Thursday, May 7, 2015

Green Tea Extract and Exercise Disrupt Progress of Alzheimer's Disease in Mice

Green Tea Extract and Exercise Disrupt Progress of Alzheimer's Disease in Mice


Amyloid-β (Aβ) induced mitochondrial dysfunction may play a role in the onset and progression of Alzheimer's disease (AD). Therefore, therapeutics targeted to improve mitochondrial function could be beneficial. Plant-derived flavonoids have shown promise in improving certain AD phenotypes, but the overall mechanism of action(s) through which flavonoids protect from AD is still unknown. From a list of 25 natural product, Epigallocatechin-3-gallate (EGCG) and luteolin were identified as the top two mitochondrial restorative compounds from the in vitro screen. The compounds were screened for their ability to restore altered mitochondrial membrane potential (MMP), reactive oxygen species (ROS) production, or ATP levels in neuroblastoma cells expressing mutant amyloid-β protein precursor (AβPP).

Increases in inflammation have been linked to Alzheimer’s disease patients and recent studies have suggested the benefits of dietary antioxidants in reducing the risk of AD. Researchers decided to investigate the effects of voluntary exercise and epigallocatechin-3-gallate (EGCG), a green tea extract, on memory function and Aβ levels in mice known to show plaque deposits and behavior deficits.


The murine model study investigated the effects of 4 months of wheel-running exercise, initiated at 2-months of age, in conjunction with the effects of the green tea catechin (-)-epigallocatechin-3-gallate (EGCG) administered orally in the drinking water (50 mg/kg daily) on:

1) Behavioral Measures: learning and memory performance in the Barnes maze, nest building, open-field, anxiety in the light-dark box.
2) Soluble Amyloid-β (Aβ)-levels in the cortex and hippocampus in TgCRND8 (Tg) mice.


In the behavioural studies, the first test was to test memory and cognition. Mice were placed in the center of a specialized maze and allowed to move around with the aim of finding the right hole, or “goal box.” In the second test, small “nestlets,” or squares containing materials to create nests, were placed in the habitats for different groups of mice. A day later, nests were scored based on shape and the amount of material used. Mice exhibiting symptoms of the disease had trouble finding their ways in the maze also their nests that were poorly formed or erratic. This was correlated by researchers as the true condition where mice with Alzheimer’s symptoms, much like people, can be apathetic about their habitat, or have forgotten how to ‘nest’ appropriately.

Researchers then administered EGCG in the drinking water of the mice and gave them access to running or exercise wheels. After re-administering the maze and nesting tests, they found remarkable improvements in the cognitive function and retention in the Alzheimer’s affected mice that were given EGCG and were allowed to exercise.

In the final part of the experiment, an analysis of mouse brain tissues to determine the effects of EGCG and exercise on Aβ levels in affected regions of the brain was performed. A decrease in Aβ level was noted.

The authors conclude asOral administration of the extract, as well as voluntary exercise, improved some of the behavioral manifestations and cognitive impairments of Alzheimer’s.

Article Citation: Sun, G. Y.; et. al. Beneficial Effects of Dietary EGCG and Voluntary Exercise on Behavior in an Alzheimer's Disease Mouse Model. J Alzheimers Dis 2015, 44, 561-572.