药学英语课本

1、Developing Drugs from TraditionalMedicinal PlantsOver three quarters of the world's population relies mainly on plants and plant extracts for health care Approximately one third of the prescription drugs in the US contain plant components， and more than 120 important prescription drugs are deriv

2、ed from plants Most of these drugs were developed because of their use in traditional medicineEconomically， this represents $800310, 000M of annual consumer spending Recent World Health Organization (WHO) studies indicate that over 30 per cent of the world's plant species have at one time or ano

3、ther been used for medicinal purposes Of the 250， 000 higher plant species on Earth， more than 80， 000 species are medicina l Although traditional medicine is widespread throughout the world， it is an integral part of each individual culture Its practice is based mainly on traditional beliefs handed

4、 down from generation to generation for hundreds or even thousands of yea rsUnfortunately， much of this ancient knowledge and many valuable plants are being lost at an alarming ra teThe scientific study of traditional medicines and the systematic preservation of medicinal plants are thus of great im

5、portanceFor quite a long time， the only way to use plant medicines was either direct application or the use of crude plant extracts With the development of organic chemistry at the beginning of this century， extraction and fractionation techniques improved significantly It became possible to isolate

6、 and identify many of the active chemicals from plants In the 1940s， advances in chemical synthesis enabled the synthesis of many plant components and their derivativ esIn western countries， it was thought that chemical synthesis of drugs would be more effective and economical than isolation from na

7、tural sources Indeed， this is true in many cases However， in many other cases， synthetic analogues are not as effective as their natural counterpartsIn additio， some synthetic drugs cost many times more than natural one s Inspired by these realisation，s coupled with the fact that many drugs with com

8、plex structures may be totally impossible to synthes，is there is now a resurgent trend of returning to natural resources for drug developmentImportant prescription drugs from plantsEphedrine is the oldest and most classic example of a prescription drug developed from a traditional medicinal plant It

9、 is derived from Ma Huang， a leafless shrub Used to relieve asthma and hay fever in China for over 5000 years， it was introduced into western medicine in 1924 by Chen and Schmidt Ephedrine is an alkaloid closely related to adrenalin，e the major product of the adrenal gland Pharmacologically， Ephedri

10、ne is used extensively to stimulate increased activity of the sympathetic nervous system It is used as a pressor agent to counteract hypotension associated with anaesthesia， and as a nasal decongestantThe drug action of this medicine is based both on its direct effect on a and 0 adrenergic receptors

11、 and on the release of endogenous noradrenalineDigitalis is one of the most frequently used medications in the treatment of heart failure and arrhythmia It increases the contractility of the heart muscle and modifies vascular resistance It also slows conduction through the atrioventricular node in t

12、he hea，rt making it useful in the treatment of atrial fibrillation and other rapid heart rhythmsDigitalis is found in the leaves and seeds of Digitalis purpurea and Digitalis lanat，a commonly known as the foxglove plantFoxglove has been used in traditional medicine in manyparts of the world-by Afric

13、an natives as arrow poisons， by the ancient Egyptians as heart medicine，and by the Romans as a diureti，c heart tonic，emetic and rat poisonTheChinese， who found this ingredient not only in plants but also in the dry skin and venom of the common toad， used it for centuries as a cardiac dru g In the we

14、stern world， the foxglove was first mentioned in 1250 in the writing of a physician，Walsh， and it was described botanically in the1500sDigitalis is a glycoside containing an aglycone， or genin， linked to between one and four sugar molecules The pharmacological activity resides in the aglycone， where

15、as the sugar residues affect the solubility and potency of the drug The aglycone is structurally related to bile acids， sterols， sex hormones and adrenocortical hormone sd-Tubocurarine and its derivatives are the most frequently used drugs in operating rooms to provide muscle relaxation and prevent

16、muscle spasm These agents interrupt the transmission of the nerve impulse at the skeletal neuromuscular junction Curare，the common name for SouthAmerican arrow poisons，has a long and interesting historyIt has been used for centuries byIndians along the Amazon and Orinoco rivers for huntingIt causes

17、paralysis of the skeletalmuscles of animals and finally results in death The methods of curare preparation were a secret entrusted only to tribal doctors Soon after their discovery of the American continen，t European explorers became interested in curar e In the late 16th century， samples of native

18、preparations were brought to Europe for investigationCurare， an alkaloid， was found in various species of Strychnos and certain species of Chondrodendron The first use of curare for muscle relaxation was reported in 1942 by Griffith and Johnson This drug offers optimal muscular relaxation without th

19、e use of high doses of anaesthetics It thus emerged as the chief drug for use in tracheal intubation and during surge ryVinblastine and Vincristine are two of the most potent antitumour drugs They are obtained from Catharanthus roseu，s commonly known as the rosy periwinkle This plant， indigenous to

20、Madagascar， is also cultivated in India，Israel and the US It was originally examined for clinicaluse because of its traditional use in treating diabete sThe leaves and roots of this plant contain more than 100 alkaloids Fractionation of these extracts yields four active alkaloids： Vinblastine， Vincr

21、istine， Vinleurosine and Vinresidine These alkaloids are asymmetric dimeric compounds referred to as vinca alkaloids，but of these， only Vinblastine and Vincristine are clinicallyimportant antitumour agents These two alkaloids are cell-cycle specific agents that block mitosis (cell division) Vincrist

22、ine sulphate is used to treat acute leukaemia in children and lymphocytic leukaemia It is also effective against Wilm's tumour， neuroblastoma， rhabdomyosarcoma (tumour of voluntary or striped muscle cells)， reticulum cell sarcoma and Hodgkin's disease Vinblastine sulphate is used in the trea

23、tment of Hodgkin's diseas， e lymphosarcoma， choriocarcinoma， neuroblastoma， carcinoma of breas，t lung and other organs， and in acute and chronic leukaemiaEmerging plant medicinesArtemisinin is the most recent anti-malaria drug developed from plant-based traditional medicineIt is isolated from th

24、e leaves and flowers of Artemisia annua L (Compositae)，commonly known as the sweet wormwood，a cousin of tarragon Indigenous to China， theextract of this plant is traditionally known as the QinghaoIt has been used to treat malaria inChina for over 2000 years Its active component， Artemisinin ， was fi

25、rst isolated in the 1970s by Chinese scientists Unlike Quinine and Chloroquine， this compound is non-toxic rapid in effect， and safe for pregnant women Furthermore， it is effective against chloroquine-resistant Plasmodium falciparum malaria and in patients with cerebral malaria It kills the parasite

26、s directly so parasitemia is quickly controlled This work was confirmed by the WHO in Africa and other parts of Southeast AsiaArtemisinin is an endoperoxide of the sesquiterpene lactone The structure of this compound is too complex to be synthesised effectively Artemisia is also found in many parts

27、of the US ， abundantly along the Potomac River in Washington DC ， but the drug content of these varieties is only about half that of the Chinese variety Currently ， the WHO and the US are jointly engaged in the cultivation of Chinese Artemisia for worldwide use This recent development offers renewed

28、 hope for using traditional medicine to provide new drugs for future medicines 1 .prescription n.处方，药方，规定2 .World Health Organization 世界卫生组织（缩写为WHO）3 .adrenergic a 肾上腺素的，类似肾上腺素的，释放肾上腺素的4 .Artemisinin 青蒿素5 .antimalaria n. 抗疟疾，防疟疾6 .fractionation n 分馏7 .counterpart n 配对物，副本，极相似的人或物8 .resurgent a 复活的，苏

29、醒的，恢复活力的9 .asthma n 哮喘10 .adrenal n.肾上腺；a.肾上腺的11 .gland n. 腺12 .pharmacologically ad.药理地，药学地，药用地13 .pressor n.升高血压的物质a.有使血压增高的，收缩血管的14 .hypotension n. 低血压15 .anaesthesia n 麻醉（法 ），感觉缺乏，麻木16 .nasal a 鼻的，护鼻的，鼻音的n 鼻音，鼻音宇17 .endogenous a. 内生的，内长的18 .noradrenalinen. =norepinephrine 去甲肾上腺素19 .digitalis n 洋

30、地黄20 .arrhythmia n 心律不齐21 .contractility n.收缩性，缩小性，伸缩力22 .vascular a.脉管的，血管的，有脉管的23 .atrioventricular a 房室的，心房与心室的24 .node n.结25 .atriala 心房的，有关心房的26 .fibrillationn 纤维性颤动27 .Digitalis purpurea 紫花毛地黄28 .Digitalis lanata 毛花洋地黄29 .foxglove n.毛地黄30 .diuretic n.利尿剂；a.利尿的31 .a heart tonic 强心药32 .venom n.毒

31、液33 .toad n.蟾蛛，癞蛤蟆34 .cardiac n.强心剂，强胃齐1J ; a.心脏的，（胃的）贲门的35 .botanically ad.植物（学）地36 .glycoside n 苷，配糖类，配糖物37 .aglycone n 配质，配基，（苷的）非糖部38 .genin n 配质，配基39 .solubility n 溶 （解 ）度，溶（解 ）性，（可 ）溶性40.potency n 效力，效验，能力，潜力，力量41.bile acid 胆汁酸42.sterol n.番醇，固醇43.sex hormone 性激素44 .adrenocortical hormone n 肾上腺

32、皮质激素45 .digoxigenin n 异羟基洋地黄毒苷，地谷新配质46 .digitoxigenin n.毛地黄毒甘配基，户（丁烯酸内酯）-14-羟番醇47 .d-tubocurarine n. d-管箭毒碱48 .relaxation n,松弛，缓和，减轻，放宽49 .spasm n.痉挛，一阵发作50 .skeletal a.骨骼的，骸骨的51 .neuromuscular a.神经肌肉的52 .curare n.箭毒，马钱子属植物，马钱子（也叫番木鳖）53 .paralysis n.瘫痪，麻痹54 .entrusted vt.委托，托管，信托55 .Strychnosn S- 马钱

33、子属，毒鼠碱56 .Chondrodendron n.南美防己属57 .tracheal a 气管的，导管的，呼吸管的1.1 intubation n.插管，插管法59 .Vinblastine n 长春碱60 .Vincristine n.长春新碱61 .antitumour n.抗癌的，抗月中瘤的62 .Catharanthus roseus 长春花63 .periwinkle n.长春花属的植物，玉黍螺1.1 indigenous a.本土的65 .Madagascar n.马达加斯加岛(非洲岛国)66 .diabetes n 糖尿病，多尿症67 .Vinleurosine n 环氧长春

34、碱68 .Vinresidine n. ( = leurosidine) 异长春碱，洛诺西 169 .asymmetric a.不对称的，不均匀的70 .dimeric a.二聚的，形成二聚物的71 .vinca n 长春花72 .Vincristine sulphate 硫酸长春新碱73 .acute a.急性的，敏锐的74 .chronic a.慢性的，延续很长的74.1 eukaemia n 白血病76.lymphocytic a.淋巴球的，淋巴细胞的77.neuroblastoma n.成神经细胞瘤78.rhabdomyosarcoma n 横纹肌肉瘤79.striped n.有斑纹的

35、80.sarcoma n 肉瘤，恶性毒瘤1.1 lymphosarcoma n. 淋巴肉瘤82 .choriocarcinoma n 绒膜癌83 .carcinoma (复carcinomas或 carcinomata) n.癌84 .anti-malaria n.抗疟疾85 .Artemisia annua L 黄花蒿屑植物，青蒿属植物86 .Compositae n.菊科87 .wormwood n 蒿属植物88 .tarragon n 龙蒿，龙蒿叶89 .malaria n.疟疾，瘴气90 .Quinine n.奎宁91 .Chloroquine n.氯唾92 .Plasmodium f

36、alciparum 恶性疟原虫，镰状疟原虫93 .cerebral a.脑的，大脑的 94.parasite n.寄生虫，食客 95.parasitemia n.寄生虫血症96 .endoperoxide n 桥过氧化物97 .sesquiterpene n.倍平菇烯98.lactone n.内酯The Autonomic and CentralNervous Systems( I )All chemical substances that have a potential for abuse produce their desirable (and often undesirable) ef

37、fects by mechanisms involving the nervous system. To understand how abused substances produce their sought-after effects and why various modalities are used to treat their toxic manifestations, a basic knowledge of the structure and function of the nervous system is necessary. The following overview

38、 presents the major components of the nervous system and their functions. This information is not intended as a comprehensive review of neuroanatomy, but rather as a basis for understanding the drug-related material to be presented in later chapters in this text. Additional information may be obtain

39、ed from the references and selected readings listed at the end of this chapter.Anatomically, the nervous system is divided into two major components: the central nervous system(CNS) and theperipheral nervous system. The CNS, composed of the brain and spinal cord, is responsible for integrative funct

40、ions related to both conscious and subconscious activities of the body. It is also ultimately responsible for the interpretation of, and reaction to, all information that the body receives from the environment. The peripheralnervous system is made up of nerve fibers that conduct information toward t

41、he CNS (afferent fibers) and nerve fibers that conduct directives from the CNS to all body areas (efferent fibers). Before undertaking a general discussion of the nervous system, a brief review of the basic unit of the nervous system, the neuron, and the mechanisms by which information is transferre

42、d throughout the nervous system is in order.The NeuronThe neuron, or nerve cell, is the base of all activities of the nervous system. Neurons differ from other body cells in two respects: 1() they can conduct information in the form of electrical impulses over long distances; and (2) they relate to

43、other nerve cells and innervated tissue in a highly specialized manner. The neuron consists of a cell body, anaxon, which carries information away from the cell body, and one or moredendrites, which carry information toward the cell body. Some axons are surrounded by a layer of fatty tissue called a

44、myelin sheath, which develops within the nervous system over a period of years and serves as a protective coating.The ability of the neuron to transmit information from one site to another is a function of its electrical transmission capability and its capacity to synthesize, store, and release high

45、ly specific chemicalsne( urotransmitters) from nerve endings. The site where two nerve endings meet or where a nerve meets the tissue that it innervates is a small gap that is termed thseynapse, or synaptic cleft. In order for electrical impulses to cross a synapse, a neurotransmitter is released fr

46、om one nerve ending to travel across the synapse and stimulate receptors on an adjacent nerve or tissue.The Peripheral Nervous SystemThe peripheral nervous systemconsists of all the nerve fibers that conduct information to and from the CNS and that lie outside the brain and spinal cord. Peripheral a

47、fferent fibers are involved with sensations such as pain, temperature, and touch, whereas peripheral efferent fibers are involved with the control of specific body functions. Efferent fibers are divided into two categories: (1) somatic fibers, which control the function of skeletal muscle, and (2) a

48、utonomic fibers, which control the activities of smooth muscle, cardiac muscle, and glands of excretion.Somatic nerve fibers leave the spinal cord at various levels, depending on the location of the innervated skeletal muscle, and continue as an uninterrupted unit from their site of origin (motor ne

49、uron) to skeletal muscle tissue. The site at which the somatic fiber meets the skeletal muscle is termed theneuromuscular junction (NMJ). The neurotransmitter at the NMJ is acetylcholine.Autonomic efferent fibers control the automatic or subconscious functioning of smooth and cardiac muscle and exoc

50、rine glands. These fibers are responsible for activities such as the maintenance of tone in the gastrointesitinal tract and blood vessels, regulation of heart rate and release of substances such as saliva, respiratory secretions, and gastric acidA. utonomic fiber tracts actually consist of two separ

51、ate fibers. The first fiber (presynaptic fiber) originates inside the spinal cord and terminates at a synapse somewhere in the periphery. The second fiber (postsynaptic fiber) originates at the synapse and terminates at the innervated tissue.In most instances, the synapses of a number of fibers are

52、grouped together and termedganglion. In such cases, the presynaptic and postsynaptic fibers are referred to as preganglionic and postglanglionic fibers, respectively. The site at which the postganglionic fiber synapses with the innervated tissue is termed the neuroeffector junction (NEJ).Autonomic f

53、ibers are categorized by two methods. The first and older method of classification is based on the sites at which preganglionic fibers leave the CNS. Nerves that exit from the thoracic and lumbar levels of the spinal cord are termedsympathetic, whereas those that exit from the sacral level of the sp

54、inal cord and cranium are termedparasympathetic.The second method of classification is based on the neurotransmitter released at the NEJ by the nerve fiber. Nerves that release acetylcholine (Ach) are termedcholinergic, whereas those that release norepinephrine (NE) are termedadrenergic. In general,

55、 the termsympatheticis interchangeable with adrenergic and the termparasympatheticis interchangeable with cholinergic. Cholinergic and adrenergic are usually the preferred terms when discussing drug effects on autonomic function because they designate the specific neurotransmitters affected by the d

56、rugs.Within the autonomic nervous system(ANS), receptor sites for Ach and NE have a very specific nomenclature based upon their location and function. Cholinergic receptor sites are found in the ganglionic synapses of both the sympathetic and parasympathetic nervous system. They are also found at th

57、e NEJ of parasympathetic fibers. Cholinergic receptor sites are categorized as being either muscarinic or nicotinic, based on whether they respond to the alkaloids muscarine or nicotine, respectively. Muscarinic receptors are found at the parasympathetic NEJ. Nicotinic receptors are found at all aut

58、onomic ganglia and at the somatic NMJ.Adrenergic receptor sites in the ANS are found only at the sympathetic NEJ. Adrenergic receptors are divided into three categoriesa: lpha, beta1, and beta2.In general, stimulation of the alpha adrenergic receptor site causesan increase in activity of the innervated tissue. Alpha receptors are found primarily in arterioles and therefore are important in the maintenance of blood pressure. Stimulation of alpha receptors by NE leads to arteriolar constriction, which increases blood pressure. B