An interdisciplinary team of Anglo-Saxon experts and microbiologists have discovered a treatment against modern antibiotic-resistant superbugs in an unlikely place: a 1,000-year-old leatherbound volume called Bald’s Leechbook. This Old English manuscript, currently residing at the British Library, is one of the earliest known medical textbooks.
The centuries-old recipe for treating eye infections calls for two types of Allium (garlic and onion or leek), wine, and oxgall (that’s bile from a cow’s stomach). The instructions, translated by University of Nottingham’s Christina Lee, are incredibly specific: It requires the use of a brass vessel for brewing, a particular straining technique to purify it, and the mixture must be left for nine days before use.
“We thought that Bald’s eye salve might show a small amount of antibiotic activity, because each of the ingredients has been shown by other researchers to have some effect on bacteria in the lab,” Nottingham’s Freya Harrison explains in a news release. Copper and bile salts can kill bacteria, and plants in the garlic family make chemicals that interfere with the microbe’s ability to damage infected tissue. “But we were absolutely blown away by just how effective the combination of ingredients was,” Harrison adds.
To recreate the topical solution, the AncientBiotics team combined equal parts garlic and either onion or leek—finely chopped and crushed in a mortar for two minutes—with 25 milliliters of English wine from a historic vineyard near Glastonbury, BBC describes. Then they added bovine salts dissolved in distilled water, and the whole thing was chilled for nine days at 4 degrees Celsius. They made four separate batches and a control solution that didn’t have the vegetable compounds.
They tested the potion on methicillin-resistant Staphylococcus aureus (or MRSA) cultures in both synthetic wounds (made by growing bacteria in collagen) and in the wounds of infected mice. MRSA is one of our most notoriously antibiotic-resistant microbes. These cells bunch together to create a sticky coating called biofilm, making it difficult for antibiotics to get at them.
The eye salve killed up to 90 percent of the MRSA, they report, though none of the individual ingredients by themselves seemed to have an effect. These results were backed up by mouse tests conducted by a U.S. team led by Texas Tech’s Kendra Rumbaugh, who says: “This ‘ancient remedy’ performed as good if not better than the conventional antibiotics we used.”
Since they weren’t sure about the dosage, the researchers tried diluting the eye salve to see what would happen. The diluted salve didn’t kill the bacteria, but it did interfere with their cell-to-cell communication (called quorum sensing). Blocking this behavior may be another way to treat the infection.
The findings will be presented at the annual Society for General Microbiology conference in Birmingham, U.K., this week.