不同产地的地黄中梓醇含量比较

目的：测定不同产地地黄中梓醇含量。方法：薄层扫描法，展开剂为氯仿－甲醇－水（7：4：0．5），显色剂为10％硫酸－乙醇，扫描波长为413nm。结果：回归方程：Y＝621．76X＋118．69，r＝0．9966，平均因收率为99．10％，RSD＝2．50％。结论：河南温县产地黄中梓醇含量较高，山东嘉祥产地黄中梓醇含量较低。     

响应面设计优化地黄中梓醇的提取工艺

目的 优化地黄中梓醇的提取工艺。方法 在单因素分析的基础上,以梓醇含量为响应值,采用响应面设计法对其提取工艺进行研究。结果 最佳工艺条件为乙醇浓度80％,提取温度85℃,料液比为1:8,提取时间为1h。结论 优选工艺稳定可靠,可为工业生产提供参考依据。     

高效液相色谱法测定地黄干茎中梓醇的含量

目的：测定地黄干茎中梓醇的含量。方法：采用高效液相色谱（HPLC）法，色谱柱为Diamond C18（150mm×4.6mm,5μm），流动相写乙腈-水（0．5：99．5），流速1．0mL／min，柱温25℃，检测波长210nm，进样量5μL。结果：地黄干茎中梓醇含量为8．5％。结论：地黄中茎中梓醇含量较高，建议对地黄干茎进行研究，以便开发利用。     

蒽酮-硫酸法测定生地黄提取物中总糖的含量

目的:建立生地黄提取物中总糖的含量测定方法.方法:以葡萄糖为对照品采用蒽酮-硫酸法于625nm处测定总糖含量.结果:葡萄糖对照品溶液在0.005～0.05 mg/mL范围内呈良好的线性关系,线性回归方程为A=15.362C 0.000 07,r=0.999 8,平均加样回收率为102.4%,RSD为2.6%.结论:本法操作简便、快速、重现性良好,可用于生地黄提取物中总糖的测定.     

HPLC法同时测定地黄中的5种核苷和碱基的含量(英文)

建立HPLC法同时测定来自中国不同地区的地黄中次黄嘌呤、尿苷、腺嘌呤、鸟苷、腺苷等5种核苷类成分的含量。采用的色谱柱为Diamonsil C18柱(250 mm×4.6 mm,5μm),流动相为乙腈-0.04 mol.L-1磷酸二氢钾溶液梯度洗脱,流速1 mL.min-1,柱温30℃,检测波长254 nm。次黄嘌呤、尿苷、腺嘌呤、鸟苷和腺苷的质量浓度分别在1.0～16.0μg.mL-1(r2=0.999 8),5.0～80.0μg.mL-1(r2=0.999 8),1.0～16.0μg.mL-1(r2=0.999 5),1.25～20.0μg.mL-1(r2=0.999 8)和1.0～16.0μg.mL-1(r2=0.999 8)内线性关系良好,平均回收率为98.8%～100.7%。结果表明,不同地区的地黄中次黄嘌呤、尿苷、腺嘌呤、鸟苷和腺苷的含量有显著性差异。该方法准确,重复性好,适用于地黄药材中5种核苷类成分的含量测定。     

Mediation of beta-endorphin by ginsenoside Rh2 to lower plasma glucose in streptozotocin-induced diabetic rats

We investigated the plasma glucose-lowering mechanism(s) of Rh2, a ginsenoside derived from Panax ginseng, in rats with streptozotocin-induced diabetes (STZ-diabetic rats). After intravenous injection over 120 min into fasting STZ-diabetic rats, Rh2 decreased plasma glucose in a dose-dependent manner. In parallel to the lowering of plasma glucose, an increase of plasma beta-endorphin-like immunoreactivity was observed. In addition, naloxone and naloxonazine at doses sufficient to block opioid mu-receptors inhibited the plasma glucose-lowering action of Rh2 in genetically wild-type, diabetic mice. In contrast, Rh2 failed to lower plasma glucose in opioid mu-receptor knockout diabetic mice. An increase in gene expression at both the mRNA and protein levels of glucose transporter subtype 4 (GLUT 4) was observed in soleus muscle obtained from STZ-diabetic rats treated with Rh2 three times daily for one day; this increase in expression was absent when opioid mu-receptors were blocked. In conclusion, our results suggest that ginsenoside Rh2 may lower plasma glucose in STZ-diabetic rats based on an increase in beta-endorphin secretion that activates opioid mu-receptors thereby resulting in an increased expression of GLUT 4.     

Mediation of beta-endorphin by the isoflavone puerarin to lower plasma glucose in streptozotocin-induced diabetic rats

We investigate the mechanism(s) of plasma glucose lowering action of puerarin in streptozotocin-induced diabetic rats (STZ-diabetic rats). Puerarin at the effective dosage to lower higher plasma glucose increased plasma beta-endorphin-like immunoreactivity (BER) in STZ-diabetic rats. Both effects of puerarin were abolished by the pretreatment with prazosin. Also, puerarin enhanced BER release from isolated rat adrenal medulla in a concentration-dependent manner that can be abolished by prazosin. Moreover, bilateral adrenalectomy in STZ-diabetic rats eliminated the actions of puerarin including the plasma glucose lowering effect and plasma BER elevating effect. In addition, naloxone and naloxonazine inhibited the plasma glucose lowering action of puerarin. Unlike in wild-type diabetic mice, puerarin failed to lower the plasma glucose in opioid micro-receptor knockout diabetic mice. In conclusion, our results suggest that puerarin may activate alpha (1)-adrenoceptors on the adrenal gland to enhance the secretion of beta-endorphin to result in a decrease of plasma glucose in STZ-diabetic rats.     

Hypoglycemic activity of polysaccharide fraction from rhizome of Rehmannia glutinosa Libosch. f. hueichingensis Hsiao and the effect on carbohydrate metabolism in normal mouse liver]

The ethanol precipitate fraction (RG-WP) obtained from the hot water extract from rhizome of Rehmannia glutinosa Libosch. f. hueichingensis Hsiao is mainly composed of pectin-like polysaccharide, and exhibited hypoglycemic activity in normal and streptozotocin-induced mice by intraperitoneal administration of the fraction. The results obtained after chemical modification and proteinase treatments of RG-WP suggest that the activity exists in the polysaccharide moiety. Furthermore, the effect of RG-WP on the activities of enzymes responsible for the glucose metabolism in the liver of normal mouse was studied to elucidate the mechanism of the hypoglycemic activity. Administration of RG-WP to normal mice significantly increased the activities of hepatic glucokinase and glucose-6-phosphatase dehydrogenase, but decreased those of hepatic glucose-6-phosphatase and phosphofructokinase. RG-WP stimulated the secretion of insulin and reduced the glycogen content in the liver of normal mouse.     

Caffeic acid as active principle from the fruit of Xanthium strumarium to lower plasma glucose in diabetic rats

The antihyperglycemic effect of caffeic acid, one of the phenolic compounds contained in the fruit of Xanthium strumarium, was investigated. After an intravenous injection of caffeic acid into diabetic rats of both streptozotocin-induced and insulin-resistant models, a dose-dependent decrease of plasma glucose was observed. However, a similar effect was not produced in normal rats. An insulin-independent action of caffeic acid can thus be considered. Otherwise, this compound reduced the elevation of plasma glucose level in insulin-resistant rats receiving a glucose challenge test. Also, glucose uptake into the isolated adipocytes was raised by caffeic acid in a concentration-dependent manner. Increase of glucose utilization by caffeic acid seems to be responsible for the lowering of plasma glucose.     

Isoferulic acid as active principle from the rhizoma of Cimicifuga dahurica to lower plasma glucose in diabetic rats

Isoferulic acid extracted from the rhizome of Cimicifuga dahurica Maxim. (Ranunculaceae) has been determined to have in vivo antihyperglycemic activity. An antihyperglycemic action of isoferulic acid in spontaneously diabetic rats, similar to type I diabetes, is presented.     

Effects of administration of oral magnesium on plasma glucose and pathological changes in the aorta and pancreas of diabetic rats

1. Magnesium deficiency has recently been proposed as a novel factor implicated in the pathogenesis of the complications of diabetes. The purpose of the present study was to determine the relationship between oral Mg supplementation and changes in plasma glucose, calcium, haemoglobin, Ca/Mg ratio, blood pressure and the histology of the pancreas and vascular system in streptozotocin-induced diabetic rats. 2. Ten days after the induction of diabetes in male Wistar rats, half the diabetic animals were divided into six groups, receiving 0, 1, 3, 10, 30 or 50 g/L MgSO4 added into the drinking water for 8 weeks. Plasma glucose and Mg were measured at days 1, 2, 3, 5, 7, 14 and 21 to find the optimum dose of Mg and the time-course of its effect. In addition, histological observations were undertaken. Eight weeks later, all animals were decapitated, the pancreas and thoracic aorta were removed carefully and immersed immediately in 10% formaldehyde for histological study. 3. To evaluate the effects of Mg on plasma glucose, calcium, haemoglobin, Mg and blood pressure, another group of animals was divided into four experimental groups, as follows: (i) non-diabetic controls received tap water for 8 weeks; (ii) acute diabetics received tap water for 10 days; (iii) chronic diabetic controls received tap water for 8 weeks; and (iv) Mg-treated chronic diabetic rats received 10 g/L MgSO4 added into the drinking water 10 days after the induction of diabetes for 8 weeks. 4. Magnesium dose dependently affects plasma glucose levels. The peak effect was reached during the first 24 h following oral administration. Administration of 10 g/L MgSO4 results in the return of normal structure in the diabetic pancreas and aorta. Moreover, this concentration of MgSO4 causes glucose, haemoglobin, calcium, the Ca/Mg ratio and blood pressure to reach normal levels. Although the Mg level increases slightly following the administration of 10 g/L MgSO4 to diabetic rats, it never reaches control levels. 5. On the basis of the results of the present study, it may be concluded that chronic Mg administration may have beneficial effects on diabetes.     

Effects of oral administration of some herbal extracts on food consumption and blood glucose levels in normal and streptozotocin-treated diabetic rats

Previous studies in our laboratories suggest that oral administration of some herbal extracts reduce blood glucose concentrations in rats, possibly by interfering with food consumption and/or gastrointestinal absorption of food. Accordingly, we monitored the amounts of food consumed and body weights in separate groups of nondiabetic and streptozotocin-treated diabetic rats, orally treated with some plant extracts (20 mg 100 g -1 body weight) daily for 5 weeks. Control animals were administered the vehicle, citrate buffer (0.1 ml 100 g -1 body weight). Separate groups of rats administered allopathic hypoglycemic drugs metformin (50 mg 100 g -1 body weight) or glibenclamide (5 microg 100 g -1 body weight) acted as positive control animals. After 5 weeks, blood glucose concentrations were reduced in all the groups. Tapinanthus nyasicus leaf, Ficus thoningii bark, Solanum incanum fruit, and Morus alba leaf extracts decreased weekly food consumption throughout the 5-week study period. Similar results were obtained for the groups treated with metformin or glibenclamide. However, food consumption was increased by S. incanum root, Aloe chabaudii leaf, or Allium sativum bulb extracts, and this was associated with high prevalence of diarrhea. The herbal extracts and metformin did not affect serum insulin concentration in nondiabetic rats, while glibenclamide increased serum insulin concentration. In conclusion, it may be inferred that the herbal extracts examined produced hypoglycemia, probably by interfering with either food intake or gastrointestinal glucose absorption (as reported for metformin). These findings merit long-term investigation.     

Myricetin as the active principle of Abelmoschus moschatus to lower plasma glucose in streptozotocin-induced diabetic rats

The antihyperglycemic action of myricetin, purified from the aerial part of Abelmoschus moschatus (Malvaceae), was investigated in streptozotocin-induced diabetic rats (STZ-diabetic rats). Bolus intravenous injection of myricetin decreased the plasma glucose concentrations in a dose-dependent manner in STZ-diabetic rats. Myricetin at the effective dose (1.0 mg/kg) significantly attenuated the increase of plasma glucose induced by an intravenous glucose challenge test in normal rats. A stimulatory effect of myricetin on glucose uptake of the soleus muscles isolated from STZ-diabetic rats was obtained in a concentration-dependent manner from 0.01 to 10.0 micromol/L. The increase of glucose utilization by myricetin was further characterized using the enhancement of glycogen synthesis in isolated hepatocytes of STZ-diabetic rats. These results suggest that myricetin has an ability to enhance glucose utilization to lower plasma glucose in diabetic rats lacking insulin.     

Effect of long-term oral administration of green tea extract on weight gain and glucose tolerance in Zucker diabetic (ZDF) rats

There have been some claims that green tea reduces weight and lowers blood glucose in diabetes. Intraperitoneal injections of green tea catechins in diabetic rats have shown beneficial effects. To determine if oral administration of green tea would prevent development of diabetes, young Zucker diabetic rats were dosed with green tea extract containing 50-125 mg/kg of Epigallocatechin gallate (EGCG) starting at 7 weeks of age, before the appearance of excessive weight gain and glucose elevation. While there was a trend toward lower weight gain and average daily glucose, there was no statistically significant difference.     

Effects of metformin on glucose uptake by isolated diaphragm from normal and diabetic rats

The effects of the antidiabetic drug metformin (Nl, Nl-dimethylbiguanide) on glucose uptake by isolated rat diaphragm muscle have been studied. A therapeutic concentration of metformin (10 μg/ml) had no effect on glucose uptake by diaphragm muscle from normal rats incubated in the absence or presence of insulin (100 and 1000 μU/ml), but increased uptake by diaphragm muscle from alloxan-diabetic rats incubated in the presence of insulin (P < 0.05). Diaphragm muscle from normal rats incubated in a medium containing sodium butyrate (0.25 mg/ml) showed a reduction in glucose uptake similar to that seen in muscle from diabetic animals. Metformin (10 μg/ml) also increased glucose uptake by this preparation in the presence of insulin (P < 0.01). A higher concentration of metformin (100 μg/ml) caused a depression of glucose uptake by diaphragms from normal rats, and the necessity for studying therapeutic concentrations of the biguanide drugs is stressed. The relation of these findings to the antidiabetic effect of the drug in man is discussed. The mechanisms involved are discussed in terms of changes in glycogen metabolism.     

地黄寡糖对谷氨酸诱导的海马神经元损伤及葡萄糖摄入的影响

目的观察地黄寡糖(ROS)对谷氨酸(Glu)诱导海马神经元损伤及葡萄糖摄入的影响。方法将培养7d的SD大鼠海马细胞随机分为对照组、活性ROS用药组(4,20及100mg.L-1)、Glu损伤组(Glu0.1mmol.L-1)及Glu损伤前ROS预处理组(ROS+Glu)。采用倒置显微镜观察细胞形态学变化,噻唑蓝(MTT)法测定细胞存活率,比色法测定培养液中的乳酸脱氢酶(LDH)活性,[3H]葡萄糖掺入法测定神经元葡萄糖的摄取。结果单纯ROS4,20及100mg.L-1组与对照组间各指标差异没有显著性(P>0.05)。ROS4,20及100mg.L-1预处理可使Glu损伤的细胞存活率由70.4%分别上升为77.8%,85.2%,92.6%,同时也改善了神经细胞形态并减少LDH的漏出;[3H]葡萄糖掺入量也由Glu损伤组的(1547±120)分别下降为(1384±181),(1303±123),(1134±123)cpm。结论ROS对Glu引起的神经元损伤具有保护作用,这种保护作用可能与其抑制神经细胞对葡萄糖的过度摄入有关。     

Comparative pharmacokinetics of a marker compound,baicalin in KOB extract after oral administration to normal and allergic-induced rats

Abstract

KOB extracts are a polyherbal medicine had been prescribed for the treatment of hyperhydrosis and allergic diseases such as allergic asthma and rhinitis in oriental clinics. Therefore, the pharmacokinetic studies of the KOB extract administered orally to normal rats and rhinitis-induced rats to understand the correlation of the efficacy and plasma concentration of KOB in patients of allergic rhinitis in future were performed. The study was conducted according to administration for pure baicalin in normal rats, baicalin in KOB extract in normal rats and rhinitis-induced rats. Baicalin in rat plasma was analyzed and validated by HPLC analysis. The interday precision based on the standard deviation of replicates of quality control samples ranged from 3.6% to 7.9% with accuracy ranging from 92.9% to 101.2% for baicalin. Based on validated analysis, pharmacokinetic study was carried out. Pure baicalin in normal rats and baicalin in KOB extract in normal rats showed bimodal curves due to direct absorption and glucuronidation. The T_max, C_max and AUC of pure baicalin in normal rats or baicalin in KOB extract in normal rats were 12?h, 0.68?µg/ml and 9.85?µg?h/ml, respectively, or 12?h, 0.46?µg/ml and 6.36?µg?h/ml, respectively. The analytical method showed excellent sensitivity, precision and accuracy, being successfully employed in a pharmacokinetic study of polyherbal medicine, KOB extract. Allergic-induced condition did not affect the pharmacokinetics of KOB extracts, suggesting KOB extracts did not require dosage adjustment in subjects with allergic-induced diseases.     

Transdermally delivered peroxovanadium can lower blood glucose levels in diabetic rats.

The element vanadium can have insulin mimetic properties and therefore has been suggested as a possible therapeutic agent for treatment of diabetes. A series of peroxovanadium compounds that are more potent at lowering blood glucose levels than sodium metavanadate, sodium orthovanadate and vanadyl sulfate have recently been synthesized. These compounds probably will not be orally active so transdermal administration is a potential option. A patch containing either the peroxovanadium compound [VO(O2)2 1-10 phenanthroline], abbreviated bpV(phen), or placebo was placed on the back of streptozotocin induced diabetic rats and was delivered either passively (16 h) or iontophoretically (0.5 mA/cm2 for 4 h). Blood samples were analyzed for glucose and vanadium levels. Mean blood glucose levels were 83+/-1% and 109+/-1% of the starting values for animals iontophoretically treated with bpV(phen) and vehicle, respectively. The compound's insulin mimetic properties were evident within 60 min of current initiation. Blood glucose levels were reduced to 74+/-14% of the original level after 16 h of passive treatment. The compound was ineffective when fed to animals. Transdermal delivery of bpV(phen) resulted in significantly greater blood levels of vanadium than the orally delivered compound (P<0.05). Overall these experiments demonstrate that peroxovanadium delivered through the skin can lower blood glucose levels in rats. Further experiments are warranted to better characterize the nature of the response and to determine the potential for using these compounds in humans.     

生地黄化学成分的分离与鉴定

目的对生地黄的化学成分进行研究。方法运用硅胶柱色谱、Sephadex LH-20柱色谱、制备HPLC等分离手段对生地黄95%乙醇提取物乙酸乙酯萃取层进行化学成分的分离纯化,根据理化性质及波谱数据鉴定其结构。结果分离得到10个化合物,分别鉴定为7-羟基异喹啉(7-isoquinoli-nol,1)、5-羟基-2-羟甲基吡啶(5-hydroxy-2-pyridinemethanol,2)、6-甲基-3-吡啶醇(6-methyl-3-pyr-idinol,3)、红景天苷(salidroside,4)、地黄苷C(rehmaionoside C,5)、地黄苷A(rehmaionoside A,6)、腺嘌呤核苷(adenosine,7)、腺嘌呤(adenine,8)、尿嘧啶核苷(uridine,9)及β-谷甾醇(β-sitosterol,10)[1]。结论化合物1-4为首次从地黄属植物中分离得到。     

Effect of Casearia esculenta root extract on blood glucose and plasma antioxidant status in streptozotocin diabetic rats

Our preliminary study shows that an oral administration of an aqueous extract of Casearia esculenta, an indigenous antidiabetic plant popularly used in South India for diabetes mellitus, lowers blood glucose level under normal and glucose load conditions, and in streptozotocin (STZ)-induced diabetes in rats. The study was further undertaken to evaluate the antioxidant potential of C. esculenta in STZ diabetic rats. Oral administration of C. esculenta root extract at doses of 200 and 300 mg/kg for 45 days resulted in significant reduction in plasma thiobarbituric acid reactive substances (TBARS), hydroperoxide and ceruloplasmin and a significant elevation in plasma reduced glutathione (GSH), ascorbic acid (vitamin C) and alpha-tocopherol (vitamin E). The study indicates that C. esculenta root extract at doses of 200 and 300 mg/kg restored all the antioxidant parameters to near normal value.