Maple syrup helps antibiotics defeat bacteria

17 Apr

Inappropriate and overuse of antibiotics has led to the emergence of drug-resistant strains and superbugs – a major public health problem that is in urgent need of

solutions. Now, a team of researchers at McGill University in Montreal, Canada, suggests

one solution may lie in the sap of trees that are abundant in North America.

E. coli
The researchers found maple syrup extract made bacteria more susceptible to antibiotics.

Writing in the journal Applied and Environmental Microbiology, Nathalie

Tufenkji, a chemical engineering professor, and colleagues describe how they found

concentrated maple syrup extract makes disease-causing bacteria more susceptible to


The researchers made their discoveries from working with lab-based colonies of

bacteria. But they hope the maple syrup extract will have the same effect on bacterial

infections in human patients.

One potential benefit would be to reduce the use of antibiotics and thus slow

the rate at which resistant strains emerge.

Maple syrup contains phenolic compounds, which are of considerable interest due to

their antiseptic and antioxidant properties. Phenolic compounds play an important role in

the growth and development of plants by helping to defend against pathogens.

Phenolic-rich extract made infection-causing bacteria susceptible to antibiotics

For the study, Prof. Tufenkji and colleagues made an extract of maple syrup comprising

mainly phenolic compounds.

They bought the maple syrup at local markets in Montreal and kept it in the freezer

until the start of each experiment where they removed a sample and put it through a

series of steps to produce the phenolic-rich extract.

They then tested the extract on a number of infection-causing bacteria such as Escherichia coli and Proteus mirabilis – a common cause of urinary tract infection.

On its own, the maple syrup extract was mildly effective against the infection-causing bacteria.

But the maple syrup extract was even more effective against bacteria when combined

with antibiotics.

The maple syrup extract and antibiotic combination was particularly effective

at destroying biofilms – resistant communities that inhabit surfaces and are particularly

hard to shift with antibiotics. Dental plaque is an example of a biofilm.

Biofilms commonly develop on catheters and cause difficult-to-treat urinary tract


Maple syrup extract undermines bacteria in several ways

The researchers say the maple syrup extract affect the bacteria in a number of ways to

make them more susceptible to antibiotics.

One effect that the extract has on bacteria is to make their cell membranes more

porous. This makes it easier for the antibiotics to enter the microbial cells.

The maple syrup extract also shuts down the “efflux pumps” that the bacteria use to

push any antibiotic that makes it through the membrane out of the cell.

And a third way that the extract weakens the bacteria is by reducing expression of

genes linked to antibiotic resistance and virulence.

The researchers say the study is a first step that proves the concept. Now, more

extensive and rigorous work needs to be done, eventually leading to clinical trials,

before they can say what the effect will be in humans.

But Prof.Tufenkji says the findings “suggest a potentially simple and effective

approach for reducing antibiotic usage,” and adds:

“I could see maple syrup extract being incorporated eventually, for

example, into the capsules of antibiotics.”

Funds for the study came from the Natural Sciences and Engineering Research Council of

Canada and the Canada Research Chairs program.

In 2011, Medical News Today reported how a researcher at Rhode Island

University discovered dozens of beneficial compounds in pure maple syrup.

Assistant pharmacy professor Navindra Seeram said several of the compounds he discovered

have antioxidant and anti-inflammatory properties, which have been shown to fight cancer,

diabetes and bacterial illnesses.