A new use for ancient remedies!

Microbiologist Luke McNally brought a potent potion to the Edinburgh Science Festival...
23 April 2019

Interview with 

Luke McNally, University of Edinburgh


Two brass vessels on a wooden table


We’ve also asked each of our guests to bring something with them to the Edinburgh Science Festival. Microbiologist Luke McNally shows Chris Smith his very potent ancient potion... Be glad you can't smell this podcast!

Luke - This is a medieval antibiotic.

Chris - It's a milky fluid. I presume the jam jar's not medieval?

Luke - No, no. That's modern. I think possibly a Sainsbury's “Taste the difference” raspberry conserve, I think!

Chris - Are you going to take the lid off?

Luke - I will if you if you want a whiff of this. I'll tell the story first of what's in it. We all know antimicrobial resistance; bacteria evolving resistance to the drugs we use to kill them, is a big problem. We're looking all the time for new ways to discover new antibiotics. We need new weapons as bacteria find ways to overcome them. And a group of British scientists, led by Freya Harrison, decided to look in the history books. This is from an Anglo-Saxon medieval medical text called “Bald’s Leechbook”, and it's an eye salve, so it’s used to treat eye styes, which are infections of the follicle of your eyelash. The recipe for this is to mix equal parts either onion or leek, they're not sure from the translation of the medieval text which it was, garlic, wine and Ox gal which is the bile from an ox, and to leave it for nine days to brew in a brass vessel, and then afterwards strain it. And then you have this eye salve, which is meant to be applied with a feather to the eye to cure your stye.

Chris - Have you tried it?

Luke - I haven't tried it, no. Unfortunately this is only half strength, and this is what's really interesting about this: I couldn't get hold of any ox bile, so it's only about half strength. We always think that, you know there's all these ancient approaches to medicine, and often we think of them as very non-sophisticated. We know garlic is anti-microbial, but in this recipe they actually showed that it's the combination of the ingredients. Any of the ingredients on their own doesn't give you the full effect. It's really this unique combination that does it.

Chris - If you put that on a petri dish with some Staph aureus that causes sort of eye and stye infections and things, will it kill it?

Luke - Yes it will. It kills MRSA really, really well, which most people have probably heard of - a hospital superbug. They did mouse infections and it's able to kill the MRSA in those as well. At the moment there’s a lot of people trying to figure out exactly how it works, because it could help guide our discovery of new antibiotics.

Chris - Just a general question: if you actually put that on your eye, would I have an eye left afterwards? Cure my MRSA infection but it would also render me blind, possibly, or would it be okay?

Luke - Possibly, the smell might give you the answer, go on.

Chris - Oh my goodness. Actually, hang on, it's growing on me. That’s okay, actually.

Luke - It's not too bad. Garlic is the is the dominant smell.

Chris S - Give this a whiff, Beth, do you like this?

Beth - I will concur. Garlic is the very dominant smell.

Chris - A lot of garlic in there. Have you got any of that in your museum then, Sophie.

Sophie - Possibly in the brasserie.

Chris - You could have after the show. We might donate it. I mean how much of a problem is superbug infections now? Because we are increasingly being told, our own chief medical officer said, that the threat from bacterial infections we can't treat is rivalling terrorism in terms of the threat to humanity. Is that hyperbole or actually is that true?

Luke - I don't think that is hyperbole. There's arguments over the estimates. One prominent report said by 2050 this will be causing on the orders of millions of deaths, and costing millions and millions of pounds. And we probably are looking at something on that scale, if we don't act to stop the problem now. But there’s some happy stories as well where things have continued to work. Penicillin has been used to treat syphilis since the 1940s. And that still works to this day. There's never been any resistance to it. And so there’s causes for hope as well.

Chris - Just as just as well it still works, isn't it? Well, I can't speak personally in this case. I've got a question here from Steph who says: what do you think we're gonna be eating in the future, and how well prepared are we in terms of our microbiomes for this. Because one of the other things that’s your interest is the microbiome: literally we are what we eat, isn't it? What we put into our mouths affects the spectrum of bacteria that live on us and in us. How will foods of the future be considered in the light of what goes on in our intestines?

Luke - Oh, that's a very interesting question. I think in terms of our microbiome being able to deal with it there is a slight worry here. There's a new initiative, The Microbiome Conservancy, which is going to sample microbiomes from hunter gatherer tribes, and things like this, to make sure we have samples of all these microbes that could potentially be lost because of our diets changing. But generally it is a very flexible organ, in essence, in our body, and will pretty much adapt to most diets. That doesn't necessarily mean it'll be healthy. A lot of the time if you eat certain diets it can increase the amount of bacteria that can be harmful in the microbiome. But I would expect it to be flexible enough to deal with most of what we'd throw at it.


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