Cyanidin, the life-extender in blueberries
Blueberries are not cheap, but it may be worthwhile to include them in your diet - if you are at a health fanatic that a. wants to get older than a century, and b. wants to run a marathon on his 100th birthday. According to an in vitro study published in Scientific Report, fruits like blueberries contain phenols that activate the longevity enzyme SIRT6.
What is SIRT6?
SIRT6 is 1 of 7 sirtuins, a group of enzymes that are involved in cellular repair processes. SIRT6 ensures the repair of broken DNA, inhibits inflammation, helps telomeres to maintain their length and allows cells to absorb glucose.
Genetically modified mice that produce extra SIRT6 live nearly 20 percent longer than normal mice, and remain remarkably healthy up to old age.
The researchers exposed human Caco2 colon cancer cells to dozens of flavonoids in our diet, of which researchers suspect that they have positive health effects. They detemined whether those flavonoids activated SIRT6.
Flavonoid number 17 was the most active compound, the researchers discovered. That was cyanidine, a flavonoid that is mainly found in berries. Cyanidine was able to increase the activity of SIRT6 by as much as a factor 55. Other flavonoids, like quercetin and myricetin, also increased the activity of SIRT6 - but not to the same extent as cyanidine.
In the cancer cells, cyanidine activated the signal molecule FOXO3. FOXO3 plays a role in the growth of muscle tissue through the recruitment of stem cells. In cancer cells it activates suicide enzymes.
At the same time cyanidin inhibited GLUT1 and Twist1 in the cancer cells. In cancer cells both genes are active to an increased extent. GLUT1 provides for the production of the GLUT1-glucose transporter, a protein with which cells take up glucose. Twist-1 plays a role in the metastasis of cancer cells.
"Among sirtuins, SIRT6, has been implicated in aging and age-related diseases, but its physiological role is not completely understood", the researchers write. "The extent to which increased SIRT6 activation affects these disease conditions is still unclear; it might offer a protective mechanism or, alternatively, represent part of the disorder process."
"Although there is considerable evidence that SIRT6 is a tumor suppressor, the effect is double-edged since it can also inactivate tumor suppressor proteins FoxO3a and p53. To further examine these opposite roles of SIRT6, there is a definite need for novel potent SIRT6 modulators, for both inhibitors and activators. These modulators make it possible to study the physiological role and therapeutic potential of SIRT6."
"Interestingly, the most prominent activators for SIRT6 among the flavonoids were the anthocyanidins, the universal plant pigment, responsible for the red, purple, and blue color in many fruits, vegetables and flowers."
"The most potent compound in the class of anthocyanidins, cyanidin, significantly increased the deacetylation activity of SIRT6. It is most abundant in red berries including bilberry, raspberry and cranberry. Studies have suggested that anthocyanidins, including cyanidin, may play important roles in helping to reduce the risk of many age-related diseases."
Sci Rep. 2018 Mar 7;8(1):4163.
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