Washington (ISJ) ? Scientists at The Scripps Research Institute (TSRI) have found, a natural compound resveratrol, found in grapes, berries, peanuts, chocolates, etc, activates an evolutionarily ancient stress response in human cells.
"This stress response represents a layer of biology that has been largely overlooked, and resveratrol turns out to activate it at much lower concentrations than those used in prior studies," said senior investigator Paul Schimmel, professor and member of the Skaggs Institute for Chemical Biology at TSRI, California, USA.
Resveratrol is a compound produced in grapes, cacao beans, Japanese knotweed and some other plants. It has attracted widespread scientific and popular interest over the past decade, as researchers have found it extended lifespan and prevented diabetes in obese mice and vastly increased the stamina of ordinary mice running on wheels.
"We have discovered a biologically relevant and functionally significant target for resveratrol. This new fundamental mechanism can explain all the health benefitting properties of resveratrol. Most importantly, the amount of resveratrol required to stimulate this pathway is in the lower micro molar range which is an amount that one can potentially obtain from consuming food products that contain resveratrol like grapes (and its products like wine), berries, peanuts, chocolates etc," leader author and a senior Research Associate at Schimmel Laboratory Mathew Sajish, a non-Resident Indian, told Indian Science Journal (ISJ) in response to an e-mail.
The discovery is reported in the advance online edition of Nature on December 22.
Some scientists in the recent times, have disagreed about the signalling pathways resveratrol activates to promote health, questioning its supposed health benefits?particularly given the unrealistically high doses used in some experiments.
Earlier Xiang-Lei Yang, a TSRI professor in the Departments of Chemical Physiology and Cell and Molecular Biology and former member of Schimmel's laboratory, began to find hints that a tRNA synthetase called TyrRS, which links the amino acid tyrosine to the genetic material that codes for it, can move to the cell nucleus under stressful conditions?apparently taking on a protective, stress-response role. Sajish noted that resveratrol appeared to have broadly similar stress-response properties and also resembled TyrRS's normal binding partner tyrosine. "I began to see TyrRS as a potential target of resveratrol," he said.
"Classically, L-tyrosine amino acid has been used as an anti-stress agent (means consumption of L-tyrsoine amino acid can relieve stress condition). As L-tyrosine is an amino acid, it is normally used in the cell as building block for the synthesis of proteins. In general, a class of enzymes called aminoacyl tRNA syntheses activate amino acids for protein synthesis," Sajish told ISJ.
Sajish and Schimmel put TyrRS and resveratrol together and showed with tests including X-ray crystallography that resveratrol does indeed mimic tyrosine, well enough to fit tightly into TyrRS?s tyrosine binding pocket. That binding to resveratrol, the team found, takes TyrRS away from its protein translation role and steers it to a function in the cell nucleus.
Red-wine has certain components that help prevent cardio-vascular diseases in population that consume more saturated fatty acids, like French people, who consume a lot of chees, still have lower cardio-cascular problems to other European countries. This is known in the scientific community, as 'French Paradox'.
-By NB Nair
Source: With inputs from TSRI
@Indian Science Journal