Cyanidins

Alkaline degradation was used to determine the stmcture of pelargonidin [134-04-3] cyanidin [528-58-5] and delphenidin [528-53-0] by treating each of them with concentrated potassium hydroxide at 140—150°C (89). Each of them produced phloroglucinol (27) and the corresponding phenoHc ben2oic acid ... 

Kyanathin, n. cyanethine, kyanethine. Kyanidin, n. cyanidine, kyanidine. kyanisieren, v.t. kyanize. 

Blemosperma nanum var. robustum lacked the flavone, but exhibited the flavonol glycosides plus cyanidin 3-0-monoglycoside [stracture 561] in some individuals. 

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... 

Six anthocyanidins are commonly found in plants and plant-derived foods and beverages pelargonidin, cyanidin, delphinidin, peonidin, petunidin, and malvidin. Their structures differ in the number and position of hydroxyl and methoxyl groups on the flavan nucleus. The most commonly occurring anthocyanidin is cyanidin, and all these anthocyanidins are found in plants as glycosides with or without acylation, leading to around 400 different stractures. 

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. 

Miilleder, U., Murkovic, M., and Pfannhauser, W., Urinary excretion of cyanidin glycosides, J. Biochem. Biophys. Methods, 53, 61, 2002. 

Tsuda, T., Horio, R, and Osawa, T., Absorption and metabolism of cyanidin 3-0-beta-D-glucoside in rats, FEBS Lett., 449, 179, 1999. 

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). 

Cyanidin, peonidin, and pelargonidin were detected in free forms in the Tolosa bean variety. This was the first report regarding the presence of aglycones in natural form in vegetable samples. On the basis of the data obtained by HPLC-MS and chemical tests, 3-methyldelphinidin and 3-methylcyanidin were identified in scarlet red runner beans and in kidney beans. ... 

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. ... 

Despite the fact that a-L-rhamnosylpyranoside usually occurs in the anthocya-nins as the dissacharide rutinose, a-rhamnose was found in acerola, linked at position 3 to cyanidin and pelargonidin and to delphinidin in Vaccinium padifolium blueberries,and at the 5 position in black raspberries, " red raspberries, " and purple mashua. The D- and L-configurations were not assigned in any of these studies. 

The pKj, value (2.43) of the hydration constant of the cyanidin was found to be lower than the pKj, values of glycosylated and acylated cyanidins, meaning lower resistance of the anthocyanidin to hydration. The stability of nonacylated 3,5-diglucosides was lower compared to the 3-glucoside because the 5 position markedly lowered the hydration constant due to decreased electron density of the pyrilium ring that favors nucleophilic attack by water, enhancing hemiacetal formation. ... 

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." ... 

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