Plant Cuttings

Modern medicines from plants: Botanical histories of some of modern medicine’s most important drugs, Edited by Henry Oakeley [authored by: Susan Burge, Timothy Cutler, Anthony Dayan, Arjun Devanesan, Graham Foster, Jane Knowles, John Newton, Henry Oakeley, Noel Snell, Michael de Swiet & Angela Tunstall], 2024. CRC Press, on behalf of the Royal College of Physicians.

In his Introduction to Modern medicines from plants, the book he has edited [and which is here appraised], Henry Oakeley tells us that around 50 plants are used in the production of modern-day prescription-only medicines [POMs] in the West. Those 50 provide the subject matter for Modern medicines from plants*. In terms of the book’s focus, that is clearly stated in the sub-title, Botanical histories of some of modern medicine’s most important drugs.

Overview of contents

Preface – tells us “This is a unique book about the historical medicinal uses of plants and the effective medicines that have been derived from them” (p. 10). A statement that, having read through the book, I’m prepared to believe.

Introduction, which tells us that ”The book describes plant-sourced treatments from Classical to modern times, documenting the transition from ‘then’ to ‘now’ and providing the information and primary sources for knowing the story of a plant and its role in producing medicines and treating disease” (p. 11). In doing so, it “recounts the successes and failures of many drugs, discovered from mouldy cattle fodder, ordeal; and arrow poisons, one-eyed lambs, an unloved chilli pepper, infected barley, serendipity, hard work, garden plants, ancient Chinese medicinal texts, etc. etc., and our unstoppable drive to know” (p. 13). If that doesn’t encourage you to want to read more, I don’t know what will.

Chapters: The main part of Modern medicines from plants – as I hope you’d expect – is the 43 numbered chapters, of named plants. From Ammi majus (the source of 8-methoxypsoralen, used to treat vitiligo) to Visnaga daucoides [interestingly, formerly known as Ammi visnaga] (source of nifedipine, amiodarone (both used for heart disease), and sodium cromoglicate, used in treatment of asthma). Along the way, we read the origin stories of many well-known drugs such as aspirin, cocaine, curare, digitoxin and digoxin (which I was surprised to read are derived from different Digitalis species), ephedrine, metformin, paclitaxel, quinine, statins, steroids, Tamiflu, vincristine, and warfarin.

The final two numbered chapters are accounts of topics rather than species. Chapter 44 deals with a wide range of plants that provide excipients – “substances added to medicine to allow it to be usable, storable or palatable” (p. 336) – and solvents. Chapter 45 is devoted to vitamins, “small organic molecules required for life and well-being” (p. 345) – not all of which are derived from plants, but are included “because of their importance to health” (p. 245). All 45 chapters are abundantly illustrated throughout – most notably with images of the plants, but also featuring some of the notable personalities in the history of plant-based medicine.

Appendix 1: Historical references consulted, listing of source literature published pre-1700, and works of Linnaeus (from 1738’s Hortus clifortianus to Materia medica from 1782) [Ed – but I’m not sure what to make of the entry “Gaertner J, Linnaeus C. De fructibus et seminibus plantarurm vol. 2, published in 1788” (p. 364), indicating that both Gaertner and Linnaeus penned this publication. Checking the details of that tome shows Gaertner as the author (e.g. here, here, and here). The apparent joint-authorship with Linnaeus is even more unlikely given Gaertner’s opposition to some of Linnaeus’ ideas.]

Appendix 2: Dramatis personae, a little about 24 writers – from ‘Alexander of Tralles’ to ‘Turner, William’ – of the historic herbals and primary sources “whose writings are frequently referenced in the book” (p. 367).

Appendix 3:Glossay, from ‘adrenal medulla’ to ‘xenograft’, but which does not contain the meaning of the chemical names or the diseases used in the text, and which excludes words explained in the text. But does include the intriguing ‘discalced (monk)’ – “a monk who goes barefoot or in sandals as part of his religious Order” (p. 373).

Index: Chemicals and drugs – from ‘Aatrilla’ to ‘Xylocaine’, and featuring the memorably-named molecule ‘godnose’**.

Index: Plant names – from ‘Acerola cherries’ to ‘Zea mays’, including common names [primarily English, but some other languages are also included, e.g. Chinese – Ma-huang, and Quetchuan – quina-quina], scientific names, and some more general ‘categories’, such as beans, palm, willow, spruce. Somewhat surprisingly, ‘tea’ is the stand-out ‘winner’ with 14 entries.

Index: Other images – a curious listing that includes a book cover, a photograph of a selection of liquorice sweets, an ergot extract bottle, and several portraits of notable medical personalities such as Nicholas Culpepper, Dioscorides, and William Withering.

What is missing – and which would have been really helpful – is an index to the diseases, etc. treated by the medicines that are covered in the book. Something for a future version or edition of the book?

To complete the book we have biographies of the book’s 11 authors***.

First things first, what is a plant?

Given that the word ‘plants’ feature so prominently in its title, what is a plant for the purposes of Modern medicines from plants? Of the 50 or so plants considered in the book, the great majority are flowering plants – angiosperms. Of the 43 plant-named chapters, three are devoted to gymnosperms: Ch9 on Cephalotaxus harringtonia; Ch16 for Ephedra sinica; and Ch30 on Taxus baccata and T. brevifolia; 39 chapters are solely named for angiosperms. Chapter 24, entitled Hordeum vulgare, Claviceps purpurea, stands out as an oddity. The first-named organism is a grass – an angiosperm – and therefore a plant. But, the second-named lifeform is a fungus, albeit one that “contains ergot alkaloids which are the cause of ergotism (Kristen Fischer) and the source of ergometrine which was previously of life-saving importance for stopping postpartum haemorrhage” (p. 195). With the single exception of this medicinally-relevant fungus – which is included because of its association with a plant – we can infer that plants, as used in Modern medicines from plants, means angiosperms and gymnosperms, i.e. seed-bearing members of the Plant Kingdom.

More about the plant chapters

Layout of Chapters 1-43 is reasonably formulaic, but with variations. Most consistent is the first page of each, which tells us: the author’s name; the scientific name(s) of the plant(s) [plant chapters are arranged alphabetically, in order of scientific name]; a statement of what compounds are sourced from the plant(s); and a very short summary of the plants [and occasionally names the family to which it belongs] and its role in medicine [which feature is usually present, but not always…].

For example;

“Chapter 26 – Noel Snell

Illicium anisatum and I. verum

The source of oseltamivir

Illicium verum (Chinese star anise) and I. anisatum (Japanese star anise) are closely-related species whose star-shaped seeds (that smell of anise) contain shikimic acid, which was used in the synthesis of the anti-influenza medication oseltamivir (Tamiflu). Illicium anisatum grows in the College Garden.”

Thereafter the plant entry contains sections such as: Introduction [which may – or may not – state the family to which the plant(s) belong], Plant profile [which category always seems to be present, although consistently without sources stated, and which may – or may not – tell us the plant’s family], Common names, History (or Historical uses), Medicinal, Chemistry, Modern medical use(s), Side effects, Toxicity, Epilogue, Conclusion, Summary, References. Not all chapters have all of those sections; some have additional sections, and sometimes section headings are repeated, e.g., there are five Chemistry sections in Chapter 3 Atropa belladonna and Datura stramonium. But, whatever the specific name or order of sections within a chapter, they indicate the section’s contents, and help to break up the text – as do the numerous illustrations.

Plant entries are usually single species, although some are multiple, e.g., Chap. 3 Atropa belladonna and Datura stramonium – “and other plants containing antimuscarine [a term explained in-text and therefore excluded from the Glossary…] tropane alkaloids”. Which chapter also therefore includes Mandragora officinarum, Scopolia carniolica, Brugmansia suaveolens, Hyoscyamus alba, and H. nigra). Chap. 5 covers Camellia sinensis, Coffea arabica, and Theobroma cacao; and Chap. 37 looks at Salix alba, Filipendula ulmaria, and Gaultheria procumbens. Chapter length varies, from 14 pages for Nicotiana tabacum, to just a couple of pages for Pilocarpus microphyllus.

Almost exclusively, the book deals with medicines derived from plants. The only exception to this is Chapter 24 ‘Hordeum vulgare, Claviceps purpurea’ with its focus upon compounds extracted from the ergot fungus – Claviceps purpurea. [Ed. – disappointingly, although we have several illustrations of the grass there are none of the all-important fungus.] And, whilst the plant-derived compounds are overwhelmingly those used to treat human ailments, Chapter 39 ‘Tanacetum cinerariifolium‘ is noteworthy because it deals with a pesticide derived from that plant, pyrethrum.

References are included

 – both in-text by author’s surname, and listed at the end of each chapter. Primarily these are scientific articles, but also included are books and URLs (with dates of access). However, inclusion of in-text citations is decidedly patchy, e.g. many paragraphs of facts are presented re quinine and malaria on pp. 96-98, but not a single reference could I find amongst that text. Generally, throughout the book, more explicit links need to be made between statements and their sources. This is something that needs to be tightened-up in any future versions of this book.

An interesting approach to evidence-based statements of facts is provided for Chapter 15 (Dioscorea polystachya and Glycine max), “instead of references to publications by individuals and groups of discoverers, papers are noted here that review broader aspects of the history of this group of compounds from an industrial and pharmaceutical perspective” (p. 133). We therefore have a Reading list for that chapter, but with no easy way to relate publications to factual statements made in-text.

Whilst sufficiency of sources is something that appears generally to be appropriate, Chapter 34 (Pilocarpus microphyllus) lists only a single item of Further reading. Reliance upon a single source for an otherwise scholarly account that provides numerous facts is rather out of line with the other chapters in this book – and not good academic practice. A final comment on references is the order in which they are included in-text. It is rather unusual to have sources listed in the way we see on p. 216: Niness, 1999; Barnes et al, 2007; Franck, 2002; Nair et al, 2010. Which ordering is neither strict alphabetical nor strict chronological.

Summary

Modern medicines from plants, edited by Henry Oakeley, is a fascinating read. It is chock-full of facts and information about medicinal plants and their relevance to people. It is well-written, well-illustrated, and a great addition to the plants-and-people genre.

* Most of which plants – along with approx. 1050 other species – are grown in the Royal College of Physicians’ garden of medicinal plants, where they can be viewed – entrance to which is free, but may need to be booked. If you are unable to visit the garden, podcasts featuring some of the 50 are available to view here. If you’re curious to know what plants are grown in the garden, the searchable database is available here. And, for more on the history of the garden, see Arthur Hollman (2009).

** Godnose is an old name for vitamin C, proposed by its discoverer Albert Szent-Gyorgyi (A Hoffer, 1989; Andrzej Grzybowski & Krzysztof Pietrzak, 2013). [Ed. – Godnose is also the name of “an Australian metalcore band from Brisbane”, and God Nose is “a 42-page American comic book produced in 1964 by Jack “Jaxon” Jackson”…].

*** The nine contributors whose names are explicitly associated with the book’s Preface, Introduction, and 45 chapters are Garden Fellows (Preface, p. 10), all of whom are senior physicians at the Royal College of Physicians (London, UK). All but one of the book’s sections of main text are single-author works; Chapter 30, on Nicotiana tabacum, is mainly contributed by John Newton, but with an epilogue on Lobelia [smoking dried leaves of which is a traditional North American remedy for respiratory ailments] and Laburnum anagyroides [which was smoked by both German and Russian troops as a tobacco substitute during World War II] provided by Noah Snell. In terms of numbers of chapter contributions, Anthony Dayan provided the most – 10; Michael de Swiet and Noah Snell penned 7 each; Timothy Cutler 6; Grahan Foster 5; Susan Burge and Arjun Devanesan each wrote 4; John Newton 2; and Henry Oakeley 1 – Citrus x limon. Additionally, and although not noted as named authors of any of the chapters, Jane Knowles and Angela Tunstall – respectively, Head Gardener, and Assistant Gardener and Gardens Database Manager, at RCP’s Garden of Medicinal Plants – contributed horticultural notes to the chapters (per Preface p. 10).

REFERENCES

Andrzej Grzybowski, Krzysztof Pietrzak, 2013. Albert Szent-Györgyi (1893-1986): The scientist who discovered vitamin C. Clinics in Dermatology 31(3): 327-331; https://doi.org/10.1016/j.clindermatol.2012.08.001

A Hoffer, 1989. The Discovery of Vitamin C, Albert Szent-Gyorgyi, M.D., Ph.D.1893 – 1986. Journal of Orthomolecular Medicine 4(1): 24-26.

Arthur Hollman, 2009. A history of the gardens of the Royal College of Physicians of London. Clin Med (Lond) 9(3): 242-246; doi: 10.7861/clinmedicine.9-3-242