UC SANTA BARBARA (US) — Two compounds found in cinnamon may delay the onset of—or even ward off—the effects of Alzheimer’s disease.
New research shows the compounds—cinnamaldehyde and epicatechin—are showing some promise in preventing the development of the filamentous “tangles” found in the brain cells that characterize the disease.
Alzheimer’s patients develop brain tangles more often and in larger amounts. (Credit: GE Healthcare/Flickr)
“Wouldn’t it be interesting if a small molecule from a spice could help?” says Donald Graves. (Credit: Amanda G. Rose/Flickr)
Responsible for the assembly of microtubules in a cell, a protein called tau plays a large role in the structure of the neurons, as well as their function.
“The problem with tau in Alzheimer’s is that it starts aggregating,” says Roshni George, a graduate student researcher at University of California, Santa Barbara. When the protein doesn’t bind properly to the microtubules that form the cell’s structure, it has a tendency to clump together, forming insoluble fibers in the neuron.
The older we get the more susceptible we are to these twists and tangles, but Alzheimer’s patients develop them more often and in larger amounts.
As reported online in the Journal of Alzheimer’s Disease, the use of cinnamaldehyde, the compound responsible for the bright, sweet smell of cinnamon, has proven effective in preventing the tau knots. By protecting tau from oxidative stress, the oil compound could inhibit the protein’s aggregation.
To do this, cinnamaldehyde binds to two residues of an amino acid called cysteine on the tau protein. The cysteine residues are vulnerable to modifications, a factor that contributes to the development of Alzheimer’s.
A protective ‘cap’
“Take, for example, sunburn, a form of oxidative damage,” says Donald Graves, adjunct professor in the department of molecular, cellular, and developmental biology.
“If you wore a hat, you could protect your face and head from the oxidation. In a sense this cinnamaldehyde is like a cap.” While it can protect the tau protein by binding to its vulnerable cysteine residues, it can also come off, which can ensure the proper functioning of the protein.
Oxidative stress is a major factor to consider in the health of cells in general. Through normal cellular processes, free radical-generating substances like peroxides are formed, but antioxidants in the cell work to neutralize them and prevent oxidation. Under some conditions however, the scales are tipped, with increased production of peroxides and free radicals, and decreased amounts of antioxidants, leading to oxidative stress.
Epicatechin, which is also present in other foods, such as blueberries, chocolate, and red wine, has proven to be a powerful antioxidant. Not only does it quench the burn of oxidation, it is actually activated by oxidation so the compound can interact with the cysteines on the tau protein in a way similar to the protective action of cinnamaldehyde.
“Cell membranes that are oxidized also produce reactive derivatives, such as Acrolein, that can damage the cysteines,” George says. “Epicatechin also sequesters those byproducts.”
Diabetes and Alzheimer’s
Studies indicate that there is a high correlation between Type 2 diabetes and the incidence of Alzheimer’s disease. The elevated glucose levels typical of diabetes lead to the overproduction of reactive oxygen species, resulting in oxidative stress, which is a common factor in both diabetes and Alzheimer’s disease. Other research has shown cinnamon’s beneficial effects in managing blood glucose and other problems associated with diabetes.
“Since tau is vulnerable to oxidative stress, this study then asks whether Alzheimer’s disease could benefit from cinnamon, especially looking at the potential of small compounds,” George says.
Although the research shows promise, Graves says scientists are “still a long way from knowing whether this will work in human beings.” The researchers caution against ingesting more than the typical amounts of cinnamon already used in cooking.
If cinnamon and its compounds do live up to their promise, it could be a significant step in the ongoing battle against Alzheimer’s. A major risk factor for the disease—age—is uncontrollable. According to the Alzheimer’s Association, in 2013, it will cost the US $203 billion.
“Wouldn’t it be interesting if a small molecule from a spice could help?” says Graves, “perhaps prevent it, or slow down the progression.”
Source: UC Santa Barbara