Category Archives: herbal medicine

The Working of Herbs, Part 8: A Protocol for Evaluating Herbal Efficacy

By Anne Stobart

In a series of posts I have explored how we can know whether herbs might have really worked. It seems quite a while since the first post where I raised some historiographical questions (Part 1). In this eighth and last post of the series I want to conclude with (a) an overview of whether the herbs in a selected recipe might have had some efficacy and (b) a protocol for how historical researchers can approach the question of ‘Did the herbs work?’.

Did the herbs work in this recipe?

The recipe I originally picked to consider is the ‘water for affter Throwes’ (Part 2) which was much copied in a privately held seventeenth-century household recipe collection in South Devon (see Figure 1). A ‘throw’ is a ‘violent spasm or pang’, while ‘throwes’ refers to ‘labour-pangs’ (Oxford English Dictionary). Thus the ‘after throwes’ may have meant pains related to the expulsion of the placenta through uterine contraction, a normal part of childbirth (usually within 15–30 minutes of giving birth), or may have been related to more general pains in the hours following birth.

Figure 1. A water for affter Throwes (Lord and Lady Clifford recipe collection, 1689, in private archive, South Devon).
Figure 1. A water for affter Throwes (Lord and Lady Clifford recipe collection, 1689, in private archive, South Devon).

So back to my original question about this particular recipe, as to whether the herbs would have had any effect? This recipe for the ‘after throws’ contained five plants (hyssop, wild mint, groundsel, pennyroyal and balm). The historical indications (Part 3) for most of these plants are based on warming qualities, and longstanding use of several of the plants in women’s conditions including promoting the ‘courses’ (menstruation) and in childbirth-related contexts.

Based on today’s knowledge of constituents and their effects, this combination of herbs provides for a number of possible actions including both stimulant and anti-spasmodic effects on the uterus. The aromatic distilled herbal constituents would include terpenes to provide both antispasmodic relief (from the pains of afterbirth) and uterine stimulation (to help ensure that the contents of the womb are expelled after childbirth). Thus, this combination of herbs might not have a single effect but provides for several relevant and, at first sight, apparently opposite actions (antispasmodic and stimulant). However, it is likely that stimulating more effective uterine expulsion could help to reduce pains after birth, so the overall effect would be the intended one. Such herbal combinations, with a diverse range of therapeutic effects, appear often both in modern and historical contexts.

So the herbs in this recipe could have been effective. However, this effect would depend on the dose given. One version of this recipe indicates that it was made to be given as a drink (‘giue a gill of this water milke warme with some sugar, in it to the patient before sleepe after deliuery being laid in bed first’, Figure 1). Some therapeutic effect is possible since a ‘gill’ is a quarter of a pint (around 150 ml) though it is not feasible to gauge this accurately.

How to approach the question ‘Did the herbs work?’: A draft protocol for considering herbal efficacy

Herbal medicines in a variety of containers] Tacuini sanitatis Elluchasem Elimithar medici de Baldath, de sex rebus non naturalibus, Joannem Schottum, 1531 p. 111. Courtesy of the National Library of Medicine.
Figure 2. [Herbal medicines in a variety of containers] Tacuini sanitatis Elluchasem Elimithar medici de Baldath, de sex rebus non naturalibus, Joannem Schottum, 1531, p. 111. Courtesy of the National Library of Medicine.
I have argued that further understanding of  the way in which particular herbs might work can be assisted by use of good quality herbal monographs (Part 4) which identify constituents and herbal actions (Part 5 and Part 6). Additional considerations are the many ways in which a recipe might be prepared (Part 7) and dosage (this post, Part 8). My posts have dipped into a few examples – so much more could be said!

Overall, the protocol which I have followed involves the following steps:

(1) Clarify the recipe purpose and identify the recipe ingredients (including species and parts of plants)

(2) Identify sources for contemporary indications for the plants (for example based on printed herbals or medical advice books)

(3) Locate reliable modern sources on the plant constituents and actions (such as a referenced monograph)

(4) Consider the extraction processes and form of preparation, possible interaction of herbs, and the dosage (if known)

(5) Summarise the contemporary understanding of the plants alongside their potential efficacy according to best scientific evidence.

An assessment of (3) and (4), evaluating the herbal constituents and actions as well as the form of preparation, could be assisted by linking up with a clinical herbal practitioner. I hope that such partnerships can be further developed so that we are more able to understand potential efficacy. Of course, even if we understand today that the medicinal herbs might have been efficacious, this does not provide evidence that the recipe was used!

Conclusion

I started out on this series of posts to think through how we can use today’s knowledge about plants in interpreting the past. It bothered me that much information on herbs is so readily repeated without adequate referencing of sources. I hope that I have made some useful suggestions in these posts about how to find and use reliable sources. I would welcome queries and the thoughts of others on the ‘Working of Herbs’.

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).