Key Natural Nutrient For
Cardiovascular Health,
Diabetes and Weight Management
According To Research
The potential health benefits of
resveratrol may be due to is ability
to activate the powerful fat controlling
hormone adiponectin, according to an
important new study.
Researchers from the University of Texas found that the antioxidant
compound resveratrol stimulates the expression of adiponectin,
a hormone released from fat cells, which plays an important
role in the regulation of insulin sensitivityand energy.
The new study, published in the Journal of Biological Chemistry,
reports that resveratrol stimulates the expression and protein
clustering (multi-merization) of adiponectin in specialized fat
cells through the activation of a protein known as disulfide
bond-A oxidoreductase- like protein (DsbA-L).
"Our study uncovers a novel mechanism by which resveratrol
exerts its health beneficial effect," said pharmacology
researchers at University of Texas.
"The results from these studies should be of interest to those
who are obese, diabetic and growing older," he added.
They said the finding that resveratrol promotes adiponectin
expression provides a novel mechanism by which resveratrol
exerts its health beneficial functions.
Resveratrol, a powerful polyphenol and anti-fungal chemical,
is regarded as the major bioactive compound in grapes, grape
seeds and red wine. It has long been associated with the
so-called "French Paradox" which describes the low incidence
of heart disease and obesity among the French, despite their
relatively high-fat diet and levels of wine consumption.
Interest in the compound exploded in 2003 when research
from from Harvard reported that resveratrol was able to
increase the lifespan of yeast cells. The research, published
in Nature, was greeted with international media attention and
stimulated hope worldwide for an effective anti-aging pill.
According to the Harvard study's findings, resveratrol
activated a gene called sirtuin1 (Sirt1), which is also activated
during calorie restriction in various species, including humans.
However, recent studies have suggested that resveratrol
may exert its beneficial functions via Sirt1-independent
mechanisms.
Adiponectin has a wide range of beneficial effects on obesity-
related medical complications, and noted that both adiponectin
and resveratrol display anti-obesity, anti-insulin resistance and
anti-aging properties.
Whilst recent research has identified that the expression
DsbA-L, a protein that is known to regulate the expression
of adiponectin, is significantly reduced in obese human
subjects and mice.
Novel Mechanism
The researchers reported that resveratrol significantly
enhanced the levels of DsbA-L in animal cells. This suggests
that the promoting effects of resveratrol on adiponectin
multimerization and expression are mainly mediated by
up-regulating DsbA-L.
The researchers reported that the stimulatory effect of
resveratrol was not affected by knocking out Sirt1, thus
confirming a novel, Sirt1 independent mechanism for the
actions of resveratrol, but was reduced by the suppression
of DsbA-L expression.
Critical Role
"We have shown that resveratrol plays a positive role in
regulating adiponectin expression and multimerization in
adipocytes via a Sirt1-independent mechanism," said the
researchers.
They added that DsbA-L plays "a critical role" in promoting the
effects of resveratrol on adiponectin, which in turn provides
beneficial metabolic effects.
The discovery of such a novel mechanism for the benefits
of resveratrol may help in the development of therapeutic
treatments for metabolic diseases; further research is needed
to quantify any dose and response relationship between
resveratrol intake and DsbA-L and adiponectin activation.
Source: Journal of Biological Chemistry
(Published online)
"Up-regulation of Adiponectin by Resveratrol: The essential
roles of the Akt/Fox01 and AMP-activated protein kinase
signaling pathways and DsbA-L"
