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.
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
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.