March 2018 Blog
by Owen Durant
Until the second half of the 20th century, most people in the Western world used some form of natural medicine. With the advent of universal health care and the availability of affordable antibiotic drugs, many common infections were effectively eradicated and the popularity of natural medicines declined. Yet, large swathes of the world's population were untouched by this medical revolution - with up to 80% continuing to rely, in some form, on natural remedies handed down by millennia-old traditions.
Where and when these healing traditions began is something of a mystery. Anthropologists suggest that - in response to their environment - early humans developed a 'sensory ecology' based on the appearance, smell, touch and taste of plants, through which they learned to find natural medicines. It has also been suggested that people also learned about medicinal plants from studying interactions between animals and plants.
In Ancient Egypt and China mythical 'bringers of knowledge' were believed to have advanced popular understanding of how the natural world functioned. In Egypt the god Thoth and, in China, Shennong - the 'god farmer' - were said to have brought knowledge of medicine and agriculture which was passed down through oral legends.
This method of knowledge transmission began to change around 3000 BC. Ancient Egyptians documented their medical knowledge into hieroglyphic texts in which lie the roots of Greek medicine and alchemy. Commonly misunderstood as the attempted manufacture of gold, alchemy was actually a sophisticated blend of astrology, sorcery, and 'primitive' chemistry. The widespread practice of alchemy in natural medicine would continue until the scientific revolution of the 17th century.
Hippocrates (460-370 BC) recapitulated some of the ancient concepts of medicine in his Hippocratic Corpus - which would go on to inspire Western medicine and ethics. His maxim "let thy food be thy medicine and thy medicine be thy food" is of continued relevance, even today - underscoring the inseparability of health and lifestyle. Less so, Hippocrates' widely believed humoral theory with its notion of the four inter-dependent humours: black bile, yellow bile, blood, and phlegm.
Around 2,000 years ago in India, Ayurvedic healers consolidated their medical ideas into three books known as the Great Trilogy (the Caraka Samhita, Sushruta Samhita, and Astanga Hridaya). In China, between 200-250 AD, the Shennong Bencaojing (or Pen-Tsʼao ching) appeared - a three volume work describing 365 herbal medicines attributed to the 'god farmer' Shennong, which classified plants according to their therapeutic properties and contained recogniseable 'recipes' for producing medicines.
Dioscorides' De Materia Medica (50-70 AD) provided the first fundamentally Western pharmacopoeia. On his travels in the Near and Middle East, the Greek physician Galen (129- 216) encountered a melting pot of medical traditions and cultures. Unani or Greco-Arab medicine, one such system to arise from this cultural exchange, was codified in Avicenna's classic the Canon of Medicine (al-Qānūn fī aṭ-Ṭibb) which - written in 1025 - remained in popular use until the 18th century.
In Europe, from the late 15th century onwards, new printing technology allowed for the reproduction and distribution of works such as the Canon of Medicine and De Materia Medica, as well as 'herbals' - elaborately illustrated books containing detailed information about the cultivation, production and folklore of herbal medicines.
Until the 16th century medicine was almost entirely plant or animal derived. Swiss born physician Paracelsus (1493-1541) began to devise 'chemical medicines' (e.g. mercury for the treatment of syphilis). He also insisted that medical texts previously published in Latin were translated into languages which 'common' people could understand. Paracelsus' ideas were, at best, viewed with suspicion - they contradicted classical humoral theory which had dictated the way in which illness was viewed and treatment chosen. There seemed to be no reason why medicine should reinvent its entire world view, but Paracelsus' ideas began to spark a quiet revolution. In his own way, Paracelsus offered a roadmap from medieval ideas of humours and herbalism to modern concepts such as dose and drug design.
Across Europe medicinal plant gardens sprang up - first at Padua and Florence (1545) followed by Leiden (1590) and Montpellier (1593). In 1673 the Apothecaries' Company, now known as the Worshipful Society of Apothecaries, founded the Chelsea Physic Garden. In London and Paris scientific societies were formed - rarefied places where the great minds of the day would gather to exchange their findings and put forward bold new scientific theories.
Nicholas Culpepper (1616-1654), an English physician, published the Complete Herbal (1653) which became a best seller and has been in print ever since. Culpepper deliberately sold 'simples' at a much lower price than the controlling apothecaries and, like Paracelsus, a century earlier, was intent on popularising knowledge of herbal medicines. Although Culpepper faced opposition from the medical establishment of his day, his accessible and systematic approach to medicine stimulated wide popular interest.
By 1668 Merck was founded in Germany, setting the scene for the mass production of medicines and the birth of a modern pharmaceutical industry. This drive towards modernity occurred against a backdrop of growing international trade between Europe, Asia and the 'new world' of the Americas. As a result of the British East India Company's explorations into Asia, exotic spices and medicines came into the hands of 'explorer-botanists', apothecaries, and herbalists. This trade in useful plants was accompanied by a growing interest in what we now call ethnobotany - the anthropological and socio-cultural study of the relationship between plants and the people who use them.
Fresh advances in knowledge during the 18th century would lay the foundations for modern prescription medicines, which would ultimately usurp the place of medicinal plants. In 1796, Edward Jenner (1749-1823) discovered small pox could be prevented by administering a vaccine containing a tiny dose of small pox. Samuel Hahnemman (1755-1843) by a similar principle, devised his 'law of similars' - giving rise to homeopathy.
In Victorian England the folk medicine tradition was still thriving, the so-called 'Language of Flowers' became a popular idea with its premise that flowers had innate personalities and emotions, harking back to the animistic world view of early healers, but in 'serious' circles herbalism was increasingly regarded as quaint and old fashioned. Throughout the 19th century huge strides were made in the understanding of plant chemistry. Dmitri Mendeleev (1834-1907) published the first periodic table in 1869; by 1900 Mikhail Tsvet (1872-1919) had devised chromatography - a technique which permitted the rapid separation and visualisation of plant chemicals. Chemists now had tools to categorise plant chemicals and a growing understanding of their structures and properties.
Meanwhile, Germany had become the major industrial producer of drugs in Europe; mass-producing plant-derived drugs such as heroin and morphine. Merck was a key player, with higher revenue than the major British pharmaceutical companies combined. Willow bark (Salix alba) had been recognised as a remedy for aches and fever since antiquity, its active principle salicin was isolated and synthesised by Bayer in 1899 and marketed as Aspirin. The accepted single compound paradigm of modern Western medicine had arrived.
World War II heralded the mass adoption of antibiotics, with the US shipping industrial quantities of Penicillin - isolated and purified from the mould Penicillium - to wounded soldiers on the battlefields of Europe. The post-war introduction of free universal health care (i.e. the NHS) was yet another blow to the popularity of herbal medicines. Although herbalism continued to be practiced, the incentive to use it was lessened by the availability of free health checks and free, or heavily subsidised, prescription medicines.
In the post-war years sophisticated analytical techniques such as High Pressure Liquid Chromatography (HPLC) and Nuclear Magnetic Resonance (NMR) could, with just a small starting sample, identify not only the chemical constituents of a plant, but also the positions and conformations of its compounds. With access to this data, scientific interest in natural medicines increased and the National Cancer Institute (NCI) in the United States embarked upon what remains the largest mass screening of natural products in history - leading to the discovery of the blockbuster drugs Taxol®, Vincristine® and Vinblastine® for the treatment of cancers.
Developments in synthetic chemistry, too, meant that compounds could now be modified and synthesised on an even grander scale. Moreover, the discovery of patterns of chemical distribution in different plant families coupled with DNA profiling, allowed for the identification, purification and standardisation of natural medicines in a way that had previously been impossible. But there were still risks as well as benefits to be gained from natural medicines. Following a spate of deaths resulting from the misidentification and mislabelling of traditional herbal medicines in the 1990s, a traditional herbal registration (THR) scheme was introduced for herbal medicines in the UK.
Today natural medicine is a global business, with the herbal supplements market worth an estimated $107 billion in 2017 and Traditional Chinese Medicine (TCM) $40 billion in China alone. The growing interest in natural medicines has brought with it a host of ethical and moral concerns regarding the ownership of traditional ethnic knowledge (TEK) and the preservation of natural resources. Attempts to address these concerns have been made through global initiatives such as the Convention on Trade in Endangered Species; the Convention on Biodiversity and the Nagoya Protocol.
The debate around natural medicines continues, usually involving issues of safety and efficacy: are natural medicines safe and do they work? It is polarising debate with many rigidly sticking to their chosen system of healing. Can these approaches be reconciled? Ethnopharmacology, the scientific study of the relationship between medicinal plants and the people who use them is perhaps the closest we have yet come to a unifying approach.
One thing is for certain, with the growing popularity of natural medicines we owe it to ourselves to continue finding out more about the ways natural medicines can help or harm us; studying natural medicine and traditional knowledge in the light of hard scientific evidence can assist us in learning the lessons nature has to offer.
Ayres, P. Britain's Green Allies: Medicinal Plants in Wartime. Leicester: Troubador (Matador), 2015
Heinrich, M. & Anagnostou, S., 2017. From Pharmacognosia to DNA-Based Medicinal Plant Authentication - Pharmacognosy through the Centuries. Planta Medica, 83(14-15), pp.1110-1116.
Porter, R. (ed.) The Cambridge History of Medicine. Cambridge: Cambridge University Press, 2006.
Shepard, G.H. 2004 A Sensory Ecology of Medicinal Plant Therapy in Two Amazonian Societies. American Anthropologist, 106, 2, pp. 252-266.
The Journal of Ethnopharmacology
UK Medicines and Healthcare products Regulatory Agency (MHRA)
Owen Durant studied Pharmacognosy at the UCL School of Pharmacy before working as a Natural Product Researcher at the Royal Botanic Gardens Kew. He founded the website phytoversity.com and writes on aspects of plant science, folk medicine and botanical history.