Laboratory Handbook for the Fractionation of Natural Extracts / by Peter J. Houghton, Amala Raman.

1.1 The need for this book - an active extract, what happens
next?
1.2 Why is it important to find outthe nature oftheactive
components?
1.3 Green chemicals - the renewed interest in natural
products as sources of bioactive compounds 4
1.4 What are we doing?
1.5 Bibliography 13
Important concepts
2.1 Introduction
2.2 Polarity
2.3 Dilution and concentration factors 14
2.4 Synergy 1
2.5 Deterioration, decomposition and storage 17
2.6 Biological variation 18
2.7 Authentication of material 20
2.8 Dereplication 21
MeAods for extraction and sampleclean-up 22
3.1 Introduction 22
3.2 Factors to be considered in selecting an extraction method 22
3.3 Generalextractionmethods 27
3.4 Extraction methods for specific phytochemical groups 39
3.5 Clean-up techniques toremove unwanted substances 45
3.6 Bibliography 2
Crude fractionation procedures 8

4.2 Choice of fractionation method 55
4.3 Common fractionation methods 56
4.4 Bibliography 5
5 Chromatographic fractionation procedures 66
5.1 Introduction 66
5.2 Theprinciples ofchromatography 66
5.3 Physico-chemical processes takingplace in chromatography 71
5.4 Bibliography 81
6 Chromatographic procedures using columns and liquid-liquid
systems 82
6.1 Column chromatography 82
6.2 Liquid-liquid partition schemes 90
6.3 Bibliography 93
7 Layer chromatography 94
7.1 Layerchromatography 94
7.2 Preparative thin-layer chromatography and paper
chromatography 102
7.3 Bibliography 112
8 Analysis of crude extracts, fractions and isolated compounds 113
8.1 Introduction 113
8.2 Qualitative analysis of mixturesand isolates 114
8.3 Quantitative analytical methods 127
8.4 Biological assays 135
8.5 Bibliography 138
9 General methods 139
9.1 Basic techniques in handling extracts 139
9.2 Isolation of active compounds 145
9.3 Chromatographic procedures 146
9.4 Basic techniques in thin-layer chromatography 150
9.5 Bibliography 153
10 Practical exercises in chemical screening and fractionation of
crude extracts from plant materials 154
10.1 Chemical screening 154
10.2 Exercises in extraction, clean-up, fractionation and
chromatographic methods 162