Handbook of Natural Colorants

Editors Thomas Bechtold, PhD, is a Professor at the Research Institute for Textile Chemistry and Textile Physics at the University of Innsbruck, Austria Avinash P. Manian, PhD, is an Assistant Professor at the Research Institute for Textile Chemistry and Textile Physics, University of Innsbruck, Austria Tung Pham, PhD, is the Head of Institute and BMK Endowed Professor at the Research Institute for Textile Chemistry and Textile Physics at the University of Innsbruck, Austria Series Editor Christian V. Stevens, Faculty of Bioscience Engineering, Ghent University, Belgium

• List of Contributors xxiSeries Preface xxvPreface xxviiI Historical Development 11 History of Natural Dyes in the Ancient Mediterranean Civilization 3Maria J. Melo1.1 Introduction 31.1.1 Ancient Mediterranean World 31.1.2 Dyes from Antiquity 41.1.3 Unveiling the Secrets of Ancient Dyes with Modern Science 71.2 Ancient Reds 71.2.1 Anthraquinone Reds 71.2.2 Redwoods 101.2.3 Flavylium/Anthocyanin Reds 121.2.3.1 Equilibria in solution 131.3 Ancient Blues 141.3.1 Indigo Blues 141.3.2 Anthocyanin Blues 151.4 Ancient Purples 161.4.1 Tyrian Purple: Real Purple from Sea Snails 161.4.2 Orchil Purples 181.4.3 Folium 181.5 Ancient Yellows 201.5.1 Flavonoid Yellows 201.5.2 Carotenoid Yellows 211.5.3 Chalcone and Aurone Yellows 22Acknowledgements 22References 222 Colors in Civilizations of the World and Natural Colorants: History under Tension 27Dominique Cardon2.1 Introduction 272.2 The Triumph of Mauveine: Synthetic Fulfillment of the Antique Purplemania 282.3 Blue: From Kingly Regional to Globally Democratic 292.4 Red and Yellow: From Micro to Macro Scales 292.5 What Is the Future for Natural Colorants in the Dawning Era of Renewable Resources? 30Acknowledgement 31References 313 History of Natural Dyes in North Africa_Egypt 33Harby Ezzeldeen Ahmed3.1 Introduction 333.2 Natural Dyes in Pharaonic Textiles 343.3 Dyeing Techniques 343.4 Dye Sources 343.4.1 Woad 353.4.2 Indigo 353.4.3 Red 353.4.4 Yellow 363.4.5 Black 363.4.6 Brown 363.4.7 Green 363.4.8 Purple 363.5 Dyeing in Coptic Textiles 363.6 Wool- Dyed Fabric with Natural Dye 383.7 Dyes in Islamic Textiles 383.8 Mordants 40References 40II Natural Colorants in Different Regions of the World 434 Sources for Natural Colorants in Europe 45Thomas Bechtold, Tung Pham and Avinash P. Manian4.1 Introduction 454.2 Cultivation 464.2.1 Potential European Dye Plants Yesterday and Now 464.2.2 Modern Cultivation Methods— General Facts 474.2.3 Blue- Dye Plants 484.2.4 Red- Dye Plants 494.2.5 Yellow- Dye Plants 494.2.6 Brown- Dye Plants 524.2.7 Production of Dye Extracts 544.3 Natural Colorants from Agro- Food Residues 554.4 Natural Colorants from Forestry and Timber Industry 564.5 Relevant Examples for the Application 574.6 Conclusions, Discussion, and Summary 58Acknowledgement 58References 595 Dyes in South America 63Veridiana Vera de Rosso and Adriana Zerlotti Mercadante5.1 Introduction 635.2 Annatto 655.3 Turmeric 675.4 Marigold 685.5 Cochineal and Carmine 69Acknowledgements 71References 716 Natural Dyes in Eastern Asia (Vietnam and Neighboring Countries) 75Tung Pham and Thomas Bechtold6.1 Introduction 756.2 Annatto (Bixa orellana L., Family Bixaceae) 756.3 Tea (Camellia sinensis (L.) Kuntze, Family Theaceae) 776.4 Umbrella Tree (Terminalia catappa L., Family Combretaceae) 776.5 Mackloeur (Diospyros mollis L. Griff, Family Ebenaceae) 786.6 Indigo (Indigofera L., Family Fabaceae) 796.6.1 Indigofera tinctoria L. 796.6.2 Indigofera galegoides dc 806.6.3 Strobilanthes cusia (Baphicacanthus) 806.7 Henna (Kok Khan or Khao Youak in Laos) (Lawsonia spinosa L., Family Lythraceae) 806.8 Nacre (African Mahogany, Khaya senegalensis, Family Meliaceae) 816.9 Sappan Wood (Caesalpinia sappan L., Family Fabaceae) 816.10 Japanese Pagoda Tree Flowers (Sophora japonica L., Family Leguminosae) 826.11 Turmeric (Curcuma longa L., Family Zingiberaceae) 826.12 Sapodilla (Manilkara zapota L. or Achras zapota, Family Sapotaceae) 826.13 Betel (Piper betel L., Family Piperaceae) 836.14 Eucalyptus (Eucalyptus, Family Myrtaceae) 836.15 Caesalpinia Yellow (Caesalpinia pulcherrima L., Family Fabaceae) 836.16 Brow- Tuber; Yam (Dioscorea cirrhosa Lour, Family Dioscoreaceae) 836.17 Others 84Acknowledgement 84References 847 Sources for Natural Colorants in China 89Ren-Cheng Tang7.1 Introduction 897.2 Sophora japonica Yellow 927.3 Turmeric 937.4 Gardenia Yellow 937.5 Emodin 937.6 Baicalin 947.7 Berberine 947.8 Henna 947.9 Monascus Red 957.10 Madder 957.11 Sorghum Red 957.12 Mulberry Red 967.13 Shikonin 967.14 Indigo 967.15 Condensed Tannins 977.16 Tea Polyphenols 987.17 Gallnut 99References 998 Sources, Application, and Analysis of Natural Colorants: An Indian Perspective 103Prof. (Dr.) Ashis Kumar Samanta and Prof. (Dr.) Deepali Singhee8.1 Introduction 1038.2 Natural Dyes in India 1048.2.1 History 1048.2.2 Traditional Processes of Dyeing with Natural Dyes in Different Parts of India 1058.2.3 Sources of Natural Dyes in India 1068.2.4 Use of Some Natural Dyes in Traditional Textiles of India 1078.3 Details of Some Dye Sources and Their Application in India 1098.3.1 Turmeric 1098.3.2 Pomegranate 1118.3.3 Flame of Forest 1148.3.4 Marigold 1168.3.5 Safflower 1188.3.6 Annatto 1208.3.7 Madder 1238.3.8 Indian Mulberry 1258.3.9 Arjuna 1278.3.10 Sappanwood 1308.3.11 Eucalyptus 1328.3.12 Catechu 1348.3.13 Gallnut 1378.3.14 Myrobolan 1408.3.15 Lac 1428.3.16 Indigo 145References 1479 Natural Dye Gardens in North America 161Wendy Weiss and Thomas Bechtold9.1 Introduction 1619.2 Participants 1629.3 Education 1639.4 Motivation to Work with Natural Dye 1669.5 Plant List— Cultivated Plants 1669.6 Chemical Background of Most Relevant Plants 1689.7 Plant List— Foraged Plants 1729.8 Plants with Indigotin 1729.9 Importance of the Fibershed Movement 1739.10 Educational and Community Gardens 1749.11 Mexico 1779.12 Canada 1779.13 Future Research 178References 178Notes 179III Colorant Production and Properties 18110 Chlorophylls 183María Roca10.1 Introduction 18310.2 Chemical Structures and Physicochemical Properties 18410.3 Chlorophylls as Colorants 18710.4 New Trends in the Use of Chlorophylls as Colorants 18910.5 Stability and Analysis 19010.6 Toxicological and Safety Aspects 191References 19211 Indigo— Production and Properties 195Philip John and Luciana Gabriella Angelini11.1 Introduction 19511.2 Agronomy 19611.2.1 Isatis 19611.2.1.1 Developmental Stages and Climate and Soil Crop Requirements 19711.2.1.2 Rotation 20111.2.1.3 Soil Tillage and Seed Sowing 20211.2.1.4 Weeds, Pests, and Diseases 20311.2.1.5 Fertilizers and Irrigation 20411.2.1.6 Harvesting and Yields 20511.2.1.7 Seed Production 20711.2.1.8 Isatis indigotica Compared with Isatis tinctoria 20811.2.2 Persicaria 20911.2.2.1 Introduction 20911.2.2.2 Developmental Stages 21111.2.2.3 Sowing, Harvesting, and Yield 21111.2.2.4 Weeds, Pests, and Diseases 21611.2.2.5 Fertilizer and Irrigation Requirement 21611.2.2.6 Seed Production 21711.2.3 Indigofera 21711.3 Methods of Determining Indigo 21911.4 Precursors in the Plants 22211.5 Direct Dyeing with Indican 22711.6 Indigo Formation 22711.7 Extraction Procedures 22911.7.1 Traditional Process Using Crushed Leaf Material 22911.7.1.1 Isatis 22911.7.1.2 Persicaria 23011.7.2 Steeping in Water 23111.7.2.1 Indigofera 23211.7.2.2 Isatis 23411.7.2.3 Persicaria 23911.8 Purity of Natural Indigo 24011.8.1 Purification by Sublimation 24111.8.2 Impurities in Natural Indigo 242Acknowledgements 245References 24512 Anthocyanins: Revisiting Nature’s Glamorous Palette 251Maria J. Melo, Fernando Pina, Natércia Teixeira and Claude Andary12.1 Chemical Basis 25112.1.1 Chemical Structures 25112.1.2 Equilibria in Solution 25312.1.3 Kinetics 25412.1.4 Color and Color Stability 25412.1.5 Anthocyanins as Antioxidants 25812.2 Natural Sources and Applications for Anthocyanins 25912.2.1 Plants Sources, Content, Influencing Parameters 25912.2.2 Food Colorants 26012.2.3 Other Uses 26112.2.4 Examples of Commercial Products and Processing 262References 263Appendix 1 267A1.1 Multi-Equilibria in Acidic and Basic Media 267A1.2 Measuring the Equilibria Constants 26913 Natural Colorants— Quinoid, Naphthoquinoid, and Anthraquinoid Dyes 271Goverdina C. H. Derksen and Thomas Bechtold13.1 Introduction 27113.2 Benzoquinone Dyes 27113.3 Diaryloylmethane Dyes 27313.4 Naphthoquinone Dyes 27313.4.1 Lawson (2- hydroxy- 1,4- naphthoquinone, CI Natural Orange 6) 27413.4.1.1 Properties and Use 27413.4.1.2 Agricultural Aspects 27613.4.2 Juglone (5- hydroxy- 1,4- naphthoquinone, CI Natural Brown 7) 27813.5 Anthraquinone Dyes 27913.5.1 Main Components Emodin and Chrysophanol— Rheum and Rumex Species 27913.5.2 Main Components Alizarin and/or Pseudopurpurin/Purpurin 28113.5.2.1 Plant Sources 28113.5.2.2 Madder CI Natural Red 8 282References 29414 Natural Colorants from Lichens and Mushrooms 317Riikka Räisänen14.1 Use of Lichen and Mushroom Colorants in History 31714.2 Cultivation of Lichens and Mushrooms 31814.3 Colorant Structures in Lichens and Mushrooms 31914.3.1 Lichen Dyes: Orchils and Litmus 32114.3.2 Yellowish, Brownish, and Reddish Colorants from Lichen 32214.3.3 Blue Terphenylquinones from Mushrooms 32214.3.4 Anthraquinones 32414.3.4.1 Bloodred Webcap (Cortinarius sanguineus) 32414.3.5 Other Colorants of Fungi 32614.3.5.1 Yellows from Grevillines 32614.3.5.2 Yellow and Orange Colors from Pulvinic Acid Derivatives 32614.3.5.3 Brown from Badiones 32614.4 Stability of Lichen and Mushroom Colorants 32614.5 New Approaches to Lichen and Fungal Colorants 327References 32815 Focus on Tannins 333Riitta Julkunen-Tiitto and Hely Häggman15.1 Introduction 33315.2 Chemical Structure, Biosynthesis, and Degradation 33515.3 Properties of Tannins 33815.4 Chemical Activities of Tannins 34015.5 Analysis of Tannins 34015.5.1 Sample Preservation 34015.5.2 Extraction and Purification 34015.5.3 Quantification of Tannins 34115.6 Use, Toxicology, and Safety Aspects of Tannins 342References 34516 Carotenoid Dyes— Properties and Production 351U. Gamage Chandrika16.1 Introduction 35116.1.1 Occurrence of Carotenoids 35116.1.2 Chemistry of Carotenoids 35116.1.3 Chemical Characteristics of Natural Carotenoids 35216.2 Properties and Functions of Carotenoids 35416.2.1 Carotenoids’ Role as Pro- vitamin A 35416.2.2 Use of Carotenoids as Markers of Dietary Practices 35616.2.3 Carotenoids as Antioxidants 35616.2.4 Carotenoids in the Macular Region of the Retina 35716.2.5 Carotenoids as Anticancer Agents 35716.2.6 Carotenoids as Natural Colorants 35716.3 General Procedure for Carotenoid Analysis 35716.3.1 Sampling 35916.3.2 Extraction 35916.3.3 Saponification of Carotenoids 35916.3.4 Chromatographic Separation 35916.3.5 Chemical Tests 36116.3.6 Detection and Identification of Carotenoids 36116.3.7 Quantification of Carotenoids 36216.4 Problems in Carotenoid Analysis 36216.5 Factors Influencing Carotenoid Composition in Plant Sources 36316.5.1 Stage of Maturity 36316.5.2 Cultivar or Varietal Differences 36316.5.3 Climatic or Geographic Effects 36416.5.4 Post- Harvest Storage and Packing 36416.5.5 Changes in Processing/Cooking 36416.5.6 Effect of Agrochemicals 366References 36617 Flavonoids as Natural Pigments 371M. Monica Giusti, Gonzalo Miyagusuku-Cruzado and Taylor C. Wallace17.1 Introduction 37117.2 Role of Localized Flavonoids in the Plant 37217.3 General Flavonoid Chemical Structure 37217.4 Biosynthesis of Flavonoids 37317.5 Anthocyanins as Natural Colorants 37317.5.1 Structure 37517.5.2 Structural Transformation and pH 37617.5.3 Temperature 37717.5.4 Oxygen and Ascorbic Acid 37717.5.5 Light 37817.5.6 Enzymes and Sugars 37917.5.7 Sulfur Dioxide 37917.5.8 Co- Pigmentation and Metal Complexation 38017.6 Other Flavonoids as Natural Colorants 38117.6.1 Yellow Flavonoid Pigments 38117.6.2 Tannins 38117.6.3 Anthocyanin- Derived Pigments: Pyranoanthocyanins 38217.7 Therapeutic Effects of Flavonoids in the Diet 38217.8 The Use of Flavonoids as Food Colors in the US and EU 383References 38418 Natural Colorants from Fungi 391Cassamo U. Mussagy, Fernanda de Oliveira and Valeria C. Santos-Ebinuma18.1 Introduction 39118.2 Types of Fungi Colorants 39218.3 Fungal Producer of Colorants 39418.4 Bioprocess 39518.4.1 Biosynthesis Pathway 39518.4.2 Production and Extraction Process 40018.5 Toxicity 40418.6 Industrial Application of Fungi Colorants 40618.7 Conclusion 407References 40719 Natural Colorants from Cyanobacteria and Algae 417Laurent Dufossé19.1 Introduction 41719.2 Phycobiliproteins from Cyanobacteria 41819.2.1 Structural Characteristics of Phycobiliproteins 42019.2.2 Food Grade Phycobiliproteins 42219.2.3 Future Trends 42219.3 Pigments from Microalgae 42219.3.1 β- Carotene from the Microalga Dunaliella, Salty but Effective! 42319.3.1.1 β- Carotene from Microalgae 42319.3.1.2 Dunaliella Species for Carotenoids 42419.3.2 Why Carotenoids from Dunaliella? 42419.3.2.1 Natural vs. Synthetic β- Carotene 42419.3.2.2 Applications of β- Carotene 42419.3.2.3 Advantages of Carotenoids Production from Dunaliella 42519.3.2.4 Process for Production of β- Carotene from Dunaliella 42519.3.2.5 Companies Producing Dunaliella 42519.3.2.6 Marketed Products of β- Carotene 42619.3.3 Haematococcus for Astaxanthin, the Red Gold Rush 42619.3.3.1 Advantages of Astaxanthin over Other Carotenoids 42719.3.3.2 Astaxanthin as Nutraceutical 42719.3.3.3 Astaxanthin as Antioxidant 42719.3.3.4 Astaxanthin for Health 42819.3.3.5 Astaxanthin for Salmon and Trout Feeds 42819.3.3.6 Astaxanthin for Humans 42919.3.3.7 Production System for Haematococcus 42919.3.3.8 Companies Producing Astaxanthin from Haematococcus 43019.3.3.9 Astaxanthin- Containing Formulations 43119.4 Natural Colorants from Macroalgae (e.g., Seaweeds) 43119.4.1 Biodiversity of Seaweeds 43119.4.2 Seasonal Variations and Environmental Threats 43219.4.3 Major Classes of Seaweed Pigments 43319.4.3.1 Chlorophylls 43319.4.3.2 Carotenoids 43319.4.3.3 Phycobiliproteins 43419.5 Conclusion 434References 43420 Biotechnological Production of Microbial Pigments: Recent Findings 439Vivian Katherine Colorado Gómez, Juan Pablo Ruiz-Sánchez, Alejandro Méndez-Zavala, Lourdes Morales-Oyervides and Julio Montañez20.1 Introduction 43920.2 Microbial Pigments Market 44020.3 Production Strategies 44020.4 Novel Extraction Technologies for Pigments Recovery 44120.5 Regulation and Biosynthesis of Microbial Pigments 44320.6 Strain Engineering Strategies for Pigment Production 44620.7 Trends in New Microbial Sources of Pigments 44820.8 Microbial Pigments Applications 44920.8.1 Solar Cells 44920.8.2 Therapeutic Application 45020.8.3 Other Applications 45020.9 Regulations on Microbial Pigments Use 45120.10 Conclusions and Future Perspectives 452References 45221 Analytical Methods for Characterization and Standardization of Natural Dyes and Pigments 459Tung Pham, Avinash Manian and Thomas Bechtold21.1 Introduction 45921.2 Chemical Analysis— Identification 46021.3 Quantification by Sum Parameters 46321.4 Applicatory Tests 46421.5 Product Performance 465References 46622 Wood— From Natural Color Patterns Toward Naturally Altered Color Impressions 469Martin Weigl-Kuska, Andreas Kandelbauer, Christian Hansmann and Ulrich Müller22.1 The Color of Wood 46922.1.1 Wood Chemical Composition 47022.1.2 Wood Anatomical Appearance 47122.1.3 Physical Properties of the Wood Surface 47222.2 Coatings 47322.3 Dyes 47722.3.1 Impregnation 47722.3.1.1 Technology 47722.3.1.2 Color 47922.3.1.3 Products 48022.4 Color Modification 48122.4.1 Drying 48222.4.1.1 Basics 48222.4.1.2 Technology 48322.4.1.3 Color 48422.4.2 Steaming 48522.4.2.1 Basics 48522.4.2.2 Technology 48522.4.2.3 Color 48622.4.3 Thermal Treatment 48722.4.3.1 Technology 48722.4.3.2 Color 48722.4.4 Ammoniation 48822.4.4.1 Basics 48822.4.4.2 Color 48922.4.5 Bleaching 49122.4.5.1 Basics 49122.4.5.2 Color 49122.4.6 Enzymatic Treatment 49222.4.6.1 Basics 49222.4.6.2 Laccases 49322.4.7 Radiation 49522.4.7.1 Basics 49522.4.7.2 Color 49522.4.7.3 Technology 49722.5 Outlook 498References 49823 The Role of Mordants in Fixation of Natural Dyes 507Avinash P. Manian23.1 Introduction 50723.2 Metal Salts 50823.3 Biomordants 50823.4 Substrate Pretreatments 50823.5 No Mordant 509References 50924 Textile Coloration with Natural Dyes and Pigments 517Thomas Bechtold, Tung Pham and Avinash P. Manian24.1 Introduction 51724.2 Reasons for Natural Coloration 51824.3 The Dyestuff–Fiber Interaction 52024.4 Design of a Dyeing Process 52124.5 Transfer of a Dyeing Process into Technical Scale 52324.6 Processes and Resources 52424.7 Technical Requirements for a Natural Dyestuff 52624.7.1 Gamut and Color Shade 52624.7.2 Fastness Criteria 52824.8 Handling of Natural Dyes in a Technical Dyehouse 53024.9 Mordanting 53124.10 Natural Dyes on an Industrial Scale 53324.10.1 Dyeing Technology— Exhaust Process 53324.10.2 Hank Dyeing of Woolen Yarn and Production of Woolen Caps 53424.10.3 Dyeing of Cones in a Yarn Dyeing Machine 53424.10.4 Dyeing of Cotton Fabric on a Jet Dyeing Machine 53524.10.5 Fabric Dyeing on a Garment Dyeing Machine 53624.10.6 Dyeing of Polyamide Tights in a Paddle Dyeing Machine 53624.10.7 Dyeing Technology— Continuous Dyeing 53624.11 Conclusion 537Acknowledgement 538References 53825 Hair Coloration with Natural Dyes and Pigments 543Thomas Bechtold25.1 Introduction 54325.2 Human Hair 54425.3 General Requirements on Hair Dyeing Concepts 54425.4 Chemical Principles of Dyestuff Binding 54625.5 Relevant Natural Dyes for Hair Dyeing 54625.5.1 Naphthoquinone Dyes— Henna and Walnut 54625.5.1.1 Henna, CI (Color Index) Natural Orange 6 54625.5.1.2 Juglon, CI Natural Brown 7 54725.5.2 Indigo 54825.5.3 Metal Complexes 54825.5.4 Metal Reaction Dyes 55025.5.5 Anthraquinoid Dyes 55125.6 Specialties 55125.7 Regulations 552References 55226 Natural Colorants in the Mass Coloration of Plastics 557Thomas Bechtold and Tung Pham26.1 Introduction 55726.2 Representative Examples 559Acknowledgement 561References 56127 Natural Colorants in Printing/Packaging 563Thomas Bechtold and Tung Pham27.1 Introduction 56327.2 Packaging Films 56427.3 Film Coloration 56727.4 Paper Dyeing 56827.5 Paints 568Acknowledgement 569References 56928 Technical Aspects and Requirements to Produce Natural Colorants— Processes and Product Standardization 573Thomas Bechtold and Avinash Manian28.1 Introduction 57328.2 Sources of Plant Material— Product I 57628.2.1 Organic Farming 57628.2.2 Sustainable Farming 57628.2.3 Native Species 57728.2.4 Farming for Food or/and Natural Colorants 57728.2.5 Residual Materials and By- Products 57728.3 Processing to Dyestuff— Product II 57928.4 Quality Control and Standardization of a Dye (Product II) 58328.4.1 Anthocyanins 58428.4.2 Flavonoids 58428.4.3 Dye Lakes 58528.5 Challenges for the Industrial Use of Natural Colorants 58528.6 Dealing with Sustainability 58628.7 Conclusions 587References 58729 Environmental and Economic Position of Natural Colorants— Energy and Resources Balances, Sustainability, Ecology, and Costs 591Susanne Geissler and Thomas Bechtold29.1 Introduction 59129.2 Dye Plant Production 59229.3 Dye Extraction and Dyestuff Production 59529.4 Transportation 59629.5 Textile Dyeing 59629.6 Commercial Aspects— Costs 59729.6.1 Basic Requirements for the Industrial Use of Natural Colorants 59829.6.1.1 Precondition 1: acceptable costs of natural colorants and dyeing processes 59929.6.1.2 Precondition 2: feasible cost of process engineering 59929.6.1.3 Precondition 3: compliance with requested colorfastness properties 59929.6.1.4 Precondition 4: competitive cost of naturally dyed products 60029.6.1.5 Precondition 5: security of natural colorant supply 60029.6.2 Consumer Expectations 60029.6.3 Market Research for Naturally Dyed Products 60129.7 Production Costs of Natural Colorant Products 60229.7.1 Cost Categories 60329.7.2 Aspects Influencing Production Costs 60329.8 Prices of Synthetic Dyes— How Much Are Textile Companies Prepared to Pay for Dyes? 60529.9 Acceptable Production Costs through a Mixed Portfolio (Agricultural Primary Production and Residues from Other Production Processes) 60629.10 Closed- Loop Economy: Toward a Zero- Emission and Zero- Waste Society 60729.11 Considerations Concerning the Life Cycle 60929.12 Conclusion: Aspects Influencing Market Development for Natural Colorants 609References 61030 Aspects of Human Toxicology and Consumer Safety 613Judith Büttler, Thomas Bechtold and Tung Pham30.1 Introduction 61330.2 Basic Aspects of Xenobiotic- Induced Toxicity 61430.3 Toxicological Aspects of Natural Colorants in Food and Medical Applications 61530.3.1 Risk Assessment 61730.3.2 Therapeutic Effects (= Risk) 61830.4 Toxicological Aspects of Natural Colorants in Cosmetics 61830.4.1 Risk Assessment 61930.5 Toxicological Aspects of Natural Colorants in Textile Dyeing 61930.5.1 Plant Extracts 62030.5.2 Pretreatment Agents and Mordants 62130.5.3 Wastewater and Antimicrobial Compounds 62130.5.4 Dyed Products 62230.6 Test Methods for Toxicity Screening 62230.6.1 Extract Preparation 62430.6.2 Cytotoxicity 62430.6.3 Mutagenicity and Carcinogenicity 62530.6.4 Antimicrobial Activity 62530.6.5 Metabolism and In Vivo Animal Bioassays 626Acknowledgement 626References 626Index 629