione content and SOD activity in the liver. The activity of serum GOT, GPT and alkaline phosphatase was also unchanged. Thus it could be concluded that the alcohol extract of the seeds of M. pruriens has an antilipid peroxidation property, which is mediated through the removal of superoxides and hydroxyl radicals.     

血府逐瘀汤对大鼠肝脏抗氧化酶及药物代谢酶的影响

血府逐瘀汤是一传统名方,在中国用于治疗心脑血管疾病已有100多年的历史,但血府逐瘀汤对抗氧化酶及药物代谢酶的影响尚未有报道。该研究观察血府逐瘀汤对大鼠肝脏内抗氧化酶及药物代谢酶的活性影响。采用雄性SD大鼠,血府逐瘀汤水提物3.51,7.02,14.04 g·kg-1,每日1次,连续灌胃15 d,末次给药后,动物取血,分离血清,摘除肝脏,差速离心法制备肝脏组织液、胞浆液及微粒体,测定其抗氧化酶及药物代谢酶。结果发现血府逐瘀汤对血清中AST无显著影响,高剂量组明显降低ALT的活性和Cr,BUN的含量(P<0.05);中、高剂量组显著升高GPX活性(P<0.05),高剂量显著升高CAT活性(P<0.05),对T-SOD无显著影响;在肝组织液中,血府低、中剂量组显著升高GPX活性(P<0.05);所有剂量组对GST,CAT,T-SOD的活性均无显著影响。在肝胞浆液中,低剂量组显著升高GST活性(P<0.05),低、中剂量显著升高T-SOD活性(P<0.05),对GPX,CAT无显著影响。在微粒体中,血府逐瘀汤水提物对细胞色素b5含量、NADPH-细胞色素还原酶、CYP3A,CYP2E1,UGT活性无显著影响;血府低、中剂量组可显著诱导GST活性(P<0.05);低、中、高剂量组显著升高GSH的含量。以上结果表明血府逐瘀汤可诱导GPX,CAT,T-SOD,GST和升高GSH,提示血府逐瘀汤可能具有解毒和抗氧化功能。     

苦瓜乙醇提取物对肥胖大鼠糖代谢和内脏脂肪的影响

目的 研究苦瓜乙醇提取物对喂饲高脂饲料所致肥胖大鼠糖代谢和内脏脂肪量的影响.方法 高脂饲料饲养制备肥胖大鼠模型.肥胖大鼠随机分为模型组,苦瓜乙醇提取物低、中、高剂量(9、18、36 g/kg)组,左旋肉碱(600 mg/kg)阳性对照组,另设对照组(正常饲料饲养)和苦瓜乙醇提取物36 g/kg给药组.各组大鼠每天ig相应药物或等体积0.5％羧甲基纤维素钠溶液,每天记录摄食量,每周记录体质量.给药第6周进行糖耐量实验:给药7周后所有动物禁食18h,麻醉后腹主动脉采血,检测血清葡萄糖和胰岛素水平;分离附睾、肾周和肠系膜脂肪并称质量,附睾脂肪组织随后进行HE染色检测脂肪细胞病变.结果 苦瓜乙醇提取物36 g/kg能够明显降低肥胖大鼠体质量,抑制大鼠食物利用率,减少附睾、肾周和肠系膜白色脂肪量,降低空腹血糖浓度,抑制附睾脂肪细胞肥大;苦瓜乙醇提取物18 g/kg也明显降低肥胖大鼠附睾脂肪质量.但苦瓜乙醇提取物对肥胖大鼠的糖耐量和胰岛素抵抗指数无明显影响.结论 苦瓜乙醇提取物通过抑制肥胖大鼠内脏脂肪聚积和附睾脂肪细胞肥大以及降低空腹血糖浓度发挥减肥和抗糖尿病作用.     

升清降糖合剂对糖尿病大鼠胰岛细胞形态及功能的影响

目的:探讨升清降糖合剂(简称SQ)对糖尿病大鼠空腹血糖水平和胰岛细胞形态及功能的影响。方法:腹腔注射链脲佐菌素(STZ)诱导建立糖尿病大鼠模型。根据不同的干预方式将糖尿病大鼠分为模型对照组、SQ低剂量组、SQ中剂量组、SQ高剂量组。每两周测空腹血糖和体重,于干预后第八周末,各组大鼠麻醉后采集血样,ELISA法测定血清C肽水平,取胰腺组织HE染色观察病理学改变。结果:空腹血糖水平,模型对照组(26.92±3.68)SQ低剂量组(23.87±2.86)SQ高剂量组(20.66±2.81)SQ中剂量组(20.66±2.81)正常对照组(4.55±0.57),SQ中、高剂量与模型对照组比较差异有统计学意义(P0.05)。血清C肽水平,正常对照组(2.27±0.47)SQ中剂量组(1.76±0.91)SQ高剂量组(1.74±0.79)SQ低剂量组(1.11±0.36)模型对照组(0.70±0.62),SQ中、高剂量组与模型对照组比较差异有统计学意义(P0.05)。胰岛病理切片形态学观察发现,模型对照组大鼠胰岛细胞数量减少,排列紊乱,胞质呈空泡状,部分细胞核固缩;SQ各组大鼠胰岛细胞受损程度较轻。结论 SQ能明显降低糖尿病大鼠的空腹血糖水平,提高血清C肽水平,保护胰岛细胞功能。     

Beneficial effects of Centella asiatica aqueous extract against arsenic-induced oxidative stress and essential metal status in rats

The efficacy of an aqueous extract of Centella asiatica (100, 200 and 500 mg/kg for 5 consecutive days) was studied in the depletion of arsenic and in the recovery of a few altered biochemical variables in arsenic pre-exposed rats (20 ppm in drinking water for 5 weeks). Exposure to arsenic significantly depleted delta-aminolevulinic acid dehydratase (ALAD) activity, reduced glutathione (GSH) level, superoxide dismutase (SOD) and increased thiobarbituric acid reactive substance (TBARS) activity in red blood cells. Significant depletion of ALAD activity, GSH level, glutathione peroxidase (GPx), SOD and catalase (CAT) activities and an increase in TBARS levels in liver tissues was also noted. There was a significant depletion of SOD, CAT and GPx activities in kidneys and an increased TBARS levels in kidney and brain accompanied by increased arsenic concentration in blood and soft tissues. Treatment with aqueous extract of Centella asiatica provided significant protection against ALAD, GSH and TBARS levels, particularly at doses of 200 and 500 mg. Centella asiatica also provided significant recovery in the inhibited liver ALAD and G6PD activities. Arsenic concentration in blood and soft tissues remained uninfluenced after Centella asiatica administration. The present study thus suggests a beneficial effect of Centella asiatica against arsenic-induced oxidative stress but possesses no chelating property.