ix d Crustochrin… 116 e)Ovoverdin 116 f)Ovorubin 116 g)Velellacyanin 116 8.Conclusions-future prospects 117 References 117 Chapter 7:Carotenoid Radicals and Radical Ions Ali El-Agamey and David J McGarvey A.Introduction 119 1.Definitions 119 2.The roles of carotenoid radicals 120 B.Radical Ions 122 1.Formation and detection of carotenoid radical ions .............. 122 a)Pulse radiolysis 122 b)Laser flash photolysis 123 c)Chemical methods 124 d)Electrochemical methods 124 2.Structural and spectroscopic properties of carotenoid radical ions 124 a)Vis/NIR spectroscopy 124 b)Electron paramagnetic resonance (EPR)......... 131 c)Electron nuclear double resonance(ENDOR) 131 d)Resonance Raman spectroscopy.................... 132 3.Reduction(redox)potentials for carotenoid radical ions 132 C.Carotenoid Neutral Radicals 136 1.Formation and detection of carotenoid neutral radicals 136 D.Unidentified Carotenoid Radicals 137 E.Reaction of Carotenoids with Oxidizing Free Radicals ............... 137 1.Factors that influence the mechanism of reactions of free radicals with carotenoids............... 137 2.Free-radical scavenging mechanisms in environments of low polarity .138 3.Free-radical scavenging mechanisms in polar and heterogeneous environments .138 a)Thiyl radicals(RS) 138 b)Sulphonyl radicals(RSO2) 138 c)Peroxyl radicals (RO).......................................... 139 d)Phenoxyl radicals(PhO) 139 e)Other radicals .................................................................... .140
ix d) Crustochrin …………………………………………………………. 116 e) Ovoverdin …………………………………………………………... 116 f) Ovorubin ……………………………………………………………. 116 g) Velellacyanin ……………………………………………………….. 116 8. Conclusions - future prospects ………………………………………….. 117 References ……………………………………………………………………… 117 Chapter 7: Carotenoid Radicals and Radical Ions Ali El-Agamey and David J McGarvey A. Introduction ………………………………………………………………… 119 1. Definitions ………………………………………………………………. 119 2. The roles of carotenoid radicals ………………………………………… 120 B. Radical Ions …………………………………………………………………. 122 1. Formation and detection of carotenoid radical ions …………………….. 122 a) Pulse radiolysis ……………………………………………………... 122 b) Laser flash photolysis ………………………………………………. 123 c) Chemical methods ………………………………………………….. 124 d) Electrochemical methods …………………………………………… 124 2. Structural and spectroscopic properties of carotenoid radical ions …….. 124 a) Vis/NIR spectroscopy ………………………………………………. 124 b) Electron paramagnetic resonance (EPR) …………………………… 131 c) Electron nuclear double resonance (ENDOR) ……………………… 131 d) Resonance Raman spectroscopy ……………………………………. 132 3. Reduction (redox) potentials for carotenoid radical ions ……………….. 132 C. Carotenoid Neutral Radicals ………………………………………………. 136 1. Formation and detection of carotenoid neutral radicals ………………… 136 D. Unidentified Carotenoid Radicals ………………………………………… 137 E. Reaction of Carotenoids with Oxidizing Free Radicals …………………. 137 1. Factors that influence the mechanism of reactions of free radicals with carotenoids ……………………………………………………………… 137 2. Free-radical scavenging mechanisms in environments of low polarity …. 138 3. Free-radical scavenging mechanisms in polar and heterogeneous environments ……………………………………………………………. 138 a) Thiyl radicals (RS ) …………………………………………………. 138 b) Sulphonyl radicals (RSO2 ) ………………………………………… 138 c) Peroxyl radicals (RO2 ) …………………………………………….. 139 d) Phenoxyl radicals (PhO ) …………………………………………… 139 e) Other radicals ……………………………………………………….. 140
F.Reactions of Carotenoid Radicals 44小小小4小 140 1.Carotenoid radical cations (CAR 140 a)Reactions with nucleophiles 140 b)De-protonation 141 c)Reactions with amino acids and peptides 141 d)Reactions with porphyrins ................... 141 e)Reactions with other carotenoids 141 Association with the parent carotenoid 142 g)Reactions with oxygen 143 h)Miscellaneous reactions 143 2.Carotenoid radical anions(CAR) 144 a)Reactions with oxygen. 144 b)Reactions with porphyrins 144 e)Other carotenoids 145 3.Carotenoid neutral radicals 146 a)Unimolecular fragmentation reactions 146 b)Ionic dissociation.. 146 c)Reactions with oxygen 146 G.Antioxidant and Pro-oxidant Properties 147 H.Conclusion...... 150 References 150 Chapter 8:Structure and Properties of Carotenoid Cations Synnove Liaaen-Jensen and Bjart Frode Lutnces A.Introduction 155 B.Carotenoid Oxonium Ions................................ 157 1.Preparation and chemistry 157 2.Vis/NIR spectra 158 C.Delocalized Carotenoid Monocarbocations and Dicarbocations 158 1.Preparation ...... 158 2.Vis/NIR spectra and stability 159 3.Cyclic voltammetry 160 4.AMI calculations 160 5.NMR spectra and structure 160 6.Relation to the soliton model 162 7.Reactions with nucleophiles 163
x F. Reactions of Carotenoid Radicals …………………………………………. 140 1. Carotenoid radical cations (CAR+ ) …………………………………….. 140 a) Reactions with nucleophiles ………………………………………... 140 b) De-protonation ……………………………………………………… 141 c) Reactions with amino acids and peptides …………………………... 141 d) Reactions with porphyrins …………………………………………... 141 e) Reactions with other carotenoids …………………………………… 141 f) Association with the parent carotenoid …………………………….. 142 g) Reactions with oxygen ……………………………………………… 143 h) Miscellaneous reactions …………………………………………….. 143 2. Carotenoid radical anions (CAR ) ……………………………………... 144 a) Reactions with oxygen ………………………………………………. 144 b) Reactions with porphyrins ………………………………………….. 144 c) Other carotenoids …………………………………………………… 145 3. Carotenoid neutral radicals ……………………………………………... 146 a) Unimolecular fragmentation reactions ……………………………… 146 b) Ionic dissociation …………………………………………………… 146 c) Reactions with oxygen ……………………………………………… 146 G. Antioxidant and Pro-oxidant Properties …………………………………. 147 H. Conclusion ………………………………………………………………….. 150 References ……………………………………………………………………… 150 Chapter 8: Structure and Properties of Carotenoid Cations Synnøve Liaaen-Jensen and Bjart Frode Lutnæs A. Introduction ………………………………………………………………… 155 B. Carotenoid Oxonium Ions …………………………………………………. 157 1. Preparation and chemistry ………………………………………………. 157 2. Vis/NIR spectra …………………………………………………………. 158 C. Delocalized Carotenoid Monocarbocations and Dicarbocations ………... 158 1. Preparation ……………………………………………………………… 158 2. Vis/NIR spectra and stability …………………………………………… 159 3. Cyclic voltammetry …………………………………………………….. 160 4. AM1 calculations ……………………………………………………….. 160 5. NMR spectra and structure ……………………………………………... 160 6. Relation to the soliton model …………………………………………… 162 7. Reactions with nucleophiles ……………………………………………. 163
xi D.Carotenoid Radical Cations 163 E.Carotenoid-Iodine Complexes 164 F.Biological Relevance 166 References 166 Chapter 9:Excited Electronic States,Photochemistry and Photophysics of Carotenoids Harry A.Frank and Ronald L.Christensen A.Introduction …167 B.Conceptual Background and Terminology … 168 1.Electronic structure and electronic states 169 2.Electronic transitions 169 3.Interconversions and loss of excitation energy *中94中1中”0卡+04”*卡中””*中49*卡中4“中 171 4.Exciton interactions 171 5.Energy transfer 171 6.Quantum yield 172 C.Absorption Spectroscopy 172 D.Fluorescence Spectroscopy 176 E.Other Optical Techniques and Aspects 178 1.Pump-probe spectroscopy 2.Two-photon spectroscopy 179 3.Resonance Rar nan spectre oscopy 小1 180 F.Experimental Considerations. 181 1.Purity of carotenoids 181 2.Fluorescence spectral corrections 182 3.Band-pass corrections 182 4.Gaussian deconvolution 82 5.Excitation spectra... 18 6.Correlation of absorption and excitation spectra 3 7.Quantum vields................. 184 8.Solvents...... 184 G.Recent Developments........ 185 1.Geometrical isomerization 185 References 186
xi D. Carotenoid Radical Cations ……………………………………………….. 163 E. Carotenoid-Iodine Complexes …………………………………………….. 164 F. Biological Relevance ………………………………………………………... 166 References ……………………………………………………………………… 166 Chapter 9: Excited Electronic States, Photochemistry and Photophysics of Carotenoids Harry A. Frank and Ronald L. Christensen A. Introduction ………………………………………………………………… 167 B. Conceptual Background and Terminology ……………………………….. 168 1. Electronic structure and electronic states ………………………………. 169 2. Electronic transitions …………………………………………………… 169 3. Interconversions and loss of excitation energy ………………………… 171 4. Exciton interactions …………………………………………………….. 171 5. Energy transfer …………………………………………………………. 171 6. Quantum yield ………………………………………………………….. 172 C. Absorption Spectroscopy ………………………………………………….. 172 D. Fluorescence Spectroscopy ………………………………………………… 176 E. Other Optical Techniques and Aspects …………………………………… 178 1. Pump-probe spectroscopy ………………………………………………. 178 2. Two-photon spectroscopy ………………………………………………. 179 3. Resonance Raman spectroscopy ………………………………………... 180 F. Experimental Considerations ……………………………………………… 181 1. Purity of carotenoids ……………………………………………………. 181 2. Fluorescence spectral corrections ………………………………………. 182 3. Band-pass corrections …………………………………………………... 182 4. Gaussian deconvolution ………………………………………………… 182 5. Excitation spectra ……………………………………………………….. 183 6. Correlation of absorption and excitation spectra ……………………….. 183 7. Quantum yields ………………………………………………………….. 184 8. Solvents …………………………………………………………………. 184 G. Recent Developments ………………………………………………………. 185 1. Geometrical isomerization ……………………………………………… 185 References ……………………………………………………………………… 186
Chapter 10:Functions of Intact Carotenoids George Britton A.Functions,Actions and Associations.............. ..189 B.Overview:Diversity of Functions 189 1.Functions involving interactions with light .................. 189 2.Functions not involving interactions with light 191 C.Light harvesting 191 1.Photosynthesis 191 a)Carotenoids and light harvesting 191 b)Protection against excess light energy 3 2.Other light-harvesting roles 193 D.Protection against Oxidative Damage.......................................... 194 1.Photoprotection … 194 2.Singlet oxygen quenching 19 a)Photosensitized by(bacterio)chlorophyll 194 b)Exogenous photosensitizers 195 c)Human erythropoietic protoporphyria 195 d)Singlet oxygen produced non-photochemically 195 3.Protection against oxidizing free radicals(antioxidant action)............ 196 E.Photoreceptors 198 1.Blue-light receptors ........ 198 2.Phototropism and phototaxis 198 a)Phototropism b)Phototaxis 198 F.Vision 199 1.Visual pigments 19g 2.Macular pigments 200 3.Retinal filters:oil droplets. 200 G.Colour 201 1.Pigmentary colours 201 2.Structural colours … 201 3.Colour in plants 202 a)Plant pigments 202 b)Chromoplasts 203 4.Carotenoids in moulds,yeasts and bacteria 203 5.Colour in animals 204 a)Colouration by carotenoids 204 b)Animal pigment cells:chromatophores 204 c)Colour changes 205
xii Chapter 10: Functions of Intact Carotenoids George Britton A. Functions, Actions and Associations ……………………………………… 189 B. Overview: Diversity of Functions …………………………………………. 189 1. Functions involving interactions with light …………………………….. 189 2. Functions not involving interactions with light ………………………… 191 C. Light harvesting ……………………………………………………………. 191 1. Photosynthesis ………………………………………………………….. 191 a) Carotenoids and light harvesting …………………………………… 191 b) Protection against excess light energy ……………………………… 193 2. Other light-harvesting roles …………………………………………….. 193 D. Protection against Oxidative Damage ……………………………………. 194 1. Photoprotection …………………………………………………………. 194 2. Singlet oxygen quenching ……………………………………………… 194 a) Photosensitized by (bacterio)chlorophyll …………………………... 194 b) Exogenous photosensitizers ………………………………………… 195 c) Human erythropoietic protoporphyria ……………………………… 195 d) Singlet oxygen produced non-photochemically ……………………. 195 3. Protection against oxidizing free radicals (antioxidant action) …………. 196 E. Photoreceptors ……………………………………………………………… 198 1. Blue-light receptors ……………………………………………………… 198 2. Phototropism and phototaxis ……………………………………………. 198 a) Phototropism ………………………………………………………… 198 b) Phototaxis …………………………………………………………... 198 F. Vision ………………………………………………………………………... 199 1. Visual pigments ………………………………………………………… 199 2. Macular pigments ………………………………………………………. 200 3. Retinal filters: oil droplets ………………………………………………. 200 G. Colour ……………………………………………………………………….. 201 1. Pigmentary colours ……………………………………………………... 201 2. Structural colours ……………………………………………………….. 201 3. Colour in plants …………………………………………………………. 202 a) Plant pigments ………………………………………………………. 202 b) Chromoplasts ……………………………………………………….. 203 4. Carotenoids in moulds, yeasts and bacteria …………………………….. 203 5. Colour in animals ……………………………………………………….. 204 a) Colouration by carotenoids …………………………………………. 204 b) Animal pigment cells: chromatophores …………………………….. 204 c) Colour changes ……………………………………………………… 205
xi H.Carotenoids in Membranes .205 1.Membrane structure 205 2.Localization and orientation of carotenoids.......................... 206 3.Effects of carotenoids on membrane structure and properties 207 4.Reinforcement of bacterial membranes.......... 208 5.Protection of membranes against oxidizing free radicals 209 6.Membrane-associated processes 209 7.Zeaxanthin in thylakoid membranes ..................................... 209 I.Fertility and Reproduction 209 J.Miscellaneous Proposed Functions ..... 210 K.Breakdown Products and Metabolites 210 L.Carotenoids in Human Health and Nutrition 211 References 211 Chapter 11:Signal Functions of Carotenoid Colouration Jonathan D.Blount and Kevin J.MeGraw A Introduction 213 1.Biological signals and their reliability 213 2.Carotenoids as signals... 214 B.Carotenoid Signals in Plants 214 I Frits and flowers 214 2.Leaves 216 C.Carotenoid Signals in Animals 217 1.Signalling to other species(heterospecifics) 217 a)Species recognition 217 b)Warning (aposematic)colouration and mimicry 218 c)Crypsis 219 2.Signalling to members of the same species (conspecifics)............... 221 a)）Sexual signalling 221 b)Social status signalling............................................... 223 c)Parent-offspring signalling 223 d)Other conspecific signal functions 224 D.Information Content of Carotenoid Signals 224 1.Nutritional state 224 2 Parasite load 226 3.Immune defence 227 4.Antioxidant activity 。。 227
xiii H. Carotenoids in Membranes ………………………………………………... 205 1. Membrane structure …………………………………………………….. 205 2. Localization and orientation of carotenoids …………………………….. 206 3. Effects of carotenoids on membrane structure and properties ………….. 207 4. Reinforcement of bacterial membranes ………………………………… 208 5. Protection of membranes against oxidizing free radicals ………………. 209 6. Membrane-associated processes ………………………………………... 209 7. Zeaxanthin in thylakoid membranes ……………………………………. 209 I. Fertility and Reproduction …………………………………………………. 209 J. Miscellaneous Proposed Functions ………………………………………… 210 K. Breakdown Products and Metabolites ……………………………………. 210 L. Carotenoids in Human Health and Nutrition …………………………….. 211 References ……………………………………………………………………… 211 Chapter 11: Signal Functions of Carotenoid Colouration Jonathan D. Blount and Kevin J. McGraw A. Introduction ………………………………………………………………… 213 1. Biological signals and their reliability ………………………………….. 213 2. Carotenoids as signals ………………………………………………….. 214 B. Carotenoid Signals in Plants ………………………………………………. 214 1. Fruits and flowers ………………………………………………………. 214 2. Leaves .………………………………………………………………….. 216 C. Carotenoid Signals in Animals …………………………………………….. 217 1. Signalling to other species (heterospecifics) ……………………………. 217 a) Species recognition …………………………………………………. 217 b) Warning (aposematic) colouration and mimicry …………………… 218 c) Crypsis ……………………………………………………………… 219 2. Signalling to members of the same species (conspecifics) …………….. 221 a) Sexual signalling ……………………………………………………. 221 b) Social status signalling …………………………………………….. 223 c) Parent - offspring signalling ………………………………………… 223 d) Other conspecific signal functions …………………………………. 224 D. Information Content of Carotenoid Signals ……………………………… 224 1. Nutritional state …………………………………………………………. 224 2. Parasite load …………………………………………………………….. 226 3. Immune defence ………………………………………………………… 227 4. Antioxidant activity …………………………………………………….. 227