Catechins cranberry

Fig. 2.71. HPLC chromatogram of the neutral (a) and acidic fractions (b) and the acid-catalysed hydrolysed product of freshly squeezed cranberry juice (c) at 280 nnm. Peaks in a 1 = ( + )-cate-chin 2 = myicetin 3 = quercetin (added as internal standard). Peaks in b 1 = anthocyanin derivative I 2 = benzoic acid 3 = p-anisic acid 4 = quercetin (added as internal standard). Peaks in c 1 = ( + )-catechin 2 = anthocyanin derivative I 3 = anthocyanin derivative II 4 = benzoic acid 5 = anthocyanin derivative III 6 = p-anisic acid 7 = myricetin 8 = quercetin. Reprinted with permission from H. Chen et al. [188].

Fruit juice contains both catechins and flavonols. Apple juice is one of the richest juice sources of catechins (containing 6.3 mg (—)-epicatechin/100 ml and 0.8 mg (+)-catechin/ 100 ml) whereas cranberry juice contains the most flavonols, mainly in the form of quercetin and myricetin (17.5 mg/100 ml and 4.7 mg/100 ml, respectively). 

TMS production involves one specific functional group (-OH, -COOH, =NH, -NH2, or -SH), which loses an activated hydrogen and is replaced by a trimethylsilyl group (Proestos et ah, 2006). To achieve silylation, some authors have used BSTFA (N,0-hA(trimethyl-silyl)trifluoroacetamide) and TMCS (trimethylchlorosilane) successfully in several matrices (e.g. aromatic plants, cranberry fixiit) (Zuo et ah, 2002 Proestos et ah, 2006). Using silylated derivatives is advantageous for several reasons phenols and carboxylic acids are prone to silylation, these compounds can be derivatized in the same part of the process, and the minor products do not impede analysis and are well documented (Little, 1999 Stalikas, 2008). A two-step methylation procedure was used to analyze catechins and tannins in plant extracts. The first step used trimethylsilyl diazomethane (TMS-diazomethane) to pre-methylate the sample, and the second step used thermally assisted hydrolysis and methylation (THM). The pre-methylation step with TMS-diazomethane stabilized the dimer molecule m/z 540) by minimizing isomerization and reducing reactivity. (Shadkami et ah, 2009). 

Flavan-3-ols (+)-Catechin (-)-Epicatechin (-)-Epicatechin 3-gal late (-)-Epigallocatechin-3- gallate (-F)-Gallocatechin (-)-Epigallocatechin Procyanidins Prodelphinidins Apples, apricots, grapes, peaches, nectarines, raspberries, cherries, blackberries, blueberries, cranberries, pears, plums, and raisins [14]... 

Other popular compounds such as lycopene, lutein, resveratrol, quercetin, catechins from tea, grapes, or cranberries, or soy isoflavones have not obtained a favorable opinion, except in cases where they were actually associated with other compounds that had already proven to have an effect like vitamin E or C. 

The American cranberry (Vaccinium macrocarpon Ait (Ericaceae)) was used by North-American Indians to fight urinary tract infections and other bacterial diseases. Proanthocyanidins, present in cranberries as oligomers of catechin and epicatechin, inhibit the docking of bacteria on tissues in vitro an anti-adhesive mechanism of cranberry-proanthocyanidins (Howell et al. 2001). The efficacy of cranberry juice and extracts as a prophylactic agent against recurrent urinary infections is well documented in women (Stothers 2002). The anti-adhesion effect of cranberry-proanthocyandins can also be applied for treatment of other common diseases of bacterial pathogenesis, e.g. Helicobacter py/on-associated gastritis and dental caries/periodontal disease (Nowack 2007). 

Fruit widely regarded as possessing bacteriostatic activity for urinary tract infections. Antibacterial activity has been variously, though not conclusively attributed to anthocyanins flavonol glycosides catechin volatile components and benzoic, quinic, malic, and citric acids (crellin and philpott). It has been suggested and disputed that the urinary antiseptic effect is due to the action of hippuric acid. Other studies suggest cranberry juice possesses antiadhesion activity to mucous membrane Escherichia coli,... 

Berries can contain substantial amounts of the flavan-3-ol monomers (-l-)-catechin and (—)-epicatechin as well as dimers, trimers and polymeric proanthocyanidins. The concentration of the polymers is usually greater than the monomers, dimers and trimers, and overall cranberries are a particularly rich source of these compounds (Table 7.2). 

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