With antibiotic resistance on the rise, Café Sci presents Dr Freya Harrison from the School of Life Sciences and Bimolecular Science at the University of Nottingham to talk about whether we can find new antibiotics in medieval medical books. Did the Anglo-Saxon methods for dealing with infection work? Is it time to bring back the leech books?
The “ancientbiotics” group is a cross discipline consortium at the university featuring members from the sciences and the humanities. They are looking at how did epidemics spread? Did people develop effective treatments? Did medieval doctors use scientific methods? The Anglo-Saxon period in Britain came between the Romans and the Normans and wasn’t really the dark ages as it’s often described. There was poetry, translation of the classics, jewellery, steel that was not bettered until the industrial revolution and medical books.
These were known as leech books as the Anglo-Saxon word for “doctor” was “leech”. They contained plenty of treatments for skin and topical infections such as Bald’s eye salve (named for the Bald, the author) This treatment had some very interesting ingredients. It contains garlic and another allium (perhaps leek or onion, we don’t’ know the translation of the Anglo-Saxon word) We know that these kill bacteria. It includes wine ie a safe liquid when we know there isn’t much clean water about. Another ingredient is bile salts – these are known to break down fat and the outside of bacteria is formed of fat. Then the whole mixture is put into copper for nine nights and we know that copper has anti-bacterial properties. The final solution is even self-sterilising – a good start.
After making up a batch, it was tested in eye styes where the bacteria forms a bio-film that stops anti-bacterials attacking them. They modelled one of these bio-films and tried Bald’s eye salve on it. After leaving it for twenty-four hours it had killed established Staphylococcus Aureus infections in the artificial wounds – down from a billion cells to just a few thousand left alive. The test has since been replicated 14 times. The individual ingredients were also tested but this effect wasn’t caused by just one of them. Leaving out individual ingredients from the mixture was also not effective. Only removing the copper pot had any appreciable impact. Also, if you make the recipe but don’t wait 9 days it doesn’t work.
Next it was time to test the recipe on animals. Bald’s eye salve killed MRSA in infections in mice wounds. In fact it was more effective than the current last line MRSA drug (note that is in this instance, in this time frame – there’s nothing to suggest that Bald’s eye salve is a new superdrug) It was also tested on other bugs but it wasn’t always effective. This is actually a good thing, it means that it’s not just a bleach.
So, we’ve seen that a 1000 year old recipe can be effective against the bacterial species that it was designed to treat. Can we data mine more of these texts to create a new drug pipeline or were we just really lucky and happened to pick the only one that works? Were particular ingredients used to treat specific symptoms or were the ingredients in Bald’s eye salve used in everything? Garlic and our mystery allium are seen together more often than you’d see by random. Network analysis show how ingredients are connected through their use in recipes. Honey, vinegar and pomegranate are all very common and when some of these are put together they are more effective than the sum of their parts. The big questions is can we find ways of combining ingredients to give active compounds that could be used in the future?
We know that garlic was cultivated at the time so it wasn’t wild garlic that was being used in these recipes. Onion and leek give very similar effects despite being chemically different. Onions and leek together are more effective than either individually. Although we don’t know what type of onions they would have used. The recipes don’t give any specific proportions of ingredients – this indicates that they assume some prior knowledge. However, the books also contain some more esoteric treatments such as crushed bees as a cure for baldness and drinking from a church bell to deal with mental illness. However, there are also a number of recipes that include mouldy bread. Of course this is a source of penicillin, and mouldy bread has been used as far back as the Egyptians.
But why 9 days? Well research has shown that it’s better than just using the mixture straight away, although tests still need to be carried out on 1-8 days. From an Anglo-Saxon perspective, 9 is seen as a trinity of trinities. Other recipes say to leave your mixture in a church until a certain number of masses have been performed. While there is a religious element to this, it’s also a very good way of measuring time before clocks. Some of these recipes last a long time – Bald’s eye salve is effective six months after it’s mixed.
The ancientbiotics team have made some fantastic discoveries but we’re still a long way away from seeing any of these recipes available in your local Boots store. There’s still a lot more testing to be done before they even start using Bald’s eye salve on people but there’s still a chance that one day our newest remedies will actually be our oldest ones.
Author’s Notes
Talk from 09/05/2016 at The Vat & Fiddle – Dr Freya Harrison: Can We Find New Antibiotics In Medieval Medical Books?
Originally published on the On Nottingham website
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