银杏叶提取物GBE50对培养细胞内胆固醇代谢的影响

目的研究银杏叶提取物GBE50对不同培养细胞内胆固醇含量的影响,及对HepG2细胞内胆固醇代谢相关基因HMGCR和SREBF2表达的调节。方法采用MTT法观察了GBE50对HepG2细胞生长的影响,用胆固醇氧化酶终点法检测GBE50对培养细胞HepG2、HUVEC、SH-SY5Y总胆固醇含量的影响;用荧光实时定量PCR技术检测了药物处理后HMGCR和SREBF2基因表达水平在HepG2细胞中的改变。结果GBE50在不影响HepG2细胞的增殖的剂量下可不同程度降低培养细胞HepG2,HUVEC内总胆固醇含量。对HepG2细胞内总胆固醇的影响呈一定的剂量及时间-效应关系,同时可以调节其中HMGCR、SREBF2基因的表达。结论GBE50可有效降低部分培养细胞内总胆固醇的含量,部分胆固醇代谢相关基因表达量的改变可能是GBE50调节HepG2细胞内胆固醇水平的机制之一。     

银杏叶提取物GBE50对HepG2细胞甘油三酯代谢的影响

目的观察银杏叶提取物GBE50对HepG2细胞内甘油三酯含量的影响以及甘油三酯代谢关键基因CPT1A表达的调节。方法检测GBE50对培养细胞HepG2甘油三酯含量的影响;测定GBE50处理HepG2细胞24 h后CPT1A酶活性,用定量PCR检测药物处理后CPT1A基因表达水平的改变,Western blot检测CPT1A蛋白表达。结果 GBE50可降低培养细胞HepG2内甘油三酯含量。同时可以促进细胞CPT1A基因的表达,且能增加CPT1A酶的活性。结论 GBE50可有效降低HepG2细胞内甘油三酯的含量,CPT1A基因表达量的改变可能是GBE50调节HepG2细胞内甘油三酯水平的机制之一。     

Interaction of Ginkgo biloba extract (GBE) with hypotensive agent, nicardipine, in rats

The effect of Ginkgo biloba extract (GBE, 0.5%) orally administered for 2 weeks on the antihypertensive action of oral nicardipine was examined in Wistar rats. GBE significantly increased hepatic P-450 content and reduced the hypotensive effect of nicardipine. GBE administration resulted in a significant decrease in maximal nicardipine plasma concentration (Cmax) and the 23-hour area under the curve (AUC0-23). Thus, it is suggested that GBE attenuated the therapeutic potency of nicardipine, probably secondary to increased hepatic drug metabolism.     

银杏叶提取物的研究进展

银杏是最古老的中生代植物,很早就被用作中药,其提取物近年来弓l起国际高度重视。银杏叶中含有黄酮和二萜内酯等化学成分,具有抗氧化、抗衰老等药理作用。综述银杏叶提取物的研发状况、化学成分和药理作用。     

Prevention by a Ginkgo biloba extract (GBE 761) of the dopaminergic neurotoxicity of MPTP

In mice implanted subcutaneously with osmotic minipumps releasing the neurotoxic agent N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 7 days (105 micrograms h-1/mouse) (approximately 100 mg kg-1 day-1) a significant reduction (approximately 25%) in the striatal dopaminergic nerve endings was observed. This neurotoxic effect was prevented by the semi-chronic ingestion of a Ginkgo biloba extract for 17 days (GBE 761, approximately 100 mg kg-1 day-1). The high concentrations (approximately 1 g L-1) at which GBE 761 in-vitro either prevented the uptake of [3H]dopamine by synaptosomes prepared from striatum, or prevented the specific binding of the pure dopamine uptake inhibitor [3H]GBR 12783 to membranes prepared from striatum suggests that the prevention of the MPTP neurotoxicity does not depend on an inhibition of the MPTP uptake by dopamine neurons. This is also suggested by the lack of prevention of the in-vitro striatal binding of [3H]GBR 12783 administered i.v. at a tracer dose, in mice pretreated for 8 days with GBE 761 (100 mg kg-1 p.o.) and receiving a supplementary gastric administration of GBE 761 (100 mg kg-1) 1 h before testing. Similar treatment with GBE 761 did not modify the toxicity for dopamine neurons of 6-hydroxydopamine (20 micrograms) directly injected into the striatum of rats.     

Intestinal absorption and presystemic elimination of the prokinetic agent, EM574, in the rabbit.

The purpose of this study was to characterize the pharmacokinetics and dose proportionality of the prokinetic macrolide, EM574, in rabbits following intravenous dosing, and to determine the intestinal absorption and intestinal and hepatic first-pass elimination of EM574 in rabbits. Two doses (0.05 and 0.25 mg/kg) of EM574 were given to rabbits intravenously in a crossover study. In a separate gut perfusion study, rabbit duodenal or jejunal segments were perfused with EM574 solution at 0.2 mL/min for 130 min. Plasma levels of EM574 were determined by a validated LC-MS/MS assay, and concentrations in perfusate were determined by HPLC with UV detection. The absorptive clearance (PeA) of EM574 was calculated from the steady-state rate of disappearance from the gut lumen during perfusion. The cumulative amount (A(app)) of drug appearing in the systemic circulation was calculated by deconvolution, where the input response was the plasma concentration-time profile during intestinal perfusion and the unit impulse response was the mean profile following intravenous bolus dosing to sham-operated rabbits in a separate experiment. F(g)F(h) was calculated from the ratio of A(app) to the total amount disappeared from gut lumen during perfusion. Hepatic first-pass elimination was measured by intraportal venous infusion. EM574 exhibits linear kinetics over the dose range studied. CL, V(ss), and terminal half-life (mean +/- SD) of EM574 were 68.6 +/- 15.5 mL/min/kg, 13.4 +/- 3.0 L/kg, and 2.7 +/- 0.8 h, respectively. EM574 is expected to be absorbed completely from the rabbit small intestine based on its high jejunal PeA values (8.1 +/- 2.2, and 5.5 +/- 1.5 microL/min/cm following low and high dose perfusion, respectively). The first-pass extraction of EM574 was substantial and dose independent. Mean F(g) and F(h) were 0.14 and 0.20, respectively, suggesting that the intestinal and hepatic first-pass elimination of EM574 were comparable. Deconvolution was successfully applied in the determination of gut wall and hepatic first-pass elimination of EM574.     

银杏叶浸膏浸取溶剂的工艺改进

目的：改进银杏叶浸膏(EGB)浸取溶剂的提取工艺，以提高有效成分的含量与得率。方法：在乙醇-水体系中，采用不同的量、温度进行提取。针对黄酮苷中酚羟基易被氧化而使黄酮含量降低的特点，采用氮气保护提取工艺以避免提取过程中黄酮被氧化。结果：采用氮气作为保护提取，使EGB的得率为2．7％，总黄酮含量为27．1％，内酯含量迭7％以上。结论：用氮气保护工艺可显著提高EGB有效成分含量及得率。     

银杏化学成分、制剂种类和不良反应的研究进展

银杏Ginkgo biloba的叶片和果实分别被《中国药典》收载,主要含有银杏黄酮、萜类内酯、酚酸类、异戊烯醇、甾体类等多种化学成分。以银杏提取物或有效成分开发的制剂有片剂、胶囊、颗粒剂、口服液、注射剂、滴丸、糖浆剂、酊剂等类型,临床上多用于心脑血管疾病的治疗,但也出现过敏、腹泻、出血、肝肾毒性等不良反应报道。对近年来有关银杏及其制剂的化学成分、剂型种类和临床出现的不良反应进行综述,以期为其深度开发与合理利用提供参考。     

应用圆二色谱法验证银杏内酯的绝对构型及银杏提取物的化学成分

目的验证银杏内酯A、B的绝对构型,并对银杏提取物的化学成分进行研究。方法应用圆二色谱法并依据Klyne内酯八区-扇形区律对银杏内酯A、B的绝对构型进行分析讨论;采用反复硅胶柱色谱、聚酰胺柱色谱、Sephadex LH-20柱色谱、高效液相色谱、重结晶等方法分离化学成分,1H-NMR1、3C-NMR等方法进行结构鉴定。结果从银杏提取物中分离得到11个化合物,分别鉴定为:芫花素(genkwanin,1)、异鼠李素(isorhamnetin,2)、山奈酚(kaempferol,3)、槲皮素(quercetin,4)、白果内酯(bilobalide,5)、银杏内酯A(ginkgolide A,6)、银杏内酯B(ginkgolide B,7)、银杏内酯C(ginkgolide C,8)、芦丁(rutin,9)、β-谷甾醇(-βsitosterol,10)、胡萝卜苷(daucosterol,11)。结论银杏内酯A、B的绝对构型与文献报道相符。     

银杏酮酯口服自微乳化给药系统的药物代谢动力学分析

目的：探讨自微乳化给药系统（SMEDDS）促进银杏酮酯（GBE50）口服吸收的效果。方法采用高效液相色谱法,以其市售颗粒剂做对照,桑色素为内标,柚皮素、黄芩素、槲皮素为对照品,进行大鼠体内生物利用度研究,并利用DAS药动学软件处理血药浓度数据。结果血药浓度数据表明,市售的对照品颗粒剂与银杏酮酯口服自微乳化给药系统（GBE50-SMEDDS）对比,发现对照品颗粒剂消除半衰期（t1/2β）、药峰浓度（Cmax）和0-25 h药时曲线下面积（AUC0-25）分别为（4.327±0.768）h,（199.49±24.59） ng/ml,（240.29±24.22）mg/（h·ml） GBE50-SMEDDS则分别为（10.975±1.887）h,（221.53±46.88）ng/ml,（378.83±20.65）mg/（h·ml）,两组t1/2β、Cmax和AUC0-25比较,差异有统计学意义（P〈0.05）。结论与市售颗粒剂相比, GBE50-SMEDDS明显提高了生物利用度,在临床上值得推广应用。     

EGb761, an extract of Ginkgo biloba leaves,reduces insulin resistance in a high-fat-fed mouse model

EGb761, a standardized and well-defined product extract of Ginkgo biloba leaves, has beneficial effects on the treatment of multiple diseases, including diabetes and dyslipidemia. However, it is still unclear whether EGb761 can increase insulin sensitivity. The objectives of the present study are to evaluate the effects of EGb761 on insulin sensitivity in an obese and insulin-resistant mouse model, established through chronic feeding of C57BL/6J mice with a high-fat diet (HFD), and to explore potential mechanisms. Mice fed with HFD for 18 weeks (starting from 4 weeks of age) developed obesity, dyslipidemia (as indicated by biochemical measurements of blood glucose, triglyceride (TG), total cholesterol (TC), and free fatty acids (FFA)), and insulin resistance (as determined by the oral glucose tolerance test (OGTT) and the homeostasis model assessment of insulin resistance (HOMA-IR) index), compared to control mice fed with a standard laboratory chow. Oral treatment of the HFD-fed mice with EGb761, at low (100 mg/kg), medium (200 mg/kg), or high (400 mg/kg) doses, via oral gavage (once daily) for 8 weeks (starting from 26 weeks of age) dose-dependently enhanced glucose tolerance in OGTT, and decreased both the insulin levels (by 29%, 55%, and 70%, respectively), and the HOMA-IR index values (by 50%, 69%, and 80%, respectively). EGb761 treatment also ameliorated HFD-induced obesity, dyslipidemia, and liver injury, as indicated by decreases in body weight (by 4%, 11%, and 16%, respectively), blood TC levels (by 23%, 32%, and 37%, respectively), blood TG levels (by 17%, 23%, and 33%, respectively), blood FAA levels (by 35%, 38%, and 46%, respectively), and liver index (liver weight/body weight) values (by 12.8%, 25%, and 28%, respectively) in the low, medium, and high EGb761 dose groups, respectively. In further mechanism studies, EGb761 was found to protect hepatic insulin receptor β and insulin receptor substrate 1 from HFD-induced degradation, and to keep the AMP-activated protein kinase, which plays a crucial role in reducing lipotoxicity, from HFD-induced inactivation. We conclude that EGb761 can effectively reduce HFD-induced insulin resistance and ameliorate other symptoms of the metabolic syndrome.     

快速高效提取并检测银杏内酯的一种新方法

目的银杏叶是参银复智制剂的君药,寻找快速简便的方法从银杏叶中提取分离检测有效成分白果内酯和银杏内酯A、B、C。方法采用超高效液相色谱法(UPLC),色谱柱:waters BEH C18,2.1×50 mm,1.7μm;流动相:甲醇-四氢呋喃-水(25∶5∶70);流速0.3 ml/min;柱温:30℃;蒸发光散射检测器(ELSD)。银杏叶采用7倍70%乙醇溶液回流提取2次,3 h/次,合并提取液,减压回收乙醇,加3倍量水使沉淀,过滤,滤液分别上大孔吸附树脂D101、AB-8、D201、聚酰胺树脂,考察洗脱剂的浓度和用量。结果选择聚酰胺树脂,2倍水洗后,用2³倍树脂床体积10%乙醇溶液洗脱,收集洗脱液,减压浓缩干燥,检测含量,银杏萜类内酯的含量都在35%以上,有效部位得率在90%以上。结论超高效液相色谱法简便快速、回收率高,为银杏叶中内酯类物质的提取分离检测提供了一种新方法。     

Occurrence of neurotoxic 4'-O-methylpyridoxine in Ginkgo biloba leaves, Ginkgo medications and Japanese Ginkgo food

4'-O-methylpyridoxine (ginkgotoxin) is a neurotoxic antivitamin B6 which occurs in Ginkgo biloba L. seeds. Contrary to a previous report by Wada et al., the toxin was also detected in Ginkgo biloba leaves. The leaves are a source of extracts (e.g. EGb761) employed in the preparation of Ginkgo medications. Consequently the toxin is also present in Ginkgo medications and is even detectable in homoeopathic preparations. The toxin occurs also in boiled Japanese Ginkgo food. However, the amount of the toxin is likely to be too low to exert a detrimental effect after administration of the medication or ingestion of food.     

银杏叶提取成分及其单体对脑缺血的保护作用

目的综述了银杏叶提取物和单体抗脑缺血的体内外实验研究及其神经保护作用的自由基机制。方法根据近年国内外公开发表的有关研究论文 ,按整体动物脑缺血的实验模型以及体外培养的神经细胞缺血缺氧实验模型的顺序 ,重点讨论银杏叶提取物、黄酮苷、萜烯内酯和单体内酯这几种成分。同时从药物对自由基的影响方面进行了机制的分析。结果与结论各种成分对实验动物的体内外脑缺血缺氧模型均有不同程度的神经保护作用 ,它们对自由基的影响可能是其抗脑缺血的作用机制之一。     

Clinical use and molecular mechanisms of action of extract of Ginkgo biloba leaves in cardiovascular diseases

Ginkgo biloba is one of the oldest living tree species that has been referred to as a living fossil. Extract from Ginkgo biloba leaves (GBE) is among the most commonly used herbal drugs and is popularized for its alleged tonic effect and possible curative and restorative properties. There is an increasing evidence of the potential role of GBE in treating cardiovascular diseases. We examined the history of GBE usage and reviewed the literature on its effects on the cardiovascular system. In the extensive studies involving cell cultures and animal models, GBE has been shown to exert its action through diverse mechanisms. GBE has been reported to have antioxidatant properties, to modify vasomotor function, to reduce adhesion of blood cells to endothelium, to inhibit activation of platelets and smooth muscle cells, to affect ion channels, and to alter signal transduction. In addition, relevant clinical trials with CBE are being carried out, particularly in the treatment of arterial and venous insufficiency and in the prevention of thrombosis. Finally, the controversial clinical findings and the possible adverse interactions between GBE and other drugs are discussed. This review underscores the potential benefits of Ginkgo biloba in cardiovascular diseases, highlights the gaps in our current research, and suggests the necessity for more rigorous systematic investigation of cardiovascular properties of CBE.     

银杏叶提取物对小鼠脑缺血再灌注损伤的拮抗作用

目的　研究银杏叶提取物 (EGb76 1)对小鼠脑缺血再灌注损伤的拮抗作用及其作用机理。方法双侧颈总动脉加迷走神经结扎法 (左侧不完全结扎 )造成小鼠局部脑缺血 5min ,再灌注 30min。DTNB法测定谷胱甘肽过氧化物酶 (GSH px)活性 ;荧光分光光度法测定脑组织线粒体膜蛋白结合铽 ;被动性回避行为学模型检测小鼠记忆能力 ;海马形态学观察。结果　小鼠局部脑缺血再灌注后 ,海马GSH px活性降低 ,海马 ,下丘脑和皮质线粒体膜蛋白结合铽降低 ,说明结合钙升高 ,海马CA1区神经元损伤 ,小鼠的记忆能力下降。EGb76 1(2 5 ,5 0 ,10 0mg·kg- 1·d- 1,ig ,连续 7d)能逆转上述变化。结论　EGb76 1拮抗小鼠脑缺血再灌注损伤的作用与抗氧化及阻止线粒体膜蛋白结合钙增加有关     

Inhibition of serum deprivation- and staurosporine-induced neuronal apoptosis by Ginkgo biloba extract and some of its constituents

Previous studies have already demonstrated that some constituents of an extract of Ginkgo biloba (EGb), such as ginkgolide B and bilobalide, protect cultured neurons from hypoxia- and glutamate-induced damage. This prompted us to investigate whether they were also able to inhibit neuronal apoptosis. We induced apoptosis in cultured chick embryonic neurons as well as in mixed cultures of neurons and astrocytes from neonatal rat hippocampus by serum deprivation and staurosporine. The increase in the percentage of apoptotic chick neurons from 12% in controls to 30% after 24 h of serum deprivation was reduced to control level by EGb (10 mg/l), ginkgolide B (10 microM), ginkgolide J (100 microM) and bilobalide (1 microM). After treatment with staurosporine (200 nM) for 24 h we observed 74% apoptotic chick neurons. This percentage of apoptotic neurons was reduced to 24%, 62% and 31% in the presence of EGb (100 mg/l), ginkgolide J (100 microM) and ginkgolide B (10 microM), respectively. Bilobalide (10 microM) decreased apoptotic damage induced by staurosporine treatment for 12 h nearly to the control level. In mixed neuronal/glial cultures, the extract of EGb (100 mg/l) and bilobalide (100 microM) rescued rat neurons from apoptosis caused by serum deprivation, whereas, bilobalide (100 microM) and ginkgolide B (100 microM) reduced staurosporine-induced apoptotic damage. Ginkgolide A revealed no anti-apoptotic effect in either serum-deprived or staurosporine-treated neurons. Our results suggest that EGb and some of its constituents possess anti-apoptotic capacity and that bilobalide is the most potent constituent.     

银杏总黄酮苷在大鼠体内的肠吸收动力学特征

目的　考察银杏总黄酮苷(TFG)在大鼠体内的肠吸收动力学特征。方法　对大鼠的十二指肠、空肠、回肠和结肠4个部位分别进行在体肠吸收实验,计算和比较TFG在各部位的吸收速率常数(Ka)和2h的累积吸收量。结果　TFG在大鼠肠道各部位的Ka 按十二指肠、空肠、回肠、结肠依次下降;在10 0～4 0 0mg·L-1浓度范围内,各肠段TFG的吸收量与浓度有良好线性关系(r>0 .994 4 ) ,Ka 值基本不变。结论　TFG在大鼠肠道内的吸收呈现一级吸收动力学特征,其吸收机制为被动扩散     

A standardized extract of Ginkgo biloba suppresses doxorubicin-induced oxidative stress and p53-mediated mitochondrial apoptosis in rat testes

Background and purpose

Doxorubicin evokes oxidative stress and precipitates cell apoptosis in testicular tissues. The aim of this study was to investigate whether the Ginkgo biloba extract 761 (EGb), a widely used herbal medicine with potent anti-oxidant and anti-apoptotic properties, could protect testes from such doxorubicin injury.

Experimental approach

Sprague-Dawley male rats (8 weeks old) were given vehicle, doxorubicin alone (3 mg kg⁻¹ every 2 days for three doses), EGb alone (5 mg kg⁻¹ every 2 days for three doses), or EGb followed by doxorubicin (each dose administered 1 day after EGb). At 7 days after the first drug treatment oxidative and apoptotic testicular toxicity was evaluated by biochemical, histological and flow cytometric analyses.

Key results

Compared with controls, testes from doxorubicin-treated rats displayed impaired spermatogenesis, depleted haploid germ cell subpopulations, increased lipid peroxidation products (malondialdehyde), depressed antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase and glutathione), reduced antioxidant enzyme expression (superoxide dismutase) and elevated apoptotic indexes (pro-apoptotic modulation of Bcl-2 family proteins, intensification of p53 and Apaf-1, release of mitochondrial cytochrome c, activation of caspase-3 and increase of terminal deoxynucleotidyl transferase nick-end labelling/sub-haploid cells), while EGb pretreatment effectively alleviated all of these doxorubicin-induced abnormalities in testes.

Conclusions and implications

These results demonstrate that EGb protected against the oxidative and apoptotic actions of doxorubicin on testes. EGb may be a promising adjuvant therapy medicine, potentially ameliorating testicular toxicity of this anti-neoplastic agent in clinical practice.     

Influence of ethanol extract of Ginkgo biloba leaves on the isolated rat heart work and mitochondria functions

In this study, we attempted to elucidate whether the effects of ethanol extract of Ginkgo biloba leaves (GBE) observed previously on isolated rat heart mitochondria may be realized in situ (in case of isolated heart perfused under normal conditions and under ischemia-reperfusion). We found that GBE at low concentrations (0.01, 0.05, and 0.1 μL/mL) does not affect the heart rate and parameters of electrocardiogram (ECG) but produces a small increase in the coronary flow. Higher concentration of GBE (0.2 and 0.3 μL/mL) diminished the heart rate, decreased the coronary flow, and tended to enhance the parameters of ECG. The contractility of isolated rat heart and mitochondrial nicotinamide adenine dinucleotide reduced form fluorescence decreased in a GBE concentration-dependent manner. Mitochondria isolated from hearts pre-perfused with GBE (0.05 μL/mL) for 20 minutes before nonflow global ischemia-reperfusion (45 min/15 min) showed higher respiratory rates with pyruvate + malate in state 2 and state 3, higher respiratory control index, and diminished H?O? generation compared with untreated group. Higher GBE concentration, 0.4 μL/mL, had no effect on H2O2 generation and did not prevent the ischemia-reperfusion-induced decrease of pyruvate + malate oxidation in state 3 but even enhanced it. However, in the case of nonischemic perfusions, this GBE concentration had no significant effect on these parameters of respiratory functions of isolated heart mitochondria.