This report contains the collective views of an in- ternational group of experts and does not necessarily represent the decisions or the stated policy of the United Nations Environment Programme, the Interna- tional Labour Organisation, or the World Health Organization Environmental Health Criteria 80 PYRROLIZIDINE ALKAI,OIDS Published under the joint sponsorshipof the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization World Health Organization Geneva, 1988 The lnternational Programme on Chemical Safety (IPCS) is a joint venture of the United Nations Environment Programme, the International Labour Organisa- tion, and the World Health Organization. The main objective of the IPCS is to carry out and disseminateevaluations of the effects of chemicals on human health and the quality ofthe environment. Supporting activities include the development of epidemiblogical,experimental laboratory, and risk-assessmentmethods that could produce irtternationally comparable results, and the development of manpower in the field of toxicology. Other activities carried out by IPCS include the develop- ment of know-how for coping with chemical accidents,coordination of laboratory testing and epidemiological studies, and promotion of researchon the mechanisms of the biological action of chemicals. rsBN 92 4 t54280 2 @World Health Organization 1988 Publications of the World Health Organization enjoy copyright protection in accordancewith the provisions of Protocol 2 of the Universal Copyright Conven- tion. For rights of reproduction or translation of WHO publications, in part or in toto, application should be made to the Office of Publications, World Health Organization, Geneva,Switzerland, The World Health Organization welcomessuch applications. The designationsemployed and the presentation of the material in this publica- tion do not imply the expression of any opinion whatsoever on the part of the Secretariat of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or of certain manufacturers' products does not imply that they are endorsed or recommendedby the World Health Organiza- tion in preferenceto others of a similar nature that are not mentioned. Errors and omissions excepted,the names of proprietary products are distinguished by initial capital letters. rssN0250-863X PRINTED IN FINLAND DASS_VAMMALA-5500 RIA FOR PYRROLIZIDINE ALKALOIDS PREFACE L2 INTRODUCTION- PYRROLI NE ALKALOIDS AND ITI'MANHEALTI{ . 13 1. ST'MMARY.A,ND 19 1.1 Sumary L9 t.2 Sources'and c alstructure... 19 1.3 Mechanisms and tures of toxicity 20 t.4 Effects on man 22 1.4.1 Nature extent of health risks . 22 1.5 Methods for tion . 24 1.6 Reconurendat ions 24 1.6.1 General tions . 24 t.6.2 tions for research 25 2. PROPERTIESAND ANAL METHODS 27 2.L ChemicaL struc re and properties 27 2.2 AnaLvtical me 32 2.2.L ExtractidnExtract.t-on 33 2.2.L.L Pl-ant tissue . 33 2.2.1.2 Biological- ffluids l-uids and tissues 33 2.2.2 Analysis for pyrrolizidine aLkaloids 33 2.2.2.1 jthin-Layer chromatography (TLC). 33 2.2.2.2 High-performance 1-iquid chromatography (HPLC) 34 2.2.2.3 Gas chromatography (GC) and mass spectrometry (MS) . 34 2 .2.2.4 Nucl-ear magnetic resonance (NMR) spectrometry . 35 2.2.2.5 The Ehrlich reaction 35 2.2.2.6 Indicator dyes . 36 2.2.2.7 DirecE weighing 36 2.3 Determinationo metabolites in animal tissues . 37 J. SOURCESAND PATHWAYSOF EXPOSUPG 3.1 Hepatotoxic pyrfolizidine alkaloids and their sources . 38 3.2 Pneumotoxic and other toxic pyrrolizidine alkaloids I -4- Page 3.3 Pathvays of exposure 42 3.3.1 Contamination of staple food crops 43 3.3.2 Herbal infusions 43 3.3.3 Use of PA-containing plants as food 47 3.3.4 Contaminated honey 50 3.3.5 Mitk 51 3.3.6 Meat 54 3.3.7 Use of PAs as chemottrerapeutic agents for cancer 54 4. METABOLISU )) 4.L Absorption, excretion, and tissue distribution . 55 4.l.L Absorption 55 4.I.2 Excretion and distribution 55 4.2 Metabolic routes 58 4.2.L Hydrolysis .. .58 4.2.2 N-oxidation 59 4.2.3 donversion to pyrrolic metabolites 59 4.3 Effects of treatments affecting metaboLism . 61 4.4 other factors affecting rnetabolism . 63 4.5 Other metabolic routes 63 4.6 Metabolism of pyrrolizidine N-oxides . 64 4.7 Metabolism in man . 64 5. MECHANISI.{SOF TOXICIIY AND OTHER BIOLOGICAT ACTIONS . 65 5.1 Metabolites responsibLe for toxicity . 65 5.l.L MetaboLic basis of toxicity 65 5.I.2 Isolation of pyrrolic rnetabolites . 66 5.1.3 Chemical aspects of pyrrolic metabolites . 66 5.1.3.1 Preparation 66 5.1.3.2 Chemistrv associated with toxic actions 67 5.L.4 Possible further metaboLites 68 5.2 Toxic actions of pyrrolic netabolites 69 5.2.L Aninals 69 5.2.t.L Pyrrolic esters (dehydro- alkal-oids ) 69 5.2.L.2 Pyrrolic alcohoLs (dehydro- necines) .....70 5.2.2 CeLl culturea . 7| 5.2.3 Possible participation of membrane lipid peroxidation.. ... .72 5.3 ChenicaL and metabolic factors affecting toxicity .....72 5.3.1 Structural featureg of a toxic alkaloid . 72 -5- Page 5.3.2 Activat and toxication 73 5.3.3 Factors ffect the toxicity of active rnetaboLi ea. 74 5.3.3.1 React ity of the metabolite . 74 5.3.3.2 The r of reactive groups 74 5.4 Metabolites 1a with the biological actions of pyrrolizid alka ids.. 75 5 .4.L Acute h city 75 5.4.2 Chronic totpxicity 75 5.4.3 Pneumoto:iicity 76 r tissues 76 77 itv.. 77 5.) t of pyrrol-izidine 78 5.5.1 Modified diets 78 5.5.2 Pre-treadment t enhance the detoxication of activd metat lites . 79 5.5.3 Other trdatment 80 6. EFFECTSoN ANIMALS J . 81 6.1 Patterns of disdase ca by different plant genera and of or{gan in lvement in different 81 tbreaks in farm animals . 81 84 l.es 87 1-ver B7 hepatotoxicity of t PAs and their N-oxides . 87 affecting hepatoEoxicity . 87 ffects 92 sm of toxic acEion 97 effects 98 6.4.2 ungs 103 ffects . 105 effects . 110 sms of toxic action . rL4 6.4.3 entral nervous svstemoJ o LLut L2L 6.4.4 organs . L2I 6.4.5 ..L24 6,4.6 ..L24 6.4.7 ..L26 damage ....129 6.4.8 .rt"i.ia"::::::::il; -5- Page 6.4.8.2 PlantmateriaLs ....L67 6.4.8.3 Pvrrolizidine alkal-oid metabolites aid analogous synthetic compounds ... 171 6.4.8.4 MoLecular structure and carcinogenicactivity ..173 6.4.9 Antimitoticactivity ...L74 6.4.10 Imunosuppression .. ..L75 6.4.11 Effects on mineral metabolism . L75 6.4.L2 Methods for the assessment of chronic hepatotoxicity and pnetmotoxicity . 176 6.5 EffectsonwiLd-life... ....L77 6.5.1 Deer ...L77 6.5.2 Fish.. ..L77 6.5.3 Insects ..178 7. EFFECTSON MAN .. .L79 7.I Clinical features of veno-occlusive disease (voD) L79 7.2 Salient pathoLogical features of veno- occlusivedisease . 181 7.3 Human cage reports of veno-occlusive disease . 183 7.4 VoD end cirrhosis of the liver . 201 7.5 Differences between VOD and Indianchildhoodcirrhosis (Icc) . 2O3 7.6 Chronic lung disease . .204 7.7 Trichodesma poisoning . 2O5 7.8 Eaiffiil?frIp betlreen dose leveL and toxic effects . ..206 7.9 Pyrrolizidine alkaloids as a chemotherapeutic agentforcancer .;.. .....2L3 7.10 Prevention of poisoning in man . 2L4 8. BIOLOGICAL CONTROL 9. EVALUATION OF ITI'MANIIEALTH RISKS AND EFFECTS ON THE ENVIRONMENT . 2L7 9.1 lluman exposure conditioirs . .2L7 9.1.1 Reported sources of hr:man exposure . 2L7 9.1.2 Plant species invoLved . 2L7 9.1.3 Modes and pathways of exposure . 2I8 9.1.3.,1 Contamination of grain crops . 2L8 9 .L.3 .2 lterbaL medicines . 218 9.L.3.3 PA-containing pLants used as food andbeverages ..2L9 9.1.3.4 Other food contaminated by PAs . 2L9 -1- Page g.L.4 Levels of intake 220 9.2 Acute effects of exposure 222 9.2.I Acute livdr disease 222 9 .3 Chronic dffects <]rfexposure 223 9.3.1 Cd.rrhosis of the liver 223 9.3.2 Mutagenic{ty and teratogenicity 223 9.3.3 Cancer of the liver . 223 9.3.4 Effeits o{t other organs 224 9.4 Effects on the edvironment 225 9.4.L Agricultufe 225 226 9.4.3 Iosects 226 9.4.4 Soil and ter .,226 227 APPENDIXI. PYRROLIZID ALKALOIDS AND TIIEIR PLANT APPENDIXII. TABIE 1. PI,ANTS HEPATOTOXICPYRROLIZIDINE ALKALOIDS 303 TABLE 2. PI,ANTS INING KNOWNALKALOIDS THAT ARE NON-IIEPA C (AI,IINOALCOHOLSAND ESTERS) . 337 -8- MIO TASK GROUPON PYRROLIZIDINE ALKALOIDS Members Professor M.S. AbduLLahodjaeva, Uzbek Republican Centre for Pathological Anatomy, Tashkent State Medical Institute, Tashkent, USSR Dr C.C.J. Culvenor, Comronwealth Scientific and Industrial Research Organization, Division of Anirnal llealth, Parkville, Victoria, AustraLia (Cttrir*") Professor P.P. Dykun, Department of Biophysica, Petrov Research Institute of Oncology, Leningrad, USSR Dr H.N.B. Gojalan, University of Nairobi, Department of Botany, Nairobi, Kenya Dr R.J. ttuxtable; Department of Pharmacology, University of Arizona, Tucson, Arizona, USA Dr A.R. Mattocks, MRCToxicology Unit, Medical Research Council Laboratories, Carshalton, Surrey, United Kingdom Dr V. Murray, NationaL Poisons Information Service, New Cross Hospital, London, United Kiogdom Dr B. Snith, Division of Food Regulatory Affairs, Food Directorate, HeaLth Protection Branch, Tunneyrs Pasture, Ottawa, Canada Professor It.D. Tandon, NationaL Academy of Medical Sciences (India), Ansari Nagar, New DeLhi, India (Chairnan) Academician F.YU.