Herbal Medicines and Pharmacy
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HERBAL MEDICINES AND PHARMACY Thesis presented by Carol Anne Newall for the degree of Doctor of Philosophy in the Faculty of Medicine, University of London Centre for Pharmacognosy The School of Pharmacy University of London 1997 ProQuest Number: 10104804 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest. ProQuest 10104804 Published by ProQuest LLC(2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. Microform Edition © ProQuest LLC. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 This thesis is dedicated to my wonderful husband Mark, without whose support this research would probably have remained incomplete, and to my parents for their continual encouragement during many years of academic pursuit. TABLE OF CONTENTS List of Tables ..................................................................................................................... viii List of Figures .................................................................................................................... x List of Abbreviations ........................................................................................................ xi Acknowledgements ............................................................................................................xiii Abstract ...............................................................................................................................xiv 1. INTRODUCTION...............................................................................................................1 1.1 Healthcare Systems....................................................................................................... 1 1.2 Complementary Medicine in Industrialised Countries .............................................3 1.3 Complementary Medicine in the U K .......................................................................... 8 1.4 Pharmacy Involvement with Complementary Therapies .........................................17 1.4.1 Homoeopathic Products .......................................................................................18 1.4.2 Healthfoods / Nutritional Supplements .............................................................. 20 1.4.3 Herbal Products .................................................................................................... 21 1.5 Aims and Objectives .................................................................................................. 24 2. LEGISLATION ON HERBAL REMEDIES................................................................ 25 2.1 Product Availability in the UK ..................................................................................25 2.2 Historical UK Legislation on Herbal Remedies ...................................................... 25 2.2.1 Medicines Act 1968 .............................................................................................25 2.2.2 Exemptions for Herbal Remedies .......................................................................31 2.2.3 Licensed and Unlicensed Herbal Remedies ...................................................... 38 2.3 Review of Herbal Remedies in the UK .....................................................................40 2.4 Recent European and UK Legislation .......................................................................43 2.5 Herbal Remedies in Europe ....................................................................................... 45 2.6 Legislation of Herbal Remedies in the United States (US) .....................................46 2.7 Discussion ....................................................................................................................48 3. QUALITY OF HERBAL REMEDIES.......................................................................... 50 3.1 European (EC) and UK Legislation .........................................................................51 3.2 Authentication of Starting Material .......................................................................... 53 3.3 Batch to Batch Variation ............................................................................................55 3.4 Identity Tests............................................................................................................... 56 3.5 Adulteration/Substitution ...........................................................................................57 3.5.1 Adulteration/Substitution with other Plant Material ......................................... 57 3.5.2 Adulteration with Synthetic Drugs .....................................................................59 3.5.3 Adulteration with Toxic Metals .......................................................................... 61 3.6 Contamination ............................................................................................................. 63 3.6.1 Microbial Organisms ............................................................................................63 3.6.2 Bacterial and Fungal Toxins ................................................................................64 3.6.3 Pesticides and Fumigants ....................................................................................65 3.6.4 Radioactivity.........................................................................................................66 3.6.5 Environmental Pollution ..................................................................................... 66 3.6.6 Ash Values ............................................................................................................68 111 3.7 Control and Stability Tests ........................................................................................ 69 3.8 Discussion ....................................................................................................................69 4. SAFETY OF HERBAL REMEDIES........................................................................... 73 4.1 General considerations ...............................................................................................73 4.2 Herbal Ingredients with Toxicologically Significant Constituents ..........................76 4.2.1 Benzophenanthridine Alkaloids .......................................................................... 78 4.2.1.1 Chemistry, Occurrence and Toxicity ...........................................................78 4.2.1.2 Bloodroot (Sanguinaria canadensis) ...........................................................79 4.2.1.3 Prickly Ash Northem/Southem (Zanthoxylum americanum/ clava- herculis)......................................................................................................................80 4.2.2 Pyrrolizidine Alkaloids ....................................................................................... 80 4.2.2.1 Chemistry and Occurrence ........................................................................... 80 4.2.2.2 Formation of Pyrrole Derivatives ................................................................ 82 4.2.2.3 Hepatotoxicity of Pyrrolizidine Alkaloids .................................................. 84 4.2.2.4 Carcinogenicity and Genotoxicity of Pyrrolizidine Alkaloids .................. 86 4.2.2.5 Pyrrolizidine Alkaloid Poisoning in Humans ..............................................86 4.2.2.6 Comfrey {Symphytum officinale) ................................................................. 91 4.2.2.7 Coltsfoot {Tussilage farfara) ........................................................................93 4.2.2.8 Borage (Baraga officinalis) .......................................................................... 94 4.2.2.9 Echinacea {Echinacea officinalis) ..................................... 94 4.2.2.10 Liferoot (Senecio aureus)........................................................................... 94 4.2.2.11 Health Risk of Human Exposure to Pyrrolizidine Alkaloids .................. 95 4.2.3 Cyanogenetic Glycosides ....................................................................................95 4.2.3.1 Chemistry, Occurrence, Toxicity ................................................................. 95 4.2.3.2 Laetrile/Apricot ..............................................................................................96 4.2.4 Diterpenes .............................................................................................................97 4.2.4.1 Chemistry, Occurrence, Toxicity ................................................................. 97 4.2.4.2 Queen’s Delight {Stillingia sylvatica) ..........................................................98 4.2.4.3 Germander {Teucrium chamaedrys)............................................................98 4.2.5 Essential O ils ....................................................................................................... 99 4.2.5.1 Alkenylbenzene Derivatives ....................................................................... 101 4.2.5.1.1 Safrole ....................................................................................................104 4.2.5.1.2 Estragole (Methylchavicol) ..................................................................105