药学英语课本.docx

药学英语课本.docx

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药学英语课本

药学英语课本

DevelopingDrugsfromTraditional

MedicinalPlants

Overthreequartersoftheworld'spopulationreliesmainlyonplantsandplantextractsforhealthcare．ApproximatelyonethirdoftheprescriptiondrugsintheUScontainplantcomponents，andmorethan120importantprescriptiondrugsarederivedfromplants．Mostofthesedrugsweredevelopedbecauseoftheiruseintraditionalmedicine．Economically，thisrepresents$8000～10，000Mofannualconsumerspending．RecentWorldHealthOrganization（WHO）studiesindicatethatover30percentoftheworld'splantspecieshaveatonetimeoranotherbeenusedformedicinalpurposes．Ofthe250，000higherplantspeciesonEarth，morethan80，000speciesaremedicinal．Althoughtraditionalmedicineiswidespreadthroughouttheworld，itisanintegralpartofeachindividualculture．Itspracticeisbasedmainlyontraditionalbeliefshandeddownfromgenerationtogenerationforhundredsoreventhousandsofyears．Unfortunately，muchofthisancientknowledgeandmanyvaluableplantsarebeinglostatanalarmingrate．Thescientificstudyoftraditionalmedicinesandthesystematicpreservationofmedicinalplantsarethusofgreatimportance．

Forquitealongtime，theonlywaytouseplantmedicineswaseitherdirectapplicationortheuseofcrudeplantextracts．Withthedevelopmentoforganicchemistryatthebeginningofthiscentury，extractionandfractionationtechniquesimprovedsignificantly．Itbecamepossibletoisolateandidentifymanyoftheactivechemicalsfromplants．Inthe1940s，advancesinchemicalsynthesisenabledthesynthesisofmanyplantcomponentsandtheirderivatives．Inwesterncountries，itwasthoughtthatchemicalsynthesisofdrugswouldbemoreeffectiveandeconomicalthanisolationfromnaturalsources．Indeed，thisistrueinmanycases．However，inmanyothercases，syntheticanaloguesarenotaseffectiveastheirnaturalcounterparts．Inadditio，somesyntheticdrugscostmanytimesmorethannaturalones．Inspiredbytheserealisations，coupledwiththefactthatmanydrugswithcomplexstructuresmaybetotallyimpossibletosynthesis，thereisnowaresurgenttrendofreturningtonaturalresourcesfordrugdevelopment．

Importantprescriptiondrugsfromplants

Ephedrineistheoldestandmostclassicexampleofaprescriptiondrugdevelopedfromatraditionalmedicinalplant．ItisderivedfromMaHuang，aleaflessshrub．UsedtorelieveasthmaandhayfeverinChinaforover5000years，itwasintroducedintowesternmedicinein1924byChenandSchmidt．Ephedrineisanalkaloidcloselyrelatedtoadrenaline，themajorproductoftheadrenalgland．Pharmacologically，Ephedrineisusedextensivelytostimulateincreasedactivityofthesympatheticnervoussystem．Itisusedasapressoragenttocounteracthypotensionassociatedwithanaesthesia，andasanasaldecongestant．Thedrugactionofthismedicineisbasedbothonitsdirecteffectonαandβadrenergicreceptorsandonthereleaseofendogenousnoradrenaline．

Digitalisisoneofthemostfrequentlyusedmedicationsinthetreatmentofheartfailureandarrhythmia．Itincreasesthecontractilityoftheheartmuscleandmodifiesvascularresistance．Italsoslowsconductionthroughtheatrioventricularnodeintheheart，makingitusefulinthetreatmentofatrialfibrillationandotherrapidheartrhythms．

DigitalisisfoundintheleavesandseedsofDigitalispurpureaandDigitalislanata，commonlyknownasthefoxgloveplant．Foxglovehasbeenusedintraditionalmedicineinmanypartsoftheworld--byAfricannativesasarrowpoisons，bytheancientEgyptiansasheartmedicine，andbytheRomansasadiuretic，hearttonic，emeticandratpoison．TheChinese，whofoundthisingredientnotonlyinplantsbutalsointhedryskinandvenomofthecommontoad，useditforcenturiesasacardiacdrug．Inthewesternworld，thefoxglovewasfirstmentionedin1250inthewritingofaphysician，Walsh，anditwasdescribedbotanicallyinthe1500s．

Digitalisisaglycosidecontaininganaglycone，orgenin，linkedtobetweenoneandfoursugarmolecules．Thepharmacologicalactivityresidesintheaglycone，whereasthesugarresiduesaffectthesolubilityandpotencyofthedrug．Theaglyconeisstructurallyrelatedtobileacids，sterols，sexhormonesandadrenocorticalhormones．

d-Tubocurarineanditsderivativesarethemostfrequentlyuseddrugsinoperatingroomstoprovidemusclerelaxationandpreventmusclespasm．Theseagentsinterruptthetransmissionofthenerveimpulseattheskeletalneuromuscularjunction．Curare，thecommonnameforSouthAmericanarrowpoisons，hasalongandinterestinghistory．IthasbeenusedforcenturiesbyIndiansalongtheAmazonandOrinocoriversforhunting．Itcausesparalysisoftheskeletalmusclesofanimalsandfinallyresultsindeath．Themethodsofcurarepreparationwereasecretentrustedonlytotribaldoctors．SoonaftertheirdiscoveryoftheAmericancontinent，Europeanexplorersbecameinterestedincurare．Inthelate16thcentury，samplesofnativepreparationswerebroughttoEuropeforinvestigation．

Curare，analkaloid，wasfoundinvariousspeciesofStrychnosandcertainspeciesofChondrodendron．Thefirstuseofcurareformusclerelaxationwasreportedin1942byGriffithandJohnson．Thisdrugoffersoptimalmuscularrelaxationwithouttheuseofhighdosesofanaesthetics．Itthusemergedasthechiefdrugforuseintrachealintubationandduringsurgery．

VinblastineandVincristinearetwoofthemostpotentantitumourdrugs．TheyareobtainedfromCatharanthusroseus，commonlyknownastherosyperiwinkle．Thisplant，indigenoustoMadagascar，isalsocultivatedinIndia，IsraelandtheUS．Itwasoriginallyexaminedforclinicalusebecauseofitstraditionaluseintreatingdiabetes．Theleavesandrootsofthisplantcontainmorethan100alkaloids．Fractionationoftheseextractsyieldsfouractivealkaloids：

Vinblastine，Vincristine，VinleurosineandVinresidine．Thesealkaloidsareasymmetricdimericcompoundsreferredtoasvincaalkaloids，butofthese，onlyVinblastineandVincristineareclinicallyimportantantitumouragents．Thesetwoalkaloidsarecell-cyclespecificagentsthatblockmitosis（celldivision）．Vincristinesulphateisusedtotreatacuteleukaemiainchildrenandlymphocyticleukaemia．ItisalsoeffectiveagainstWilm'stumour，neuroblastoma，rhabdomyosarcoma（tumourofvoluntaryorstripedmusclecells），reticulumcellsarcomaandHodgkin'sdisease．VinblastinesulphateisusedinthetreatmentofHodgkin'sdisease，lymphosarcoma，choriocarcinoma，neuroblastoma，carcinomaofbreast，lungandotherorgans，andinacuteandchronicleukaemia．

Emergingplantmedicines

Artemisininisthemostrecentanti-malariadrugdevelopedfromplant-basedtraditionalmedicine．ItisisolatedfromtheleavesandflowersofArtemisiaannuaL．（Compositae），commonlyknownasthesweetwormwood，acousinoftarragon．IndigenoustoChina，theextractofthisplantistraditionallyknownastheQinghao．IthasbeenusedtotreatmalariainChinaforover2000years．Itsactivecomponent，Artemisinin，wasfirstisolatedinthe1970sbyChinesescientists．UnlikeQuinineandChloroquine，thiscompoundisnon-toxicrapidineffect，andsafeforpregnantwomen．Furthermore，itiseffectiveagainstchloroquine-resistantPlasmodiumfalciparummalariaandinpatientswithcerebralmalaria．Itkillstheparasitesdirectlysoparasitemiaisquicklycontrolled．ThisworkwasconfirmedbytheWHOinAfricaandotherpartsofSoutheastAsia．

Artemisininisanendoperoxideofthesesquiterpenelactone．Thestructureofthiscompoundistoocomplextobesynthesisedeffectively．ArtemisiaisalsofoundinmanypartsoftheUS，abundantlyalongthePotomacRiverinWashingtonDC，butthedrugcontentofthesevarietiesisonlyabouthalfthatoftheChinesevariety．Currently，theWHOandtheUSarejointlyengagedinthecultivationofChineseArtemisiaforworldwideuse．Thisrecentdevelopmentoffersrenewedhopeforusingtraditionalmedicinetoprovidenewdrugsforfuturemedicines．

1.prescriptionn.处方，药方，规定

2.WorldHealthOrganization世界卫生组织（缩写为WHO）

3.adrenergica．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.antimalarian．抗疟疾，防疟疾

6.fractionationn．分馏

7.counterpartn．配对物，副本，极相似的人或物

8.resurgenta．复活的，苏醒的，恢复活力的

9.asthman．哮喘

10.adrenaln.肾上腺;a.肾上腺的

11.glandn.腺

12.pharmacologicallyad．药理地，药学地，药用地

13.pressorn．升高血压的物质a.有使血压增高的，收缩血管的

14.hypotensionn．低血压

15.anaesthesian．麻醉（法），感觉缺乏，麻木

16.nasala．鼻的，护鼻的，鼻音的n．鼻音，鼻音宇

17.endogenousa.内生的，内长的

18.noradrenalinen.=norepinephrine去甲肾上腺素

19.digitalisn．洋地黄

20.arrhythmian．心律不齐

21.contractilityn．收缩性，缩小性，伸缩力

22.vasculara．脉管的，血管的，有脉管的

23.atrioventriculara．房室的，心房与心室的

24.noden．结

25.atriala．心房的，有关心房的

26.fibrillationn．纤维性颤动

27.Digitalispurpurea紫花毛地黄

28.Digitalislanata毛花洋地黄

29.foxgloven．毛地黄

30.diureticn．利尿剂;a．利尿的

31.ahearttonic强心药

32.venomn．毒液

33.toadn．蟾蜍，癞蛤蟆

34.cardiacn．强心剂，强胃剂;a．心脏的，（胃的）贲门的

35.botanicallyad．植物（学）地

36.glycosiden．苷，配糖类，配糖物

37.aglyconen．配质，配基，（苷的）非糖部

38.geninn．配质，配基

39.solubilityn．溶（解）度，溶（解）性，（可）溶性

40.potencyn．效力，效验，能力，潜力，力量

41.bileacid胆汁酸

42.steroln．甾醇，固醇

43.sexhormone性激素

44.adrenocorticalhormonen．肾上腺皮质激素

45.digoxigeninn．异羟基洋地黄毒苷，地谷新配质

46.digitoxigeninn．毛地黄毒苷配基，户（丁烯酸内酯）-14-羟甾醇

47.d-tubocurarinen．d-管箭毒碱

48.relaxationn．松弛，缓和，减轻，放宽

49.spasmn．痉挛，一阵发作

50.skeletala．骨骼的，骸骨的

51.neuromusculara．神经肌肉的

52.curaren．箭毒，马钱子属植物，马钱子（也叫番木鳖）

53.paralysisn．瘫痪，麻痹

54.entrustedvt.委托，托管，信托

55.Strychnosn．[S-]马钱子属，毒鼠碱

56.Chondrodendronn.南美防己属

57.tracheala．气管的，导管的，呼吸管的

58.intubationn．插管，插管法

59.Vinblastinen．长春碱

60.Vincristinen．长春新碱

61.antitumourn.抗癌的，抗肿瘤的

62.Catharanthusroseus长春花

63.periwinklen．长春花属的植物，玉黍螺

64.indigenousa．本土的

65.Madagascarn．马达加斯加岛（非洲岛国）

66.diabetesn．糖尿病，多尿症

67.Vinleurosine