Proanthocyanidin: Difference between revisions
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==Distribution in plants== |
==Distribution in plants== |
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Proanthocyanidins represent a group of condensed flavan-3-ols, such as procyanidins, prodelphinidins and propelargonidins, that can be found in many plants, most notably [[apple]]s, [[maritime pine]] bark, cinnamon, cocoa, grape seed, grape skin ([[procyanidins]] and [[prodelphinidins]])<ref> |
Proanthocyanidins represent a group of condensed flavan-3-ols, such as procyanidins, prodelphinidins and propelargonidins, that can be found in many plants, most notably [[apple]]s, [[maritime pine]] bark, cinnamon, cocoa, grape seed, grape skin ([[procyanidins]] and [[prodelphinidins]]),<ref>{{cite journal |doi=10.1016/0031-9422(96)00301-9}}</ref> and [[red wine]]s of ''[[Vitis vinifera]]'' (the common grape). However, [[bilberry]], [[cranberry]], [[black currant]], [[green tea]], [[black tea]], and other plants also contain these flavonoids. The berries of [[chokeberry]], specifically black chokeberry, have the highest measured concentrations of proanthocyanidin found in any plant to date.<ref>{{cite journal |pages=7846–56 |doi=10.1021/jf0486850}}</ref><ref>{{cite journal |first1=Liwei |last1=Gu |first2=Mark A. |last2=Kelm |first3=John F. |last3=Hammerstone |first4=Gary |last4=Beecher |first5=Joanne |last5=Holden |first6=David |last6=Haytowitz |first7=Susan |last7=Gebhardt |first8=Ronald L. |last8=Prior |title=Concentrations of proanthocyanidins in common foods and estimations of normal consumption |journal=J. Nutr. |volume=134 |issue=3 |pages=613–7 |month=March |year=2004 |pmid=14988456 |url=http://jn.nutrition.org/cgi/content/full/134/3/613}}</ref> |
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<ref>{{cite journal |
<ref>{{cite journal |pages=4057–61 |doi=10.1021/jf060360r}}</ref> Proanthocyanidins can also be isolated from ''[[Quercus petraea]]'' and ''[[Quercus robur|Q. robur]]'' heartwood (wine barrel [[Oak (wine)|oaks]]).<ref>{{cite journal |doi=10.1016/j.crci.2005.09.001}}</ref> |
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Apples contain on average per serving about eight times the amount of proanthocyanidin found in wine, with some of the highest amounts found in the [[Red Delicious]] and [[Granny Smith]] varieties.<ref>{{cite journal | |
Apples contain on average per serving about eight times the amount of proanthocyanidin found in wine, with some of the highest amounts found in the [[Red Delicious]] and [[Granny Smith]] varieties.<ref>{{cite journal |first1=John F. |last1=Hammerstone |first2=Sheryl A. |last2=Lazarus |first3=Harold H. |last3=Schmitz |title=Procyanidin content and variation in some commonly consumed foods |volume=130 |issue=8S Suppl |pages=2086S–92S |month=August |year=2000 |pmid=10917927 |url=http://jn.nutrition.org/cgi/content/full/130/8/2086S |quote=Figure 5}}</ref> A patented extract of [[maritime pine]] bark called Pycnogenol bears 65-75 percent proanthocyanidins (procyanidins).<ref name="Medline">{{cite journal |pmid=11996210}}</ref> Thus a 100 mg serving would contain 65 to 75 mg of proanthocyanidins (procyanidins). |
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Proanthocyanidin [[glycoside]]s can be isolated from [[cocoa liquor]].<ref>{{cite journal |doi=10.1016/S0031-9422(02)00051-1}}</ref> |
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Proanthocyanidin [[glycoside]]s can be isolated from [[cocoa liquor]]<ref>[http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TH7-4557218-1&_user=4296857&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1037783513&_rerunOrigin=google&_acct=C000012518&_version=1&_urlVersion=0&_userid=4296857&md5=de846459af63ea9f041ff2b5a383e80c Proanthocyanidin glycosides and related polyphenols from cacao liquor and their antioxidant effects. Tsutomu Hatanoa, Haruka Miyatakea, Midori Natsumeb, Naomi Osakabeb, Toshio Takizawab, Hideyuki Itoa and Takashi Yoshida, 2002]</ref>. |
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==Analysis== |
==Analysis== |
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[[DMACA reagent|DMACA]] is a dye that is particularly useful for localization of proanthocyanidin compounds in plant histology. The use of the reagent results in blue staining<ref> |
[[DMACA reagent|DMACA]] is a dye that is particularly useful for localization of proanthocyanidin compounds in plant histology. The use of the reagent results in blue staining.<ref>{{cite journal |pmid=17208963}}</ref> It can also be used to titrate proanthocyanidins. |
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Total phenols can be measured using the [[Folin-Ciocalteu reagent|Folin-Ciocalteu reaction]]. Results are typically expressed as gallic acid equivalents (GAE). |
Total phenols can be measured using the [[Folin-Ciocalteu reagent|Folin-Ciocalteu reaction]]. Results are typically expressed as gallic acid equivalents (GAE). |
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Proanthocyanidins can be titrated using the ''Procyanidolic Index'' (also called the ''Bates-Smith Assay''). It is a testing method that measures the change in color when the product is mixed with certain chemicals. The greater the color changes, the higher the OPCs content is. It must be noted, however, that the Procyanidolic Index is a relative value that can measure well over 100. Unfortunately, a Procyanidolic Index of 95 was erroneously taken to mean 95% OPC by some and began appearing on the labels of finished products. All current methods of analysis suggest that the actual OPC content of these products is much lower than 95%<ref>[http://www.activin.com/Testing%20White%20paper__.html Grape Seed Extract, White paper, The Grape Seed Method Evaluation Committee, Under the Auspices of NNFA ComPli]</ref> |
Proanthocyanidins can be titrated using the ''Procyanidolic Index'' (also called the ''Bates-Smith Assay''). It is a testing method that measures the change in color when the product is mixed with certain chemicals. The greater the color changes, the higher the OPCs content is. It must be noted, however, that the Procyanidolic Index is a relative value that can measure well over 100. Unfortunately, a Procyanidolic Index of 95 was erroneously taken to mean 95% OPC by some and began appearing on the labels of finished products. All current methods of analysis suggest that the actual OPC content of these products is much lower than 95%.<ref>[http://www.activin.com/Testing%20White%20paper__.html Grape Seed Extract, White paper, The Grape Seed Method Evaluation Committee, Under the Auspices of NNFA ComPli]</ref> |
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An improved colorimetric test, called the ''Porter Assay'' or ''butanol-HCl-iron method'', is the most common OPC assay currently in use<ref>[http://www.activin.com/learn/truthopc.pdf The Truth About OPCs, Debasis Bagchi, Ph.D. on www.activin.com]</ref> |
An improved colorimetric test, called the ''Porter Assay'' or ''butanol-HCl-iron method'', is the most common OPC assay currently in use.<ref>[http://www.activin.com/learn/truthopc.pdf The Truth About OPCs, Debasis Bagchi, Ph.D. on www.activin.com]</ref> The unit of measurement of the Porter Assay is the PVU (Porter Value Unit). The Porter Assay is a chemical test to help determine the potency of procyanidin containing compounds, such as grape seed extract. It is an acid hydrolysis, which splits larger chain units (dimers and trimers) into single unit monomers and oxidizes them. This leads to a colour change, which can be measured using a [[spectrophotometer]]. The greater the asorbance at a certain wavelength of light, the greater the potency. Ranges for grape seed extract are from 25 PVU for low grade material to over 300 for premium grape seed extracts<ref>[http://www.omegabiotech.com/product_analysis_certification.htm Prter Assay on www.omegabiotech.com]</ref>. |
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[[Gel permeation chromatography]] (GPC) analysis allows to separate monomers from larger OPC molecules. |
[[Gel permeation chromatography]] (GPC) analysis allows to separate monomers from larger OPC molecules. |
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Monomers of proanthocyanidins can be characterized by [[High pressure liquid chromatography|HPLC]] analysis. [[Condensed tannins]] can undergo acid-catalyzed cleavage in the presence of a [[nucleophile]] like [[phloroglucinol]], [[benzyl mercaptan]] or [[cysteamine]] (process called [[thiolysis]]<ref> |
Monomers of proanthocyanidins can be characterized by [[High pressure liquid chromatography|HPLC]] analysis. [[Condensed tannins]] can undergo acid-catalyzed cleavage in the presence of a [[nucleophile]] like [[phloroglucinol]], [[benzyl mercaptan]] or [[cysteamine]] (process called [[thiolysis]]<ref>{{cite journal |doi=10.1007/BF02491211}}</ref>) leading to the formation of oligomers that can be further analyzed. An excess phloroglucinol in a process called ''phloroglucinolysis'' produces proanthocyanidins<ref>[http://cat.inist.fr/?aModele=afficheN&cpsidt=15916101 Analysis of the oxidative degradation of proanthocyanidins under basic conditions. Jorgensen Emily M.; Marin Anna B.; Kennedy James A. 2004]</ref>. |
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==Uses== |
==Uses== |
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This information attracted the attention of public news media, describing that red wine consumption was associated with favorable intake of health-promoting flavonoids which correlate with [[oxygen radical absorbance capacity]] (ORAC). |
This information attracted the attention of public news media, describing that red wine consumption was associated with favorable intake of health-promoting flavonoids which correlate with [[oxygen radical absorbance capacity]] (ORAC). |
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In red wines, total oligomeric proanthocyanidin content, including [[catechins]], was substantially higher (177.18 ± 96.06 mg/L) than that in white wines (8.75 ± 4.53 mg/L). A relative high correlation in red wines was found between ORAC values and [[malvidin]] compounds (r = 0.75, P < 0.10), and proanthocyanidins (r = 0.87, P < 0.05).<ref>{{cite journal |
In red wines, total oligomeric proanthocyanidin content, including [[catechins]], was substantially higher (177.18 ± 96.06 mg/L) than that in white wines (8.75 ± 4.53 mg/L). A relative high correlation in red wines was found between ORAC values and [[malvidin]] compounds (r = 0.75, P < 0.10), and proanthocyanidins (r = 0.87, P < 0.05).<ref>{{cite journal |pages=4889–96 |doi=10.1021/jf030081t}}</ref> |
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In white wines, a significant correlation was found between the trimeric proanthocyanidin fraction and peroxyl radical scavenging values (r = 0.86, P < 0.10). |
In white wines, a significant correlation was found between the trimeric proanthocyanidin fraction and peroxyl radical scavenging values (r = 0.86, P < 0.10). |
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A moderate drink (1 drink per day, about 140 mL) of red wine, or white wine, or wine made from highbush [[blueberry]] corresponded to an intake of 2.04 ± 0.81 mmol of TE ''(Trolox equivalents)'' , 0.47 ± 0.15 mmol of TE, and 2.42 ± 0.88 mmol of TE of ORAC/day, respectively.<ref> |
A moderate drink (1 drink per day, about 140 mL) of red wine, or white wine, or wine made from highbush [[blueberry]] corresponded to an intake of 2.04 ± 0.81 mmol of TE ''(Trolox equivalents)'' , 0.47 ± 0.15 mmol of TE, and 2.42 ± 0.88 mmol of TE of ORAC/day, respectively.<ref>{{cite journal |pmid=12903941}}</ref><ref>http://www.blueberry.org/antioxidants.htm</ref> |
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Proanthocyanidins are the principal vasoactive polyphenols in red wine which is linked to a reduced risk of coronary heart disease and to lower overall mortality.<ref name=Corder06>{{cite journal |
Proanthocyanidins are the principal vasoactive polyphenols in red wine which is linked to a reduced risk of coronary heart disease and to lower overall mortality.<ref name=Corder06>{{cite journal |pages=566 |doi=10.1038/444566a}}</ref> Proanthocyanidins are present at higher concentrations in wines from areas of southwestern France and Sardinia which are associated with increased longevity in the population. Earlier studies that attributed this health benefit to [[resveratrol]] were premature because of the negligible amount of resveratrol in red wine. |
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Proanthocyanidins suppress production of a protein [[endothelin-1]] that constricts blood vessels.<ref name=Corder06/> |
Proanthocyanidins suppress production of a protein [[endothelin-1]] that constricts blood vessels.<ref name=Corder06/> |
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Proanthocyanidins have antioxidant activity and they play a role in the stabilization of collagen and maintenance of elastin — two critical proteins in connective tissue that support organs, joints, blood vessels, and muscle. Possibly because of their effects on blood vessels, proanthocyanidins have been reported in double-blind research to reduce the duration of edema after face-lift surgery from 15.9 to 11.5 days.{{Citation needed|date=August 2008}} In preliminary research, proanthocyanidins were reported to have anti-[[mutagenic]] activity (i.e., to prevent chromosomal mutations).{{Citation needed|date=January 2010}} |
Proanthocyanidins have antioxidant activity and they play a role in the stabilization of collagen and maintenance of elastin — two critical proteins in connective tissue that support organs, joints, blood vessels, and muscle. Possibly because of their effects on blood vessels, proanthocyanidins have been reported in double-blind research to reduce the duration of edema after face-lift surgery from 15.9 to 11.5 days.{{Citation needed|date=August 2008}} In preliminary research, proanthocyanidins were reported to have anti-[[mutagenic]] activity (i.e., to prevent chromosomal mutations).{{Citation needed|date=January 2010}} |
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Common antioxidants currently used are [[vitamin C]] and [[vitamin E]]; however, studies show that proanthocyanidins antioxidant capabilities are 20 times more powerful than vitamin C and 50 times more potent than [[vitamin E]] |
Common antioxidants currently used are [[vitamin C]] and [[vitamin E]]; however, studies show that proanthocyanidins antioxidant capabilities are 20 times more powerful than vitamin C and 50 times more potent than [[vitamin E]].<ref>{{cite journal |pages=291–9 |doi=10.1089/109662003772519831}}</ref> Proanthocyanidins found in French [[maritime pine]] bark and grape seed extract work directly to help strengthen all the [[blood vessels]] and improve the delivery of oxygen to the cells. Proanthocyanidins also have an affinity for cell membranes, providing nutritional support to reduce capillary permeability and fragility.{{Citation needed|date=January 2010}} Although [[flavonoids]] are widespread in nature, the powerful proanthocyanidin compound is most abundant and available from the bark of the maritime pine and in grape seeds, or pips. In addition, the particular proanthocyanidins found in the propriety extract for [[maritime pine]] bark called Pycnogenol have been shown to optimize the production of nitric acid in the artery walls so as to relax them and allow greater blood flow and reduced pressure.<ref name="Medline Second Reference">{{cite journal |pmid=18037769}}</ref> Additionally, this same preparation, Pycnogenol, has been found to normalize platelet adhesion (aggregation) so as to facilitate normal blood flow.<ref name="Medline Third Reference">{{cite journal |pmid=10498385}}</ref> |
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</ref>. Proanthocyanidins found in French [[maritime pine]] bark and grape seed extract work directly to help strengthen all the [[blood vessels]] and improve the delivery of oxygen to the cells. Proanthocyanidins also have an affinity for cell membranes, providing nutritional support to reduce capillary permeability and fragility.{{Citation needed|date=January 2010}} Although [[flavonoids]] are widespread in nature, the powerful proanthocyanidin compound is most abundant and available from the bark of the maritime pine and in grape seeds, or pips. In addition, the particular proanthocyanidins found in the propriety extract for [[maritime pine]] bark called Pycnogenol have been shown to optimize the production of nitric acid in the artery walls so as to relax them and allow greater blood flow and reduced pressure<ref name="Medline Second Reference">{{cite web |url=http://www.ncbi.nlm.nih.gov/pubmed/18037769|title=Pycnogenol, French maritime pine bark extract, augments endothelium-dependent vasodilation in humans|}}</ref>. Additionally, this same preparation, Pycnogenol, has been found to normalize platelet adhesion (aggregation) so as to facilitate normal blood flow <ref name="Medline Third Reference">{{cite web |url=http://www.ncbi.nlm.nih.gov/pubmed/10498385|title=Inhibition of smoking-induced platelet aggregation by aspirin and pycnogenol|}}</ref>. |
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==Oligomeric proanthocyanidins== |
==Oligomeric proanthocyanidins== |
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In 1948 Jack Masquelier discovered ''oligomeric proanthocyanidins'' (OPCs) in the skin of a [[peanut]] by accident. Oligomeric proanthocyanidins are a class of [[flavonoid]] complexes. OPCs are found in most plants and thus are a part of the human diet. Especially the skin, seeds and seed coverings of plants contain large amounts of oligomeric proanthocyanidins. They can be found in large quantities in grape seed extract and skin, in red grapes, in the red skins of peanuts, in [[coconut]]s, apples (dimeric [[procyanidin B2]]), in cocoa, and in the bark of ''[[Pinus pinaster]]'' (formerly known as ''Pinus maritima''). It can also be found in [[sea buckthorn oil]]<ref>{{cite journal |
In 1948 Jack Masquelier discovered ''oligomeric proanthocyanidins'' (OPCs) in the skin of a [[peanut]] by accident. Oligomeric proanthocyanidins are a class of [[flavonoid]] complexes. OPCs are found in most plants and thus are a part of the human diet. Especially the skin, seeds and seed coverings of plants contain large amounts of oligomeric proanthocyanidins. They can be found in large quantities in grape seed extract and skin, in red grapes, in the red skins of peanuts, in [[coconut]]s, apples (dimeric [[procyanidin B2]]), in cocoa, and in the bark of ''[[Pinus pinaster]]'' (formerly known as ''Pinus maritima''). It can also be found in [[sea buckthorn oil]].<ref>{{cite journal |pages=6712–8 |doi=10.1021/jf040241g}}</ref> |
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Oligomeric proanthocyanidins can be obtained by the mean of ''[[Vaccinium pahalae]]'' ''in vitro'' cell culture<ref> |
Oligomeric proanthocyanidins can be obtained by the mean of ''[[Vaccinium pahalae]]'' ''in vitro'' cell culture.<ref>{{cite journal |doi=10.1007/s11627-000-0088-1}}</ref> |
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===Biological signifiance=== |
===Biological signifiance=== |
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===Health benefits=== |
===Health benefits=== |
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In the human body, they might act as [[antioxidant]]s ([[free radical]] scavengers).{{Citation needed|date=February 2009}} OPCs may help protect against the effects of internal and environmental stresses such as cigarette smoking and pollution, as well as supporting normal body metabolic processes. The effects may include depressing blood fat, emolliating blood vessels, lowering blood pressure, preventing blood vessel scleroses, dropping blood viscidity and preventing [[thrombus]] formation |
In the human body, they might act as [[antioxidant]]s ([[free radical]] scavengers).{{Citation needed|date=February 2009}} OPCs may help protect against the effects of internal and environmental stresses such as cigarette smoking and pollution, as well as supporting normal body metabolic processes. The effects may include depressing blood fat, emolliating blood vessels, lowering blood pressure, preventing blood vessel scleroses, dropping blood viscidity and preventing [[thrombus]] formation.<ref>{{cite journal |first1=Karen J. |last1=Murphy |first2=Andriana K. |last2=Chronopoulos |first3=Indu |last3=Singh |first4=Maureen A. |last4=Francis |first5=Helen |last5=Moriarty |first6=Marilyn J. |last6=Pike |first7=Alan H. |last7=Turner |first8=Neil J. |last8=Mann |first9=Andrew J. |last9=Sinclair |title=Dietary flavanols and procyanidin oligomers from cocoa (''Theobroma cacao'') inhibit platelet function |volume=77 |issue=6 |pages=1466–73 |month=June |year=2003 |pmid=12791625 |url=http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=12791625 }}</ref> |
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| ⚫ | A French [[maritime pine]] bark extract of OPCs, Pycnogenol, has been shown to improve microcirculation, retinal edema and visual acuity in the early stages of [[diabetic retinopathy]]<ref>http://www.eurekalert.org/pub_releases/2009-12/mg-ssp113009.php "Study shows pine bark improves circulation, swelling and visual acuity in early diabetic retinopathy" Dec 2009</ref>. Further study has shown that Pycnogenol maintains [[antioxidant]] and anti-inflammatory properties, selectively binds to collagen and elastin in the body, and aids in the production of endothelial<ref name="WebMD">{{cite web |url=http://www.webmd.com/hypertension-high-blood-pressure/news/20040220/antioxidant-help-lower-blood-pressure|title=Antioxidant May Help Lower Blood Pressure|}}</ref> nitric oxide. Pycnogenol has also been shown to help normalize blood glucose (sugar) levels<ref name="American Diabetes Association">{{cite |
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| ⚫ | A French [[maritime pine]] bark extract of OPCs, Pycnogenol, has been shown to improve microcirculation, retinal edema and visual acuity in the early stages of [[diabetic retinopathy]]<ref>http://www.eurekalert.org/pub_releases/2009-12/mg-ssp113009.php "Study shows pine bark improves circulation, swelling and visual acuity in early diabetic retinopathy" Dec 2009</ref>. Further study has shown that Pycnogenol maintains [[antioxidant]] and anti-inflammatory properties, selectively binds to collagen and elastin in the body, and aids in the production of endothelial<ref name="WebMD">{{cite web |url=http://www.webmd.com/hypertension-high-blood-pressure/news/20040220/antioxidant-help-lower-blood-pressure|title=Antioxidant May Help Lower Blood Pressure|}}</ref> nitric oxide. Pycnogenol has also been shown to help normalize blood glucose (sugar) levels,<ref name="American Diabetes Association">{{cite journal |doi=10.2337/diacare.27.3.839}}</ref> and delay sugar absorption.<ref name="Medline Fourth Reference">{{cite journal |pmid=17098323}}</ref> |
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OPCs are available from fresh grapes, grape juice, and [[red wine]]. Although in milligrams per ounce red wine may contain more OPCs than red grape juice, red grape juice contains more OPCs per average serving size. An 8 ounce serving of grape juice averages 124 milligrams OPCs, while a 5 ounce serving of red wine averages 91 milligrams.<ref name=USDAdb>USDA Database for the Proanthocyanidin Content of Selected Foods – 2004 (http://www.nal.usda.gov/fnic/foodcomp/Data/PA/PA.html)</ref><ref name=mednews>Grape Juice Beats Wine in New Antioxidant Tests (http://www.medicalnewstoday.com/medicalnews.php?newsid=15553)</ref> Many other foods and beverages also contain high amounts of OPCs, but very few come close to the levels found in red grape seeds and skins (which readily disperse into grape juice when crushed).<ref name=USDAdb/> |
OPCs are available from fresh grapes, grape juice, and [[red wine]]. Although in milligrams per ounce red wine may contain more OPCs than red grape juice, red grape juice contains more OPCs per average serving size. An 8 ounce serving of grape juice averages 124 milligrams OPCs, while a 5 ounce serving of red wine averages 91 milligrams.<ref name=USDAdb>USDA Database for the Proanthocyanidin Content of Selected Foods – 2004 (http://www.nal.usda.gov/fnic/foodcomp/Data/PA/PA.html)</ref><ref name=mednews>Grape Juice Beats Wine in New Antioxidant Tests (http://www.medicalnewstoday.com/medicalnews.php?newsid=15553)</ref> Many other foods and beverages also contain high amounts of OPCs, but very few come close to the levels found in red grape seeds and skins (which readily disperse into grape juice when crushed).<ref name=USDAdb/> |
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==References== |
==References== |
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{{Reflist}} |
{{Reflist}} |
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==External links== |
==External links== |
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* {{cite journal |pages=45–54 |doi= 10.1248/jhs.49.45}} |
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* {{cite journal |author= Nakamura, Yumiko|title=Analysis of Proanthocyanidins in Grape Seed Extracts, Health Foods and Grape Seed Oils |journal=J. Health Sci. |volume=49 |issue=1 |pages=45–54 |year=2003 |url=http://jhs.pharm.or.jp/49(1)/49_45.htm |doi= 10.1248/jhs.49.45 |last2= Tsuji |first2= Sumiko |last3= Tonogai |first3= Yasuhide}} |
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* {{cite journal |
* {{cite journal |pages=144–51 |year=2000 |month=April |pmid=10767669 |url=http://www.thorne.com/altmedrev/.fulltext/5/2/144.pdf}} |
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* [http://www.nal.usda.gov/fnic/foodcomp/Data/PA/PA.html "USDA Database for the Proanthocyanidin Content of Selected Foods - 2004"] |
* [http://www.nal.usda.gov/fnic/foodcomp/Data/PA/PA.html "USDA Database for the Proanthocyanidin Content of Selected Foods - 2004"] |
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* [http://www.eurekalert.org/pub_releases/2006-10/aafc-gse101606.php Grape seed extract halts cell cycle, checking growth of colorectal tumors in mice] |
* [http://www.eurekalert.org/pub_releases/2006-10/aafc-gse101606.php Grape seed extract halts cell cycle, checking growth of colorectal tumors in mice] |
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Revision as of 10:24, 9 October 2010
 | It has been suggested that this article be merged with A Type Proanthocyanidin. (Discuss) Proposed since September 2009. |
 | This article needs attention from an expert in Chemistry. Please add a reason or a talk parameter to this template to explain the issue with the article. (November 2008) |
Proanthocyanidin (PA or PAC), also known as procyanidin, oligomeric proanthocyanidin (OPC), leukocyanidin, leucoanthocyanin and condensed tannins, is a class of flavanols. Proanthocyanidins are essentially polymer chains of flavonoids such as catechins.[1] One was discovered in 1948 by Jacques Masquelier and called Vitamin P, although this name did not gain official category status and has since fallen out of usage. It was Masquelier who first developed techniques for the extraction of proanthocyanidins from certain plant species.
Proanthocyanidins have been sold as nutritional and therapeutic supplements in Europe since the 1980s. In contrast, the introduction of proanthocyanidins to the United States market has been relatively recent.
Distribution in plants
Proanthocyanidins represent a group of condensed flavan-3-ols, such as procyanidins, prodelphinidins and propelargonidins, that can be found in many plants, most notably apples, maritime pine bark, cinnamon, cocoa, grape seed, grape skin (procyanidins and prodelphinidins),[2] and red wines of Vitis vinifera (the common grape). However, bilberry, cranberry, black currant, green tea, black tea, and other plants also contain these flavonoids. The berries of chokeberry, specifically black chokeberry, have the highest measured concentrations of proanthocyanidin found in any plant to date.[3][4] [5] Proanthocyanidins can also be isolated from Quercus petraea and Q. robur heartwood (wine barrel oaks).[6]
Apples contain on average per serving about eight times the amount of proanthocyanidin found in wine, with some of the highest amounts found in the Red Delicious and Granny Smith varieties.[7] A patented extract of maritime pine bark called Pycnogenol bears 65-75 percent proanthocyanidins (procyanidins).[8] Thus a 100 mg serving would contain 65 to 75 mg of proanthocyanidins (procyanidins).
Proanthocyanidin glycosides can be isolated from cocoa liquor.[9]
Analysis
DMACA is a dye that is particularly useful for localization of proanthocyanidin compounds in plant histology. The use of the reagent results in blue staining.[10] It can also be used to titrate proanthocyanidins.
Total phenols can be measured using the Folin-Ciocalteu reaction. Results are typically expressed as gallic acid equivalents (GAE).
Proanthocyanidins can be titrated using the Procyanidolic Index (also called the Bates-Smith Assay). It is a testing method that measures the change in color when the product is mixed with certain chemicals. The greater the color changes, the higher the OPCs content is. It must be noted, however, that the Procyanidolic Index is a relative value that can measure well over 100. Unfortunately, a Procyanidolic Index of 95 was erroneously taken to mean 95% OPC by some and began appearing on the labels of finished products. All current methods of analysis suggest that the actual OPC content of these products is much lower than 95%.[11]
An improved colorimetric test, called the Porter Assay or butanol-HCl-iron method, is the most common OPC assay currently in use.[12] The unit of measurement of the Porter Assay is the PVU (Porter Value Unit). The Porter Assay is a chemical test to help determine the potency of procyanidin containing compounds, such as grape seed extract. It is an acid hydrolysis, which splits larger chain units (dimers and trimers) into single unit monomers and oxidizes them. This leads to a colour change, which can be measured using a spectrophotometer. The greater the asorbance at a certain wavelength of light, the greater the potency. Ranges for grape seed extract are from 25 PVU for low grade material to over 300 for premium grape seed extracts[13].
Gel permeation chromatography (GPC) analysis allows to separate monomers from larger OPC molecules.
Monomers of proanthocyanidins can be characterized by HPLC analysis. Condensed tannins can undergo acid-catalyzed cleavage in the presence of a nucleophile like phloroglucinol, benzyl mercaptan or cysteamine (process called thiolysis[14]) leading to the formation of oligomers that can be further analyzed. An excess phloroglucinol in a process called phloroglucinolysis produces proanthocyanidins[15].
Uses
This information attracted the attention of public news media, describing that red wine consumption was associated with favorable intake of health-promoting flavonoids which correlate with oxygen radical absorbance capacity (ORAC).
In red wines, total oligomeric proanthocyanidin content, including catechins, was substantially higher (177.18 ± 96.06 mg/L) than that in white wines (8.75 ± 4.53 mg/L). A relative high correlation in red wines was found between ORAC values and malvidin compounds (r = 0.75, P < 0.10), and proanthocyanidins (r = 0.87, P < 0.05).[16]
In white wines, a significant correlation was found between the trimeric proanthocyanidin fraction and peroxyl radical scavenging values (r = 0.86, P < 0.10).
A moderate drink (1 drink per day, about 140 mL) of red wine, or white wine, or wine made from highbush blueberry corresponded to an intake of 2.04 ± 0.81 mmol of TE (Trolox equivalents) , 0.47 ± 0.15 mmol of TE, and 2.42 ± 0.88 mmol of TE of ORAC/day, respectively.[17][18]
Proanthocyanidins are the principal vasoactive polyphenols in red wine which is linked to a reduced risk of coronary heart disease and to lower overall mortality.[19] Proanthocyanidins are present at higher concentrations in wines from areas of southwestern France and Sardinia which are associated with increased longevity in the population. Earlier studies that attributed this health benefit to resveratrol were premature because of the negligible amount of resveratrol in red wine.
Proanthocyanidins suppress production of a protein endothelin-1 that constricts blood vessels.[19]
These studies provide data supporting the French Paradox which hypothesizes that intake of proanthocyanidins and other flavonoids from regular consumption of red wines prevents occurrence of a higher disease rate (cardiovascular diseases, diabetes) in French citizens on high-fat diets.[19]
Proanthocyanidins have antioxidant activity and they play a role in the stabilization of collagen and maintenance of elastin — two critical proteins in connective tissue that support organs, joints, blood vessels, and muscle. Possibly because of their effects on blood vessels, proanthocyanidins have been reported in double-blind research to reduce the duration of edema after face-lift surgery from 15.9 to 11.5 days.[citation needed] In preliminary research, proanthocyanidins were reported to have anti-mutagenic activity (i.e., to prevent chromosomal mutations).[citation needed]
Common antioxidants currently used are vitamin C and vitamin E; however, studies show that proanthocyanidins antioxidant capabilities are 20 times more powerful than vitamin C and 50 times more potent than vitamin E.[20] Proanthocyanidins found in French maritime pine bark and grape seed extract work directly to help strengthen all the blood vessels and improve the delivery of oxygen to the cells. Proanthocyanidins also have an affinity for cell membranes, providing nutritional support to reduce capillary permeability and fragility.[citation needed] Although flavonoids are widespread in nature, the powerful proanthocyanidin compound is most abundant and available from the bark of the maritime pine and in grape seeds, or pips. In addition, the particular proanthocyanidins found in the propriety extract for maritime pine bark called Pycnogenol have been shown to optimize the production of nitric acid in the artery walls so as to relax them and allow greater blood flow and reduced pressure.[21] Additionally, this same preparation, Pycnogenol, has been found to normalize platelet adhesion (aggregation) so as to facilitate normal blood flow.[22]
Oligomeric proanthocyanidins
In 1948 Jack Masquelier discovered oligomeric proanthocyanidins (OPCs) in the skin of a peanut by accident. Oligomeric proanthocyanidins are a class of flavonoid complexes. OPCs are found in most plants and thus are a part of the human diet. Especially the skin, seeds and seed coverings of plants contain large amounts of oligomeric proanthocyanidins. They can be found in large quantities in grape seed extract and skin, in red grapes, in the red skins of peanuts, in coconuts, apples (dimeric procyanidin B2), in cocoa, and in the bark of Pinus pinaster (formerly known as Pinus maritima). It can also be found in sea buckthorn oil.[23]
Oligomeric proanthocyanidins can be obtained by the mean of Vaccinium pahalae in vitro cell culture.[24]
Biological signifiance
In nature, it is possible that OPCs serve as a plant defense against herbivory.
Health benefits
In the human body, they might act as antioxidants (free radical scavengers).[citation needed] OPCs may help protect against the effects of internal and environmental stresses such as cigarette smoking and pollution, as well as supporting normal body metabolic processes. The effects may include depressing blood fat, emolliating blood vessels, lowering blood pressure, preventing blood vessel scleroses, dropping blood viscidity and preventing thrombus formation.[25]
Additionally, studies have shown that OPCs may prevent cardiovascular diseases by counteracting the negative effects of high cholesterol on the heart and blood vessels.
A French maritime pine bark extract of OPCs, Pycnogenol, has been shown to improve microcirculation, retinal edema and visual acuity in the early stages of diabetic retinopathy[26]. Further study has shown that Pycnogenol maintains antioxidant and anti-inflammatory properties, selectively binds to collagen and elastin in the body, and aids in the production of endothelial[27] nitric oxide. Pycnogenol has also been shown to help normalize blood glucose (sugar) levels,[28] and delay sugar absorption.[29]
OPCs are available from fresh grapes, grape juice, and red wine. Although in milligrams per ounce red wine may contain more OPCs than red grape juice, red grape juice contains more OPCs per average serving size. An 8 ounce serving of grape juice averages 124 milligrams OPCs, while a 5 ounce serving of red wine averages 91 milligrams.[30][31] Many other foods and beverages also contain high amounts of OPCs, but very few come close to the levels found in red grape seeds and skins (which readily disperse into grape juice when crushed).[30]
Grape seed oil controversy
A number of grape seed oil vendors have claimed that grape seed oil is high in OPCs. However independent studies have indicated that grape seed oil is actually the grape product with the lowest concentration of OPCs. This is because OPCs are polar molecules which have very low solubility in nonpolar solvents such as oils.
See also
References
 |
- ^ "PhenolicsInterm". www.herbalchem.net. Retrieved 2008-03-17.
- ^ . doi:10.1016/0031-9422(96)00301-9.
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{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ Gu, Liwei; Kelm, Mark A.; Hammerstone, John F.; Beecher, Gary; Holden, Joanne; Haytowitz, David; Gebhardt, Susan; Prior, Ronald L. (2004). "Concentrations of proanthocyanidins in common foods and estimations of normal consumption". J. Nutr. 134 (3): 613–7. PMID 14988456.
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{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ Hammerstone, John F.; Lazarus, Sheryl A.; Schmitz, Harold H. (2000). "Procyanidin content and variation in some commonly consumed foods". 130 (8S Suppl): 2086S–92S. PMID 10917927.
Figure 5
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{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ . PMID 17208963.
{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ Grape Seed Extract, White paper, The Grape Seed Method Evaluation Committee, Under the Auspices of NNFA ComPli
- ^ The Truth About OPCs, Debasis Bagchi, Ph.D. on www.activin.com
- ^ Prter Assay on www.omegabiotech.com
- ^ . doi:10.1007/BF02491211.
{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ Analysis of the oxidative degradation of proanthocyanidins under basic conditions. Jorgensen Emily M.; Marin Anna B.; Kennedy James A. 2004
- ^ : 4889–96. doi:10.1021/jf030081t.
{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ . PMID 12903941.
{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ http://www.blueberry.org/antioxidants.htm
- ^ a b c : 566. doi:10.1038/444566a.
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{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ . PMID 18037769.
{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ . PMID 10498385.
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{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ . doi:10.1007/s11627-000-0088-1.
{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ Murphy, Karen J.; Chronopoulos, Andriana K.; Singh, Indu; Francis, Maureen A.; Moriarty, Helen; Pike, Marilyn J.; Turner, Alan H.; Mann, Neil J.; Sinclair, Andrew J. (2003). "Dietary flavanols and procyanidin oligomers from cocoa (Theobroma cacao) inhibit platelet function". 77 (6): 1466–73. PMID 12791625.
{{cite journal}}: Cite journal requires|journal=(help); Unknown parameter|month=ignored (help) - ^ http://www.eurekalert.org/pub_releases/2009-12/mg-ssp113009.php "Study shows pine bark improves circulation, swelling and visual acuity in early diabetic retinopathy" Dec 2009
- ^ "Antioxidant May Help Lower Blood Pressure".
{{cite web}}: Cite has empty unknown parameter:|1=(help) - ^ . doi:10.2337/diacare.27.3.839.
{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ . PMID 17098323.
{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - ^ a b USDA Database for the Proanthocyanidin Content of Selected Foods – 2004 (http://www.nal.usda.gov/fnic/foodcomp/Data/PA/PA.html)
- ^ Grape Juice Beats Wine in New Antioxidant Tests (http://www.medicalnewstoday.com/medicalnews.php?newsid=15553)
Further reading
- Campagna P (2008). Farmaci vegetali – Manuale ragionato di fitoterapia. Torino: Minerva Medica. ISBN 9788877116031.
External links
- : 45–54. doi:10.1248/jhs.49.45.
{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help) - . 2000: 144–51. PMID 10767669 http://www.thorne.com/altmedrev/.fulltext/5/2/144.pdf.
{{cite journal}}: Cite journal requires|journal=(help); Missing or empty|title=(help); Unknown parameter|month=ignored (help) - "USDA Database for the Proanthocyanidin Content of Selected Foods - 2004"
- Grape seed extract halts cell cycle, checking growth of colorectal tumors in mice