A team of UK researchers has found some hope in an unexpected place: a medieval manuscript.
A 1,000-year-old natural remedy made from onion, garlic, wine and bile salts has shown antibacterial potential, with promise to treat diabetic foot and leg infections, new research published Tuesday suggested.
Known as Bald’s eyesalve, the treatment has the potential to tackle biofilm infections — communities of bacteria which resist antibiotics — making them much harder to treat, the researchers said.
Biofilm infections are estimated to cost the United Kingdom alone more than 1 billion pounds ($1.3 billion) every year, the study said.
“This is the real detailed hard slog of finding out more information and seeing if it really could be developed into something clinically useful,” said Freya Harrison, a microbiologist at the School of Life Sciences at the University of Warwick in the UK and an author of the study.
“We think it has particular promise for treating diabetic foot infections. They are the ultimate, super-resistant biofilm infection. They are a huge health and economic burden. They really can become untreatable,” she said.
“There’s a high risk that these diabetic foot ulcers are completely resistant to any antibiotic treatment. Then there’s a risk of a person developing sepsis … and people end up having their foot or lower leg amputated.”
Early medical text
The concoction was among the recipes for medicines, salves and treatments in “Bald’s Leechbook,” an Old English leatherbound book held in the British Library. It’s one of the earliest known medical texts.
“When you read it as a microbiologist, you think that it’s got to do something because every ingredient in it has some antibacterial activity when you test it in a test tube. It seemed like a sensible one to put together,” Harrison said.
“It’s also very clearly targeted to a bacterial infection from the description of the symptoms in the book.”
They made the mixture using garlic and onions purchased from ordinary supermarkets or greengrocers, while the wine was an English white. The bile salts come from a cow’s stomach.
The research project came about by chance after Harrison, who has a passion for medieval history and enjoys historical reenactment, heard about the book. She teamed up with former colleague Christina Lee, a specialist in Old English at the University of Nottingham, where Harrison used to work.
“To be honest, we didn’t go into this thinking that five years down the line this would be something we would have translational funding for. We thought it would simply be an interesting piece of microbiology.”
Curiously, Harrison said that “Bald’s Leechbook” also contained a remedy for malaria using wormwood, which was endemic in parts of England in the early medieval period.
“All of that time essentially the same remedy was sitting in an English medieval text but no one had taken it seriously,” she said.
Antibiotics underpin modern medicine, and if they lose their effectiveness medical procedures like surgery and chemotherapy could become too dangerous.
One of the key findings from the study was that it was the mixture of natural products, rather than a single compound, that gave Bald’s eyesalve its “potent anti-biofilm activity.”
The team has also been testing the safety of the mixture and preliminary research expected to publish soon shows “it has a promising safety profile,” Harrison said. The next step then would be to chemically characterize the mixture and begin patch testing on human skin, but the latter had been delayed by the coronavirus pandemic.
Harrison said the nature of researching a combination of ingredients, rather than single plant or compound, could make the development and regulatory approval process more time consuming.
“In the next year we hope to have some idea of the chemistry, a better idea of the safety, and then it would be a case of saying is it actually effective but I’m sure you’re aware this work does take a long time,” Harrison said.
“It’s important to recognize that most exciting-looking, potential anti-microbials ultimately fail to translate into a product. So we have to be very realistic and do a lot of detailed work to see if it will be useful.”