What is resveratrol?
Resveratrol is a phytoalexin with antioxidant properties, which is one of the polyphenols.
History and naming
The first describing and naming as resveratrol was carried out in Japan in 1939 by Michio Takaoka. He isolated grandiflorum the connection from the medicinal plant Veratrum. The name Resveratrol can be seen as portmanteau, which is composed due to the chemical affinity of the first syllable of the name of resorcinols, the generic name Verartrum and systematic suffix "-ol" for alcohols. 1976 succeeded the detection of resveratrol in grapes.
Physical and Chemical Properties
Resveratrol is a poorly soluble in alcohol and oils in water and good white solid. Chemically, Resveratrol is a stilbenoid, a derivative of stilbene. In plants it is produced under the catalytic action of the enzyme stilbene.
Resveratrol exists as trans- and cis-isomer. The trans form may be converted into the cis-form under the action of UV radiation. trans-resveratrol is the more stable form of the two isomers. In the skin of grapes, as in the pomace, resveratrol survive the fermentation process and long storage times.
Occurrence
Resveratrol is found in a number of plants and plant foods, especially in grapes, raspberries, mulberries, plums, peanuts, and Japanese knotweed. As part of a screening program of the National Cancer Institute in which several thousands of plants was assayed for anti-carcinogenic substances, it has resveratrol found in 72 plant species; in relatively large quantities in the skin of red grapes: In fresh white grape juice has up to 200 ug / l in fresh red up to 1100 ug / L resveratrol can prove. In red wine the concentration is considerably higher, at about 2 to 12 mg / l. White and rosé wines contain lower concentrations of resveratrol.
In his role as phytoalexin it protects plants during humid periods from parasites and fungal infections. Thus, it is made of the vine mainly in the leaves and grape skins in attack by mildew or botrytis. Stress, such as ultraviolet light, also leads to increased Resveratrolbildung.
In nature, both isomers of the substance exist - the trans form occurs much more frequently - as derived glucosides, which are also known as Piceide.
Effect
In vitro studies have suggested a possible activity against cancer cells have provided. Experiments on living organism are still pending. Other studies have demonstrated positive effects of the substance in diseases such as atherosclerosis, heart disease, Alzheimer's disease, arthritis and certain autoimmune diseases.
-Resveratrol promotes, as well as a low-calorie diet (caloric restriction), the expression of sirtuin genes such as Sir2. As a result, a life-prolonging effect was observed in various experimental animals. After several attempts questioned the effect of resveratrol on Sirtruin in question, the evidence of this effect in a new study now succeeded yet again.
-In an animal experiment study, mice were given a particularly high-fat diet. Co-administration of resveratrol decreased significantly while the weight gain. Under the highest resveratrol doses doubling the endurance performance was observed.
-Resveratrol helps in killing cancer cells by inhibiting it acts on a protein that is essential to the survival of cancer cells. This as NF-KB (nuclear factor kappa B) designated key protein is found in the nuclei of all cells. There, it is responsible for the activation of genes that are responsible for the survival of the cells. Resveratrol acts as an on NF-kB, that it can not exert its survival-promoting effect. This in turn leads to the affected cancer cells apoptosis, ie self-destruction. Researchers hope that the use of NF-KB inhibitors such as resveratrol can improve the effectiveness of established therapies against cancer significantly. However, the insolubility of resveratrol could still be a problem: Possibly it can not be absorbed by the body in sufficient quantity and so does not exert its effect against cancer and cardiovascular disease sufficiently.
Recent findings also show independent of NF-kB activity of resveratrol on various cancer cells. Thus, it brings about a reduction in these of the expression of the protein Bcl-2, which protects the degenerate cells before cell death. At the same time you could find an increased expression of zelltodfördernden (proapoptotic) protein Bax.
In the context of cancer must always be mentioned that most of the studies with resveratrol were made in vitro or in animal models. There is a lack of clinical studies and possible interactions with chemotherapy should always be considered and precisely considered. Two studies illustrate this aspect. In rats to which human cancer cells were implanted, resveratrol has the effect of the chemotherapeutic agents cisplatin and doxorubicin improved and at the same time develops a cardioprotective effect, thus protecting the heart cells from the toxicity of these agents. Resveratrol was administered simultaneously with the drug paclitaxel (Taxol) against cancer cells in vitro, it slowed down the krebstötende effect of paclitaxel. This is due to the fact that resveratrol inhibits the entry of cancer cells into the S phase of the cell cycle and the effect of paclitaxel unfolded exactly in this phase. The pre-treatment of cancer cells at an earlier stage, ie before the chemotherapy with paclitaxel, in turn, led to a synergistic effect, causing an increased cell death of the treated cancer cells.
-The activation of NF-kB plays a role in disease progression of multiple sclerosis. NF-kB inhibitors may therefore represent a therapeutic option in the future too.
-Resveratrol has a neuroprotective effect in glaucoma. An elevated intraocular pressure increased oxidative stress in the retina and trabecular meshwork. This leads to increased inflammatory markers such as interleukin-1α, interleukin-6, interleukin-8 and accelerate cell aging by oxidative species, such as lipofuscin in the cells of the trabecular meshwork and optic nerve. Resveratrol reduces the expression of these substances and therefore has an antioxidant and antiapoptotic in the trabecular meshwork and in the neurons of the optic nerve.
Trading
Nowadays you can buy resveratrol supplements in the United States as a dietary supplement in the free sale. Also in Germany since resveratrol supplements, usually produced from grape extract and offered for sale.
Chinese scientists have developed by the introduction of an additional gene of the stilbene a grape that in the red wine grape has six times more resveratrol than the parent strain. Moreover, the gene can be introduced into other plants that then produce resveratrol. This was tentatively performed successfully with the silver poplars (Populus alba).