Peonidin-3, 5-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."°... 

Direct condensation product between catechin and peonidin-3-glucoside... 

Fig. 2.120. Chromatograms recorded at 520 nm of model solutions (six days reaction time at 35°C) containing mv3gl and B2-3 -gallate mediated by different aldehydes (mv3gl), malidin-3-glucoside Pn3gl, peonidin-3-glucoside. Numbers refer to pigments in Table 2.94. Reprinted with permission from J. Pissarra et al. [266].

Do, C.B. and Cormier, F., Accumulation of peonidin 3-glucoside enhanced by osmotic stress in grape Vitis vinifera L.) cell suspension. Plant Cell Tissue Organ Culture, 24, 49, 1991. 

Figure 5.4 Chromatograms with multiple reaction monitoring (MRM) transitions at 625/287 (A) and 639/301 (B) that show the multiple glucuronide forms of cyaniding-3-glucoside and peonidin-3-glucoside, respectively. (From Hager, 2008).

Evidence in wine. The caftaric-malvidin-3-glucoside condensation product in flavylium form has been detected in red wine after the oxidation of Camay grapes, together with the corresponding derivative of peonidin-3-glucoside (Labarbe 2000). 

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