Researchers at the University of Warwick have found naturally occurring anti-microbials, which could be used to help tackle antibiotic-resistant infections, in a 1,000-year-old eye salve.

Scientists examined natural remedies used in early medieval history in its research investigating alternatives to antibiotics, as bacteria becomes increasingly resistant to modern medicine.

Using Bald’s Leechbook, a collection of medical remedies written in old English and first published in Winchester between 925 and 950AD, as a starting point, researchers recreated a treatment known as Bald’s Eyesalve, which used onion, garlic, wine, and bile salts, amongst other ingredients to treat common eye infections.

Garlic contains allicin, which is known to help reduce inflammation and offer antioxidant benefits. However, scientists say it was the combination of ingredients that proved particularly powerful in making the salve effective.

The reconstructed remedy was found to have strong anti-bacterial activity against both a range of pathogens but also against five bacteria which were part of a multicellular biofilm, biofilms are often highly resistant to antibiotics.

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Dr Freya Harrison, from the University of Warwick, said: “We have shown that a medieval remedy made from onion, garlic, wine, and bile can kill a range of problematic bacteria grown both planktonically and as biofilms.

“Because the mixture did not cause much damage to human cells in the lab, or to mice, we could potentially develop a safe and effective antibacterial treatment from the remedy.

“Most antibiotics that we use today are derived from natural compounds, but our work highlights the need to explore not only single compounds but mixtures of natural products for treating biofilm infections.

“We think that future discovery of antibiotics from natural products could be enhanced by studying combinations of ingredients, rather than single plants or compounds,” Dr Harrison added.

“In this first instance, we think this combination could suggest new treatments for infected wounds, such as diabetic foot and leg ulcers.”

Co-author Dr Jessica Furner-Pardoe, said: “Our work demonstrates just how important it is to use realistic models in the lab when looking for new antibiotics from plants.”

Dr Furner-Purdoe added: “Although a single component is enough to kill planktonic cultures, it fails against more realistic infection models, where the full remedy succeeds.”

The research followed a similar study by Nottingham University in 2015 – watch the YouTube video above to find out more.