Alzheimer's disease (AD) is a
form of dementia (loss of brain function) that affects memory, thinking and
behavior, and is known to gradually get worse over time. Although the cause of
AD is not clear, scientists consider certain changes in the tau proteins in the
brain tissue to be associated with the disease.
Tau proteins are proteins that stabilize microtubules
present in the nerve cells in the brain by binding to the microtubules. Tau
proteins control microtubule stability through glycoform and phosphorylation.
When tau proteins undergo abnormal modifications and form filamentous tangles,
they can no longer stabilize microtubules properly, and can result in dementias
such as Alzheimer's disease.
"The problem with tau in
Alzheimer's is that it starts aggregating," said Roshini George, a graduate
student researcher at University of California and one of the authors of this
study. "When the protein does not bind properly to the microtubules that form
the cell's structure, it has a tendency to clump together forming insoluble
fibers in the neuron".
"Wouldn't it be interesting if a small molecule
from a spice could help? Perhaps prevent it, or slow down the progression?"
commented Donald Graves, lead researcher of the study and adjunct professor in
UCSB's Department of Molecular, Cellular, and Developmental Biology.
The researchers found that
compounds, cinnamaldehyde and the oxidized form of epicatechin, in the cinnamon
extract could help stop these 'tangles' from forming in the brain.
What cinnamaldehyde does is, it
binds to two residues of an amino acid called cysteine on the tau protein and
protects the tau from oxidative stress thus inhibiting aggregation of the
"Take, for example, sunburn, a
form of oxidative damage," said Graves. "If you wore a hat, you could protect
your face and head from the oxidation. In a sense this cinnamaldehyde is like a
Similarly, epicatechin, another
powerful antioxidant, 'quenches' the burn of oxidation and interacts with the
cysteines on the tau protein just the way cinnamaldehyde does.
"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," said George.
However, the authors feel they are "still a long
way from knowing whether this will work in human beings" and caution
against ingesting more than the typical amounts of cinnamon already used in