Scientists from McGill University tested concentrated maple syrup extract on in vitro infectious strains of E.coli, P. aeruginosa and P. mirabilis, which commonly causes urinary tract infections. They found that the six polyphenols that naturally occur in maple syrup, are especially efficacious when combined with synthetic antibiotics.
Lead researcher Nathalie Tufenkji said: "The findings suggest a potentially simple and effective approach for reducing antibiotic usage. I could see maple syrup extract being incorporated eventually, for example, into the capsules of antibiotics."
She added that in vivo tests and clinical trials were needed to test the effects in humans.
According to the researchers, whose findings have been published in the Journal of Applied and Environmental Microbiology, the efficacy of antibiotics is low due to antibiotic resistance – an inevitable evolutionary survival mechanism of bacteria –and the formation of biofilms.
Biofilms are clusters of microbes which form on the surface of bacteria, forming a barrier and meaning that higher doses of antibiotics are required to penetrate it.
The scientists purchased ordinary maple syrup and used organic solvents to extract the six main polyphenols found in maple syrup - gallic acid, 1,2-dihydroxybenzene (catechol), 3,4-dihydroxybenzaldehyde (catechaldehyde), syringaldehyde, vanillin, and 3-hydroxybenzoic acid.
The most potent polyphenol-antibiotic combinations were with gallic acid-catechol and gallic acid-catechaldehyde pairs.
The polyphenols also had significant inhibitory effects on the formation of biofilm – up to 70% for E.coli at a concentration of 6.25 mg, 70% for P. mirabilis for a 12.5 mg concentration and 83% for P.aeruginosa at 12.5 mg.
“Our results further show that phenolic rich maple syrup extract synergistically interacts with conventional antibiotics (…) to inhibit the growth of the chosen bacterial strains.
“By combining antibiotics with mild antimicrobial agents (such as phenolic rich maple syrup extract) that exhibit synergistic interaction, it may be possible to decrease the dosage of antibiotics used to eradicate
Maple syrup is not the only source of polyphenols that show anti-biotic potential - erythromycin or vancomycin have also been found to work in synergy with synthetic drugs.
Maple syrup was first collected by Native Americans who used it for sores, cough and diarrhoea as well as for culinary purposes.
It is produced when the starch stored in tree trunks during winter is converted into sugar in spring.
Source: Applied and Environmental Microbiology
First published online 27 March 2015, doi:10.1128/AEM.00239-15
"Polyphenolic Extract from Maple Syrup Potentiates Antibiotic Susceptibility and Reduces Biofilm Formation of Pathogenic Bacteria"
Authors: N. Tufenkji et al.