Polyphenols

What are Polyphenols?

Polyphenols are compounds found in nature. More specifically they are found in plants and provide coloring for some. Their purpose appears to be a potent, natural antioxidant. There are many plants that we consume that contain polyphenols. Concentrations are high in Olive oil and Green Tea and have been the subject of many health articles and promoted to enhance your health.

How do Polyphenols work?

These antioxidants eliminate free radicals, unstable molecules that are the major cause of both aging and disease, in both plants and humans. Free radicals continually attack the body. Free radicals are a normal product of metabolism and result in a process called oxidation. Polyphenols and other antioxidants, including beta carotene (a vitamin A precursor), vitamin C, vitamin E, and selenium, scavenge these free radicals and help to prevent formation of unstable oxygen molecules, known as oxidation. Oxidation can damage healthy cells in the body and have been linked to many diseases including cancer, heart disease and stroke. Polyphenols not only work to prevent diseases but may also help to reduce abnormal cells and inflammation; get rid of cancer causing agents and restore cells back to normal health.

What foods contain Polyphenols?

There are many but there are only a few, which contain particularly high levels. They include red wine, olive oil, black and green tea. Green Tea is the #1 source of polyphenols. These extremely high levels of polyphenols deliver green tea's unique results in several ways. Just one example is a subgroup of polyphenols, exclusive to green tea, called catechins. EGCG, the most abundant and powerful of green tea's 5 main catechins, is dubbed the 'super antioxidant' because it is 200 times more powerful than the popular antioxidant vitamin E. Unfortunately, polyphenols have a short life span (short half life) of about 3 hours, thus the scientific reason behind researchers' recommendation to drink green tea a minimum of 8 times a day.

Not only may green tea protect and heal the body from disease but also clinical trials, conducted by the University of Geneva, in Switzerland, indicate that green tea raises metabolic rates and speed up fat oxidation. In addition to caffeine, green tea's catechin polyphenols raise thermogenesis (the rate at which calories are burned) and hence increases energy expenditure. And, research at the University of Chicago has shown green tea extract injections in rats to cause appetite suppression. They consumed 60 percent less food and lost 21 percent of their body weight. However, as explained by the scientists, a person would have to drink green tea almost constantly to obtain these results.

Research is still continuing with green tea and more health benefits continue to be discovered. For instance, EGCG's may one day play a role in treatment of mad cow disease (Nature Structural and Molecular Biology, DOI:10.1038/nsmb743). And the formation of unstable oxygen molecules in the body is unavoidable. Aging, smoke, and environmental pollutants are all sources of the damaging free radicals. Japan and China have benefited from drinking green tea vs. black tea, like the rest of us, for centuries. The west is just now catching on to the benefits of green tea. With green tea being no more harmful than a cup of coffee (and actually containing less caffeine) there's no reason why you shouldn't begin today to benefit from green tea too.

Apple Polyphenols, Phloretin and Phloridzin: New Trapping Agents of Reactive Dicarbonyl Species.

Shao X, Bai N, He K, Ho CT, Yang CS, Sang S. Chem Res Toxicol. 2008 Sep 6. [Epub ahead of print]
Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers University, 164 Frelinghuysen Road, Piscataway, NJ 08854-8020; Human Nutrition research program, Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, North Carolina Research Campus, 500 Laureate Way, Kannapolis, NC 28081; Department of Food Science, Rutgers University, 65 Dudley Road, New Brunswick, NJ 08901-8520; Naturex, 375 Huyler Street, South Hackensack, NJ 07606; and Department of Chemistry, North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707 ssang@nccu.edu.

Reactive dicarbonyl species, such as methylglyoxal (MGO) and glyoxal (GO), have received extensive attention recently due to their high reactivity and ability to form advanced glycation end products (AGEs) with biological substances such as proteins, phospholipids, and DNA. In the present study, we found that both phloretin and its glucoside, phloridzin, the major bioactive apple polyphenols, could efficiently trap reactive MGO or GO to form mono- and di-MGO or GO adducts under physiological conditions (pH 7.4, 37 degrees C).

More than 80% MGO was trapped within 10 min, and 68% GO was trapped within 24 h by phloretin. Phloridzin also had strong trapping efficiency by quenching more than 70% MGO and 60% GO within 24 h. The glucosylation of the hydroxyl group at position 2 could significantly slow down the trapping rate and the formation of MGO or GO adducts. The products formed from phloretin (or phloridzin) and MGO (or GO), combined at different ratios, were analyzed using LC/MS. We successfully purified the major mono-MGO adduct of phloridzin and found that it was a mixture of tautomers based on the one- and two-dimensional NMR spectra.

Our LC/MS and NMR data showed that positions 3 and 5 of the phloretin or phloridzin A ring were the major active sites for trapping reactive dicarbonyl species. We also found that phloretin was more reactive than lysine and arginine in terms of trapping reactive dicarbonyl species, MGO or GO. Our results suggest that dietary flavonoids that have the same A ring structure as phloretin may have the potential to trap reactive dicarbonyl species and therefore inhibit the formation of AGEs.

Polyphenol levels and free radical scavenging activities of four apple cultivars from integrated and organic farming in different italian areas.

Polyphenol levels and free radical scavenging activities of four apple cultivars from integrated and organic farming in different italian areas.

Lamperi L, Chiuminatto U, Cincinelli A, Galvan P, Giordani E, Lepri L, Del Bubba M.
Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Florence, Italy.
This paper investigates the influence of cultivar (Annurca, Golden Delicious, Red Chief, and Stayman Neepling), rural practice (integrated and organic), and growing region (different Italian regions) on polyphenol composition and antiradical activity of the pulp and skin of apples, as presented to the consumer at the market. Antiradical activity of fruit was strongly related with the total polyphenolic content, determined both by the spectrophotometric Folin-Ciocalteu method ( R (2) = 0.90; P < 0.01) and by HPLC ( R (2) = 0.85; P < 0.01). Considering the edible portion of the fruit, polyphenolics contribute toward explaining approximately 90% of the overall antiradical activity, thus highlighting their important role in human health protection. Therefore, the data indirectly indicated that ascorbic acid and other antiradical molecules differing from polyphenols play a much less important role in explaining the health-protecting properties of apples. Cultivar effect was by far the most important, and Annurca and Golden Delicious were respectively the best and the worst apples from the point of view of the health-protecting attributes.

apple_polyphenols_longevity_annurca

Urinary flavonoids and phenolic acids as biomarkers of intake for polyphenol-rich foods.

Mennen LI, Sapinho D, Ito H, Bertrais S, Galan P, Hercberg S, Scalbert A.
UMR INSERM U557/INRA/CNAM, ISTNA-CNAM, 5 rue du Vertbois, 75003 Paris, France. louise.mennen@cnam.fr Br J Nutr. 2006 Jul;96(1):191-8.

Estimation of dietary intake of polyphenols is difficult, due to limited availability of food composition data and bias inherent to dietary assessment methods. The aim of the present study was to evaluate the associations between the intake of polyphenol-rich foods and the urinary excretion of several phenolic compounds and therefore explore whether these phenolic compounds could be used as a biomarker of intake.

Fifty-three participants of the SU.VI.MAX study (a randomised primary-prevention trial evaluating the effect of daily antioxidant supplementation on chronic diseases) collected a 24 h urine and a spot urine sample and filled a dietary record during a 2 d period. Thirteen polyphenols and metabolites, chlorogenic acid, caffeic acid, m-coumaric acid, gallic acid, 4-O-methylgallic acid, quercetin, isorhamnetin, kaempferol, hesperetin, naringenin, phloretin, enterolactone and enterodiol, were measured using HPLC-electrospray ionisation-MS-MS.

In spot samples apple consumption was positively correlated to phloretin, grapefruit consumption to naringenin, orange to hesperetin, citrus fruit consumption to both naringenin and hesperetin, with r coefficients ranging from 0.31 to 0.57 (P < 0.05). The combination of fruits and/or fruit juices was positively correlated to gallic acid and 4-O-methylgallic acid, isorhamnetin, kaempferol, hesperetin, naringenin and phloretin (r 0.24-0.44, P < 0.05).

Coffee consumption was positively correlated to caffeic and chlorogenic acids (r 0.29 and 0.63, P < 0.05 respectively). Black tea and wine consumption were positively correlated with gallic and 4-O-methylgallic acids (r 0.37-0.54, P < 0.001). The present results suggest that several polyphenols measured in a spot urine sample can be used as biomarkers of polyphenol-rich food intake.