How have plants supported the health of mankind through millennia? How have they been discovered to have medicinal properties of some sort? How did this develop, and what does the future hold? These are just a few of the fascinating facts that Dr Jenny Stephenson explained. She also pointed out that the talk was not about herbalism, but plant-based medicines.
A recently retired GP with a longstanding interest in botany and illustration, Jenny explained that at least 30 per cent of drugs used today by GPs had origins in plant chemistry. The active chemical, or alkaloid, in each plant is used for its medicinal properties, and have been shown in many cases to have, for example, anti-inflammatory or antibacterial action. The plant makes these alkaloids for its own benefit, for example to deter insects from eating it.
The talk commenced with an overview of ancient civilisations and the development of medical theories in China, Asia and the Arab world. The Trade Routes spread the writings and recipes of these learned people, together with their medicinal plants, to Europe. From there, Europe benefitted and was also able to source exotic plants (like cinchona, or quinine – used in treating fevers) and spices, never before seen and used. Early research and study were performed in the Society of Apothecaries and Hans Sloan at Chelsea, together with other doctors along the way. With time, theories were proved or disproved, and this stimulated further research and enquiry.
We were shown illustrations of common medicinal plants such as Foxglove (Digitalis purpurea), Deadly Nightshade (Atropa belladonna), and willow (salix) and learnt that although these are considered fairly toxic, they were used as medicines in small doses or topically. Some were used for their propensity to produce vomiting and diarrhoea, with the aim to ‘remove disease’ from the body. The talk brought into relief the wonder of this natural chemistry all around us, and concluded with a discussion of the use of plant-based materials and alkaloids in the constant hunt for new pharmaceuticals.