Pharmacognosy: Fundamentals, Applications, and Strategies

Pharmacognosy: Fundamentals, Applications and Strategies, Second Edition represents a comprehensive compilation of the philosophical, scientific and technological aspects of contemporary pharmacognosy. The book examines the impact of the advanced techniques of pharmacognosy on improving the quality, safety and effectiveness of traditional medicines, and how pharmacokinetics and pharmacodynamics have a crucial role to play in discerning the relationships of active metabolites to bioavailability and function at the active sites, as well as the metabolism of plant constituents.

Structured in seven parts, the book covers the foundational aspects of Pharmacognosy, the chemistry of plant metabolites, their effects, other sources of metabolites, crude drugs from animals, basic animal anatomy and physiology, technological applications and biotechnology, and the current trends in research. New to this edition is a chapter on plant metabolites and SARS-Cov-2, extensive updates on existing chapters and the development of a Laboratory Guide to support instructors execute practical activities on the laboratory setting.

• Covers the main sources of natural bioactive substances
• Contains practice questions and laboratory exercises at the end of every chapter to test learning and retention
• Describes how pharmacokinetics and pharmacodynamics play a crucial role in discerning the relationships of active metabolites to bioavailability and function at active sites
• Includes a dedicated chapter on the effect of plant metabolites on SARS-CoV-2

• Language: English
• Publisher: Academic Press
• Release date: Oct 13, 2023
• ISBN: 9780443186585

Book preview

Front Cover for Pharmacognosy - Fundamentals, Applications, and Strategies - Second Edition - by Simone Badal McCreath, Yuri N. Clement

Pharmacognosy

Fundamentals, Applications, and Strategies

Second Edition

Edited by

Simone Badal McCreath

Department of Basic Medical Sciences, Faculty of Medical Sciences Teaching and Research Complex University of the West Indies, Mona Campus, Kingston, Jamaica

Yuri N. Clement

Department of Paraclinical Sciences, Faculty of Medical Sciences, University of the West Indies, St. Augustine, Trinidad and Tobago

Table of Contents

Cover image

Title page

Copyright

List of contributors

Foreword

Preface

Acknowledgments

Section 1: Pharmacognosy 101

Chapter 1. Background to pharmacognosy

Abstract

Chapter Outline

1.1 History and evolution of pharmacognosy

1.2 Scope of pharmacognosy

1.3 Emerging areas in pharmacognosy

1.4 Pharmacognosy in society

1.5 Basic terminology in pharmacognosy

1.6 Conclusions

1.7 Review questions

References

Chapter 2. Traditional medicine

Abstract

Chapter Outline

2.1 Traditional Chinese medicine

2.2 The Indian systems of medicine

2.3 African traditional medicine

References

Further reading

Chapter 3. Plant anatomy and physiology

Abstract

Chapter Outline

3.1 Plant structure

3.2 Plant function

3.3 Review questions

Lab exercise—plant anatomy and physiology

Further reading

Chapter 4. Plant constituents: carbohydrates, oils, resins, balsams, and plant hormones

Abstract

Chapter Outline

4.1 Carbohydrates: classification, function, and uses in medicine

4.2 Nonessential oils

4.3 Essential oils

4.4 Resins and balsams

4.5 Plant hormones and growth factors

4.6 Summary

4.7 Review questions

Laboratory exercise

References

Chapter 5. Plant crude drugs

Abstract

Chapter Outline

5.1 Background

5.2 Classification of crude drugs

5.3 Plant cultivation and collection

5.4 Herbarium specimen preparation and significance

5.5 Plant crude drug extraction and production

5.6 Conclusion

5.7 Review questions

Lab exercise

References

Section 2: Plant metabolites: their chemistry

Chapter 6. Evolutionary perspectives on the role of plant secondary metabolites

Abstract

Chapter Outline

6.1 Introduction

6.2 What are secondary metabolites?

6.3 At the beginning

6.4 The transitions

6.5 Evidence for evolutionary theory

6.6 The expression of secondary metabolites

6.7 Secondary metabolites, a worthy investment: further support

6.8 Conclusion

References

Chapter 7. Glycosides

Abstract

Chapter Outline

7.1 Introduction

7.2 Extraction of glycosides

7.3 Chemical tests

7.4 Phenolic glycosides

7.5 Coumarin glycosides and chromone glycosides

7.6 Flavonoid glycosides

7.7 Anthraquinone glycosides

7.8 Saponin glycosides

7.9 Cardiac glycosides

7.10 Cyanogenic glycosides

7.11 Thioglycosides

7.12 Conclusion

7.13 Review questions

Laboratory exercise: detection of glycosides in plant extracts

References

Chapter 8. Alkaloids

Abstract

Chapter Outline

8.1 Introduction

8.2 Physicochemical properties of alkaloids

8.3 Tests for alkaloids

8.4 Classification of alkaloids

8.5 Heterocyclic alkaloids

8.6 L-Tyrosine derivatives

8.7 L-Ornithine derivatives

8.8 Asparaginate and glutamate derivatives

8.9 L-Tryptophan derivatives

8.10 Anthranilic acid derivatives

8.11 L-Lysine derivatives

8.12 Histidine derivatives

8.13 Other alkaloids

8.14 Nonheterocyclic alkaloids

8.15 Conclusion

8.16 Review questions

Lab exercise

Isolation of piperine from black pepper

References

Chapter 9. Tannins

Abstract

Chapter Outline

9.1 Definition

9.2 Types of tannins

9.3 Bioactivity of tannins

9.4 Clinical trials

9.5 Extraction processes

9.6 Chemical tests

9.7 Spectroscopic determinations

9.8 Nutraceutical application

9.9 Pharmaceutical application

9.10 Adverse effects

9.11 Metabolic profile of widely used tannin products

9.12 Conclusion

9.13 Review questions

Laboratory exercises: using colorimetric assays and titrimetric analysis to assess plant extracts for tannins

References

Chapter 10. Terpenoids

Abstract

Chapter Outline

10.1 Introduction

10.2 Types of terpenoids

10.3 Plants containing terpenoids

10.4 Bioactivity of terpenoids

10.5 Extraction and chemical tests

10.6 Pharmaceutical applications

10.7 Nutraceutical applications

10.8 Conclusions

10.9 Review questions

Lab exercise

References

Chapter 11. Other plant metabolites

Abstract

Chapter Outline

11.1 Lignins

11.2 Polyacetylenes

11.3 Conclusion

11.4 Review questions

Laboratory exercises

References

Chapter 12. Vitamins

Abstract

Chapter Outline

12.1 Introduction

12.2 Water-soluble vitamins

12.3 Fat-soluble vitamins

12.4 Conclusion

12.5 Review questions

Vitamin analysis using simple lab tests

References

Section 3: Plant metabolites: their effects

Chapter 13. Chemotherapeutics

Abstract

Chapter Outline

13.1 The burden of cancer

13.2 What is cancer?

13.3 Types of cancer

13.4 Prevalence of cancer types

13.5 Drugs in the treatment of cancer

13.6 Natural products, isolates, and extracts in the prevention and treatment of cancer

13.7 Conclusion

13.8 Review questions

References

Further reading

Chapter 14. Bioactive plant molecules, sources, and mechanisms of action in the treatment of cardiovascular diseases

Abstract

Chapter Outline

14.1 Introduction—the burden of cardiovascular diseases

14.2 Hyperlipidemia and atherosclerosis

14.3 Hypertension

14.4 Conclusion

14.5 Review questions

References

Chapter 15. Plant metabolites for treating diseases

Abstract

Chapter Outline

15.1 Introduction

15.2 Diseases

15.3 Conclusion

15.4 Review questions

Student laboratory activity

Acknowledgement

References

Chapter 16. Psychoactive drugs

Abstract

Chapter Outline

16.1 Definition and examples

16.2 Cannabis

16.3 Psilocybe

16.4 Areca catechu

16.5 Amanita muscaria

16.6 Review questions

16.7 Conclusion

References

Section 4: Metabolites from other sources

Chapter 17. Marine metabolites: oceans of opportunity

Abstract

Chapter Outline

17.1 Introduction

17.2 Collection, extraction, and isolation of marine natural products

17.3 In vivo and in vitro bioactivity of metabolites from macroinvertebrates, macroalgae, and microorganisms

17.4 Evaluation of marine extracts

17.5 Drugs in clinical trials

17.6 Drugs of marine origin to treat diseases

17.7 Discussion

17.8 Review questions

Laboratory exercise: assessing the bioactivity of sponges using thin layer chromatography bioautography

References

Chapter 18. Animal metabolites: from amphibians, reptiles, Aves/birds, and invertebrates,

Abstract

Chapter Outline

18.1 Introduction

18.2 Extraction of metabolites

18.3 Metabolites in vertebrates

18.4 Metabolites in invertebrates

18.5 Importance of metabolites

18.6 Conclusion

18.7 Review questions

Lab exercises

References

Further reading

Chapter 19. Fungal ms: a focus on endophytes

Abstract

Chapter Outline

19.1 Introduction

19.2 Classification

19.3 Extraction of endophytes

19.4 Types of metabolites from fungal endophytes

19.5 Future implications

19.6 Review questions

Laboratory exercise 1: detection of fungal metabolites

Laboratory exercise 2: growth and extraction of fungi

References

Section 5: Crude Drugs from animals

Chapter 20. Fats

Abstract

Chapter Outline

20.1 Introduction

20.2 Classification of lipids

20.3 Extraction of animal fats

20.4 Nutraceutical applications

20.5 Pharmaceutical applications

20.6 Fats and health

20.7 Conclusion

20.8 Review questions

Lab exercises

References

Chapter 21. Waxes

Abstract

Chapter Outline

21.1 Introduction

21.2 Characteristics of waxes

21.3 Composition of waxes

21.4 Classification of waxes

21.5 Sources of waxes

21.6 Biosynthesis of plant waxes

21.7 Applications of waxes

21.8 Synthetic waxes and esters

21.9 Plant waxes

21.10 Animal waxes

21.11 Marine waxes

21.12 Mineral waxes

21.13 Bioactivity of waxes

21.14 Review questions

Lab exercise

References

Section 6: Basic animal anatomy and physiology

Chapter 22. The form and function of the animal cell

Abstract

Chapter Outline

22.1 Why do we study the animal cell?

22.2 The components of the animal cell

22.3 The nucleus

22.4 The cell membrane

22.5 The cytoplasm

22.6 The centrosome

22.7 The mitochondria

22.8 Lysosomes

22.9 Peroxisomes

22.10 The endoplasmic reticulum

22.11 The Golgi apparatus

22.12 Cell signaling

22.13 Review questions

22.14 Student practical 1: a model for diffusion of molecules through the cytoplasm

22.15 Student practical 2: crossing the membrane—osmosis in animal cells

References

Chapter 23. Proteins

Abstract

Chapter Outline

23.1 Introduction

23.2 General properties

23.3 From amino acid to protein: protein biosynthesis

23.4 Protein structure

23.5 Effect of heat, pH, and chemical agents on protein folding

23.6 Protein classification

23.7 Pharmaceutical applications

23.8 Conclusion

23.9 Review questions

Lab activity

References

Chapter 24. Pharmacokinetics

Abstract

Chapter Outline

24.1 Introduction to pharmacokinetics

24.2 Determination of pharmacokinetic parameters

24.3 Pharmacokinetics and drug interactions

24.4 Conclusion and future work

24.5 Review questions

References

Chapter 25. Pharmacodynamics—a pharmacognosy perspective

Abstract

Chapter Outline

25.1 Definitions

25.2 Drug targets

25.3 Concluding remarks—drug targets

25.4 Adverse drug reactions

25.5 Concluding remarks

25.6 Review questions

Laboratory exercise

References

Chapter 26. Drug metabolism

Abstract

Chapter Outline

26.1 Introduction

26.2 Phase I

26.3 Phase II

26.4 Drug transporters

26.5 Summary and outcomes

26.6 Looking to the future

Student Exercise 1: Personalised drug therapy with warfarin, a CYP2C9 substrate

26.7 Review questions

References

Section 7: Technological applications using biological systems

Chapter 27. Biotechnology: principles and applications

Abstract

Chapter Outline

27.1 Definition

27.2 Biotechnology, bioengineering, and biomedical engineering

27.3 History of biotechnology

27.4 Biotechnology in color

27.5 Genetic engineering techniques

27.6 Review questions

Lab exercise

References

Section 8: Current trends in pharmacognosy research

Chapter 28. Nuclear magnetic resonance spectroscopy in drug discovery

Abstract

Chapter Outline

28.1 Introduction

28.2 Basics of nuclear magnetic resonance spectroscopy and nuclear magnetic resonance parameters

28.3 Pulsed Fourier transform nuclear magnetic resonance

28.4 Key features of nuclear magnetic resonance spectrometers

28.5 Acquiring and processing ¹H and ¹³C spectra

28.6 Two-dimensional nuclear magnetic resonance

28.7 Using combinations of spectra to determine structures and fully assign spectra

28.8 Dereplication of natural products

28.9 Review questions

Lab excercise

References

Chapter 29. Metabolomics approach in pharmacognosy

Abstract

Chapter Outline

29.1 Introduction

29.2 Important aspects in metabolomics

29.3 Important issues in metabolomics-based research

29.4 Mass spectrometry and nuclear magnetic resonance platforms in metabolomics-based analysis

29.5 Data acquisition and processing

29.6 Statistical data processing

29.7 Metabolite identification

29.8 Plant metabolomics

29.9 Summary

29.10 Review questions

Laboratory exercises

References

Chapter 30. Novel targets in drug discovery

Abstract

Chapter Outline

30.1 Strategies and techniques in target discovery

30.2 Selected examples of novel targets

30.3 Drug development and future prospects

30.4 Review questions

Lab exercise 1: A systems approach in drug discovery

Lab exercise 2: A molecular approach in drug discovery

References

Chapter 31. Nanotechnology: creating, manipulating, and observing nanostructured systems in biology and medicine

Abstract

Chapter Outline

31.1 Introduction

31.2 Creating small things—nanostructures

31.3 Micro/nanofabrication

31.4 Optical lithography: masks, resists, and selectivity to patterning

31.5 Electron beam lithography

31.6 Atomically precise thickness—two-dimensional materials

31.7 Bottom-up self-assembly of nanostructures

31.8 Tools for observing small things—nanostructures

31.9 High-resolution light microscopy

31.10 Electron microscopy and probe microscopy

31.11 Computational nanotechnology

31.12 Conclusion and prospects

31.13 Review questions

Laboratory exercise

References

Chapter 32. Ethical aspects of working with local communities and their biological resources

Abstract

Chapter Outline

32.1 Introduction

32.2 Local communities, local knowledge versus traditional knowledge

32.3 Intellectual property rights

32.4 The legal framework of field research with local communities

32.5 Beyond the legal: establishing ethical research partnerships with local communities

32.6 What about ethics in laboratory research?

32.7 Conclusion

References

Chapter 33. Factors to consider in development of nutraceutical and dietary supplements

Abstract

Chapter Outline

33.1 Introduction

33.2 Botanicals as nutraceutical and dietary supplements

33.3 Development and process validation of botanicals as functional food

33.4 Identification and authentication of the plant material

33.5 Metabolite profiling and chemo-analysis

33.6 Regulatory aspects, standardization, and scientific validation

33.7 Pharmacovigilance

33.8 Review questions

Acknowledgments

Lab protocol

References

Chapter 34. The global regulatory framework for medicinal plants

Abstract

Chapter Outline

34.1 Why regulate?

34.2 Regulatory categories and frameworks

34.3 Review of current regulations

34.4 The challenges in regulating medicinal plant products

34.5 Conclusion

34.6 Review questions

References

Index

Copyright

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List of contributors

F. Abas,     University Putra Malaysia, Serdang, Selangor, Malaysia

I.I. Amarakoon,     Basic Medical Sciences, The University of the West Indies, Mona, Kingston, Jamaica

S. Amos,     School of Pharmacy, Cedarville University, Cedarville, OH, United States

K. Andrae-Marobela,     University of Botswana, Gaborone, Botswana

S. Austin,     The University of the West Indies, Cave Hill Campus, Barbados, West Indies

S. Badal,     Department of Basic Medical Sciences, Faculty of Medical Sciences Teaching and Research Complex University of the West Indies, Mona Campus, Kingston, Jamaica

G.F. Barclay,     The University of the West Indies, St. Augustine, Trinidad and Tobago

M. Bartnik,     Medical University of Lublin, Lublin, Poland

C.S. Bowen-Forbes,     The University of the West Indies, Kingston, Jamaica

K.J. Brown,     University of Technology, Jamaica, Kingston, Jamaica

D.C. Browne,     Department of Biological and Chemical Sciences, The University of the West Indies, Cave Hill Campus, Barbados

J.E. Campbell,     Department of Basic Medical Sciences, Faculty of Medical Sciences, The University of the West Indies, Mona Campus, Jamaica

C.-T. Che,     University of Illinois at Chicago, Chicago, IL, United States

S. Clarke

University of Oxford, United Kingdom

Department of Basic Medical Sciences, Faculty of Medical Sciences Teaching and Research Complex University of the West Indies, Mona Campus, Kingston, Jamaica

Yuri N. Clement,     Department of Paraclinical Sciences, Faculty of Medical Sciences, The University of the West Indies, St. Augustine, Trinidad and Tobago

D.H. Cohall,     Department of Preclinical and Health Sciences, Faculty of Medical Sciences, The University of the West Indies, Cavehill Campus, Barbados

D.K. Daley

University of Technology, Jamaica, Kingston, Jamaica

Natural Soothing Remedies Ltd, Kingston, Jamaica

R. Delgoda,     The University of the West Indies, Kingston, Jamaica

L.L. Dilworth,     University of the West Indies, Kingston, Jamaica

P. Facey

University of the West Indies, St. Augustine, Trinidad and Tobago

Department of Chemistry, University of the West Indies, St. Augustine, Trinidad and Tobago

V. George

Mar Dioscoros College of Pharmacy, Thiruvananthapuram, Kerala, India

The National Society of Ethnopharmacology, Mannamoola, Thiruvananthapuram, Kerala, India

A. Goldson-Barnaby,     The University of the West Indies, Kingston, Jamaica

M. Gossell-Williams,     Department of Basic Medical Sciences, The University of the West Indies, Mona Campus, Kingston, Jamaica

C.-L. Hamilton,     Biotechnology Department, The University of the West Indies, Mona Campus, Kingston, Jamaica

T.P. Ijinu

The National Society of Ethnopharmacology, Mannamoola, Thiruvananthapuram, Kerala, India

Naturæ Scientific, Kerala University Business Innovation and Incubation Centre, Karyavattom Campus, Thiruvananthapuram, Kerala, India

I. Ismail,     University Putra Malaysia, Serdang, Selangor, Malaysia

M. Jackson,     Department of Basic Medical Sciences, Faculty of Medical Sciences Teaching and Research Complex University of the West Indies, Mona Campus, Kingston, Jamaica

M. Jalali,     University of Minnesota, Minneapolis, MN, United States

S. Jankie,     School of Pharmacy, Faculty of Medical Sciences, The University of the West Indies, St. Augustine, Trinidad and Tobago

D. Jean-Louis,     School of Pharmacy, Cedarville University, Cedarville, OH, United States

N. Lajis,     University Putra Malaysia, Serdang, Selangor, Malaysia

N. Laurieri,     University of Oxford, Oxford, United Kingdom

F.B. Lopez,     The University of the West Indies, Cave Hill, Barbados

J. Marti,     University of Minnesota, Minneapolis, MN, United States

M. Maulidiani,     University Putra Malaysia, Serdang, Selangor, Malaysia

G.J. Miller,     Taylor University, Upland, IN, United States

S.A. Mitchell,     Biotechnology Department, The University of the West Indies, Mona Campus, Kingston, Jamaica

A.L.C. Morris,     Elan Chemical Company, Newark, NJ, United States

D. Picking,     Natural Products Institute, The University of the West Indies, Mona Campus, Jamaica

Y.L. Powder-George,     Department of Chemistry, The University of the West Indies, St. Augustine, Trinidad and Tobago

P. Pushpangadan

The National Society of Ethnopharmacology, Mannamoola, Thiruvananthapuram, Kerala, India

Amity Institute for Herbal and Biotech Products Development, Thiruvananthapuram, Kerala, India

C.K. Riley

University of the West Indies, Kingston, Jamaica

Research and Product Development Solutions, Mona, Kingston, Jamaica

M.E. Roye,     Biotechnology Department, The University of the West Indies, Mona Campus, Kingston, Jamaica

P.L. Ruddock

Department of Chemistry, The University of the West Indies, Mona Campus, Kingston, Jamaica

Faculty of Science and Sport, The University of Technology, Jamaica

W.M. Sattley,     Indiana Wesleyan University, Marion, IN, United States

S. Singh,     School of Pharmacy, Faculty of Medical Sciences, The University of the West Indies, St. Augustine, Trinidad and Tobago

L.A. Stanley

Investigative Toxicology, Linlithgow, United Kingdom

School of Applied Sciences, Edinburgh Napier University, Edinburgh, United Kingdom

D.K. Stennett,     Transitional Year Programme, University of Toronto, Toronto, Canada

R.A. Taylor,     Department of Chemistry, The University of the West Indies, St. Augustine, Trinidad and Tobago

P.F. Tennant

Biotechnology Department, The University of the West Indies, Mona Campus, Kingston, Jamaica

Department of Life Sciences, The University of the West Indies, Mona, Kingston, Jamaica

P.G. Thomas-Brown

Department of Basic Medical Sciences, The University of the West Indies, Mona Campus, Kingston, Jamaica

Department of Basic Medical Sciences, Faculty of Medical Sciences, The University of the West Indies, Mona Campus, Jamaica

Sabina Wangui Wachira,     Kenya Medical Research Institute, Centre for Traditional Medicine and Drug Research Nairobi, Kenya

A.F. Williams-Persad,     Pharmacology Unit - The Department of Para Clinical Sciences, Faculty of Medical Sciences, The University of the West Indies, Trinidad and Tobago, West Indies

F.F. Youssef,     Department of Preclinical Sciences, The University of the West Indies, St. Augustine, Trinidad and Tobago

Foreword

Geoffrey A. Cordell, Natural Products Inc., Evanston, IL, United States

Plants as a source of healing medicaments, either individually or in combination, have been an essential aspect human healing practices for many thousands of years, as discussed in Chapter 1 of this second edition of an excellent volume on pharmacognosy. Although not a widely known term in the lay literature, pharmacognosy was elaborated as the first discipline in the evolution of the pharmaceutical sciences in the early 19th century. That prominence was subsequently overshadowed, first by the development of medicinal chemistry, where it became apparent that structural changes in a metabolite could manifest biological changes, and then by the development of in vivo, in vitro, and later enzyme- and receptor-based systems for understanding biological and then enzyme-based mechanisms of action and the assessment of clinical potential of natural products. In the 1960s and 1970s, the role of pharmacognosy as a part of the curriculum in many pharmacy programs around the world diminished as the focus grew in medicinal chemistry and developments in pharmaceutics, while the emphasis remained on the classical identification of plants and their metabolite classes. Some visionary pharmacognosists expanded the notion of what the potential (real) role of pharmacognosy was, and now is, in society and began to explore plants from a drug discovery perspective, initially in programs for anticancer agents, and subsequently for other, sometimes neglected, disease needs, including malaria and other parasitic diseases, cancer chemoprevention, fertility regulating agents, HIV-AIDS, diabetes, and more recently for the Covid-19 SARS-CoV-2 virus. Natural product scientists also saw opportunities in organisms other than plants, based on the pharmaceutical industry successes in discovering new antibiotic compounds in the United States and in Japan from soil-derived microbes. Other researchers examined the potential of the plethora of organisms in the coastal and alternative marine locations for their biological potential. The use of medicinal plants by animals also became an area of study and more and more diverse ecosystems are now being studied for biologically significant metabolites from microbial sources, some of which serve as evolutionary ecological symbionts.

In parallel with the diversification in natural origins, a rapid development of the technologies applied to pharmacognosy was occurring, taking the science substantially beyond macro- and microscopic identification coupled with specific color tests for plant identification and analysis. The integration of chromatographic techniques and various forms of spectroscopy fundamentally changed the science, dramatically shortening the time for structure elucidation in exquisite detail. With the concomitant development of biological techniques, the scientific level of pharmacognosy globally was markedly enhanced. The integration of these evolutionary steps continues unabated, with applications to seek new biological candidates through in silico drug discovery processes, biosynthetic investigations at the genome level, and the most sophisticated applications of spectroscopic and chromatographic techniques. In addition, the developments of extensive data systems, which accumulate various aspects of natural product information, are now facilitating compound identification in complex biological matrices through the application of artificial intelligence. With the burgeoning of machine learning, a new era of focused discovery targeting is underway through which the direction of discovery and utilization initiatives for new and existing biologically active metabolites will be significantly enhanced, which brings us to biosynthesis and its exceptional contemporary relevance.

My first natural product chemistry teacher, Prof. Arthur J. Birch, taught that Nature does not produce what it cannot produce. While eminently logical, it is now critical from several perspectives to integrate that euphemism into pharmacognosy, and to invert the implications. For the effectiveness of a traditional medicine, or for the process of drug discovery from any organism, or for the production of an antibiotic, the active metabolite has to be there. It must be made, biosynthetically, by the encoded enzymes in the genome of the organism under study, at the time of assessment or acquisition for beneficent purposes. For many microorganisms, those processes are now beginning to be understood and controlled, though not yet optimized from a regulatory perspective. For plants, that exploration is one of the exciting future areas for development. How to regulate plant biosynthesis at the gene level to produce the metabolite(s) of biological and possibly clinical relevance is for several reasons a very high priority challenge.

The impacts of the Fourth and Fifth Industrial Revolutions with the Quintuple Helix philosophies and practices are having a dramatic impact on pharmacognosy. Together with deep-seated concerns regarding sustainability and environmental change due to climate modulation, the newly evolving, people-centered roles of pharmacognosy in society, now as the most high-tech of the pharmaceutical sciences, have become even more critical, and its reach into the diverse applications of biologically active natural products has expanded significantly. The importance of sustainability has many implications for pharmacognosy, and the term ecopharmacognosy, the study of sustainable biological natural products, evolved to express those pertinent philosophies and laboratory and industrial practices, including the chemical and biological implications of a circular economy. Subsequently, the term cyberecoethnopharmacolomics was proposed to emphasize how essential a holistic and fully integrated technological approach to pharmacognosy is to comprehend the importance of the science and the relationship to translational outcomes for enhanced global healthcare and wellness. This high-tech view of pharmacognosy is also of critical significance to global health as continuing access to safe, effective, and consistent natural medicines is threatened by a changing climatic environment and rising sea levels. Those changes dramatically impact the growth, availability, and metabolite profiles of medicinal plants, and thus their biological activity, in unpredictable ways. Detailed examination of these modulations is essential to meet the demands of medicines security as an important aspect of integrated healthcare systems. These are times of vast research opportunities for pharmacognosy, in areas of science undreamed of even 5 years ago, taking full advantage of blending the contemporary technologies into discovery, quality control, and environmental safety investigations. This fine volume serves as an initial introduction to those opportunities by laying out many aspects of the foundational sciences for an understanding the enormous potential of biologically active natural products in society.

The result is much more than a simple book on pharmacognosy, the 34 chapters also cover several important and associated areas which allow the reader, students of pharmacy, and scientists in natural products chemistry and biology, to acquire an initial understanding of the broad dimensions of pharmacognosy in society on a day-to day basis. Chapter 1 focuses on the history of pharmacognosy and how it has evolved practically and theoretically. Chapter 2 shines a light on the global therapeutic significance of medicinal plants in three major regions of the world, China, through Traditional Chinese Medicine, India, through Ayurveda, Sidda, and Unani medicine, and the diverse systems of the multitude of indigenous groups in various parts of Africa.

The structures of plants and their functional elements are reviewed in Chapter 3, while Chapter 4 initiates the discussions of the various metabolic products of plants which find important uses such as essential oils, resins, plant hormones, and carbohydrates. Much of the world focuses on the presentation of materials as so-called crude drugs and those derived from plant sources are discussed in Chapter 5. An evolutionary perspective of plants from the Cambrian period is presented in Chapter 6 with a focus placed on the development of secondary metabolites. The transport of metabolites in plants frequently occurs as their glycosides and they also provide some powerful biological and pharmaceutical agents as discussed in Chapter 7. The earliest metabolites derived from medicinal plants were alkaloids, and important sources of these metabolites from plants, based on their biosynthetic origin, are presented in Chapter 8, together with a marine-derived group, the manzamines, and the ergot alkaloids. The importance of tannins as functional foods is one aspect of emphasis in Chapter 9.

Collectively, the largest group of natural products based on their biosynthetic origin are the terpenoids. Representative examples of the terpenoid classes are discussed and the importance of some of the individual compounds as hormonal and pharmaceutical agents, as well as some of their many diverse applications, are presented in Chapter 10. Lignans are the focus of Chapter 11 and the water-soluble and fat-soluble vitamins are covered in Chapter 12.

A more detailed discussion of the importance of pharmacognosy in the development of anticancer agents is presented in Chapter 13, while Chapter 14 emphasizes the cardiovascular agents that are plant-derived, and Chapter 15 illuminates those metabolites used for the treatment of various infectious diseases. Several metabolites from plant and fungal sources are known to have important psychoactive effects, including the cannabinoids, psilocin, and areca nut constituents, as indicated in Chapter 16. Some of the significant metabolites from marine organisms are presented in Chapter 17, those from animals in Chapter 18 and from the endophytes associated with plants in Chapter 19. The fats (Chapter 20) and waxes of plant and animal origin (Chapter 21) are frequently overlooked aspects of pharmacognosy, despite their daily importance in human life. How animal cells function is discussed in Chapter 22 and the broad topic of proteins and their structures and functions are outlined in Chapter 23.

The importance of the pharmacokinetics and pharmacodynamics of natural products in their biological effectiveness are presented in Chapters 24 and 25, respectively, and the metabolism of drugs is described in Chapter 26. The vast and burgeoning area in contemporary pharmacognosy of biotechnology and genetic engineering is introduced in Chapter 27. Natural product structure elucidation relies very heavily on the interpretation of NMR spectral data and this area as applied to drug discovery is emphasized in Chapter 28. The holistic approach to the study of metabolite diversity in an organism is termed metabolomics and this important strategy and practice is discussed in Chapter 29. The ongoing role of natural products in target-focused drug discovery is described in Chapter 30, while Chapter 31 presents another lively and relatively new area in pharmacognosy and the application of natural products, specifically their involvement in various applications in nanotechnology. The acquisition of plant materials and of the knowledge of their use under the terms of the Convention on Biological Diversity and the Nagoya Protocol involves important ethical considerations, which are discussed in Chapter 32. From a commercial perspective, the development of nutraceuticals and dietary supplements is an ongoing enterprise of pharmacognosy as new materials are brought into the retail market, and as discussed in Chapter 33. Finally, how this plethora of products is, or is not, regulated in various parts of the world is presented in Chapter 34.

This is a thoughtful, comprehensive, and significant contribution to the pharmaceutical sciences literature and particularly the impact of pharmacognosy in society, and the teaching thereof. Many of the chapters have specific learning objectives associated with them, and some also have sections with suggested student laboratory experiments to illustrate some of the basic techniques in pharmacognosy. These are important additions that significantly increase the overall value of the book as a teaching aid. The volume is well-written by authors from many different parts of the world, and the editors have performed excellent work to bring these diverse aspects of pharmacognosy together in one place.

Preface

Simone Badal McCreath

Simone Badal Yuri N.

Drugs of natural origin, which have roots in many medical traditions, are of inordinate significance due to the substantial growth in usage around the world. In addition, nature-based medicines are the topic of increased inquiry in the quest for novel pharmacophores that hold the prospect of enhanced therapy. The award of the 2015 Nobel Prize in Physiology or Medicine to nature-based drugs, Avermectin and Artemisinin, used in the treatment of infections caused by roundworm parasites and malaria, respectively, underscores such trends and highlights, in particular, the potential value of naturally derived medicines in targeting neglected tropical diseases. This development follows the World Health Organization’s 2008 ratification of The Beijing Declaration, which promotes the safe and effective use of traditional and alternative medicines and calls for greater assimilation of these into national health care systems. Issues of quality, safety, efficacy measurements, commercial production, regulation, and ethics of natural drugs are now, more than ever, of paramount importance.

Pharmacognosy has evolved from a descriptive botanical subject to a multidisciplinary field inclusive of continuous advances in cell and molecular biology, ethnobotany, phytotherapy, analytical chemistry, and phytochemistry. It has embraced innovations for functional analysis of molecular targets that aid the development of targeted therapies. This book therefore aims to provide the student of pharmacognosy, and the related fields of pharmacy, medicine, medical herbalism, nursing, medicine, and pharmacology, a fundamental comprehension of naturally derived drugs within the historical context of their development, in addition to providing an update on recent developments in the field.

The Second Edition comprises eight sections. The first section includes an overview of the fabric of pharmacognosy based on plant metabolites, their origins, their diverse chemistry, and their impact on human diseases. A subsequent section, unique to this text (as far as we are aware), highlights secondary metabolites and drugs derived from animal sources. The section on animal anatomy and physiology will assist the student to comprehend the functional application of these natural drugs. Several later sections of the book focus on a variety of topics covering latest opinions on industrial, technological, regulatory, ethical, and sustainability developments, which are of potential relevance to undergraduate and graduate students and researchers in the field as well as policy makers. As humans exploit nature’s unique gifts for alleviating disease, this should be achieved with safety, sustainability, and equitable benefit-sharing considerations in mind. These were some of the ideas that inspired the content of this book, although it is in no way an attempt to be fully comprehensive on all aspects of pharmacognosy.

This Second Edition provides current information on the different sections, improved readability for our audience, and lab exercises that will help academics and research staff to plan and conduct hands-on laboratory exercises with under- and postgraduates alike.

Acknowledgments

Forty-three distinguished scholars from multiple regions around the world, mostly recognized as global authorities in their respective fields, were invited to submit chapters. Each submitted chapter was subject to review by one or both editors with some assistance from Dr. Petrea Facey (University of the West Indies, St. Augustine). The editors would like to express sincere gratitude to each contributing author for accepting the invitation to contribute, for the dedicated and timely submission of their work, and for their patience during the editing and production stages of this book. In addition, special appreciation goes to Geoffrey Cordell who not only reviewed multiple chapters but also wrote the Foreword for this book.

Finally, personal gratitude is extended to family members. Simone Badal would like to offer special thanks to her husband, Gregory McCreath, whose inspiration paved the way for the birth of this book; to her father, Lloyd Badal, whose constant support and encouragement created a buffer and motivational shield for completion; and to her mother, Elsa Ramsay, friends, and family members for their constant support and encouraging words. Yuri Clement would like to thank his wife, Jiselle, for always pushing him beyond his limits. He also acknowledges his mother, Lenora Redman, for her belief that her children would go beyond her own mark. His children, Christine and Emmanuel, are constant reminders that we must all strive to make our sphere a better place.

Section 1

Pharmacognosy 101

Outline

Chapter 1 Background to pharmacognosy ent

Chapter 2 Traditional medicine

Chapter 3 Plant anatomy and physiology

Chapter 4 Plant constituents: carbohydrates, oils, resins, balsams, and plant hormones

Chapter 5 Plant crude drugs ent

Chapter 1

Background to pharmacognosy ent

S. Badal¹ and Yuri N. Clement²,    ¹Department of Basic Medical Sciences, Faculty of Medical Sciences Teaching and Research Complex University of the West Indies, Mona Campus, Kingston, Jamaica,    ²Department of Paraclinical Sciences, Faculty of Medical Sciences, The University of the West Indies, St. Augustine, Trinidad and Tobago

Abstract

This chapter present an introduction to pharmacognosy and provides a global history of medicinal plant use over several centuries. It covers the developmental changes in the field over the years and defines related terms associated with natural products research. It also provides insight into various participatory roles of scientists in the field and lays the foundation for the varied contributions. Some emerging areas within the field are discussed.

Keywords

Ayurveda; crude drugs; Dioscorides; ecopharmacognosy; forensic pharmacognosy; galen; Materia Medica; molecular pharmacognosy; phytochemistry

Chapter Outline

Outline

1.1 History and evolution of pharmacognosy 3

1.1.1 A brief history of medicinal plant use 3

1.1.2 History of pharmacognosy 4

1.2 Scope of pharmacognosy 5

1.3 Emerging areas in pharmacognosy 5

1.3.1 Forensic pharmacognosy 5

1.3.2 Molecular pharmacognosy 6

1.3.3 Ecopharmacognosy 6

1.4 Pharmacognosy in society 7

1.5 Basic terminology in pharmacognosy 7

1.5.1 Chromatography 7

1.5.2 Crude drugs 7

1.5.3 Ethnobotany 7

1.5.4 Ethnopharmacology 7

1.5.5 Extraction 8

1.5.6 Herbs 8

1.5.7 Medicinal plants 8

1.5.8 Natural products 8

1.5.9 Phytotherapy 8

1.6 Conclusions 8

1.7 Review questions 8

References 8

1.1 History and evolution of pharmacognosy

1.1.1 A brief history of medicinal plant use

The use of plants in the management of disease predates historical records and almost every culture of the world has documented use or an oral tradition of herbal use in their healing practices. Nonetheless, the first documented records of medicinal plant use were found in Sumerian and Akkadian scrolls in the third millennium BCE. The ancient Egyptian records also dates to 3000 BCE with the first recorded prescriptions found in Egyptian tombs to include the Hieratic Papyri, Ebers Papyrus, and the Gynecologic Papyrus [1,2]. The Ebers Papyrus (1500 BCE) contained 811 prescriptions and 700 crude drugs [3] for the treatment and cure of diseases. Egyptian priest doctors diagnosed, prescribed, and prepared crude drugs which included onions, coriander, melon, myrrh, aloes, gum, poppy, castor, and anise. Similarly, the Babylonians recorded their use of crude drug recipes of plant and mineral origin in their practice of medicine as early as 1770 BCE [4,5]. Their earliest record has 250 plant-based crude drugs that included opium, ricinus, myrrh, menthe thymus, and over 120 minerals [6].

On the Indian subcontinent, the practice of Riveda and Ayurveda medicine started around 2000 BCE and continues today. These systems of medicine involve the use of sacred medicinal plants and important crude drugs include sandalwood, aloes, sesame oil, castor oil, ginger, benzoin, cannabis, caraway, clove, cardamom, and pepper. The Traditional Chinese medicine (TCM) system, believed to be over 5000 years old, is based on two separate theories regarding natural laws that govern good health and longevity, namely yin and yang, and the five elements (wuxing). TCM includes several plant-based products, as documented in the volume Pen Ts’ao Kang Moa (3000 BCE) which contained records of drugs of plant and animal origin to include anise, ginseng, rhubarb, ephedra, and pomegranate [2]. The legendary emperor Shen Nung discussed medicinal herbs in his work, which was probably written around 2700 BCE [7]. However, TCM as a series of practices was systematized and written between 100 BCE and 200 BCE. A complete reference to Chinese medicine prescriptions is the Modern-Day Encyclopedia of Chinese Materia Medica published in 1977. It lists nearly 6000 drugs of which 4800 are of plant origin [8].

Subsequently, the Islamic era between CE 770 and 1197 ushered in an era when natural product use gained further attention in the treatment of diseases and infections. Abu Bakr Mohammad Ibn Zakariya Razi, also known as Rhazes (AD 865–925), born in Iran, is known for extending the analytical approach Hippocrates and Galen. His primary focus was urology and was the first to develop a treatment for kidney stones [9]. The physicians of Arabia added many new plants and medicaments to those already recorded by the Greeks and Romans. In the days of the Arab contribution, pharmacy as a subject, attained elevated attention and recognition allowing it to become an independent branch of medicine [10]. The medieval Persian traditional medicine was pioneered by Rhazes (865–925 AD) and Avicenna (AD 980–1037), who are regarded as founders of the golden days of the Persian medical sciences [11]. According to the literature, Freidoon used knife, fire, and many plant materials to treat injured soldiers. He was known as the first Iranian surgeon and the pioneer of the Saenamargha school of medicine [12].

Pythagoras (560 BCE), the Greek philosopher and mathematician, used mustard and squill preparations to treat particular diseases, and the use of natural products toward the treatment of various ailments was also shared by Hippocrates, a Greek physician (466 BCE). Between 460 and 377 BCE, Hippocrates, the father of medicines, contributed to general medical development by proposing that causes of disease are not necessarily spiritual [2]. Thus he acknowledged treatment with plants and other natural products. Galen (130–200 BCE), a Roman physician and first pharmacist was known to use Galenical preparations to manage pain and several diseases, such as Uvaeursi folium as an uroantiseptic and a mild diuretic which is still used nowadays. He also compiled the first list of drugs with supposedly similar or identical actions and thus interchangeable De succedanus. Dioscorides, also a Greek physician, in CE 77 was one of the first to describe drugs in his work, and he is often referred to as the father of Pharmacogonosy [13]. His work De Materia Medica, documented the use of 944 drugs of which 657 were of plant origin [2,13].

In the 10th and 11th centuries, Avicenna (a Muslim scientist) contributed significantly to medicine through his work, Al Canon from which many publications and teaching programs arose [14]. It was recorded that Paracelsus (1493–1541), who played an important role in formulating drugs from minerals, burned Avicenna’s Canon, the then Bible of learned medicine, and justified his actions by saying remove all the old books of learning and practice medicine as I have learnt in the real world [15]. John Gerarde (1545–1612) a botanist and herbalist first published The Generall Historie of Plantes, in 1597, which was regarded as the most widely circulated botany text written in English in the 17th century [16].

1.1.2 History of pharmacognosy

The term pharmacognosy has evolved significantly since it was first coined by Johann Adam Schmidt (1759–1809). It appeared in his manuscript entitled Analecta Pharmacognostical in 1811 after his death [17]. In those early days, the discipline focused primarily on the botanical description and phytochemical analysis of crude drugs prepared from medicinal plants. The botanical descriptions and microscopic applications of pharmacognosy were further developed in the 19th and 20th centuries [1] and formed the regulatory basis for the use of herbal preparations as medicine based on pharmacopoeial definitions. During these formative years, the discipline was considered a branch of medical sciences associated with the use of drugs in their crude state.

Over time, the discipline became progressively more inclusive with Flückiger (1828–94) defining pharmacognosy as the simultaneous application of various scientific disciplines with the object of acquiring knowledge of drugs from every point of view [17]. And over the next century, there was a shift from medicines derived from plants to natural sources defined by Tyler [18] as an applied science that deals with the biologic, biochemical, and economic features of natural drugs and their constituents. It involved the investigation of medicinal substances from the plant, animal, and mineral kingdoms in their natural, crude or unprepared state or in the form of such primary derivatives as oil, waxes, gums, and resins [19,20].

During that same era, pharmacognosy evolved from an application-based understanding of natural drugs to an overall systematic knowledge of not just natural drugs, but more specifically, crude drugs from animal and vegetable origin as described by Greenish [21]. He suggested that pharmacognosy is a science that aimed at a complete and systematic knowledge of crude drugs of animal and vegetable origin" [17].

By the 1960s and 1970s, pharmacognosy morphed from a mostly descriptive botanical research discipline into a more integrated chemical and biologically oriented approach [1]. In the last few decades, pharmacognosy has embraced drug-receptor relationships that … explores naturally occurring structure–activity relationships with a drug potential [22], while also exploring the structural, physical, chemical, and sensory characters of crude drugs of plant, animal, or mineral origin [23].

Nowadays, pharmacognosy is a discipline taught at most pharmacy programs around the world, with the classical botanical approach focusing on macro- and microscopic identification, botanical description, and authentication of drugs of natural origin. However, there has been significant advancement of the science and other disciplines including pharmaceutical biology, phytochemistry, and natural product research have incorporated various aspects of pharmacognosy. However, the primary purpose of classical pharmacognosy is for the preliminary standardization (by chromatographic fingerprinting) and quality control processes useful in the development of official pharmacopoeial standards [24–27].

Over time, a shift occurred from classical pharmacognosy to a more chemically and biologically focused discipline, involving the isolation and characterization of bioactive principles from natural sources, as well as the evaluation of structure–activity relationships of isolates with pharmacological activity with potential as lead compounds in drug development. For many years the isolation of secondary metabolites from plant and natural sources was the mainstay of drug discovery, to include morphine, strychnine, quinine, caffeine, nicotine, atropine, colchicine, and cocaine. In the 20th century, the search and discovery of many new drugs from natural sources, particularly microorganisms and marine flora, have become a major focus [28].

Today, pharmacognosy encompasses several areas of science, including botany, chemistry, enzymology, genetics, pharmacology, toxicology, horticulture, quality control, and biotechnology. Other ancillary disciplines include pharmaceutics, pharmacoeconomics, pharmacovigilance, regulatory law, and conservation. Pharmacognosists are involved in many research areas including analytical chemistry, bioactivity assessment, biocatalysis, biosynthesis, biotechnology, cell biology, chemotaxonomy, clinical studies, cultivation of medicinal plants, ethnobotany, genetics, marine chemistry, molecular biology, synthetic modification of natural products, pharmacology, phytochemistry, phytotherapy, standardization of traditional medicines, taxonomy, tissue culture and zoopharmacognosy [29,30].

1.2 Scope of pharmacognosy

The scope of pharmacognosy has expanded in recent years to involve specialist scientists (pharmacognosists) who are involved in the identification or authentication of crude drugs (using macroscopic, microscopic, or chemical methods), and the crude drugs’ biopharmacological and clinical evaluations [31]. Research areas also include phytochemistry, microbial chemistry, biosynthesis, biotransformation, bioinformatics, and chemotaxonomy. Pharmacognosy has also become an important link between pharmacology and medicinal chemistry [32]. Additionally, pharmacognosists are involved in the cultivation and collection of medicinal plants, preparation and qualitative and quantitative analysis of specific formulations, the development of plant tissue cultures, and the use of several spectroscopic and molecular techniques for natural product identification. More recently, molecular biological techniques include DNA fingerprinting (random-amplified ploymorphism DNA (RAPD), restriction fragment length polymorphism (RFLP), amplified fragment length polymorphism (AFLP)) that are used for the identification and authentication of various medicinal plants [33–35]. Besides those areas already mentioned, pharmacognosists are also involved in protocol development and/or implementation of processes involved in the collection, drying, and preservation of crude drug material.

1.3 Emerging areas in pharmacognosy

1.3.1 Forensic pharmacognosy

Forensic pharmacognosy is the application of methods and techniques in pharmacognosy for the investigation of crimes arising out of the misuse of plants and crude drugs of plant, animal, and mineral origin. Misuse includes the use of plant-based substances in homicides, natural drug abuse, and in sports to gain unfair advantage. This field utilizes conventional and modern analytical techniques including botany, microscopy, quantitative microscopy, and phytochemical methods to unravel crimes arising from the misuse of plants. In most cases, the prosecution of offenders and criminals is challenging, as sufficient high-quality evidence must be tendered in the court of law.

Most secondary plant metabolites appear at very low concentrations in the blood following oral ingestion, which makes their extraction and analysis very challenging [36]. However, recent technological advancements in metabolomics have allowed for the enhanced detection of secondary plant metabolites with higher sensitivity [37–39]. A wide array of analytical techniques is applied to forensic pharmacognosy that include physical, biological, morphological, microscopic and chemical evaluation.

Physical evaluation of crude drugs is achieved by the determination of various physical parameters using physicochemical techniques. These include parameters such as the determination of solubility; specific gravity; optical rotation; viscosity; refractive index; water content; degree of fiber elasticity; ash values, extractive values; and foreign organic matter.

Biological evaluation refers to the evaluation of therapeutic/pharmacological, enzymatic, gene modulating, and toxicological activity of the crude drug and/or its active principle using several models. A recent model of noted interest is network pharmacology where multitarget drugs may prove more efficacious than traditional ones [40]. Ultimately, biological evaluation determines therapeutic activity of the drug or active principle, potency, as well as toxicity, based on the chemical constituents present and their content.

Morphological evaluation uses sensory organs (skin, eye, tongue, and nose) to obtain a qualitative evaluation of the plant. Such evaluations involve macroscopic observations such as color, odor, taste, size, shape, and other special features [41].

Microscopic examination involves a detailed examination of the drug and is mostly used for the qualitative evaluation of established crude drugs in entire and powdered forms [42]. Microscopy is used to detect various cellular tissues, such as trichomes, stomata, starch granules, calcium oxalate crystals, and aleurone grains. Crude drugs are identified microscopically by preparing transverse or longitudinal sections and staining to identify specific components of plants. Microscopy is also used to study constituents of complex, powdered drug mixtures. Quantitative aspects of microscopy comprise the stomata number and index, palisade ratio, vein-islet number, size of starch grains, and length of fibers [41,43].

Chemical analysis is used to identify, quantify and/or evaluate the purity of drugs, secondary metabolites, and extracts of crude drugs. First, preliminary phytochemical screening may be important for the chemical evaluation [41], such as the determination of acid saponification values. Methods that provide more definitive answers, such as identification of active constituents and/or the quantitation of these, include photometric analysis; spectroscopic analysis (UV, IR, Ms, and NMR); thin layer chromatography; high-performance liquid chromatography; and gas chromatography.

1.3.2 Molecular pharmacognosy

The use of molecular cloning, genetic engineering, tissue culture, and molecular markers in pharmacognosy now represents a highly interdisciplinary, cutting-edge science in the field. Molecular Pharmacognosy involves the classification, identification, cultivation, and conservation of medicinal materials and the production of their components at a molecular level, as well as the modulation of secondary metabolites [44]. Molecular pharmacognosy investigates medicinal plants at the level of nucleic acids and proteins that utilizes techniques such as molecular markers, gene chips, recombinant DNA, and protein analysis.

The concept of molecular pharmacognosy involves various techniques with minimal environmental impact. These techniques include molecular identification that precisely describe medicinal raw materials using molecular markers, the use of phylogenetic trees to identify potential drugs in closely related medicinal plant species, the preservation of germplasm for sustainable propagation, and the biosynthesis and regulation of bioactive metabolites with the use of transgenic techniques aimed at boosting concentration of active components. Additionally, molecular pharmacognosy aims to conserve genetic biodiversity to protect species employing molecular markers, based on DNA polymorphisms and gene sequences that facilitate evaluation DNA variation, thereby identifying plants to be actively protected.

There are diverse applications for the utility of molecular pharmacognosy that include quality control and standardization of plant-based medicinal agents, identification and validation of new drugs, accumulation of secondary metabolites, DNA expression, and genetic diversity. Prospects include molecular identification of medicinal plants, functional genome research related to secondary plant metabolites and the development of novel approaches for core identification and collection of genes.

1.3.3 Ecopharmacognosy

Ecopharmacognosy is defined as the study of sustainable, biologically active natural resources and from a philosophical perspective, it provides a contextual framework for the development of novel strategies and scientific approaches to improve future global product accessibility and assured beneficial outcome [45]. A wide range of ecological/environmental factors determine the levels of secondary plant metabolites produced and include drought [46], salinity [47], temperature [48], climate change [49], light [50], and nutrient stress [51]. Therefore, environmental changes may negatively affect these natural resources and reduce our ability to exploit these resources for our benefit in the future.

1.4 Pharmacognosy in society

There are wide variations in health care delivery in countries throughout the world including per capita expenditure [52], ratio of trained physicians per thousand population [53], and access to drugs (including for rare diseases) [54–56]. In developing countries, where there is a greater reliance on medicinal plants for healthcare, there are environmental concerns regarding the deleterious impact of human activities on natural resources [44].

There is also the issue of major disparities regarding the allocation of funds for research, with approximately 90% of funding to investigate about 10% of global health problems [57]. In most cases, resources are directed to research in health conditions affecting populations in wealthy countries. This approach could stifle innovation in drug discovery with insufficient funding available for research in natural products and herbal medicines. In this regard, there is a direct impact on the number of trained professionals to advance research in the field.

On a positive note, there was the establishment of the Japanese Liaison of Oriental Medicine (http://www.jlom.umin.jp) which provides an environment where major scientific societies and the WHO Collaborating Centers for Traditional Medicine could cooperate to further research in traditional medicine. Such initiatives would encourage professionals to enter the field and steer the future in natural products research and drug development. Additionally, other benefits include providing a forum for open discourse regarding the need for more feasible global access to relevant medicaments.

Encouraging collaborative efforts in natural products research between developing and developed countries is another route that can be initiated by international organizations, such as the WHO, or through independent bodies, such as the African Caribbean Cancer Consortium (AC3). In 2006 the WHO Commission on Intellectual Property, Innovation, and Public Health encouraged initiatives that would boost patent protection within developing countries toward improving the declining quality and quantity of drug innovation and narrowing the gap of drug discoveries in the developing world. In addition, several funding agencies such as Third World Academy of Sciences (TWAS), Organization for Women in Science for the Developing World (OWSD), and the Gates Foundation have supported research activities in developing countries to narrow these deficits. Organizations, such as AC3 [58], facilitate intellectual discourse and collaborative research between scientists from the developed and developing countries with a primary focus on improving health benefits for the Black population with cancer.

1.5 Basic terminology in pharmacognosy

The following are brief definitions of some widely used terms in pharmacognosy.

1.5.1 Chromatography

Laboratory methods used for separating complex chemical mixtures using a mobile phase (liquid or gas) and stationary phase (solid or liquid) for quantitative and qualitative analysis. The technique is mainly used for isolation and purification, but wider applications include structural elucidation on chromatographic characteristics.

1.5.2 Crude drugs

Complex mixtures of natural products, extracts and exudates that are not pure compounds. Crude drugs are usually dried plants, animal material, or minerals of pharmaceutical or medicinal importance. They are also defined as products that have not been advanced in value or improved in condition by grinding, chipping, crushing, distilling, evaporating, extracting, artificial mixing with other process or treatment beyond what is essential to its proper packing and the prevention of decay or deterioration pending manufacture [59].

1.5.3 Ethnobotany

The study of the human use of plants for furniture, shelter, transportation, food, religion, and medicine.

1.5.4 Ethnopharmacology

The study of how different cultures and ethnic groups use plants as medicines. It covers a wide range of topics based on the anthropological, historical and other socio-cultural studies of local and traditional plants, fungi and animals; as well as the biological and clinical studies of resources used as medicines, toxins and foods, among other applications [60].

1.5.5 Extraction

The laboratory separation of substance(s) from a mixture using suitable solvents. The methods most used to isolate and/or purify natural products and employ solid–liquid, liquid–liquid, and acid–base extraction techniques.

1.5.6 Herbs

This term is more appropriately applied when referring to culinary plants and refers to crude materials, which may be obtained from lichens, algae, fungi, or higher plants such as leaves, flowers, fruits, seeds, stem, back, roots, rhizomes, or other parts which may be whole, fragmented, or powdered [61]. The term is probably misused when applied to medicinal plants for therapeutic use, unless there is a dual use, for example, ginger, turmeric, or garlic.

1.5.7 Medicinal plants

Wild or cultivated plants used for the management and treatment of disease.

1.5.8 Natural products

A generic term used for an extract, exudate, partially fractionated preparation, or isolated pure compounds derived from an entire organism (plant, animal, microorganism, etc.) or part of an organism (leaf, flower, isolated glands, etc.).

1.5.9 Phytotherapy

This subdiscipline is concerned with the clinical use of crude drug extracts or partially purified mixtures from plants and focuses on scientific studies of these bioactive plant-based medicines.

1.6 Conclusions

There have been major shifts in pharmacognosy since the term was first coined in the early 19th century. The field has evolved over the years from the botanical description and phytochemical analysis of medicinal plants to include DNA fingerprinting, metabolomics, and functional genome research to the sustainable use of environmentally sensitive natural resources. These various aspects have enabled the field to make greater contributions to the management of human and animal health. As new advances develop and are refined it is hoped that pharmacognosy would make a significant mark on the advancement of medicine.

1.7 Review questions

1. Discuss how pharmacognosy has developed since the early 19th century.

2. Discuss how pharmacognosy could contribute to crime detection.

3. From a historical perspective, discuss the documentation of medicinal plant use in different areas around the world.

4. Discuss the concepts, applications, and prospects of molecular pharmacognosy.

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