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07.12.2020

Quercetin prevents stress hormone cortisol from breaking down muscle cells

Athletes who consume a relatively large amount of quercetin through their diet or supplementation protect their muscles against breakdown by stress hormones such as cortisol and its pharmacological variants, such as betamethasone [structural formula shown here]. This is evident from an in vitro study that Taiwanese pharmacologists from Kaohsiung Medical University published in Molecules.

Study
The researchers exposed C2C12 muscle cells to different concentrations of dexamethasone and quercetin.

Results
Exposure to dexamethasone reduced the vitality of the muscle cells. The greater the concentration, the stronger the effect. You can see this at the bottom left.

Quercetin did not reduce muscle cell vitality, as you can see in the center of the figure below. However, quercetin could largely cancel the effect of betamethasone. You can see this at the bottom right.

Click on the figure for a larger version.

Exposure to dexamethasone increased the production of free radicals [ROS] in the muscle cells, and more muscle cells died [Apoptotic cells]. Quercetin partially cancelled this effect.

Dexamethasone increased the production of suicide enzymes by the muscle cells. This effect was, like dexamethasone's other effects, lessened by quercetin.

The researchers think that dexamethasone and other corticosteroids kill muscle cells by reducing their energy supply. This is done by compromising through the mitochondria in the muscle cells.

The Taiwanese deduce this from the effect of betamethasone on the Bax protein, among other things. Bax inhibits energy production by mitochondria and plays a role in many cellular suicide mechanisms.

Conclusion
"This study demonstrated that quercetin can reduce dexamethasone-induced mitochondrial malfunction in skeletal muscle cells through the downregulation of Bax and reactive oxygen species production", write the researchers.

"As a food supplement, quercetin has substantial benefits in relieving dexamethasone-induced skeletal muscle injury and could serve as an alternative natural plant resource for the prevention or treatment of muscle atrophy syndrome."

"The potent antioxidant activity of quercetin renders it suitable to be used as a dietary supplement for patients under long-term dexamethasone treatment to regulate mitochondria health in skeletal muscle."

Source:
Molecules. 2020 Jul 17;25(14):3267.

More:
Supplementing with quercetin or red onion forces the body into giving muscle preferential treatment over fat 06.12.2020
Quercetin reduces cortisol peak after stress 30.05.2009
In vitro: quercetin undermines functioning of estradiol 16.08.2011

Archives:
Blocking Cortisol
Quercetin

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