Most people think of herbal medicine as a distinctly ‘alternative’ option – something that you might try for a cough or cold that won’t budge, but not for life-threatening illnesses. Medical historian Dr Johannes Mayer, however, takes it all much more seriously: he believes that the herbal remedies described in medieval texts can provide excellent starting points for highly effective modern treatments, even for diseases such as cancer. And he is not alone, as his work has already attracted the attention (and funding!) of pharmaceutical giant GlaxoSmithKline.
The focus for Dr Mayer’s research group at the University of Würzburg, Germany, is monastic medicine (Klostermedizin in German). For the past 30 years, group members have been sifting through monastic manuscripts dating from the 8th century onwards, translating and publishing details of plant remedies and the ailments that they are intended to treat.
Their work moved from the historical towards the more scientific some 14 years ago, when the group received a visit from a manager at GlaxoSmithKline. When the visitor asked “What is monastic medicine? Is it praying or something?”, Dr Mayer explained that in fact it meant elucidating the herbal treatments documented by monasteries and investigating their physiological effects.
That visit led to a research group being established at the university, with sponsorship from GlaxoSmithKline, to look for effective modern remedies derived from medieval monastic knowledge. So far the collaboration has led to the development of some products to treat the common cold, sold under the appropriately named brand Abtei (German for ‘abbey’). The group now has other links with pharmaceutical companies, as well as with Würzburg University Hospital.
The initial source of such fruitful results is the huge range of historical texts. “First we tried to research the plants that were documented in monasteries used in the early and higher Middle Ages, between the 8th and 12th centuries,” says Dr Mayer. “But now we are researching the whole history of medicinal plants in Europe up to the modern day, looking for indications of what might be useful.”
The research involves several steps: translating the texts (often from medieval Latin), identifying precisely which plant was used for which treatment – no easy task given the inconsistent and varied common names used for many plants – and then finding the active ingredients.
Some of these ingredients are then tested in laboratories at Würzburg University Hospital or at their partner pharmaceutical companies. For example, scientists in the ear, nose and throat department at the hospital are currently testing the effect of water- and alcohol-based extracts of Osmunda regalis (old world royal fern) and Chelidonium majus (greater celandine) on cultures of ear cancer cells. Finally, a few promising leads have been passed on for development as potential new drugs, undergoing clinical trials and other testing to conform to legislative requirements. If the fern and celandine extracts prove effective, for example, the clinical trials will be carried out at the hospital.
This complex process is reflected in the multidisciplinary expertise of Dr Mayer’s team, which comprises academics from a variety of backgrounds: historians of medicine and scholars of Latin and ancient Greek, plus chemists, biologists and pharmacists – all of whom are needed to fully understand the medieval recipes. There are also outside specialists that the group can call on – including a Cistercian monk who is a biologist.
Dr Mayer’s own background is in history. “I first studied history, and then the history of medicine and that’s how I found out that we didn’t know what plants they really were using in the Middle Ages. So I started to make a database about historical plants used in Europe,” he says.
Although most of the key texts are written in Latin, in many cases this is a translation from earlier texts written in Arabic, some of which also contain knowledge preserved from ancient Greek authors such as Aristotle. As Dr Mayer explains: “In the early Middle Ages there was not much literature here in Europe, and Pliny the Elder (23-79 AD) was the most important antique author for monastery medicine. Then in the 11th century, they started to translate Arabic texts into Latin, and so a lot of new plants came into European medicine.”
One example of this is Alpinia officinarum, a plant used to treat respiratory problems and also for relaxation. Although this plant is endemic to Europe, its medicinal use started only after the Arabic medicine texts arrived.
In time, the translation of Arabic texts came to overshadow the epoch of monastic medicine because it led to the foundation of many universities in the 13th century. So from this time onwards there were professional physicians, and monastic medicine became less important.
There was, however, a new period of monastic medicine in the 16th century, because many missionaries sent to the newly discovered lands in the Americas were monks. “The missionaries were interested in finding out what the native Americans did with the special plants in Central and South America. So they wrote books about the use of these plants, and sent the information back to Europe,” says Dr Mayer.
Today, Dr Mayer’s group collaborates not only with industry but also with working monasteries, advising on special plants to grow in the monastery gardens and on their uses in tea-style infusions and in lotions. They even run courses for the public at the local monastery in Oberzell – which brings in some useful additional funding for the group.
Dr Mayer has found that cultivating plants is not always the best way to obtain them, either because it’s hard to get them to grow or because the ingredients obtained from wild plants are better than those from cultivated plants.
“You must go out in the woods to find these plants, like Arnica montana; it’s very difficult to cultivate the plants and to get enough flowers,” he says. “But in the wild it grows well.” Which is perhaps a fitting reminder of the fabulous complexity of nature, as evident today as it was to the people of the Middle Ages.
Although many plants have been used traditionally in medicine, few have been investigated scientifically to find out whether they are indeed safe and effective remedies for the conditions they are said to treat. In addition to laboratory studies, such as those carried out by Dr Mayer’s group, the clinical efficacy of a treatment also needs to be tested.
- The treatment being studied is compared to one or more alternative control treatments, including a placebo (one that has no direct pharmacological effect, such as a sugar pill).
- Participants in the trial are randomly assigned to the different treatments.
- Neither the patients themselves, nor the people giving them the treatment, know which treatment each has been given; this is called double-blinding.
- The trial needs to have enough people taking part so that the results could not easily have occurred by chance (the more data there is, the less likely this is to happen).
While this all may seem very complicated, without these precautions the results could easily be due to factors other than the treatment itself, so they would not be reliable. Even when a high-quality study has been done, the results need to be examined alongside those from other such trials to see what the total evidence suggests. (To learn more about clinical trials, see Garner & Thomas, 2010, and Brown, 2011.)
Herbal treatments that are supported by good-quality evidence include these:
- Artichoke (Cynara scolymus) can aid digestive problems as it increases the flow of bile, which helps to digest fats. See The Handbook of Clinically Tested Herbal Remediesw1 for evidence.
- Cranberry (Vaccinium macrocarpon) may help prevent urinary tract infections: drinking cranberry juice is thought to make bacteria less able to adhere to walls of the urinary tract. (However, a recent evidence review concluded cranberry is less effective than previously thought.) See the Cochrane Collaboration websitew2 for evidence.
- St. John’s wort (Hypericum perforatum) is as effective in treating depression as some pharmaceutical antidepressants, but like them it can also have side effects. See The Handbook of Clinically Tested Herbal Remediesw1 for evidence.
- Brown A (2011) Just the placebo effect?Science in School21: 52-56.
- Garner S, Thomas R (2010) Evaluating a medical treatment. Science in School 16: 54-59.
- Schellenberg R et al. (2004) The fixed combination of valerian and hops (Ze91019) acts via a central adenosine mechanism. Planta Medica70(7): 594–597
- Scholey AB et al. (2008) An extract of Salvia (sage) with anticholinesterase properties improves memory and attention in healthy older volunteers. Psychopharmacology198:127–139. doi: 10.1007/s00213-008-1101-3
- w1 – A good compilation of evaluative information about herbal treatments is: Barratt M (2004) The Handbook of Clinically Tested Herbal Remedies Volume 2. USA: Haworth Press, Inc. ISBN: 0-7890-2724-0.
- w2 – The Cochrane Collaboration produces reviews of clinical trials data, including trials of herbal medicines, which can be accessed via the Cochrane website.
- The most recent review of evidence for the effectiveness of cranberries in the prevention of urinary tract infections showed no significant benefit.
- The Science and Plants for Schools website offers a teaching resource about medicines and drugs from plants. Using a card-game format, the activity is suitable for teaching students aged 16+ about plant-derived pharmaceuticals, or it could be used to introduce younger students to poisons.
- To learn more about Arabic science and medicine between the 7th and 17thcenturies, see:
- Khan Y (2006) 1000 years of missing science. Science in School 3: 67-70.
- To learn more about the work of Dr Mayer’s research group, visit the Forschergruppe Klostermedizin website (in German).
Originally published by Science in School 27, 08.16.2013, under the terms of a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported license.