As scientific director of the Institute for the Preservation of Medical Traditions at the Smithsonian, Alain Touwaide is compiling a database of medicinal plants of antiquity. Proficient in 12 languages, he has a PhD in classics from the Catholic University of Louvain (UCL) in Belgium. New Scientist asked him about his mission to unearth lost medicinal knowledge from ancient manuscripts.
What would the ancient Greek physician Hippocrates have used to treat, say, a bad headache?
A cataplasm—or poultice—made of iris mixed with vinegar and rose perfume. And for a chronic headache, squirting cucumber.
What if he had a stomach ailment?
Dates, a hen's broth and cultivated lettuce.
What is the most memorable remedy you've come across?
Spiders' webs. Amazingly, I found spiders' webs and many other materia medica mentioned in the ancient literature when my wife and I visited the shop of a traditional healer in the Turkish city of Konya. We felt as if we had traveled back in time 2,000 years.
How do you find out about these remedies?
I search for them in ancient manuscripts from libraries all over the world—the British Library in London, the Vatican Library or in the many collections housed in the monasteries on the Athos peninsula in Greece. It's what I call my fieldwork. But many manuscripts are also in smaller libraries scattered all through Europe. I also follow the antiquarian book market.
I specialize in the ancient medico-pharmaceutical literature based on Mediterranean flora, and I study the texts in their original language—Greek, Latin, Arabic.
In the hunt for new plant-based medicines, broccoli is a popular target. Has it been used as a medicine in the past?
We have discovered a wealth of data on broccoli in the ancient literature. Originally it was mainly used to treat gynecological disorders. Then from the 3rd century B.C. it was also used for digestive troubles, tetanus and possibly dropsy. In the 1st century A.D., skin infections were the most important illnesses treated with broccoli, followed by troubles of the digestive system.
The ancient Roman Cato felt all Roman citizens should grow broccoli in their orchard to use as a sort of all-purpose medicine, and the Greek physician Galen prescribed broccoli to treat a medical condition that was most probably colon cancer.
Are there other plants mentioned in classical texts that have potential as new medicines?
Walnut, and the herbs black horehound and white horehound. These plants are credited with a disinfectant and anti-inflammatory action in the ancient literature. They appear to be active against the bacterium Staphylococcus aureus, even drug-resistant strains. And red raspberry (Rubus idaeus) is recommended for treating inflammation in ancient literature. In modern-day tests it appears to be active against superficial skin inflammation.
Have any new medicines come out from studying ancient ones?
The best example is artemisin—the malaria treatment derived from the Artemisia plant. Malaria plagued the ancient world, and we have found more than 70 agents to treat it in the Greek medical literature of the classical period, from the 5th century B.C. to 3rd century A.D.—including Artemisia. It was identified quite recently by Chinese pharmacologists on the basis of their ancient literature.
Currently, we have quite a range of plants on our databases that should be tested for the treatment of malaria.
Have you managed to get hold of some of these ancient medicines, rather than just written accounts of them?
Ships often traded natural substances across the Mediterranean, including medicinal plants, so shipwrecks and their cargo are a precious reservoir of material for us. As early as 2002, I suspected that shipwrecks could be a source of information not available anywhere else. Shortly afterwards we heard about what seemed to be medicines, recovered from the wreck of a ship called Relitto del Pozzino, dating from 140 to 120 B.C. We've been lucky enough to receive fragments of these archaeological remains. With DNA analysis we identified the plant components of these medicines: carrot, parsley, onion and sunflower.
We have recently received material from the famous Casa del chirurgo or House of the surgeon in Rimini, Italy, but we haven't analysed this yet.
What have you learned about the way ancient cultures used medicinal plants?
Their medicines were based on a core of 45 plants, which were cultivated in the orchard close to the homes of the patients to be treated.
What is striking from the writings attributed to Hippocrates is that the plants mentioned are very common: hellebore, garlic, mercurialis, celery, leek, flax, anise, beet and cabbage among others. This list is significant because it shows that food and medicines are just two faces of the same coin, and that the best medicine is preventive medicine. Myrrh was also used as an antiseptic, antibiotic agent. If you have a disinfectant and a good range of basic substances with which to treat a broad range of illnesses, you have quite a good therapeutic arsenal at your disposal.
Does your work shed any light on the diseases that were prevalent many years ago?
From the literature we've found that the most important group of diseases were skin infections, followed by those of the digestive system, the urinary tract and gynecological ailments. We don't have explicit data about the epidemiology of the populations we're working on, but we can reconstruct it hypothetically on the basis of texts and human remains.
Do any of the ancient texts contain the sort of case studies we find in modern medical literature?
Yes. We can even consider some of the ancient texts as a series of reports put together like a clinical folder. I remember a description of heart failure in a 12th-century treatise, which is the Greek translation of a work originally written in Arabic. Since the ancient physicians didn't have an overarching notion of heart failure, they fragmented the description into a series of symptoms, each of which was considered as an independent entity, for example, acute pain in the thorax and the back, a feeling of radiating heat. Reading ancient texts requires you to be in a high state of alert because few things indicate clearly what condition is being described. It's up to the reader to be able to translate the description, starting from one key sign and then deciphering further from the rest of the description.
Your work focuses on the Mediterranean regions. Have you looked into the ancient Chinese medical literature?
No. I don't work on Chinese medicine—this is another universe. However, we've started a new research programme on the diffusion of Greek medicine into China, through the Arabic world and India, and, conversely, the trade of medicinal plants from China to the west as far as the Mediterranean. Going with this trade, there was also knowledge.
Have you been tempted to try any of the ancient remedies that you study?
No. I wouldn't practice self-medication! Studying these ancient remedies is a scientific activity for me, not a lifestyle "quest."
This article originally appeared in New Scientist.