Resveratrol is a naturally occurring phytoalexin produced by some higher plants
in response to injury or fungal infection. Phytoalexins are chemical substances
produced by plants as a defense against infection by pathogenic microorganisms,
such as fungi. Epidemiological, in vitro and animal studies suggest that a high
resveretrol intake is associated with a reduced incidence of cardiovascular
disease, and a reduced risk for cancer. Resveratrol is touted by nutritionists
and biochemists because of its potential as an anticancer and cardioprotective
compound.
Resveratrol belongs to the phytoalexin class of phytochemicals and functions as
a moderate antioxidant, quenching free radical damage linked to several cancers.
The compound has also demonstrated anti-inflammatory properties that help it to
block reactions associated with the cancer process.
Resveratrol, which is also known as 3,4',5 trihydroxystilbene and
3,4',5-stilbenetriol, exists in cis- and trans-stereoisomeric forms. Resveratrol
is the parent molecule of a family of polymers called viniferins. Cis- and
trans-resveratrol occur naturally as do their glucosides.
Resveratrol-3-O-beta-D-glucoside is also known as piceid, and the respective
cis- and trans-glucosides are called cis-piceid and trans-piceid. The molecular
formula of resveratrol is C14H12O3 and its molecular weight is 228.25 daltons.
Some benefits of resveratrol include:
1) Powerful antioxidant. Antioxidants are substances that can neutralize free
radicals, which are highly reactive compounds that, if left unchecked, can lead
to cellular damage. Free radicals are believed by some experts to be a major
culprit in heart disease, cancer, and aging itself.
2) The study conducted by Dr. Pezzuto showed that resveratrol was effective
against the progression of cancer. Most impressively, it was effective in all
the major stages of cancer -- the initiation, promotion, and progression.
3) Resveratrol has been shown to help lower bad cholesterol (LDL), and,
therefore, may be a potent nutrient in preventing cardiovascular disease. It has
also shown to reduce the clumping of platelets. Thus, such conditions as
atherosclerosis and heart attacks, which are often caused by arterial blockages,
may potentially be reduced by this potent substance.
Resveratrol has several activities that may account for its possible
cardioprotective action. These include inhibition of the oxidation of
low-density lipoprotein (LDL), inhibition of smooth muscle cell proliferation
and inhibition of platelet aggregation. Resveratrol has also been found to
reduce the synthesis of lipids in rat liver and to inhibit the production of
proatherogenic eicosanoids by human platelets and neutrophils. Resveratrol's
antioxidant activity may play an important role in its possible cardioprotective
action. Above, was mentioned its ability to inhibit the oxidation of LDL.
Resveratrol also has been found to exert a strong inhibitory effect on
superoxide anion and hydrogen peroxide production by macrophages stimulated by
lipopolysaccharides or phorbol esters. It also has been demonstrated to decrease
arachidonic acid release induced by lipopolysaccharides or phorbol esters, or by
exposure to superoxide or hydrogen peroxide. It has hydroxyl-radical scavenging
activity and has recently been found to possess glutathione-sparing activity.
Resveratrol's possible phytoestrogenic activity may also contribute to its
possible cardioprotective action. Resveratrol appears to act as a mixed
agonist/antagonist for estrogen receptors alpha and beta. It has been found to
bind estrogen receptor beta and estrogen receptor alpha with comparable affinity
but with 7,000-fold lower affinity than estradiol. Resveratrol differs from
other phytoestrogens, which bind estrogen receptor beta with higher affinity
than they bind estrogen receptor alpha. Resveratrol also shows estradiol
antagonistic behavior for estrogen receptor alpha with some estrogen receptors.
It does not show estradiol antagonistic activity with estrogen receptor beta.
Resveratrol's possible antiproliferative activity also may be accounted for in
several different ways. Resveratrol's antioxidant activity was discussed above.
It also has antimutagenic activity, as illustrated by its dose-dependent
inhibition of the mutagenic response induced by treatment of Salmonella
typhimurium strain TM677 with 7,12-dimethylbenz(a)anthracene (DMBA). Resveratrol
has been found to inhibit cellular events associated with tumor initiation,
promotion and progression. It has been found to inhibit cyclooxygenase (COX)
activities in different cancer models, suggesting an effect at the level of
tumor promotion. It has also been found to reverse tumor-promoter-induced
inhibition of gap-junctional intracellular communication in rat epithelial
cells. Inhibition of gap-junctional intracellular communication is an important
mechanism of tumor promotion. Resveratrol has demonstrated inhibition of growth
of several cancer cell lines and tumors, suggesting that it has an inhibitory
effect on cancer promotion/progression. It has been found to inhibit
ribonucleotide reductase, DNA polymerase, the transcription of COX-2 in human
mammary epithelial cells and the activity of ornithine decarboxylase. Ornithine
decarboxylase is a key enzyme of polyamine biosynthesis, which is enhanced in
tumor growth. Resveratrol has also been found to induce phase II metabolizing
enzymes which are involved in the detoxification of carcinogens, to upregulate
apoptosis, to inhibit the progression of cancer by inducing cell differentiation
and to inhibit protein kinase D and possibly protein kinase C. Recently,
resveratrol has been shown to inhibit both NF-kappaB activation and
NF-kappaB-dependent gene expression via its ability to inhibit IkappaB kinase
activity, the key regulator of NF-kappaB activation. This appears to upregulate
apoptosis.. （ from "greatvista chemicals")

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Resveratrol is an antioxidant but its antioxidant properties are weaker that those of quercetin and epicatechin. It has anticancer properties and inhibits lipid peroxidation of low-density lipoprotein and prevents the cytotoxicity of oxidized LDL. Resveratrol also increases the activity of some antiretroviral drugs in vitro.
Antioxidant
In vitro studies have shown that resveratrol inhibits the oxidative damage caused by the heavy metal cadmium. The antioxidant activity of resveratrol reduces damage to endothelial cells exposed to nitrite radicals and protects skin cells against damage caused by UV radiation.
Anticancer
The antioxidant action of resveratrol helps to prevent damage to DNA but it also influences the transcriptions of genes responsible for redox metabolism and inhibits proliferartion of cancer cells. Resveratrol appears to decrease tumor promotion activity by inhibiting the enzyme cyclooxygenase-1, which converts arachidonic acid to substances that promote tumor growth.
Benefits for diabetes
Resveratrol may be benificial for diabetes. Administration of resveratrol may protect against oxidative damage caused by high glucose levels. It also reduces diabetic neuropathic pain.
Heart health
Resveratrol protects our heart and blood vessels by directly scavenging oxidants, which could cause oxidation of lipids, and by preventing apoptosis of endothelial cells. It may also help to prevent heart damage after a cardiac arrest. Reduced platelet ggregation has been attributes to resveratrol, thereby reducing the risk of atherosclerosis.
Increase of lifespan
Tests with animals have shown that that high food intake reduces lifespan. One study showed that resveratrol was able to able to increase the life span of mice on a high calorie diet.
Antitoxic
Many studies on animals have shown antitoxic effects of resveratrol. Resveratrol was able to reverse damages caused by the administration of the chemotherapeutic drug bleomycin. Resveratrol also helped to reduce brain damage and oxidative damage of the liver during ethanol intoxication. It also reduced kidney damage of rats treated with the antibiotic gentamicin
（ from "phytochemicals info")