Of polyphenol derivatives

Rios LY, Gonthier MP, Remesy C, Mila I, Lapierre C, Lazarus SA, Williamson G, Scalbert A. 2003. Chocolate intake increases urinary excretion of polyphenol-derived phenolic acids in healthy human subjects. Am J Clin Nutr 77 912-918. 

For about ten years, I have been interested in the antioxidant properties of polyphenol derivatives, i.e., interaction with various reactive oxygen species such as hydroxyl radical (OH0) superoxide (O2 0) as well as their enzymatic source (xanthine oxidase)[53-56]. 

So what causes this unique effect of red wine Part of the story is the high trace element content in comparison with beer or spirits, but this is not all. White wine and red wine are very similar as far as the main components are concerned. Red wine, however, contains about 20 times more of polyphenol derivatives than white wine. Alcohohc beverages are pro-oxidants, which means that they increase the intensity of oxidation processes. Alcohol itself is responsible for this effect. Red wine, however, is an antioxidant (—>3.31) thanks to its polyphenol content. Antioxidants were very intensely researched in the 1980s and 1990s, which also contributed to the increasing interest in red wine. The presence of polyphenols is required for this effect, but this is still not the whole story. 

Kammerer ei aL1(n m have conducted extensive studies on the template polymerization of acrylate or methacrylate derivatives of polyphenolic oligomers 22 with X n < 5 (Scheme 8.14). Under conditions of low "monomer" and high initiator concentration they found that X n for the daughter polymer was the same as X n for the parent. The possibility of using such templates to control microstructure was considered but not reported. 

In addition to the bitter acids and essential oils, the flowers of hops offer a rich array of polyphenolic compounds, primarily chalcones and their accompanying flavanones, many of which are prenylated derivatives (Stevens et al., 1997,1999a, b). The most prominent flavonoid in all plants studied was xanthohumol [342] (3 -prenyl-6 -0-methylchalconaringenin chalconaringenin is 2, 4, 6, 4-tetrahydroxychalcone) (see Fig. 4.11 for structures 342-346). Several additional chalcones—variously adorned with 0-methyl and/or C-prenyl functions—were also encountered, along with their respective flavanones. Three new compounds were described in the Stevens et al. 

The conclusions about the role phenol plays as an antioxidant in real food systems are often reached by comparing the oxidative behaviour of food samples with different contents of phenolic compounds. The variations in phenolics are usually obtained by using products made from different raw materials (e.g. malts containing different levels of polyphenols for production of beer (Andersen et al, 2000)). However, using different raw materials not only affects the levels of phenols, but also affects the levels of transition metals and enzymes which can have profound effects on the oxidative behaviour of the finished product. It is, therefore, often advantageous to study the oxidative behaviour of samples derived from a single batch of production where the level of phenols has either been increased by addition or decreased... 

Recent scientific investigations of natural polyphenols have demonstrated their powerful antioxidant property (Niki et al, 1995). Several classes of polyphenols have been chemically identified. Some of these are grape polyphenols, tea polyphenols, soy polyphenols, oligomeric proanthocyanidines (OPA) and other natural polyphenols of the flavone class. Rice bran polyphenols are different from the above in that they are p-hydroxy cinnamic acid derivatives such as p-coumaric acid, ferulic acid and p-sinapic acid. Tricin, a flavone derivative, has also been isolated from rice bran. 

Studies by Hudson et al, (2000) have demonstrated the presence of eight polyphenols in rice bran by using high-pressure liquid chromatography. They are protocatechuic acid, p-coumaric acid, ferulic acid, sinapic aci vanillic acid, caffeic acid, which is a methoxycirmamic acid derivative, and tricin. The effect of these polyphenols on cell viability and on the colony-forming ability of human-derived MDA MB 468 and HBL 100 breast cells, colon-derived SW 480 and human colonic epithelial cells was assessed. These authors concluded that rice bran polyphenols have putative cancer chemopreventive properties. 

Males et al. [103] used aqueous mobile phase with formic acid for the separation of flavonoids and phenolic acids in the extract of Sambuci flos. In a cited paper, authors listed ten mobile phases with addition of acids used by other investigators for chromatography of polyphenolic material. For micropreparative separation and isolation of antraquinone derivatives (aloine and aloeemodine) from the hardened sap of aloe (Liliaceae family), Wawrzynowicz et al. used 0.5-mm silica precoated plates and isopropanol-methanol-acetic acid as the mobile phase [104]. The addition of small amounts of acid to the mobile phase suppressed the dissociation of acidic groups (phenolic, carboxylic) and thus prevented band diffusions. 

George S, Brat P, Alter P and Amiot MJ. 2005. Rapid determination of polyphenols and vitamin C in plant-derived products. J Agric Food Chem 53(5) 1370-1373. 

Papagiannopoulos M, Wollseifen HR, Mellenthin A, Haber B and Galensa R. 2004. Identification and quantification of polyphenols in carob fruits (Ceratonia siliqua L.) and derived products by HPLC-UV-ESI/MSn. J Agric Food Chem 52(12) 3784-3791. 

There is the often-overlooked group of polyphenols containing the derivatives of hydro-xycinnamic and hydroxybenzoic acids such as caffeic, chlorogenic, and gallic acids (Figure 29.8), which occur in food and exhibit certain antioxidant activity. For example, some caffeic acid esters isolated from propolis from honeybee hives showed antiinflammatory... 

Moore NL, Mariam DH, Williams AL, Dashek WV. Substrate specificity, de novo synthesis and partial purification of polyphenol oxidase derived from the wood-decay fungus, Coriolus versicolor. J Indust Microbiol 1989 4 349-364. 

Gamier, N., Richardin, P., Cheynier, V. and Regert, M. (2003). Characterization of thermally assisted hydrolysis and methylation products of polyphenols from modern and archaeological vine derivatives using gas chromatography-mass spectrometry. Analytica Chimica Acta 493 137-157. 

Resveratrol is another type of polyphenol, a stilbene derivative, that has assumed greater relevance in recent years as a constituent of grapes and wine, as well as other food products, with antioxidant, anti-inflammatory, anti-platelet, and cancer preventative properties. Coupled with the cardiovascular benefits of moderate amounts of alcohol, and the beneficial antioxidant effects of flavonoids, red wine has now emerged as an unlikely but most acceptable medicinal agent. 

The terms epoxy resin (EP) and ethoxyline resin are used to describe polyphenol derivatives and other compounds which resinify by ring opening of oxirane rings. The polyphenols are typically diphenylolmethane or bis henol A [2,2-bis(4-hydroxyphenyl)propane] the latter diol is obtained by the condensation of phenol and acetone. Bisphenol A, is the most widely used phenol for epoxy resin production. 

Polyphenolics constitute a wide range of chemical compounds composed of aromatic ring(s) with one or more hydroxyl substituents, including their functional derivatives. Methods for extraction and isolation of polyphenolics from plant material are described in this unit. Extraction and isolation are the first important steps for separation, characterization, and quantification of polyphenolics from plant material. Polyphenolics are often most soluble in organic solvents less polar than water. The solubility is dependent on the polar properties of the polyphenolics. The correct selection of the extracting solvent is not as simple as it may seem. Aqueous methanol is a popular choice of solvent (see Background Information). 

Fingerprinting methods such as the anthocyanin methods and the Kirksey method for polyphenols (Kirksey el al., 1995) offer good ways to check for the addition of other fruits in a product. As the adulterators have become more sophisticated in the approaches that they use to extend juices, there has been a need for more complex methods of analysis. This means that it is now not uncommon to have to use fingerprinting techniques and isotopic methods to detect the most sophisticated forms of adulteration. These sophisticated analytical methods can even involve detection of the isotope ratios within a class of compounds such as sugars (Hammond el al., 1998). Using the RSSL 13C-IRIS approach, which was developed with financial support from the UK Food Standards Agency, it was possible to reduce the detection limit for the addition of C4-derived sugars to juices by about a factor of two. 

Other Physicochemical Aspects Associated to the Chain-Breaking Antioxidant Effect The Stability of the Polyphenol-Derived Free Radicals... 

Curcumin is a hydrophobic polyphenol derived from turmeric the rhizome of the herb Curcuma longa. Traditionally, turmeric and other curcuminoids have been used in therapeutic preparations for various ailments in different parts of the world. Numerous therapeutic effects of curcumin/turmeric have been confirmed by modern scientific research. It is a highly pleiotropic molecule that modulates numerous targets, including the activation of transcription factors (e.g., NF-kB, STAT-3, AP-1, NRF-2, PPR-y, HIF-1), receptors (e.g., HER-2, IL-8, CXCR-4), kinases (e.g., EGFR, ERK, JAK, AAPK), cytokines (e.g., TNF, IL, MIP, MCP), enzymes (e.g., MMP, iNOS, GST, ATPase), and... 

---