University Health Network - Toronto

Toronto chemist Don Weaver sweetened maple syrup’s appeal, discovering how it might fight the molecular symptoms of Alzheimer’s disease. Photo credit: University Health Network – Toronto

Don Weaver, a chemist and director of the Krembil Research Institute within Toronto’s University Health Network, recently found occasion to bring science to the public within the humble confines of a subway car full of morning commuters. Weaver overheard a discussion three women were having about a newspaper story describing how constituents of maple syrup could prevent Alzheimer’s disease, theorized to be caused by the accumulation of abnormally folded amyloid beta protein in the brains of patients. When Weaver realized that they were associating this effect with popular brands of “table syrup,” he couldn’t resist interrupting to point out that such products consist of little more than flavoured corn sugar and would have none of these medicinal qualities. “And how would you know that?” they queried. “I pointed at the paper and said, ‘Because that’s me in there.’ ”

Only a few days earlier, Weaver had been in California presenting the maple syrup findings at an American Chemical Society meeting. The discovery struck a chord among Canadian observers but he confesses that it was the result of a much broader research agenda that had begun several years earlier. “We have been endeavouring to come up with small molecules that bind to either beta amyloid or tau peptide,” he says, referring to the key cellular proteins linked to Alzheimer’s. After conducting high-throughput screening with some standard compound libraries, Weaver and his colleagues turned to botanicals such as apples and chocolate.

Weaver arbitrarily added components of maple syrup to the list of novel polyphenols being investigated. It turned out that the polyphenol compounds within the maple syrup may have a potent ability to interfere with protein misfolding. He outlined that result as co-author of a paper that appeared in the Canadian Journal of Neurological Sciences earlier this year. “Whether it has the ability to cross the blood-brain barrier is a completely different question,” he says, acknowledging that this feature might ultimately limit the effectiveness of the agent as a potential drug. That aspect is being explored by American researchers who are moving from in vitro studies to analyses using roundworms as a model organism.

Meanwhile, Weaver found it no less interesting that these properties are not found in maple sap but only in the processed syrup. “These polyphenols are actually made during the boiling process,” he says. “That heat is enough to facilitate some interesting chemistry in the sap and causes the biosynthesis.”

Of course, most Canadians need little convincing to consume maple syrup and Weaver points out that in this respect his efforts were actually counterproductive. The ethyl acetate extraction to isolate the polyphenols turned our national topping from an alluring viscous treat into a nondescript brown powder. “It was a horrible thing to do to maple syrup,” he says.