Grape skin extract improves muscle function and extends the lifespan of flies with Parkinson’s disease, a study shows.
The neuroprotective effect of grape skin extract was due to its potential to rescue mitochondria — cells’ powerhouses — from defects caused by the disease.
The study, “Skin extract improves muscle function and extends lifespan of a Drosophila model of Parkinson’s disease through activation of mitophagy,” was published in the journal Experimental Gerontology.
The health benefits of drinking red wine have been widely reported, and evidence is accumulating to suggest that wine consumption has potential value against age-related neurodegenerative disorders, such as Alzheimer’s disease and Parkinson’s disease.
The antioxidant and anti-inflammatory activities of red wine polyphenols, such as resveratrol, have been pointed to as the main reasons for its beneficial effects. But studies also have revealed that resveratrol could prevent the formation of toxic amyloid aggregates that often characterize neurodegenerative diseases.
Besides polyphenols, grape skin and seeds also contain anti-oxidative components, including proanthocyanidine and quarcetin, which may actively contribute to protecting against oxidative stress and mediated tissue injury.
Oxidative stress is an imbalance between the production of free radicals and the ability of cells to detoxify them. These free radicals, or reactive oxygen species, are harmful to the cells and are associated with a number of diseases, including Parkinson’s disease.
Researchers at Stanford University School of Medicine evaluated the effect of dietary supplementation with grape skin extract left from red wine-production in a fly model of Parkinson’s disease.
Loss of function of the PINK1 gene led to a significant reduction in flies’ lifespan, from a median time of roughly 18 days down to 11 days. Diet supplementation with 8% grape skin extract improved flies’ survival time to a median of 15 days. A similar improvement was achieved with a high dose of resveratrol.
Further assessments revealed that PINK1 mutated flies had abnormal wing posture, a feature that was partially reversed with 8% and 16% grape skin extract, as well as with a high dose of resveratrol.
These results suggest that grape skin extract have potential to improve survival and prevent indirect flight muscle degeneration, and its beneficial effect is mediated by components other than resveratrol alone.
The researchers found that both treatment with grape skin extract and resveratrol could significantly reduce — by about half — the amount of damaging oxygen reactive elements. In addition, it also could prevent the aggregation of mitochondria in muscle and in dopamine-producing nerve cells, protecting them from dying.
After further experiments the team confirmed that the beneficial impact of grape skin extract was sustained by its protective effect on mitochondria activity, and re-activation of the destruction process of damaged mitochondria.
Collectively, these results suggest that “manipulation of the mitochondrial pathways,” with pharmacological agents or alternative strategies such as grape skin extract, “may prove beneficial to combat Parkinson’s disease,” researchers wrote.
“The various components in grape skin extract may act together in a multi-pronged manner” targeting several damaging mechanisms involved in Parkinson’s, “including mitochondrial dysfunction and oxidative damage, to exert their neuroprotective effects,” they concluded.