榼藤藤茎醋酸乙酯部位化学成分的研究

目的对榼藤Entada phaseoloide藤茎醋酸乙酯部位的化学成分进行研究。方法综合运用硅胶、反相硅胶RPC18、SephadexLH-20等色谱法进行分离,NMR、MS等波谱学方法进行结构鉴定。结果从榼藤藤茎甲醇提取物的醋酸乙酯萃取部位中分离得到了11个化合物,通过波谱分析鉴定为表没食子儿茶素没食子酸酯(1)、表儿茶素没食子酸酯(2)、落新妇苷(3)、木犀草素(4)、(?)-表儿茶素(5)、甘草苷(6)、β-香树脂醇(7)和日耳曼醇(8)的混合物、没食子酸(9)、β-谷甾醇(10)、胡萝卜苷(11)。结论所有化合物均为首次从榼藤中分离得到,其中化合物1～9在榼藤子属植物首次报道。     

表没食子儿茶素没食子酸酯药理作用研究进展

表没食子儿茶素没食子酸酯是从绿茶中提取分离的一种多酚类单体化合物,是绿茶中儿茶素类化合物的主要组成部分。近年研究发现,其在体内外具有抗肿瘤、抗氧化、抗炎、降血脂、防辐射等多种重要的生物活性。综述了近5年来对表没食子儿茶素没食子酸酯药理作用及作用机制的研究进展。     

表没食子儿茶素没食子酸酯对大鼠肾衰的治疗研究进展

茶叶富含多酚类化合物，大部分为黄烷醇，通称儿茶素，其混合体称茶多酚。主要为表没食子儿茶素没食子酸酯（EGCG）、表没食子酸酯、表没食子EGCG和表儿茶素等，以EGCG含量最高，占儿茶素80％。大量动物实验和临床实践已证明EGCG具有多种作用．对大鼠肾衰模型的疗效显著，主要治理机制在于：     

(-)表没食子儿茶素没食子酸酯在D-半乳糖所致痴呆小鼠体内的抗氧化作用

目的研究(-)表没食子儿茶素没食子酸酯在D-半乳糖所致痴呆小鼠体内的抗氧化作用。方法通过给小鼠皮下注射D-半乳糖(150mg·kg-1)的方法,每天一次,连续注射六周,以制备痴呆小鼠模型。两周后,用(-)表没食子儿茶素没食子酸酯(2mg·kg-1或6mg·kg-1)对模型小鼠灌胃四周治疗。通过进行水迷宫与避暗实验观察(-)表没食子儿茶素没食子酸酯对D-半乳糖所致痴呆小鼠的学习与记忆力的影响。通过对生化指标检测观察(-)表没食子儿茶素没食子酸酯对D-半乳糖所致痴呆小鼠海马的超氧化物歧化酶与谷胱甘肽过氧化物酶活性及丙二醛的含量的影响。结果皮下注射D-半乳糖削弱了小鼠的记忆及学习能力,使D-半乳糖所致痴呆小鼠海马中超氧化物歧化酶与谷胱甘肽过氧化物酶活性下降和丙二醛含量增加。灌胃给予(-)表没食子儿茶素没食子酸酯(2mg·kg-1或6mg·kg-1)明显的改善了小鼠的认知能力,提高了D-半乳糖所致痴呆小鼠海马中超氧化物歧化酶与谷胱甘肽过氧化物酶活性,减少了丙二醛的含量。结论(-)表没食子儿茶素没食子酸酯对D-半乳糖所致痴呆小鼠发挥了一定的抗氧化作用。     

高效液相色谱法测定心脑健胶囊中表没食子儿茶素没食子酸酯

目的建立测定心脑健胶囊中表没食子儿茶素没食子酸酯含量的高效液相色谱法。方法采用Hypersil ODSC18(250 mm×4.6 mm,5μm)色谱柱,流动相为0.04 mol.L-1枸橼酸溶液-N,N二甲基甲酰胺-四氢呋喃(45∶8∶2),检测波长为278 nm,流速为1.0 mL.min-1,柱温为25℃。结果表没食子儿茶素没食子酸酯在0.408~4.08μg具有良好的线性关系,回归方程为:A=105.226 46C+1 210.413 71,r=0.999 9。平均回收率98.59%,RSD为0.78%。结论该方法操作简单,重现性好,适用于心脑健胶囊中表没食子儿茶素没食子酸酯的含量测定。     

表没食子儿茶素对LoVo细胞生长周期的影响和诱导其凋亡的研究

目的探讨表没食子儿茶素对体外培养的人大肠癌ＬｏＶｏ细胞株生长周期的影响以及诱导该细胞凋亡的作用。方法用流式细胞术、琼脂糖凝胶电泳、ＨＥ染色观察表没食子儿茶素处理ＬｏＶｏ细胞后其细胞周期的改变以及细胞凋亡形态学和生化方面的改变。结果表没食子儿茶素在低浓度时（３２．５μｍｏｌ·Ｌ－１）对ＬｏＶｏ细胞的周期有明显的影响，主要是Ｓ期和Ｍ／Ｇ２期明显降低，引起ＬｏＶｏ细胞生长阻滞在Ｇ１期；在较高浓度（１６２．５～３２５μｍｏｌ·Ｌ－１）作用２４ｈ，流式细胞仪ＰＩ染色出现亚二倍体峰，ＨＥ染色可见ＬｏＶｏ细胞有典型的凋亡细胞形态改变：细胞变小变圆、固缩，细胞膜出泡，细胞核固缩、边集和碎裂以及凋亡小体的形成；琼脂糖凝胶电泳呈典型的“梯状（Ｌａｄｄｅｒ）”带。结论表没食子儿茶素对体外培养的ＬｏＶｏ细胞具有抑制和杀伤作用，其机制是通过影响ＬｏＶｏ细胞的生长周期和诱导其凋亡而实现。     

武当地区及其他产地茶叶中咖啡因和表没食子儿茶素没食子酸酯的含量测定

目的:采用HPLC法测定武当地区不同品种茶叶及其他地区茶叶的咖啡因和表没食子儿茶素没食子酸酯的含量。方法:以Luna-C18柱(250 mm×4.6 mm,5μm)为色谱柱,流动相为乙腈-0.2%磷酸水溶液,梯度洗脱,流速为0.75 ml·min^-1,检测波长为272 nm,柱温为25℃。结果:咖啡因和表没食子儿茶素没食子酸酯的线性范围分别为10.21~102.10μg·ml^-1(r=0.9994)、16.21~162.10μg·ml-1(r=0.9991),平均回收率分别为98.67%(RSD=1.86%,n=6),98.19%(RSD=2.28%,n=6)。结论:该方法用于武当地区及其他地区茶叶的咖啡因及表没食子儿茶素没食子酸酯含量的快速测定,具有简便、稳定性好、准确度高等特点,可以作为茶叶中咖啡因及表没食子儿茶素没食子酸酯含量的测定。     

绿茶有效成分表没食子儿茶素没食子酸酯的肿瘤防治作用

表没食子儿茶素食子酸酯（ＥＧＣＧ）是绿茶中最重要的有效成分之一，本文综述ＥＧＣＧ的抑制癌变作用及其主要作用机制，研究表明，ＥＧＣＧ有抗突变、抗促癌、抗氧化以及抑制肿瘤细胞增殖、促进肿瘤细胞凋亡和分化的作用，并影响癌基因的表达等。     

表没食子儿茶素没食子酸酯抗肝癌作用机制研究进展

茶的饮用量仅次于水,其保健作用也被世人认可.表没食子儿茶素没食子酸酯[(一)-epigallocatechin-3-gallate,EGCG]是绿茶中含量最高的生物活性成分,其癌症防治作用和细胞作用靶点已被深入研究.本文主要就EGCG的抗肝癌作用机制研究进展综述如下.     

绿茶成分心血管保护机制研究进展

绿茶的成分很多，但大多报道都集中在对儿茶素的研究。绿茶至少含有四种儿茶素：表没食子儿茶素没食子酸酯（EGCG）、表没食子儿茶素（EGC）、表儿茶素没食子酸酯（ECG）和表儿茶素（EC）。EGCG作为绿茶的主要成分，且具有最强的抗氧化性，因此成为近年来疾病预防研究的重要对象。     

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.     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

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.