In spite of a wet and windy night there was a very good turnout at our November meeting. Fifty people, including several visitors, were entertained and informed by Dr Henry Oakeley, the Garden Fellow of the Royal College of Physicians medicinal garden.
The garden has 1300 plants in a relatively small space and has been in existence since 1965. Traditional medicinal plants from various cultures, plants with known medical value and those connected with physicians are arranged in beds, mainly according to their geographical origins.
Dr Oakeley’s talk explored why and how plants have been used as medicines for the past 3,000 years. He began by taking us back 300 million years when the plants which were edible did not survive the evolutionary process and those that were poisonous and tended to be bitter and foul tasting were left untouched and therefore did survive. We learnt that most plants are, to some degree, poisonous and that 20% of modern medicines owe their origin to plants. Even some of the plants which we eat today are poisonous, for example yams (large underground tubers) – some of which are poisonous in their raw state but by cooking or soaking in water can be rendered harmless.
In answering the question of why people use plants for medicines Dr Oakeley related the germination and life cycle of plants to the Ancient Greek Doctrine of Humours. This theory held that the human body was filled with four basic substances, called humours, which are in balance in a healthy person. All disease was supposedly caused by an imbalance of these humours and through vapours inhaled or absorbed by the body. They, in turn, were related to the four elements of earth, air, fire and water, associated with dry, cold, warm and moist conditions needed for the survival of both plants and animals. As we are aware, seeds need moisture, warmth and light to germinate and grow and some seeds require fire or cold to make them viable. This theory formed the basis of Western medicine and had a huge influence up to the 19th century. This was illustrated by the belief that scurvy in sailors, who spent many months at sea, was as a result of the hot air below deck and that when they disembarked the land provided the cool air they needed to recover. We now know, of course, that their improvement stemmed from the vitamin C in the fresh fruit and vegetables they were able to obtain on shore.
Dr Oakeley then went on to discuss the Doctrine of Signatures. It was believed that the Creator “signed”, by shape or colour, all plants to indicate their uses for mankind. For example, arnica and calendula flowers have a centre that looks like an eye and therefore they were used to treat eye conditions.
The leaves of pulmonaria are shaped like a lung and were used to treat diseases of the lung,
Dr Oakeley gave many more examples and spoke at some length about St John’s Wort, the flowers of which are traditionally gathered on Midsummer Day and thought to be imbued with the power of the sun – a light that shines in the darkness – used originally for people possessed of the devil. It went out of use for 200 years but is now found to be effective in treating mild depression. However, it is banned as an “across-the-counter” medicine for self medication for depression and there are 30 groups of medicine with which it interacts adversely.
We learnt about many of the plants that come from medical history, those that contain atropine that enter the nerve receptors and block reaction of the nervous system, those that provide pain relief, those that provide local anaesthetic and those that inhibit cell division. Many of the plants we know well, poppy, chilli peppers, capsicum, foxglove, ammi majus, aloe vera, star anise, yew – to name but a few are used extensively in medicine today and plants which have proved to be beneficial are now breed specifically to provide a greater level of useful compounds/therapeutic agents within each plant.
I have touched only very briefly on Dr Oakeley’s fascinating and comprehensive talk, but if you would like to hear more he conducts garden tours on the first Wednesday of each month, starting at 2pm, except in winter, at the Royal College of Physicians, London NW1 4LE
» Please do join us for the Gardeners Association Christmas Party on Tuesday 18th December, 8pm in the Village Hall