从大黄中提取大黄素的研究

报道一种能有效提高从大黄中提取大黄素收率的方法。首先用氯仿—酸回流4～5h提取大黄蒽醌,再用pH8.0和pH9.9缓冲溶液提取分离大黄蒽醌中的大黄素。大黄素纯品收率达0.52%。     

中药大黄的生物化学研究XXXXⅡ大黄蒽醌衍生物系统分离的方法改进

将生大黄小碎片加入20%硫酸和氯仿混合液，在水浴回流水解提取。氯仿提取液依次以5%碳酸氢钾、5%碳酸钠、0.25%氢氧化钾和5%氢氧化钾振荡提取。提取液分别以盐酸酸化，即分别得大黄酸、大黄素、芦荟大黄素和大黄酚-大黄素甲醚混俣物黄色沉淀物。后者再以硅胶柱层析分离，可得大黄酚和大黄素甲醚单体。上述五种蒽醌衍生物再经结晶即得纯品。     

黄芩对大黄蒽醌在提取精制过程中转化的影响

目的探讨黄芩对大黄中5种蒽醌类成分在提取精制过程中相互转化的影响。方法 HPLC测定药材和提取物中5种成分的含量,比较药材和提取物中芦荟大黄素、大黄酸、大黄素、大黄酚和大黄素甲醚的相对比例;再分别用5种蒽醌的对照品加入和不加黄芩药材提取液模拟提取精制过程,考察5种蒽醌成分之间的转化情况。结果大黄药材和提取物中5种成分的相对比例有明显变化,大黄酸在提取物中的比例增高;同时采用对照品模拟提取精制过程时各个成分并无转化,而加入黄芩药材提取液后,大黄酸经过提取精制处理后能部分转化为大黄素,其余4种成分之间无转化。结论黄芩和大黄药材配伍提取可以使大黄蒽醌类成分发生转化。     

大孔吸附树脂法纯化大黄中结合型蒽醌总提取物的研究

大黄为常用中药，主要成分为蒽醌类、二苯乙烯苷类、色酮类及鞣质等化合物。结合型蒽醌类成分水溶性大。通常认为是利胆和泻下的主要成分，而大黄酚、大黄素、大黄素甲醚等游离蒽醌苷元几乎无泻下活性。传统提取工艺复杂，且提取物杂质含量较高，特别是制备注射剂时蒽醌苷元及鞣质类成分常常对溶液的澄明度产生较大的影响。我们以大孔吸附树脂柱色谱法分离大黄中结合型蒽醌提取物，采用比色法考察总提取物中结合型蒽醌的含量．为大黄提取物的纯化与精制生产工艺作一新的尝试。     

均匀设计法优选决明子中蒽醌类物质的提取工艺

目的：优选决明子中蒽醌类成分的最佳提取方法和提取工艺。方法：以决明子中总蒽醌、芦荟大黄素、大黄酸、大黄素、大黄酚、大黄素甲醚的含量为指标,考察超声法、加热回流法和索氏提取法提取决明子中蒽醌类成分优劣,确定索氏提取法为最佳提取方法。通过均匀设计法研究总蒽醌、芦荟大黄素、大黄酸、大黄素、大黄酚、大黄素甲醚的提取工艺,其中总蒽醌含量用紫外分光光度法测定,5种蒽醌类化合物含量用HPLC法测定。结果：最佳提取工艺：提取时间61min,提取次数1次,甲醇浓度95度．蒽醌类成分综合评分可达0．1751。结论：该工艺简便合理,稳定准确,适用于决明子中蒽醌类物质的提取。     

常压柱色谱与快速制备色谱分离纯化洋铁酸模中蒽醌成分

目的：比较常压柱色谱与快速制备色谱分离洋铁酸模蒽醌成分纯化程度。方法常压柱色谱柱采用硅胶（200-300目）,流速15mL/min;快速制备色谱法柱采用FlashCS硅胶柱（柱规格40g）,流速40mL/min。两方法均以石油醚-乙酸乙酯为洗脱剂,检测波长254nm。结果洋铁酸模乙酸乙酯萃取物经两种色谱法分离后得到蒽醌类成分之大黄素,经超高效液相分析,纯度差异不大。常压柱色谱中,分离过程溶剂经洗脱再回收利用后消耗量大,耗时较长。与快速制备色谱相比,该法快速、准确、灵敏度高。结论快速制备色谱法可准确、快速、高效分离洋铁酸模蒽醌成分,适合在工作量较大的分离纯化项目中应用;但快速制备分离色谱通常难以胜任对药物复杂体系如较多类物质的分离。     

大黄中提取分离蒽醌类有效成分

目的:考察并建立从大黄中提取分离大黄蒽醌类有效成分的方法并提高收率和纯度。     

大黄中大黄酚的提取、分离和纯化方法研究

目的探讨获得高纯度大黄酚的可行性。方法先用稀硫酸溶液将大黄中总蒽醌苷水解成苷元,再用热氯仿提取苷元,以碱液将氯仿液中大黄酸、大黄素、芦荟大黄素除去,并用柱层析法分离大黄酚和大黄素,经乙醇反复多次重结晶,得高纯度的大黄酚;采用高效液相色谱法测定其中大黄酚的含量。结果本方法提纯得到的大黄酚纯度达98%以上。结论本方法操作简单、重现性好、成本低、毒性小,可用于大批量生产。     

决明子发酵前后5种蒽醌类成分变化研究

目的:探讨固态发酵对决明子中5种蒽醌类成分含量的影响。方法:采用高效液相色谱法测定决明子发酵前后芦荟大黄素、大黄酸、大黄素、大黄酚、大黄素甲醚的含量并进行对比研究。色谱柱为C18-ODS反相柱(250mm×4.6mm,5μm),流动相为甲醇-0.1%磷酸水溶液(梯度洗脱),流速为1mL.min-1,检测波长为280nm。结果:决明子经过发酵后,游离型蒽醌含量呈上升趋势。以未发酵成分含量为100%计算,5种成分变化分别为104.6%、102.2%、93.4%、215.6%、134.8%,其中芦荟大黄素、大黄酸和大黄素变化不明显,大黄酚与大黄素甲醚分别增加至2.15倍和1.34倍,可见发酵增加了蒽醌苷元的含量。结论:决明子通过发酵,有利于增加活性成分蒽醌苷元的含量。     

塔黄的化学成分研究

目的对塔黄的化学成分进行研究。方法通过各种柱色谱对其成分进行分离纯化,通过波谱解析进行结构鉴定。结果从中分离得到8个化合物,分别鉴定为:大黄素(1),大黄酚(2),大黄素甲醚(3),1,8-二羟基-2,3-甲氧基-6-甲基蒽醌(4),大黄酚葡萄糖苷(5),大黄素葡萄糖苷(6),β-谷甾醇(7),胡萝卜素(8)。结论所有化合物均为首次从该植物中分离得到。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.