Cyanidin Anthocyanins

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. 

Stintzing, F. et al., Color and antioxidant properties of cyanidin-based anthocyanin pigments, J. Agric. Food Chem., 50, 6172, 2002. 

Whereas the anthocyanins bear hues from orange (pelargonidin) to red (cyanidin) to blue (delphinidin), the betalains may be subdivided into distinct yellow-orange (betaxanthins) and red-violet stractures (betacyanins). On the other hand, betalainic... 

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. 

Catechol-O-methyltransferase (COMT EC 2.1.1.6) is located in many tissues and catalyzes the methylation of polyphenols. The methylation is a well-established pathway in the metabolism of flavonoids such as those that undergo 3, 4 -dihydrox-ylation of ring B excreted as 3 -0-methyl ether metabohtes in rat bile. " Recently, the apparent methylation of both cyanidin-3-glucoside and cyanidin-3-sambubioside (cyanidin is an anthocyanin with a 3, 4 -dihydroxylation of ring B) to peonidin-3-glucoside and peonidin-3-sambubioside was reported in humans. In rats, this transformation occurred mainly in the liver and was catalyzed by COMT."°... 

Wu, X., Cao, G., and Prior, R.L., Absorption and metabolism of anthocyanins in elderly women after consumption of elderberry or blueberry, J. Nutr, 132,1865, 2002. Matsumoto, H. et al.. Orally administered delphinidin 3-rutinoside and cyanidin 3-rutinoside are directly absorbed in rats and humans and appear in the blood as the intact forms, J. Agric. Food Chem., 49, 1546, 2001. 

The most widespread anthocyanidin in foods is cyanidin, as can be seen in Table 4.3.1 through Table 4.3.4. It was found in amounts greater than 10% of the total anthocyanin content in 39 of 44 different fruits listed in Table 4.3.1 and in 9 of 13 vegetables shown in Table 4.3.3. On the other hand, cyanidin was presented in high amounts only in non-Vitis vinifera species, such as cv. Concorde " and Cynthiana (Table 4.3.2). 

Four cyanidins with 4 -glucosidation were recently isolated in minor amounts from pigmented scales of red onion. Two were the only anthocyanins with B ring sugar substitutions and no glycosyl moieties in anthocyanidin position 3, whereas the other two were also glycosilated at the usual position 3. ... 

The color stability of strawberry syrup with or without fortification with anthocyanins from black currants (cyanidin and delphinidin 3-glucosides and 3-rutino-sides) and/or AA with levels equivalent to those existing in black currant syrup was investigated. Black currant-fortified strawberry anthocyanins showed higher stability the addition of AA diminished stability. ... 

The stability of cyanidin 3-glncosyl-arabinoside was investigated in different solvents, water, and dimethyl snlfoxide (DMSO, an aprotic solvent) under the same conditions. The valnes nnexpectedly showed that the anthocyanin was more stable in water solntion. DMSO was chosen as a solvent so that it would make the addition of DMSO to C-2 difficnlt and thus the anthocyanin would be more stable in DMSO than in a water solntion. However, since the experiment took place in acidic solntion (pK > pKj,), the preferential addition at C-2 or C-4 of the flavylium ion probably took place by a protonated molecule of DMSO. ... 

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. "... 

Slimestad, R. and Andersen, 0.M., Cyanidin 3-(2-glucosylgalactoside) and other anthocyanins from frnits of Comus suecica. Phytochemistry, 49, 2163, 1998. 

Wharton, P.S. and Nicholson, R.L., Temporal synthesis and radiolabelling of the sorghum 3-deoxyanthocyanidin phytoalexins and the anthocyanin, cyanidin 3-dima-lonyl glucoside, New Phytol, 145, 457, 2000. 

Adams, J.B., Thermal degradation of anthocyanins with particular reference to the 3-glucoside of cyanidin. 1. In acidified aqueous solutions at 100°C, J. Set FoodAgric., 24, 747, 1973. 

Quantitation of anthocyanins has become simple and fast since many anthocy-anin standards became commercially available as external standards in the past decade. When the standards are not available, individual anthocyanins or total monomeric anthocyanins can be determined by the use of a generic external standard such as commercial cyanidin-3-glucoside or other compound structurally similar to the analytes of interest. Individual and total peak areas are measured at 520 nm or their and quantified using external standards by which values are typically slightly different from those via the pH differential method. ... 

Another problem is that the anthocyanin mixtures may be very complicated and not all absorptivity coefficients may be known. Even when they are known, it is necessary to first evaluate whether the objective is the estimation of total anthocyanin content or the determination of individual pigments, and then to decide which absorption coefficient(s) to use. The absorptivity is dependent on both the chemical structure of the pigment and also on the solvent used, and preferably the coefficient used should be one obtained in the same solvent system as the one used in the experiment. If the identity of the pigment is unknown, it has been suggested that it could be expressed as cyanidin-3-glucoside since that is the most abundant anthocyanin in nature. 

Strack, D. et al., Cyanidin 3-oxalylglncoside in orchids, J. BioscL, 41, 707, 1986. Choung, M.-G. et al.. Isolation and determination of anthocyanins in seed coats of black soybean (Glycine max (L.) Merr.), J. Agric. Food Chem., 49, 5848, 2001. Covey, T., Analytical characteristics of the electrospray ionization process, in Biochemical and Biotechnological Applications of Electrospray Ionization Mass Spectrometry, ACS Symposium Series, Snyder, A.P. and Anaheim, C. A., Eds., Washington, D.C., 1995, chap. 2. 

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