药学英语课本

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

2、d from plantsMost of these drugs were developed because of their use in traditional medicineEconomically，this represents $800010，000M of annual consumer spendingRecent World Health Organization (WHO) studies indicate that over 30 per cent of the world's plant species have at one time or another

3、been used for medicinal purposesOf the 250，000 higher plant species on Earth，more than 80，000 species are medicinalAlthough traditional medicine is widespread throughout the world，it is an integral part of each individual cultureIts practice is based mainly on traditional beliefs handed down from ge

4、neration to generation for hundreds or even thousands of yearsUnfortunately，much of this ancient knowledge and many valuable plants are being lost at an alarming rateThe scientific study of traditional medicines and the systematic preservation of medicinal plants are thus of great importanceFor quit

5、e a long time，the only way to use plant medicines was either direct application or the use of crude plant extractsWith the development of organic chemistry at the beginning of this century，extraction and fractionation techniques improved significantlyIt became possible to isolate and identify many o

6、f the active chemicals from plantsIn the 1940s，advances in chemical synthesis enabled the synthesis of many plant components and their derivativesIn western countries，it was thought that chemical synthesis of drugs would be more effective and economical than isolation from natural sourcesIndeed，this

7、 is true in many casesHowever，in many other cases，synthetic analogues are not as effective as their natural counterpartsIn additio，some synthetic drugs cost many times more than natural onesInspired by these realisations，coupled with the fact that many drugs with complex structures may be totally im

8、possible to synthesis，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 plantIt is derived from Ma Huang，a leafles

9、s shrubUsed to relieve asthma and hay fever in China for over 5000 years，it was introduced into western medicine in 1924 by Chen and SchmidtEphedrine is an alkaloid closely related to adrenaline，the major product of the adrenal glandPharmacologically，Ephedrine is used extensively to stimulate increa

10、sed activity of the sympathetic nervous systemIt 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 and adrenergic receptors and on the release of endogenous noradrenalineD

11、igitalis is one of the most frequently used medications in the treatment of heart failure and arrhythmiaIt increases the contractility of the heart muscle and modifies vascular resistance It also slows conduction through the atrioventricular node in the heart，making it useful in the treatment of atr

12、ial fibrillation and other rapid heart rhythmsDigitalis is found in the leaves and seeds of Digitalis purpurea and Digitalis lanata， commonly known as the foxglove plant Foxglove has been used in traditional medicine in many parts of the world-by African natives as arrow poisons，by the ancient Egypt

13、ians as heart medicine， and by the Romans as a diuretic， heart tonic， emetic and rat poison The Chinese， 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 drugIn the western world，the foxglove was first mentioned in

14、1250 in the writing of a physician， Walsh，and it was described botanically in the 1500sDigitalis is a glycoside containing an aglycone，or genin，linked to between one and four sugar molecules The pharmacological activity resides in the aglycone，whereas the sugar residues affect the solubility and pot

15、ency of the drugThe aglycone is structurally related to bile acids，sterols，sex hormones and adrenocortical hormonesd-Tubocurarine and its derivatives are the most frequently used drugs in operating rooms to provide muscle relaxation and prevent muscle spasm These agents interrupt the transmission of

16、 the nerve impulse at the skeletal neuromuscular junction Curare， the common name for South American arrow poisons， has a long and interesting history It has been used for centuries by Indians along the Amazon and Orinoco rivers for hunting It causes paralysis of the skeletal muscles of animals and

17、finally results in deathThe methods of curare preparation were a secret entrusted only to tribal doctorsSoon after their discovery of the American continent，European explorers became interested in curare In the late 16th century，samples of native preparations were brought to Europe for investigation

18、Curare，an alkaloid，was found in various species of Strychnos and certain species of ChondrodendronThe first use of curare for muscle relaxation was reported in 1942 by Griffith and JohnsonThis drug offers optimal muscular relaxation without the use of high doses of anaestheticsIt thus emerged as the

19、 chief drug for use in tracheal intubation and during surgeryVinblastine and Vincristine are two of the most potent antitumour drugsThey are obtained from Catharanthus roseus，commonly known as the rosy periwinkleThis plant，indigenous to Madagascar，is also cultivated in India， Israel and the USIt was

20、 originally examined for clinical use because of its traditional use in treating diabetesThe leaves and roots of this plant contain more than 100 alkaloidsFractionation of these extracts yields four active alkaloids：Vinblastine，Vincristine，Vinleurosine and VinresidineThese alkaloids are asymmetric d

21、imeric compounds referred to as vinca alkaloids， but of these，only Vinblastine and Vincristine are clinically important antitumour agentsThese two alkaloids are cell-cycle specific agents that block mitosis (cell division)Vincristine sulphate is used to treat acute leukaemia in children and lymphocy

22、tic leukaemiaIt is also effective against Wilm's tumour，neuroblastoma，rhabdomyosarcoma (tumour of voluntary or striped muscle cells)，reticulum cell sarcoma and Hodgkin's diseaseVinblastine sulphate is used in the treatment of Hodgkin's disease， lymphosarcoma，choriocarcinoma，neuroblastoma

23、，carcinoma of breast，lung and other organs，and in acute and chronic leukaemiaEmerging plant medicinesArtemisinin is the most recent anti-malaria drug developed from plant-based traditional medicine It is isolated from the leaves and flowers of Artemisia annua L(Compositae)，commonly known as the swee

24、t wormwood， a cousin of tarragonIndigenous to China，the extract of this plant is traditionally known as the Qinghao It has been used to treat malaria in China for over 2000 yearsIts active component，Artemisinin，was first isolated in the 1970s by Chinese scientistsUnlike Quinine and Chloroquine，this

25、compound is non-toxic rapid in effect，and safe for pregnant womenFurthermore，it is effective against chloroquine-resistant Plasmodium falciparum malaria and in patients with cerebral malariaIt kills the parasites directly so parasitemia is quickly controlledThis work was confirmed by the WHO in Afri

26、ca and other parts of Southeast AsiaArtemisinin is an endoperoxide of the sesquiterpene lactoneThe structure of this compound is too complex to be synthesised effectivelyArtemisia is also found in many parts of the US，abundantly along the Potomac River in Washington DC，but the drug content of these

27、varieties is only about half that of the Chinese varietyCurrently，the WHO and the US are jointly engaged in the cultivation of Chinese Artemisia for worldwide useThis recent development offers renewed hope for using traditional medicine to provide new drugs for future medicines 1.prescription n.处方，药

28、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

29、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.noradrenaline n. =norepinephrine 去甲肾上腺素19.digitalis n洋地黄 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

30、 25.atrial a心房的，有关心房的26.fibrillation n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毒液 33.toad n蟾蜍，癞蛤蟆34.cardiac n强心剂，强胃剂; 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

31、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甾醇，固醇 43.sex hormone 性激素44.adrenocortical hormone n肾上腺皮质激素45.digoxigenin n异羟基洋地黄毒苷，地谷新配质46.digitoxigenin n毛地黄毒苷配基，户(丁烯酸内酯)-14-羟甾醇47.d-tubocurarine nd-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.skelet

32、al 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.Strychnos nS-马钱子属，毒鼠碱56.Chondrodendron n.南美防己属57.tracheal a气管的，导管的，呼吸管的58.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，抗肿瘤的62.Catharanthus roseus 长春花63.periw

33、inkle n长春花属的植物， 玉黍螺64.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环氧长春碱68.Vinresidine n(leurosidine) 异长春碱，洛诺西丁69.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 75.leukaemia n白血病 76.lymph

34、ocytic 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 80.sarcoma n肉瘤，恶性毒瘤81.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

35、蒿叶 89.malaria n疟疾，瘴气90.Quinine n奎宁 91.Chloroquine n氯喹92.Plasmodium falciparum 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倍半萜烯 98.lactone n内酯The Autonomic and Central Nervous Systems()All chemical substances that have a potential fo

36、r abuse produce their desirable (and often undesirable) effects 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

37、of the nervous system is necessary. The following overview 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 c

38、hapters in this text. Additional information may be obtained 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 the peripheral nervous system. The CNS, composed of th

39、e brain and spinal cord, is responsible for integrative functions 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 peripheral nervous syste

40、m is made up of nerve fibers that conduct information toward the 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

41、 neuron, and the mechanisms by which information is transferred 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 el

42、ectrical impulses over long distances; and (2) they relate to other nerve cells and innervated tissue in a highly specialized manner. The neuron consists of a cell body, an axon, which carries information away from the cell body, and one or more dendrites, which carry information toward the cell bod

43、y. Some axons are surrounded by a layer of fatty tissue called a 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

44、capability and its capacity to synthesize, store, and release highly specific chemicals (neurotransmitters) 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 the synapse, or synaptic cleft. In order for electr

45、ical impulses to cross a synapse, a neurotransmitter is released from one nerve ending to travel across the synapse and stimulate receptors on an adjacent nerve or tissue.The Peripheral Nervous SystemThe peripheral nervous system consists of all the nerve fibers that conduct information to and from

46、the CNS and that lie outside the brain and spinal cord. Peripheral afferent 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) soma

47、tic fibers, which control the function of skeletal muscle, and (2) autonomic 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

48、continue as an uninterrupted unit from their site of origin (motor neuron) to skeletal muscle tissue. The site at which the somatic fiber meets the skeletal muscle is termed the neuromuscular junction (NMJ). The neurotransmitter at the NMJ is acetylcholine. Autonomic efferent fibers control the auto

49、matic or subconscious functioning of smooth and cardiac muscle and exocrine 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,

50、 and gastric acid. Autonomic fiber tracts actually consist of two separate 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 inner

51、vated tissue. In most instances, the synapses of a number of fibers are grouped together and termed a ganglion. 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 t

52、he innervated tissue is termed the neuroeffector junction (NEJ). Autonomic fibers 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 ar

53、e termed sympathetic, whereas those that exit from the sacral level of the spinal cord and cranium are termed parasympathetic. The second method of classification is based on the neurotransmitter released at the NEJ by the nerve fiber. Nerves that release acetylcholine (Ach) are termed cholinergic,

54、whereas those that release norepinephrine (NE) are termed adrenergic. In general, the term sympathetic is interchangeable with adrenergic and the term parasympathetic is interchangeable with cholinergic. Cholinergic and adrenergic are usually the preferred terms when discussing drug effects on auton

55、omic function because they designate the specific neurotransmitters affected by the drugs. 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 synapse

56、s of both the sympathetic and parasympathetic nervous system. They are also found at the 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 r

57、eceptors are found at the parasympathetic NEJ. Nicotinic receptors are found at all autonomic 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 categories: alpha, beta1, and beta2. In general, stimulation of the alpha adrenergic receptor site causes an 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 re