Category Archives: herbal medicine

The Working of Herbs, Part 7: Preparing Herbs Together in a Recipe

By Anne Stobart

In a previous post I looked at how herbs in a recipe might work medicinally. But medicinal recipes rarely contain a single ingredient (which would be known as a ‘simple’), and so we should also assess how the herbal ingredients in a recipe might work together. Much depends on the kind of preparation used in a recipe and how the combination of herbs might work together.

What kind of preparation?

Fortunately many recipes tell us about the processing steps involved–which may include grinding, mixing, straining, heating and more. Once we identify the form of preparation, we can consider

  1. which medicinal constituents might be extracted
  2. the likely bio-availability of the constituents and
  3. other benefits or disadvantages arising from combining the herbs.

(1) Extracting medicinal constituents

The way in which recipe ingredients are processed is significant as, broadly speaking, different plant constituents will dissolve best in water or alcohol. Most of us are familiar with the process of standing leafy herbs in hot water to make tea, and such an infusion will dissolve constituents like tannins and alkaloids. A decoction is based on a lengthier process of boiling bark and roots and may extract more constituents. However aromatic or resinous constituents need to be dissolved in alcohol or evaporated. The process of distillation is likely to produce more aromatic results which I look at it in more detail below. Other processes might not involve liquids at all, for example when ingredients are burnt to ashes – leaving mostly mineral salts.

(2) Bio-availability and choice of preparation

Bio-availability refers to the extent of absorption of nutrients or medicaments in the body and the amount of active substance which is made available in the body. The type of preparation indicated in a recipe can have a considerable effect. For example, the use of oils and fats as a vehicle (or carrier) in an ointment is essential for plant constituents to be absorbed and penetrate the skin barrier. However, the importance of preparation and bio-availability is an aspect of herbal history which is poorly understood despite numerous research studies in ethnopharmacology.[1]

(3) Combining herbs

Synergy (the whole is greater than the parts) is an important concept in modern clinical herbal practice. Some plant constituents are known to enhance the action of others or make phytochemicals more readily available in the body.[2,3]

Distillation – the process

Woman with bellows. Michael Schrick, Von allen geprenten Wassern (Nürenberg: Jobst Gutknecht, 1530, title page). Image credit: National Library of Medicine.
Woman with bellows. Michael Schrick, Von allen geprenten Wassern (Nürenberg: Jobst Gutknecht, 1530, title page). Image credit: National Library of Medicine.

The process of distillation would have had a significant effect in isolating the more soluble and readily evaporated plant constituents, the terpenes. This usually involved boiling plants in water and collecting the steam when cooled back to a liquid, as in the image above.[4] The product of distillation includes both floral waters and essential oils which float on top of the water and so can be separated. As a rough guide, many plants yield around 1% of essential oil from steam-treated plant material, as well as larger quantities of a floral water. [5] The recipe I have been looking at in recent posts involves distillation.

The receit of the water for affter Throwes

Take two hanfull of Isope two of peneroyall and two hanfull of Groundsell one handfull of wild mints two hanfulls of balme: …. then still the hearbes and water togather in a rose still then let the Glass bottle stand in the Sume Sinnce two Months Close Stopped from any Ayre it Makes the water much better.

This recipe would have produced a distilled water containing small amounts of essential oils, known as a hydrolat.[6] Of particular note, the immediate products of a distillation are often chemically reactive and the instruction to let the distilled water stand for two months would give a more stable aromatic product. The resulting water would have contained greater quantities of terpenes or essential oils than an infusion and relatively few alkaloids.

Towards a protocol for the working of herbs

In this series of posts I have been aiming to make explicit the various issues and resources that may be relevant in thinking about the potential medicinal actions of herbs in recipes. In the next post (and last in the series of eight) I will overview the protocol as a whole.

Notes

[1] See ‘Introduction’ in Susan Francia and Anne Stobart, eds. Critical Approaches to the History of Western Herbal Medicine: From Classical Antiquity to the Early Modern Period. London: Bloomsbury, 2014, p.6 and n.22.

[2] Simon Mills and Kerry Bone. Principles and Practice of Phytotherapy. Churchill Livingstone, 2000, p.23.

[3] See Francis J. Brinker. Complex Herbs – Complete Medicines: A Merger of Eclectic & Naturopathic Visions of Botanical Medicine. Sandy, Oregon: Eclectic Medical Publications, 2004.

[4] See also Anne C. Wilson, Water of Life: A History of Wine-Distilling and Spirits, 500 BC-AD 2000. Totnes: Prospect Books, 2006.

[5] Jane Buckle. Clinical Aromatherapy: Essential Oils in Practice. 2nd ed. Philadelphia: Churchill Livingstone, 2003, pp.59-61.

[6] Shirley Price and Len Price. Understanding Hydrolats: The Specific Hydrosols for Aromatherapy. Edinburgh: Churchill Livingstone, 2004.

The Working of Herbs, Part 5: Medicinal Herb Constituents and Actions

By Anne Stobart

In this post I look at some plant constituents and actions. I am especially interested in the plants in a seventeenth-century recipe introduced in Working of Herbs, Part 2. Previously I raised issues related to finding out how medicinal herbs might work (Part 1), and locating modern herbal monographs (Part 4). Here I look at herb constituents and their actions because these are directly relevant to considering how a herb may take effect (or not) in a recipe. Of course, not everyone feels comfortable with the chemistry of plants so I have added some further suggestions in case this topic makes you go ‘AAArgh!’.

Phytochemicals and actions

Phytochemicals, or herb constituents, are fascinating (to me at least!). Knowing the likely effects of some key phytochemicals can be a great help in considering the herbs in recipes. Amongst the  thousands of chemicals in each plant, it is often the ‘secondary metabolites’ produced as a defence against pests and diseases that can be used to some effect in our own bodies.[1] Some have powerful effects, like Groundsel (Senecio vulgaris) which contains toxic alkaloids (Figure 1). Many phytochemicals are surprisingly well-researched so that we know about their likely effects – their herbal actions – even though clinical uses are much less well researched. Here I introduce an important group of plant constituents – the terpenes.

Figure 1. Groundsel (Senecio vulgaris) image from Wikipedia
Figure 1. Groundsel (Senecio vulgaris) image from Wikipedia

What are terpenes?

Terpenes consist of chains of carbon and hydrogen units. They act as a deterrent to insect pests as well as inhibiting fungi and bacteria. The terpenes and related compounds are highly aromatic: many evaporate readily and form the basis of essential oils extracted from plants by distillation.

Plants in the Mint family (Lamiaceae, previously known as Labiatae) contain terpenes which vary considerably in action from stimulant to sedative effects. The simpler stimulant monoterpenes include molecules like menthol with a recognisable minty aroma. Some of these smaller molecules are highly active, often metabolized quickly in the body, with significant neurotoxic effects. Thujone (Figure 2)  is one such monoterpene with a reputation for toxicity. It is found in wormwood (Artemisia absinthum), an extremely bitter-tasting plant in the Daisy family used in the making of absinthe.[2] Thujone is also found in some Mint family members like hyssop (Hyssopus officinalis) and sage (Salvia officinalis). This monoterpene acts on uterine muscle, causing contractions, and hence has a reputation as an abortifacient. Such plant constituents are one reason for caution regarding the use of essential oils in pregnancy.[3]

Figure 2. Thujone
Figure 2. Thujone

Other terpenes, such as diterpenes and sesquiterpenes, have a wide range of therapeutic effects – often particularly anti-spasmodic and calming actions. Both the Mint family (such as lemon balm (Melissa officinalis) and lavender (Lavandula angustifolia)), and the Daisy family (such as chamomile (Matricaria chamomilla) and yarrow (Achillea millefolium)  demonstrate these actions.

 

Other plant constituent groups

Figure 3. Cyanidin, a flavonoid (Wikipedia)
Figure 3. Cyanidin, a flavonoid (Wikipedia)

Another important group of constituents is that of flavonoids which can often be recognised by plant colouring (especially yellows, reds, purples). Flavonoids are polyphenols, consisting of linked rings of carbon atoms (Figure 3), and many are antinflammatory. Some other groups of plant constituents are less obvious, such as the colourless and odourless alkaloids. Alkaloids can significantly affect the nervous system either as stimulants (like caffeine in coffee berries) or as sedatives (morphine-like compounds in poppies). These and other kinds of plant constituents provide for an extensive range of herbal actions.

Conclusion – ask a herbal expert!

I guess some readers will be thinking ‘This is too much chemistry – help!’. If you are not so keen on the chemistry then perhaps you could link up with a clinical herbal practitioner who can help with understanding herb constituents and actions. In the UK you can find a herbalist through a professional organisation like the National Institute of Medical Herbalists. Alternatively you could consider posting a question to HIST-HERB-MED. This is a JISC-MAIL email discussion list which I help to co-ordinate for active researchers in the history of herbal medicine – replies are not guaranteed but might provide useful leads to helpful individuals or sources.

Notes

[1] A standard text on plant constituents is William C. Evans, Trease and Evans’ Pharmacognosy, 16th ed. (Elsevier, 2009). Also see Gunnar Samuelsson, Drugs of Natural Origin: A Textbook of Pharmacognosy (Stockholm: Swedish Pharmaceutical Press, 1992).

[2] However, the toxicity of absinthe may be partly due to the high level of alcohol consumed by regular drinkers, Karin M. Hold, et al., ‘A-thujone (the active component of absinthe): G-aminobutyric acid type a receptor modulation and metabolic detoxification’. Proc. Natl. Acad. Sci. USA 97, no. 8 (2000): 3826–31.

[3] More on herbs with abortifacient actions in John Riddle, Eve’s Herbs: A History of Contraception and Abortion in the West  (Cambridge: Harvard University Press, 1997).

The Working of Herbs, Part 4: The Herb Monograph

By Anne Stobart
In my previous posts I have raised issues about looking at medicinal herbs in terms of contemporary and modern understandings (see the Working of Herbs, Part 1, Part 2 and Part 3). My interest stems from my background as historical researcher and also as a trained clinical practitioner of herbal medicine in the UK. I have spent over a decade teaching students on one of the few professional practitioner degree courses in the UK at Middlesex University.
So, how do we get accurate information which is based on modern knowledge for each of the herbal ingredients in a recipe? What referenced sources are readily available, and how do we recognise when information about herbs is reliable?  Here I suggest that a way forward is to look for sources that can provide a good herb monograph.

What is a herb monograph?

Essentially, a modern herb monograph is a compilation or report about a specific herb providing detailed information which is organised in a logical structure, including botanical and pharmaceutical information.[1] Monographs can vary in length, from a single page summary to a multi-page text, and may include the following details:

  • botanical and common name(s)
  • identifying characteristics of the plant
  • traditional uses
  • constituents
  • herbal actions
  • research findings
  • clinical indications
  • preparations and products
  • prescribing information with dosages
  • references

Published herb monographs have served an important role in ensuring the quality of herbal supplies by including detailed descriptions of their physical characteristics, particularly of dried herbs in trade.[2] More recently, some excellent updated herb monographs have been compiled by professional clinical practitioners and include safety information such as contraindications and potential side effects, alongside extensive listings of research papers.[3] Such monographs provide a basic foundation for herbal practitioners in training (often students are asked to compile their own). If herb monographs are comprehensive and effectively referenced, with the inclusion of key plant constituents and herbal actions, they should also be helpful to historical researchers. Finding a good range of reliable herb monographs can be a challenge …. but there are some sources online.

Where can you find herbal monographs online?

Figure 1. American Botanic Council monographs
Figure 1. American Botanic Council monographs

(a) The American Botanic Council  has published an extensive set of herbal monographs which are available online to subscribers, particularly useful for herbal clinical practitioners.

(b) European Medicines Agency. These (not very aptly named) ‘community herbal monographs’ are published online, forming the basis of herbal medicine and traditional product regulation in the European Community. A limited range of herbs is covered: for example ash, bittersweet, horehound, lime flower, liquorice, oregano, primula, thyme. Each monograph includes common names in all languages within the European Community and this may be of interest for some researchers.

Figure 2. World Health Organization Monographs
Figure 2. World Health Organization Monographs

(c) World Health Organisation. A range of monographs were published in four volumes between 1999-2005 and some give extensive detail online, including herbs such as cinnamon, lemon balm, mallow, rosemary. Volume 1 can be found online and links to the other volumes are provided. An index is provided for each volume with listings of plant constituents.

(d) Several online subscription-based sources of monographs are regularly updated with the latest clinical research findings. These can provide considerable detail on individual herbs, for example the Natural Standard database where both summaries and extensive versions of natural product monographs can be obtained. Some other collections of information appear to draw on these monographs, for example, the Plant Profiler‘ pages.

Figure 3. Natural Standard on 'Foods, Herbs and Supplements'
Figure 3. Natural Standard on ‘Foods, Herbs and Supplements’

What makes a good herb monograph?

There is no agreed standard for herb monographs and length of monograph is not a guide to quality of information! Some good sources are ‘potted’ versions [4] but others may give very limited information and lack references. Be wary of the summary such as Herbs at a Glance which provides a condensed version of details drawn from other sources, and lacks clear referencing. Or WebMD (for example on Hyssop) which rarely indicates herb constituents and provides very limited references. On the other hand, some lengthy monographs can be so repetitive and technical to the point that it is hard to understand them. Overall, a ‘good’ monograph source should ideally be comprehensible and be well-referenced, but there are several key things to look out for – these are herb constituents and actions.

Need to know herbal constituents and actions

With the rise of evidence-based medicine, many plant monographs are being revised to exclude traditional uses of plants unless some published research has been carried out. This can narrow down details considerably. For historical researchers the modern designations given to health complaints are not necessarily appropriate, indeed sometimes there is no way to identify a specific condition in the past. However, if it is possible to identify herb constituents and associated actions then we can make sense of the many ways in which a herb might be used. Herbal actions are closely connected with plant constituents – for example, an astringent action or drying effect is found in herbs which are rich in tannins. – this may be appropriate in numerous internal and external complaints, for example, from injuries with blood loss to weeping sores. Monograph sources which provide details of plant constituents and herbal actions are definitely worth seeking out and the references below [3 and 4] are useful examples.

Conclusion

The herbal monograph provides an organised set of information about an individual plant, ideally giving details of traditional uses, constituents, actions, and research findings with references.  A reliable herbal monograph saves a lot of time and effort searching for evidence. In my next post I consider further detail about plants in a particular recipe in terms of their active constituents and medicinal actions.

Notes

[1] A useful web site in the US which outlines finding and using herbal monographs is run by Bastyr University.

[2] Such information is still useful for bulk herb supplies in the pharmaceutical trade, for example William C. Evans, Trease and Evans’ Pharmacognosy, 16th ed (Elsevier, 2009). Also see British Herbal Medicine Association Scientific Committee, British Herbal Pharmacopoeia (Bournemouth: BHMA, 1983). Some highly detailed US monographs are individually published, such as Roy Upton, ed. American Herbal Pharmacopoeia and Therapeutic Compendium: Willow Bark, Salix Spp. Analytical, Quality Control and Therapeutic Monograph. (Santa Cruz: America Herbal Pharmacopoeia, December 1999).

[3] An authoritative text compiled by herbal practitioners is that of Kerry Bone and Simon Mills, The Principles and Practice of Phytotherapy: Modern Herbal Medicine  (Edinburgh: Churchill Livingstone, 2000). This text is currently being re-issued in expanded form (and would be a good Christmas present for a herbal practitioner!).

[4] For example, the useful brief herb descriptions in Potter’s New Cyclopedia (covering many native and exotic herbal remedies) which have been considerably revised, to the extent that it may be preferable to locate an older edition such as R. C. Wren, Elizabeth M. Williamson, and Fred J. Evans. Potter’s New Cyclopaedia of Botanical Drugs and Preparations, rev. ed. (Saffron Walden: C. W. Daniel, 1988).

The Working of Herbs, Part 2: Take One Herbal Recipe

By Anne Stobart

In the first post of this series, I flagged up some problems in finding out how herbs might work in a medicinal recipe. The question of medicinal herbs and their historical efficacy is a rather difficult area.[1] Through study of one recipe, I hope to provide pointers to useful sources, to indicate their relevance and to suggest caution where appropriate. Any recipe would work, but the one I have chosen is of particular interest because it has cropped up several times in my study of the late seventeenth-century recipe collections of a Devon household.

A water for After throwes

The receit of the water for affter Throwes.
The receit of the water for affter Throwes.

Take two hanfull of Isope [hyssop] two of peneroyall and two hanfull of Groundsell one handfull of wild mints two hanfulls of balme: These hearbs Cleane pickt and Sume fare water put upun all these hearbs togeather wash them Claine [‘and lay them in’ crossed out] then lay them in a pott or Earthen vessell: Shred these hearbs and put them in a quart of Spring water and let them lye in the water for a day and a night: then still the hearbes and water togather in a rose still then let the Glass bottle stand in the Sume Sinnce two Months Close Stopped from andy Ayre it Makes the water mush better. [2]

We will have to assume for this discussion that these plants are correctly identified as hyssop, pennyroyal, groundsel, wild mint and balm–although plant identification is another uncertain factor in considering recipes! Ideally we need to know:

  • the seventeenth-century indications for these plants.
  • the key constituents.
  • the likely physiological actions of these constituents.
  • the potential combinations of herbs in a preparation.
  • the dosage and its likely effects in the body.
Hyssop (Hyssopus officinalis)
Hyssop (Hyssopus officinalis)

My first step is to explore Internet sources using hyssop as an example.The Internet brings a wealth of information, but finding out about a particular medicinal herb can be frustrating. This problem is worse if you seek a ‘historical’ source. Many sites readily repeat information about ‘traditional’ uses without reference to sources. For example, numerous sites claim that hyssop has been used for millennia and dates back to the Bible. If you search for ‘herbal medicine hyssop’ in Google, you are likely to draw up Wikipedia, Mrs Grieve’s herbal, commercial websites offering herbal medicines and medical databases.

Relatively few of these sites give accurate historical background. However, a reasonable starting point is Maud Grieve’s A Modern Herbal, which still provides more detail than most sources on medicinal constituents, actions, uses and preparations.[3] First published in 1931, the book is good value as a secondhand hard copy purchase and provides succinct information on many plants. Grieve draws on a variety of classical to early modern sources for constituents, medicinal actions and uses. But… A Modern Herbal needs considerable updating.

A more recent publication from Tobyn et al. follows selected herbs in texts from Dioscorides onwards, including hyssop, and provides details of therapeutic use with constituents and clinical research evidence.[4] Although limited to 27 plants, this text has a useful overview of relevant authors from classical to modern times.

Internet searching can be confusing if you are looking for reliable sources on historical use of plants and their consituents and medicinal actions. In my next two posts, I will outline some qualities and indications of the herbs in this recipe and the benefits of locating a good quality herb monograph.

Notes

[1] For example: John K. Crellin, ‘Revisiting Eve’s Herbs: Reflections on Therapeutic Outcomes’, In Herbs and Healers from the Ancient Mediterranean through the Medieval West: Essays in Honour of John M Riddle, edited by Anne Van Arsdall and Timothy Graham (Farnham, UK: Ashgate, 2012, pp.307-27).

[2] ‘The Right Honorable The Lady Receipt Booke Anno Dom 1690’, p.82, Ugbrooke House, Chudleigh, Devon. My thanks to Lord and Lady Clifford for permission to access their private archive.

[3] Maud Grieve, A Modern Herbal: The Medicinal, Culinary, Cosmetic and Economic Properties, Cultivation and Folklore of Herbs, Grasses, Fungi, Shrubs and Trees with All Their Modern Scientific Uses. First 1931 ed. (London: Penguin, 1980).

[4] Graeme Tobyn, Alison Denham, and Margaret Whitelegg, The Western Herbal Tradition: 2000 Years of Medicinal Plant Knowledge (Edinburgh: Churchill Livingstone/ Elsevier, 2010).