银杏内酯的提取纯化与分离

以银杏叶标准化提取物为原料,经乙酸乙酯提取纯化得高纯度的银杏内酯混合物,方法简单,银杏内酯含量达95．1％,再以其混合物经硅胶柱层析,得到银杏内酯A,银杏内酯B及银杏内酯C的单体化合物。     

银杏内酯药代动力学及其剂型的研究进展

银杏内酯是银杏叶的重要活性成分,主要包括银杏内酯A、B、C和白果内酯等,具有调节血压和拮抗血小板活化因子等多种药理作用。本文总结分析了近年来有关银杏内酯药代动力学的研究,主要包括银杏内酯在体内吸收、分布、代谢和排泄的过程。为了提高其生物利用度和药效,现研究者采用多种新剂型、新技术制备银杏内酯制剂。文中归纳总结了银杏内酯制剂的制备和特点,旨在为提高银杏内酯生物利用度的研究提供参考。     

大孔树脂对银杏根皮中银杏内酯C富集工艺研究

目的:建立银杏根皮中银杏内酯C的大孔树脂分离纯化工艺。方法:以银杏根皮为原料,研究大孔树脂分离纯化银杏根皮中银杏内酯C工艺中树脂型号、树脂吸附及洗脱参数。结果:树脂选型为AB-8,其对银杏内酯C的最大静态吸附容量为15.81 mg/g;树脂径高比为1∶8;洗脱流速为3 m L/min;除杂用3 BV纯水;富集洗脱银杏内酯C用8 BV 30%乙醇,柱洗脱液浓缩得银杏根皮提取物,其银杏内酯C含量可从银杏根皮中的0.13%提高至5.24%。结论:本方法可有效地初步分离富集银杏根皮中的银杏内酯C。     

银杏萜内酯提取分离工艺研究

银杏内酯A、B、C及白果内酯(文中简称GA、GB、GC和BB)分子极性依次增强。因此,不同极性的有机溶剂对4种银杏萜内酯有不同的选择溶解性。通过丙酮,乙酸乙酯与乙醇三级溶解并为每一级溶解液匹配合适的柱层析吸附剂与洗脱液,从银杏提取物中分离纯化极有药用价值的银杏萜内酯。结果表明,本方法可将银杏内酯的纯度由6%提高至80%以上,并可将它们逐一分离。     

银杏内酯的亚临界水提取工艺研究

为了提高银杏内酯的提取率及提取效率,采用亚临界水提取银杏叶中银杏内酯,通过单因素实验探讨了提取温度、提取时间、提取次数和料液比对银杏叶中银杏内酯提取率的影响。运用正交实验优化提取工艺条件如下:提取温度180℃,提取时间30min,提取3次,料液比1∶25(g∶mL),在此条件下,银杏内酯提取率为0.4623%。亚临界水提取银杏内酯具有绿色环保、无有机溶剂残留、提取率高等特点。     

萃取银杏内酯动态变化的研究

以银杏叶为材料,研究了超临界CO₂萃取过程中银杏内酯A、B、C在不同时间段内即时质量分数与总获得量的动态变化。采用液相色谱与蒸发光检测器联用检测银杏内酯。结果表明,银杏萃取物的质量随萃取时间的延长而越来越少,前40 min萃取物质量占总量的55.9%。银杏内酯质量分数随萃取时间的延长先增加后减少。银杏内酯A的即时质量分数最高值出现在60～80 min时间段内,为0.403%,银杏内酯B、C即时质量分数最高值在40～60 min时间段内,分别为0.289%、0.246%。银杏内酯A、B、C总获得量随萃取时间的延长而减少,0～20 min时间段内是最高的,分别占整个180 min获得量的33.6%、33.3%、35.4%。     

银杏叶超临界CO_2萃取银杏内酯动态变化的研究

以银杏叶为材料,研究了超临界CO2萃取过程中银杏内酯A、B、C在不同时间段内即时质量分数与总获得量的动态变化。采用液相色谱与蒸发光检测器联用检测银杏内酯。结果表明,银杏萃取物的质量随萃取时间的延长而越来越少,前40 min萃取物质量占总量的55.9%。银杏内酯质量分数随萃取时间的延长先增加后减少。银杏内酯A的即时质量分数最高值出现在60~80 min时间段内,为0.403%,银杏内酯B、C即时质量分数最高值在40~60 min时间段内,分别为0.289%、0.246%。银杏内酯A、B、C总获得量随萃取时间的延长而减少,0~20 min时间段内是最高的,分别占整个180 min获得量的33.6%、33.3%、35.4%。     

HPLC-ELSD法测定银杏内酯B脂微球中银杏内酯B的含量

建立了银杏内酯B脂微球中银杏内酯B的含量测定方法。采用HPLC法,色谱柱为C18柱(250mm×4.6mm,5μm),流动相为甲醇-四氢呋喃-水(25∶10∶65),流速为1.0mL·min-1,柱温为30℃,蒸发光散射检测器,载气压力为4.0bar,漂移管温度40℃。结果银杏内酯B在80.91～269.70μg·m L-1时,线性关系良好(r=0.9998),平均加样回收率为100.25%,RSD为1.44%。该法准确,重现性好,可用于银杏内酯B脂微球中银杏内酯B的含量测定。     

银杏叶中四种银杏内酯的含量测定

建立HPLC-ELSD法测定了30批银杏叶中4种银杏内酯的含量,并对所得数据进行分析研究.色谱条件为:phenonoonon C18色谱柱(250 mm×4.6 mm,5 μm),35%(体积分数)甲醇为流动相,1.000 mL/min的流速,ELSD检测器漂移管温度为60 ℃,氮气压力为1.72×105 Pa.得出红土栽培,未嫁接,树龄6～7 a的银杏叶中银杏内酯含量较高;4种银杏内酯总量集中在0.3%～0.5%(质量分数).该方法准确,重现性好,适用于银杏叶中4种银杏内酯的含量测定;银杏内酯的含量受生长环境影响差别较大,影响因素有待深入研究.     

超临界萃取银杏黄酮内酯项目动工

由国家经贸委、国家林业部、中国农业发展银行总行审查批准的“二氧化碳超临界萃取生产银杏黄酮内酯和辣椒红色素项目’’,近日在河南西峡县动工兴建。该项目总投资2650万元。项目建成后,可年产银杏黄酮内酯1.5t,辣椒红包素21t。超临界萃取银杏黄酮内酯项目动工~~     

Effects of PAF antagonists on renal vascular escape and tachyphylaxis in perfused rabbit kidney

Renal vascular escape is a physiological phenomenon of adaptation that occurs in vascular smooth muscle. It has been described in many preparations subjected to electrical stimulation or treated with vasoactive agents, such as noreprinephrine, angiotensin and vasopressin. We have recently demonstrated that a naturally occurring ginkgolide (BN 52021), which is a PAF antagonist, was able to block norepinephrine-induced escape in perfused rabbit kidney. In the present work other PAF antagonists, such as the ginkgolides BN 52022 and BN 52024, and the synthetic compounds 48740 RP and WEB 2086, were tested. Their effects on renal vascular escape, perfusion pressure and tachyphylaxis were evaluated. They all were shown to block the escape. Among the ginkgolides, BN 52024 is generally recognized as one of the weaker PAF antagonists. However, in spite of this, BN 52024 was able to significantly and simultaneously block renal vascular escape and tachyphylaxis in perfused rabbit kidney infused with norepinephrine. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 1989.     

注射用银杏内酯B在比格犬体内的药代动力学研究

通过测定注射用银杏内酯B静脉给药比格犬血药代谢动力学,为指导临床安全、合理用药提供理论依据.对18只比格犬,静脉注射给药,给药后于不同时间在经前肢静脉采血2.5-3mL,用气相-质谱联用法(GC-MS)测定血药浓度,计算药代动力学参数.结果如下:比格犬静脉给予注射用银杏内酯B 0.5,1,2mg/kg,分布半衰期t1/...     

The Signaling Cascades of Ginkgolide B-Induced Apoptosis in MCF-7 Breast Cancer Cells

Ginkgolide B, the major active component of Ginkgo biloba extracts, can both stimulate and inhibit apoptotic signaling. Here, we demonstrate that ginkgolide B can induce the production of reactive oxygen species in MCF-7 breast cancer cells, leading to an increase in the intracellular concentrations of cytoplasmic free Ca²⁺ and nitric oxide (NO), loss of mitochondrial membrane potential (MMP), activation of caspase-9 and -3, and increase the mRNA expression levels of p53 and p21, which are known to be involved in apoptotic signaling. In addition, prevention of ROS generation by pretreatment with N-acetyl cysteine (NAC) could effectively block intracellular Ca²⁺ concentrations increases and apoptosis in ginkgolide B-treated MCF-7 cells. Moreover, pretreatment with nitric oxide (NO) scavengers could inhibit ginkgolide B-induced MMP change and sequent apoptotic processes. Overall, our results signify that both ROS and NO played important roles in ginkgolide B-induced apoptosis of MCF-7 cells. Based on these study results, we propose a model for ginkgolide B-induced cell apoptosis signaling cascades in MCF-7 cells.     

银杏内酯A和B的分离纯化研究

In this paper a simple preparative method for isolation and purification of ginkgolides A and B was developed,As starting material,a commercially available standardized ginkgo extract (EGb761,containing 24% flavonoid and 6% terpene trilactones) was used,After a pretreatment step,optimized by the uniform design method ,the concentrated intermediate extract with high content of GA and gb( 90%) was separated into the individual terpenes by preparative liquid chromatography eluted with petroleum ether-ethylacetate,Analysis of products was carried out by means of HPLC-ELSD(evaporative light -scattering detector),The results show that ginkgolides A and B are obtained in higher yield and better purity.     

Enhanced upconversion emission in Yb3+ and Er3+ codoped NaGdF4 nanocrystals by introducing Li+ ions

β-NaGdF(4)?:?Yb(3+)/Er(3+) nanoparticles (NPs) codoped with Li(+) ions were prepared for the first time via a thermal decomposition reaction of trifluoroacetates in oleylamine. The influence of site occupancy of Li(+) on the upconversion emission of β-NaGdF(4)?:?Yb(3+)/Er(3+) NPs was investigated in detail. The upconversion emission intensity was significantly enhanced by introducing different concentrations of Li(+) ions. In contrast to lithium-free β-NaGdF(4)?:?Yb(3+)/Er(3+), the green and red UC emission intensities of the NPs codoped with 7 mol% Li(+) ions were enhanced by about 47 and 23 times, respectively. The luminescence enhancement should be attributed to the distortion of the local asymmetry around Er(3+) ions. The mechanisms for the enhancement of upconversion emission were discussed. In addition, it was found in our research work that β-NaGdF(4)?:?Yb(3+)/Er(3+) NPs exhibited paramagnetic features at room temperature and the magnetization was slightly increased by introducing Li(+) ions.     

纯化银杏总内酯的新工艺

将模拟移动床色谱精细分离技术用于纯化银杏总内酯,取代现行的单柱柱层析,使银杏总内酯产品的纯度提高、收率增加、成本降低,工艺简化、生产清洁度进一步提高。     

单组分聚氨酯反应型热熔胶制备与性能研究

以聚己二酸丁二醇酯二醇 (PBA) ,聚四氢呋喃二醇 (PTMG)及聚氧化丙烯二醇 (PPG)为软段 ,以 4,4’ -二苯甲烷二异氰酸酯 (MDI)和 1,4-丁二醇为硬软 ,制备了一系列快速固化单组分聚氨酯反应型热熔胶 ,考察了不同软段对热熔胶的粘接强度、耐水性、耐热性、结晶度等的影响。结果表明 ,以PTMG为软段制得的热熔胶具有较佳的综合性能     

先进陶瓷快速无模成型方法研究的进展

介绍了快速无模成型的发展历史和特点,重点介绍了激光选区烧结成型（Selective Laser Sintering,SLS)、三维打印成型（3Dimensional Printing,3DP)、熔融沉积成型（Fused Deposition of Ceramics,FDC)、分层制造成型（Laminated Object Manufacturing,LOM)、立体光刻成型9Stereilithography,SL)、喷墨打印成型（Ink-jet Printing,I-JP）、选区凝胶成型（Selective Gelation,SG)和激光选区气相沉积成型（Selective Area Laser Deposition,SALD)等8种先进陶瓷的成型方法,并分析了目前该技术产业化所面临的一些问题。     

天然药物银杏内酯研究进展

本文就银杏叶药用现状,发展趋势进行了分析。对银杏内酯的化学结构、药理作用与临床应用、制备及分析方法等方面作了介绍,并讨论了它的应用开发前景。     

银杏叶中有效成分的提取及作用

银杏叶中富含具有药理作用的黄酮类化合物与银杏内脂。它们对因高心脑血脂引起心脑血管疾病的患者能起到活血化淤、通脉舒络的作用。用生物分离方法进行提取,可大大提高银杏叶提取物中有效成分的含量。