Resveratrol

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Resveratrol
Chemical 9–69 structure of trans-resveratrol
Chemical structure of trans-resveratrol
Chemical structures of cis- and trans-resveratrols
Chemical structures of cis- ((Z)-resveratrol, left) and trans-resveratrol ((E)-resveratrol, right)[1]
Names
Other names
trans-3,5,4'-Trihydroxystilbene;
3,4',5-Stilbenetriol;
trans-Resveratrol;
(E)-5-(p-Hydroxystyryl)resorcinol;
(E)-5-(4-hydroxystyryl)benzene-1,3-diol
Identifiers
501-36-0 YesY
ChEBI CHEBI:45713 YesY
ChEMBL ChEMBL165 YesY
ChemSpider 392875 YesY
DrugBank DB02709 YesY
Jmol 3D model Interactive image
KEGG C03582 YesY
PubChem 445154
RTECS number CZ8987000
UNII Q369O8926L YesY
  • InChI=1S/C14H12O3/c15-12-5-3-10(4-6-12)1-2-11-7-13(16)9-14(17)8-11/h1-9,15-17H/b2-1+ YesY
    Key: LUKBXSAWLPMMSZ-OWOJBTEDSA-N YesY
  • InChI=1/C14H12O3/c15-
    12-5-3-10(4-6-12)
    1-2-11-7-13(16)9-
    14(17)8-11/h1-9,15-
    17H/b2-1+
  • Oc2ccc(C=Cc1cc(O)cc(O)c1)cc2
Properties
C14H12O3
Molar mass 228.25 g·mol−1
Appearance white powder with
slight yellow cast
Melting point 261 to 263 °C (502 to 505 °F; 534 to 536 K)[2]
Solubility in water 0.03 g/L
Solubility in DMSO 16 g/L
Solubility in ethanol 50 g/L
UV-vismax) 304nm (trans-resveratrol, in water)
286nm (cis-resveratrol, in water)[1]
Vapor pressure {{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references
UV visible spectrum of trans-resveratrol

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a stilbenoid, a type of natural phenol, and a phytoalexin produced naturally by several plants in response to injury or when the plant is under attack by pathogens such as bacteria or fungi.[3] Food sources of resveratrol include the skin of grapes, blueberries, raspberries, and mulberries.[4] As of 2015, there is limited evidence of health effects in humans.

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Health effects

Heart disease

There is little evidence of benefit from resveratrol in those who already have heart disease.[5] A 2014 meta-analysis found that resveratrol supplementation at usual doses has no effect on blood pressure but may help if high doses are used.[6]

Cancer

As of 2014, evidence of an effect of resveratrol on cancer in humans is inconsistent.[7]

Metabolism

There is very little human evidence of an effect of resveratrol on metabolism.[8] Tentative data supports a potential benefit in controlling some biomarkers in diabetes but further evidence is needed before it can be recommended.[9]

Lifespan

The effect of resveratrol on lifespan in humans is unclear as of 2011.[10]

Adverse effects

Long-term effects of using resveratrol are currently unknown but clinical trials have shown that it is well tolerated during the trials.[6][9]

Discovery and name

The first mention of resveratrol was in a Japanese article in 1939 by Michio Takaoka, who isolated it from the poisonous, but medicinal, Veratrum album, variety grandiflorum.[11] The name presumably comes from the fact that it is a resorcinol derivative coming from a Veratrum species.[12] In 2003, D. Sinclair from Harvard Medical School reported in Nature that resveratrol activated sirtuins in yeast cells. This was immediately followed by the launch of Sirtris Pharmaceuticals. While pharmacological effects of resveratrol did not turn out to be commercially viable, their discovery led to efforts to develop other types of SIRT genes' activators.

Pharmacokinetics

One way of administering resveratrol in humans may be buccal delivery, that is without swallowing, by direct absorption through tissues on the inside of the mouth. When one milligram of resveratrol in 50 ml 50% alcohol/ water solution was retained in the mouth for one minute before swallowing, 37 ng/ml of free resveratrol were measured in plasma two minutes later. This level of unchanged resveratrol in blood can only be achieved with 250 mg of resveratrol taken in a pill form.[13] However, the viability of a buccal delivery method is called into question due to the low aqueous solubility of the molecule. For a drug to be absorbed transmucosally it must be in free-form or dissolved.[14][15] Resveratrol fits the criteria for oral transmucosal dosing, except for this caveat. The low aqueous solubility greatly limits the amount that can be absorbed through the buccal mucosa. Resveratrol that is attempted to be taken buccally was expected to pass through the mucous membrane of the mouth and be absorbed as an oral dose,[16] however, the need to explore buccal delivery in future pharmaceutical formulations was expressed.[15][17]

While 70% of orally administered resveratrol is absorbed its oral bioavailability is approximately 0.5% due to extensive hepatic glucuronidation and sulfation.[18] Only trace amounts (below 5 ng/ml) of unchanged resveratrol could be detected in the blood after 25 mg oral dose.[18] Even when a very large dose (2.5 and 5 g) was given as an uncoated pill, the concentration of resveratrol in blood failed to reach the level claimed to be necessary for the systemic cancer prevention.[19] A formulation of resveratrol in a chewing gum form is now in production, and this would be expected to achieve much higher blood levels than oral formulations. Resveratrol given in a proprietary formulation SRT-501 (3 or 5 g), developed by Sirtris Pharmaceuticals, reached five to eight times higher blood levels. These levels did approach the concentration necessary to exert the effects shown in animal models and in vitro experiments.[20] On May 5, 2010, however, GlaxoSmithKline (GSK) said it had suspended a small clinical trial of SRT501, a proprietary form of resveratrol, due to safety concerns, and terminated the study on December 2, 2010.[21]

In humans and rats less than 5% of the oral dose was observed as free resveratrol in blood plasma.[18][19][22][23][24] The most abundant resveratrol metabolites in humans, rats, and mice are trans-resveratrol-3-O-glucuronide and trans-resveratrol-3-sulfate.[25] Walle suggests sulfate conjugates are the primary source of activity,[18] Wang et al. suggests the glucuronides,[26] and Boocock et al. also emphasized the need for further study of the effects of the metabolites, including the possibility of deconjugation to free resveratrol inside cells. Goldberd, who studied the pharmacokinetics of resveratrol, catechin and quercetin in humans, concluded "it seems that the potential health benefits of these compounds based upon the in vitro activities of the unconjugated compounds are unrealistic and have been greatly exaggerated. Indeed, the profusion of papers describing such activities can legitimately be described as irrelevant and misleading. Henceforth, investigations of this nature should focus upon the potential health benefits of their glucuronide and sulfate conjugates."[27]

The hypothesis that resveratrol from wine could have higher bioavailability than resveratrol from a pill[28][29] has been refuted by experimental data.[27][30] For example, after five men took 600 ml of red wine with the resveratrol content of 3.2 mg/l (total dose about 2 mg) before breakfast, unchanged resveratrol was detected in the blood of only two of them, and only in trace amounts (below 2.5 ng/ml). Resveratrol levels appeared to be slightly higher if red wine (600 ml of red wine containing 0.6 µg/ml resveratrol; total dose about 0.5 mg) was taken with a meal: trace amounts (1–6 ng/ml) were found in four out of ten subjects.[30] In another study, the pharmacokinetics of resveratrol (25 mg) did not change whether it was taken with vegetable juice, white wine, or white grape juice. The highest level of unchanged resveratrol in the serum (7–9 ng/ml) was achieved after 30 minutes, and it completely disappeared from blood after four hours.[27] The authors of both studies concluded the trace amounts of resveratrol reached in the blood are insufficient to explain the French paradox. The beneficial effects of wine apparently could be explained by the effects of alcohol[27] or the whole complex of substances wine contains;[30] for example, the cardiovascular benefits of wine appear to correlate with the content of procyanidins.[31]

Mechanisms of action