Cyanidin 3-glucoside

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."°... 

Cyanidin 3-glucoside and cyanidin 3-rutinoside were degraded at 100°C in weak acidic solutions at pH range 1 to 4 under aerobic and anaerobic conditions." The degradation revealed that cyanidin 3-glucoside was more stable under both conditions." ... 

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... 

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. 

Calogero and Di Marco used the red antioxidant cyanidine-3-glucoside and a mixture of cis and trans isomers ofdelphinidin 3-[4-(p-coumaroyl)-L-rhamnosyl-(l-6)-glucopyranoside]-5-glucopyranoside (Figure 9.4), extracted from the red Sicilian... 

FIGURE 5.S Anthocyanin reactions with caffeoyltartaric acid o-quinone coupled oxidation of cyanidin 3-glucoside (A) and nucleophilic addition of anthocyanins (B). Anthocyanin-caffeoyltartaric acid adducts are represented as one of the possible isomers, namely 2-(8-anthocyanin) caffeoyltartaric acid (5 1). 

Miyazawa, T., Nakagawa, K., Kudo, M., Muraishi, K., and Someya, K., Direct intestinal absorption of red fruit anthocyanins, cyanidin-3-glucoside and cyanidin-3,5-diglucoside, into rats and humans, J. Agric. Food Chem., 47, 1083, 1999. 

Xu, J.W., Ikeda, K., and Yamori, Y., Cyanidin-3-glucoside regulates phosphorylation of endothelial nitric oxide synthase, FEES Lett., 574, 176, 2004. 

Gossypium sp. Cyanidin-3-glucoside (anthocyanin) Tobacco budworm. 5, 363... 

IMPORTANT NOTE The MW and e used in this formula correspond to the predominant anthocyanin in the sample. Use the e reported in the literature for the anthocyanin pigment in acidic aqueous solvent. If the e of the major pigment is not available, or if the sample composition is unknown, calculate pigment content as cyanidin-3-glucoside, where MW -449.2 and e = 26,900 (see Background Information, discussion of Molar Absorptivity). 

Fig. 16 RP-HPLC separation of black currant juice. Peaks 1 = delphinidin 3-glucoside 2 = delphinidin 3-rutinoside 3 = cyanidin 3-glucoside 4 = cyanidin 3-rutinoside 5 = pelargonidin 3-glucoside (= int. std.) 6 = pelargonidin 3-rutinoside. (From Ref. 157.)...

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