The Biological Activity of Phytochemicals (eBook)

Preface 6
Contents 9
Contributors 11
1 The Pursuit of Potent Anti-influenza Activity from the Antarctic Red Marine Alga Gigartina skottsbergii 14
1.1 The Necessity for Antiviral Treatments 14
1.2 Natural Products: Red Marine Algae and the Antarctic Peninsula 15
1.3 Primary and Secondary Screening of Extract Library 16
1.4 Purification of Active Extract 18
1.5 Insight into the Mechanism of Action via Hemagglutination Assay and Drug Combination Studies 20
1.6 Conclusions 22
1.7 Experimental 22
References 24
2 Ginsenosides: Phytoanticipins or Host Recognition Factors 26
2.1 Introduction 26
2.2 Saponins 26
2.2.1 Chemical Structure and Diversity 26
2.2.2 Involvement of Saponins in Host--Pathogen Interactions 28
2.2.2.1 Avenacin A-1 and -Tomatine as Models for Plant Defense 28
2.2.2.2 Mode of Action Through Membrane Disruption 29
2.3 Ginsenosides Are Bidesmosidic Saponins with Mild Fungitoxicity 29
2.3.1 Structure, Nomenclature, and Biosynthesis of Ginseng Saponins 29
2.3.2 Distribution of Ginsenosides Within the Plant 30
2.3.3 Fungitoxicity of Ginsenosides 31
2.3.4 Ginsenosides in the Rhizosphere 32
2.4 Some Pathogens Can Degrade/Detoxify Saponins 32
2.4.1 Overview of ''Saponinases'' from Plant Pathogens 32
2.4.2 The Metabolism of Ginsenosides by Pathogens of Ginseng 34
2.4.3 P. irregulare Specifically Deglycosylates 20(S)-Protopanaxadiol Ginsenosides into Ginsenoside F2 35
2.4.4 P. irregulare Ginsenosidases Are Induced by Exposure to Ginsenosides In Vitro 35
2.4.5 Purification and Characterization of Ginsenosidases from P. irregulare 38
2.5 The Involvement of Ginsenosides and Ginsenosidases in the Ginseng-P. irregulare Pathosystem 39
2.6 Summary and Future Directions 41
References 41
3 Fractionation of Grape Seed Proanthocyanidins for Bioactivity Assessment 46
3.1 Introduction 46
3.2 Methods for PA Extraction, Separation, and Analysis 48
3.2.1 Extraction of Grape Seed PAs 48
3.2.2 Fractionation of PAs 48
3.2.2.1 Solvent Precipitation 49
3.2.2.2 Fractionation on Toyopearl HW-40S 50
3.2.3 Quantification of PAs 51
3.2.4 Determination of PA Complexity 52
3.2.5 Determination of the Mean Degree of Polymerization of PAs 53
3.3 Case Studies for Fractionation of MegaNatural-AZ GSE 53
3.3.1 Solvent Precipitation 54
3.3.2 Fractionation on Toyopearl Resin 56
3.4 Conclusions 57
References 58
4 Coloring Soybeans with Anthocyanins 60
4.1 Anthocyanin Biosynthesis in Black Soybean for the Visual Identification of Transgenic Grains 60
4.2 Anthocyanins in Black Soybean 61
4.2.1 Anthocyanin Composition in the Seed Coat of Black Soybean 61
4.2.2 Anthocyanin Biosynthesis, Flux, and Accumulation in Black Soybean 61
4.3 Is the Black Color in Plants Determined by Anthocyanins 65
4.3.1 Anthocyanin Levels Versus Composition in Black Plant Tissues 65
4.3.2 Are Anthocyanic Vacuolar Inclusions (AVIs) Required to Color Plant Tissues Black? 65
4.3.3 Does Co-pigmentation and Oxidation Have a Role in Blackening Seeds? 67
4.4 Engineering Seed Coat Color for the Visual Identification of Transgenic Grains 67
4.5 Concluding Remarks and Future Perspectives 68
References 68
5 Pharmacogenetics in Potential HerbDrug Interactions: Effects of Ginseng on CYP3A4 and CYP2C9 Allelic Variants 71
5.1 Introduction: Ginseng Drug Interactions 71
5.2 Cytochrome P450 (CYP) Enzymes 71
5.3 The Role of Polymorphisms 72
5.4 Recent Results on CYP3A4 and CYP2C9 Allelic Variants 73
5.5 Future Implications 75
5.6 Conclusions 76
References 77
6 Biosynthesis and Function of Citrus Glycosylated Flavonoids 78
6.1 Citrus Flavonoids and Flavonoid Glycosides 78
6.2 Biosynthesis of Flavonoids in Citrus 80
6.2.1 Phenylalanine Ammonia Lyase 80
6.2.2 Cinnamate 4-Hydroxylase 83
6.2.3 4-Coumarate:CoA Ligase 84
6.2.4 Chalcone Synthase 84
6.2.5 Chalcone Isomerase 85
6.2.6 Flavanone 3-Hydroxylase 86
6.2.7 Flavone Synthase 87
6.2.8 Flavonol Synthase 88
6.2.9 Dihydroflavonol 4-Reductase 89
6.2.10 Anthocyanidin Synthase 90
6.2.11 Flavanone 3'-Hydroxylase 90
6.2.12 Flavanone 3', 5'-Hydroxylase 91
6.3 Flavonoid Glycosylation in Citrus 91
6.3.1 Specificity of Flavonoid Glycosyltransferases in Citrus 97
6.4 Function of Citrus Flavonoid Glycosides 97
6.5 Concluding Remarks and Future Perspectives 98
References 98
7 Ginsenoside Variation Within and Between Ontario Ginseng Landraces: Relating Phytochemistry to Biological Activity 107
7.1 Introduction 107
7.2 Methods 108
7.2.1 Ginseng Collection and Extraction 108
7.2.2 HPLC-DAD Analysis 109
7.2.3 Anti-glycation Activity 109
7.2.4 Antioxidant Activity 109
7.2.5 Statistics 110
7.3 Results and Discussion 110
7.3.1 Ginsenoside Variation 110
7.3.2 Anti-glycation and Antioxidant Activity of Ginseng In Vitro 113
7.4 Conclusions and Future Directions 114
References 116
8 Heat, Color, and Flavor Compounds in Capsicum Fruit 118
8.1 Peppers 118
8.2 Pigments 119
8.2.1 Chlorophyll 119
8.2.2 Carotenoids 120
8.3 Biosynthesis of Carotenoids in Peppers 121
8.4 Carotenoid Analysis 123
8.4.1 Anthocyanins 125
8.5 Capsaicinoids 125
8.5.1 Capsaicinoids Are Products of the Phenylpropanoid Pathway and the Branched Chain Fatty Acid Pathway 127
8.5.2 Capsaicinoids Accumulate in the Epidermal Cells of the Placenta 128
8.5.3 Genetic and Environmental Effects on the Expression of Pungency 128
8.6 Flavors or Volatile Aroma Compounds 129
8.7 Concluding Remarks 130
References 130
9 Fungal Attack and Cruciferous Defenses: Tricking Plant Pathogens 136
9.1 PlantPathogen Interactions: A Never-Ending Arms Race 136
9.2 Pathogen Attack: Phytotoxins and Elicitors from Cruciferous Fungi 137
9.3 Cruciferous Defenses: Phytoanticipins and Phytoalexins 141
9.4 Pathogen Counterattack: Fungal Detoxifying Enzymes and Paldoxins 144
9.5 Concluding Remarks and Future Perspectives 145
References 146
10 Glucosinolate Degradation Products in Fermented Meadowfoam Seed Meal and Their Herbicidal Activities 149
10.1 Introduction 149
10.2 Analytical Procedures 151
10.2.1 Isolation and Structure Determination of Glucolimnanthin from Meadowfoam Seed Meal 151
10.2.2 HPLC Analysis of Glucolimnanthin 152
10.2.3 Characterization of Glucosinolates by HPLC--Mass Spectrometry Using Precursor Ion Scanning 155
10.2.4 Identification of the Aglycone Moiety of the L. floccosa Glucosinolate with m/z 424 155
10.3 Herbicidal Activity of Glucolimnanthin and Its Degradation Products 158
10.3.1 Fermentation of Meadowfoam Seed Meal 158
10.3.2 Herbicidal Activity of Glucolimnanthin 1 and Its Individual Degradation Products 2--5 159
10.3.3 Herbicidal Activity of Fermented Meadowfoam Seed Meal 160
References 162
11 Elucidating the Metabolism of Plant Terpene Volatiles: Alternative Tools for Engineering Plant Defenses 166
11.1 Introduction 166
11.2 Targeting Volatile Terpene Biosynthesis for Manipulating Indirect Plant Defenses 168
11.3 Arabidopsis: A Small Weed and Its Genetic Resources for Volatile Terpene Biosynthesis 170
11.4 How Does Arabidopsis Assemble Homoterpene Volatiles 171
11.4.1 Formation of Alcohol Precursors 171
11.4.2 Oxidative Degradation of Geranyllinalool to TMTT 175
11.4.3 Subcellular Compartmentalization of Homoterpene Biosynthesis 176
11.5 Metabolic Engineering of Homoterpene Volatiles 177
11.6 Conclusions and Future Challenges 179
References 180
12 Stereoselectivity of the Biosynthesis of Norlignans and Related Compounds 186
12.1 Introduction 186
12.2 Norlignan Biosynthesis 187
12.3 Lignan Biosynthesis 191
12.3.1Lignans with 9(9')-Oxygen 191
12.3.2 Other Types of Lignans 197
12.3.3 Biosynthesis of Neolignans 198
12.4 Concluding Remarks 200
References 201
Index 205