Pelargonidin, structure

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. 

FIGURE 13.4 Typical structures for main classes of flavonoids naringin chalcone, 4,6,4 -trihydroxyaurone, apigenin (flavone), and pelargonidin (anthocyanidin). 

Fig. 2.112. The structures of the flavan-3-ol(4a — 8)pelargonidin 3-0-/f-glucopyranosides (1-4) isolated from strawberry extract. The letter A denotes the aglycone ring systems belonging to the anthocyanidin substructure, whereas the letter F denotes the aglycone ring system belonging to the flavanol substructure. Reprinted with permission from T. Fossen et al. [252].

FIGURE 10.2 The number of anthocyanins based on the various anthocyanidins. The upper dark part of each bar represents the anthocyanins reported later than 1992. Pg, pelargonidin Cy, cyanidin Pn, peonidin, Dp, delphinidin Pt, petunidin Mv, malvidin RMS, rare methylated structures 60H, 6-hydroxy- Des, desoxy- Pyr, pyrano- Sp, sphagnorubins. See Table 10.1 for structures. 

The reports on anthocyanins from Anemone coronaria Pulsatilla cernua and Ranunculus asiaticus reveal structures that are very different from the anthocyanins described above. Many of these latter pigments are based on lathyroside or sambubioside residues located at the 3-hydroxyl of delphinidin, pelargonidin, or cyanidin (Table 10.2). Among these, four unusual anthocyanins containing the acyl moiety tartaryl have been isolated from Anemone coronaria Six of the anthocyanins in this plant have a glucur-onoside in the 3 -position. 

All anihocyanidins have tile 2 phcnylhen/opyrylium or flavylitim cation structure, a resonance hybrid of oxonium forms and carbcnium forms. There are three fundamental groups of anihocyanidins to which all the other anihocyanidins could be referred. In the following structure R = R = H designates pelargonidin R = OH. R = H is cyanidin and R = R = OH is dclphinidin. 

Fig. 21 Structures of cyanidin (51), cyanidin 3-O-glucoside (60),peonidin 3-O-glucoside (92), peonidin 3-O-xyloside (96), pelargonidin 3-O-glucoside (94) and pelargonidin (50) found mainly in metabolites of blackberry and strawberry...

Andersen, O.M. 1988. Semipreparative isolation and structure determination of pelargonidin 3-0-(3-l-rhamnopyranosyl-(l (3 2)-(3-D-glucopyranoside and other anthocyanins from the tree Dacrycar-pus dacrydioides. Acta Chem. Scand. B. 42, 462-468. 

Anthocyanidins (aglycones), flavyliun salts (chlorides), are shown generally by (1), the anthocyanins (3-monoglucosides) by (2), and 3,5-diglucosides by (3). The major anthocyanidins are cyanidin, delphinidin, malvidin, pelargonidin, peonidin and petunidin and the substituents in their structures are shown below for the formula (1). Table 3... 

The benzopyrylium ion structure is widespread in nature. It is frequently found substituted with a 2-phenyl group, and such structures (3.59) are known as flavylium ions. Various hydroxylated forms, the anthocyanidins, are usually responsible for the beautiful colors of flowers and fruits. An example of such a structure is the reddish-brown pelargonidin chloride (3.60). 

Fig. 4.31 The colors and structures of different anthocyanidins depending on the pH of the medium (the base decomposition of chalcone is not shown). The dyes in roses are derivatives of cyanidin, peonidin and pelargonidin in which the carbohydrate units are connected to positions 3...

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