Anthocyanins effect

Overexpression of P-glycoprotein associated with multidrug resistance represents a serious problem in cancer treatment. Evaluation of catechins, fla-vonoids, isoflavonoids, and anthocyanins effects on multidrug-resistant human epidermal carcinoma cells has demonstrated that catechins and antho-cyanidins are most effective inhibitors of P-gp overexpression. It was observed that hydrophobicity enhances planar flavonoids inhibitory effects without affecting nonplanar flavanols activity that significantly depended on their chemical structure [119]. 

Anthocyanins seem to be absorbed very rapidly but rather inefficiently [49]. However, the bioavailability of anthocyanins may have been underestimated due to either methodological inaccuracy or the different chemical forms that anthocyanins can take depending on pH. This may explain why all anthocyanins effects are contingent on sufficient bioavailability in terms of exposure at both cell and organism level through the diet [50]. 

Anthocyanins and anthocyanidins, compounds present with high structural diversity in fruits and wines, showed a pattern as antioxidants different from that of the tea catechins with respect to the effect of substituents. In a liposomal model system induced peroxidation was inhibited increasingly by anthocyanins/ anthocyanidins with an increasing number of hydroxyl groups in the B-ring (Fig. 16.6), while the opposite was seen for the catechins (Seeram and Nair, 2002). For anthocyanidins, the presence of a 3-hydroxy group is important... 

The effects of pH under model conditions (0.6 to 5.5 for 24 hr) were covered by Nielsen et al. for four anthocyanins (3-O-glucoside, glycosylated cyanidin, rutinoside, and delphinidin rutinoside). After 24 hr, over 90% of the anthocyanins were intact up to pH 3.3, while instabihty greatly increased at pH greater than 4.5. 

Turker, N. et al., Effect of storage temperature on the stability of anthocyanins of a fermented black carrot Daucus carota var. L.) beverage shalgam, J. Agric. Food Chem., 52, 3807, 2004. 

Eiro, M.J. and Heinonen, M., Anthocyanin color behavior and stability during storage effect of intermolecular copigmentation, J. Agric. Food Chem., 50, 7461, 2002. 

Fruifs and vegetables also contain ofher bioactive substances such as polyphenols (including well-known pigments anthocyanins, flavonols) and non-provitamin A carotenoids (mainly lycopene, lutein, and zeaxanthin) that may have protective effects on chronic diseases. Polyphenols and carotenoids are known to display antioxidant activities, counteracting oxidative alterations in cells. Besides these antioxidant properties, these colored bioactive substances may exert other actions on cell signaling and gene expression. 

The purpose of this chapter is to provide an overview of our present knowledge about the health benehts of pigments, particularly their effects on chronic diseases. We examine the effects of lipophilic (carotenoids, chlorophylls) and hydrophilic pigments (anthocyanins and flavones-flavonols), and curcumin. Descriptive and mechanistic studies are reviewed in regard to common chronic diseases. 

Cyanidin is the most common anthocyanin in foods. In addition, anthocyanins are stabilized by the formation of complexes with other flavonoids (co-pigmentation). In the United States, the daily anthocyanin consumption is estimated at about 200 mg. Several promising studies have reported that consumption of anthocyanin-rich foods is associated with reductions of the risks of cancers - and atherosclerosis and with preventive effects against age-related neuronal and behavioral declines. These beneficial effects of anthocyanins might be related to their reported biological actions such as modulators of immune response and as antioxidants. Knowledge of anthocyanin bioavailability and metabolism is thus essential to better understand their positive health effects. 

Finally, the fact that anthocyanins can reach the brain represents a beginning of an explanation of the purported neuroprotection effects of anthocyanins. Anthocyanins may be eliminated via urinary and biliary excretion routes. " The extent of elimination of anthocyanins via urine is usually very low (< 0.2% intake) in rats and in humans, indicating either a more pronounced elimination via the bile route or extensive metabolism. As mentioned earlier, in the colon, non-absorbed or biliary excreted anthocyanins can be metabolized by the intestinal microflora into simpler break-down compounds such as phenolic acids that may be (re)absorbed and conjugated with glycine, glucuronic acid, or sulfate and also exhibit some biological... 

Considerable studies have been done on the effects of the most important chemical and physical factors involved in the degradation of anthocyanins (temperature, light, pH, SO2, metal, sugar, and oxygen) in model systems and food extracts. In addition, anthocyanin concentrations, its chemical structures, and media compositions are fundamental factors influencing stability. 

The anthocyanin stabilities of grape-marc, elderberry, and black currant extracts were lower in all sucrose (100 g/L)-added systems as compared to the controls at pH values of 3, 4, and 5, whereas the brown index did not change with the addition of sugar. On the contrary, a protective effect of 20% sucrose added to frozen crowberries and strawberries was reported and the stabilities of anthocyanin juices from aronia were higher in syrups than in diluted extracts. Roselles pre-... 

Anthocyanins were decolorized at pH 3.0 by the addition of sodinm sulfite at the C-2 or C-4 of the chromophore, a reaction that was rapidly reversible on acidification. Snlfnr dioxide, EDTA, and a combination of snlfnr dioxide and EDTA exerted very small effects on the losses of anthocyanins in strawberry pnrees and juices during 10 wk of storage at -20°C. Conversely, the addition of snlfnr dioxide and storage at 20°C slowed the anthocyanin losses and concnrrently decreased the formation of polymeric componnds, especially in pnrees. EDTA had a slight effect on color stability. ... 

Attempts to stabilize anthocyanins by complex inclusion with a- and P-cyclo-dextrins failed on the contrary, a discoloration of anthocyanin solutions was observed.Thermodynamic and kinetic investigations demonstrated that inclusion and copigmentation had opposite effects. In the anthocyanins, the cw-chalcone colorless structure is the best species adapted to inclusion into the P-dextrin cavity, shifting the equilibrium toward colorless forms. "... 

Research into the copigmentation of anthocyanins started as early as 1913 when Willstatter and Everest determined the chemical structure of cyanidin 3-glucoside isolated from blue cornflowers and red roses, and attributed the color changes to different pH levels in cell saps. This theory, however, was questioned and in 1916, Willstatter and Zollinger,revising the previous work, proposed a new theory according to which the colors of the anthocyanins varied significantly by the effects... 

Stability of anthocyanins can be attained by self-association, that is, when two or more anthocyanin molecules are associated. This effect was verihed by increasing the concentration of the cyanidin 3,5-diglucoside solution from 10 M to 10 M with a consequent bathochromic shift in maximum wavelength absorption in the visible region. "... 

The magnitude of the copigmentation is influenced by pH value, pigment and copigment concentrations, chemical structure of anthocyanin, temperature, and ionic strength of the medium. As to the effect of the solvent, the important issue is the hydrogen-bonded molecular structure of the liquid water, not the polarity of the medium. ... 

Chlorogenic acid enhanced the colors of strawberry and chokeberry juices in concentrations higher than those of the anthocyanins present. However, the effects on purified pigments were lower, indicating the presence of other stabilizing compounds in the juices. ... 

Bakker, J. and Bridle, R, Strawberry juice color — The effect of sulfur-dioxide and EDTA on the stability of anthocyanins, J. Sci. Food Agric., 60, All, 1992. 

Suthanthangjai, W., Kajda, R, and Zabetakis, I., The effect of high hydrostatic pressure on the anthocyanins of raspberry (Rubus iudaeus). Food Chem., 90, 193, 2005. 

Dangles, O., Wigand, M.C., and Brouillard, R., Anthocyanin anti-copigment effect. Phytochemistry, 31, 3811, 1992. 

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