Natural Solution: Extract Synthesized from Maple Syrup Boosts Efficiency of Antibiotics

In the ongoing search to find better ways to use antibiotics, an extract made from maple syrup has some surprisingly important medical benefits.

As bacteria continue to outmaneuver antibiotics, our options for treating infections narrow. Plus, slimy bacterial communities called biofilms are rapidly proving a difficult and dangerous problem in healthcare settings and on medical devices.

In research presented from McGill University at the National Meeting and Exposition of the American Chemical Society in San Francisco on April 3, scientists discussed how an extract isolated from maple syrup reduced biofilm formation and increased sensitivity of bacteria to antibiotics—among other benefits.

Taking a page from traditional Canadian folk medicine, McGill researchers took a close look at how compounds from maple syrup might help improve our chances of fighting bacteria that hide out in biofilm communities.

How Bacteria Become Slime

Given the opportunity, like a lot of humans, most bacteria like to live in these biofilm communities. If you haven't really washed your water bottle recently, there is biofilm in there, as well as between your teeth, probably in your toilet, and almost certainly in your bathtub drain. You can't always see a biofilm, but you can usually feel their slime when they get big enough.

Single bacteria cells that float in liquid, like your bloodstream, and tend to cause treatable infections, are called planktonic bacteria. That sounds like plankton, tiny one-celled organisms (which can be animals, plants, bacteria, or algae) that fuel ocean-going food chains—but they are not related.

Scanning electron microscope image of a biofilm containing Proteus mirabilis.

When planktonic bacteria decide to settle down, they form organized, productive, biofilm communities. A biofilm is as much architecture as it is a specific type of bacterial group. The bacteria in the biofilm create a structural matrix that allows them to live relatively unperturbed. That slime in your shower is not going away until you scrub it off—a gentle rinse will not do.

In healthcare settings, on implanted medical devices and in the human body, biofilms boost chronic disease and can be deadly. While infection with planktonic forms of bacteria can generally be resolved with antibiotics, that is often not the case for infections associated with biofilms.

Making the most out of safety in numbers, biofilms produce a barrier of slime that deters antibiotics, and organize themselves to pump out antibiotics that succeed in getting through the slime. These neighborhoods are built in layers, so even if the outside group of bacteria are killed, there are more at the center of the film waiting to replace them. Plus, there are very slow-growing biofilm bacteria that only develop when others in the community die.

Used in folk medicine to treat conditions as diverse as cough, diarrhea, and cataracts, scientists wondered how the compounds in maple syrup stack up against bacteria in a laboratory setting.

From Sweet Sap to Antibiotic Booster

Winter into spring is sugaring season, the time of year when sap runs fast and thin in North American sugar maples. Collected through taps in trees, the sap is boiled down and concentrated into syrup. It takes about 40 gallons of sap to make one gallon of syrup.

Dr. Nathalie Tufenkji holds the Canada Research Chair in Biocolloids and Surfaces at McGill University, and is interested in natural compounds, like cranberry extracts, that deter bacteria. With an interest in the science behind Canadian folk medicines that use maple syrup, Tufenkji sent her post-doctoral assistant to the grocery store for maple syrup.

From the maple syrup, Tufenkji's research team prepared an extract by separating the sugar and water from phenolic compounds in the syrup. Common in plants, phenolic compounds are known to show antioxidant properties and are found in fruits, vegetables, spices, and even dark chocolate.

From the syrup, researchers created a purified, enriched extract high in phenolic compounds and other maple syrup molecules. The extract, called PRMSE, was evaluated throughout the experiment with chromatography analysis, several assays, including those for biofilm permeability and integrity.

Initial tests with the extract alone did not result in an antibiotic effect. Researchers then created a chemical cocktail with the maple extract and different antibiotics, including carbenicillin and ciprofloxacin, and the results were impressive:

• When combined with these antibiotics against bacteria including Proteus mirabilis, Escherichia coli, and Pseudomonas aeruginosa, the potion proved powerful against microbes and biofilms, P. mirabilis is a common bacteria that causes urinary tract infections. P. aeruginosa is a culprit in infections acquired in healthcare settings, and E. coli is responsible for food-borne and other dangerous illnesses.
• The antibiotic and extract preparation slowed down the formation of biofilms, and improved penetration of biofilm communities by the antibiotics. Plus, the preparation reduced the virulence, or spread, of the bacteria. The compound also reduced the ability of biofilms to pump antibiotics out of their community, and improved the uptake of the antimicrobials.
• The combination of drugs and extract gave researchers the same antimicrobial effect while using 90% less antibiotic. In practice, using less antibiotics means fewer "good" bacteria are killed in treatment and are less likely to form drug resistance.
• The McGill team is now studying the extract in fruit flies, moth larvae, and mouse studies, and are seeing some interesting results. Tufenkji told Invisiverse that "The insect work shows that the maple syrup extract (PRMSE) acts synergistically with an antibiotic to protect fruit flies and moth larvae from bacterial infection."

Despite its use in folk medicine, consider some advice. Before you stock up on maple syrup for medicinal purposes, remember the compounds in the PRMSE extract were carefully refined in a laboratory setting. As helpful as it might seem, the only impact you might see from throwing back a couple of bottles of maple syrup is a stomach ache and an expanding waistline.

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Cover image via Dave Pape/Wikimedia Commons