Anthocyanins anthocyanidins and

Yue, X. Xu, Z. 2008. Changes of anthocyanins, anthocyanidins, and antioxidant activity in bilberry extract during dry heating. J. Food Sci. 73 C494-C499. 

Jacobucci, G.A. and Sweeny, J.G., The chemistry of anthocyanins, anthocyanidins and related flavylium salts, Tetrahedron, 39, 3005, 1983. 

Seeram, N.P. and Nair, M.G. 2002. Inhibition of lipid peroxidation and structure-activity-related studies of the dietary constituents anthocyanins, anthocyanidins, and catechins , /. Agric. Food. Chem., 50 5308 5312. 

Anthocyanins and anthocyanidins, compounds present with high structural diversity in fruits and wines, showed a pattern as antioxidants different from that of the tea catechins with respect to the effect of substituents. In a liposomal model system induced peroxidation was inhibited increasingly by anthocyanins/ anthocyanidins with an increasing number of hydroxyl groups in the B-ring (Fig. 16.6), while the opposite was seen for the catechins (Seeram and Nair, 2002). For anthocyanidins, the presence of a 3-hydroxy group is important... 

As we have seen above, anthocyanins comprise an aglycone fraction commonly known as anthocyanidin and a frequently acylated osidic substituent. This characteristic leads to two different approaches for the analysis of these pigments (1) a direct anthocyanin analysis without a hydrolysis stage requiring identification of a number of molecules (several hundreds in the plant kingdom) or (2) an analysis of the anthocyanidin fraction only after hydrolysis of the anthocyanins present in the medium. 

Timberlake, C.F. and Bridle, P., Flavylium salts anthocyanidins and anthocyanins. Structural transformations in acid solutions, J. Sci. Food Agric., 18, 473, 1967. 

Figure 3.7. Structural relationships among flavonols, anthocyanidin, and anthocyanin.

Flavan-3,4-diols FIavan-3,4-diols, also known as leucoanthocyanidins, are not particularly prevalent in the plant kingdom, instead being themselves precursors of flavan-3-ols (catechins), anthocyanidins, and condensed tannins (proanthocyanidins) (see Fig. 5.4). Flavan-3,4-diols are synthesized from dihydroflavonol precursors by the enzyme dihydroflavonol 4-reductase (DFR), through an NADPH-dependent reaction (Anderson and Markham 2006). The substrate binding affinity of DFR is paramount in determining which types of downstream anthocyanins are synthesized, with many fruits and flowers unable to synthesize pelargonidin type anthocyanins, because their particular DFR enzymes cannot accept dihydrokaempferol as a substrate (Anderson and Markham 2006). 

Chemically, anthocyanins are glycosides of anthocyanidins and are based on a 2-phenylbenzopyrilium structure. The properties of the anthocyanins depend on the anthocyanidins from which they originate. 

IDENTIFIED ANTHOCYANINS AND ANTHOCYANIDINS AND THEIR OCCURRENCE IN VARIOUS RED FRUIT JUICE... 

In addition to the 18 anthocyanidins listed previously, Table 10.1 contains seven new desoxyanthocyanidins and a novel type of anthocyanidin called pyranoanthocyanidins. While 31 monomeric anthocyanidins have been properly identified, most of the anthocyanins are based on cyanidin (30%i), delphinidin (22%i), and pelargonidin (18%), respectively (Figure 10.2). Altogether 20%i of the anthocyanins are based on the three common anthocyanidins (peonidin, malvidin, and petunidin) that are methylated. Around 3, 3, and 2% of the anthocyanins or anthocyanidins are labeled as 3-desoxyanthocyanidins, rare methylated anthocyanidins, and 6-hydroxyanthocyanidins, respectively. 

One of the best-established functions of anthocyanins is in the production of flower color and the provision of colors attractive to plant pollinators. Considerable effort has been made to give explanations for the color variations expressed by anthocyanins in plants. Various factors including concentration and nature of the anthocyanidin, anthocyanidin equilibrium forms, the extent of anthocyanin glycosidation and acylation, the nature and concentration of copigmentation, metal complexes, intra- and intermolecular association mechanisms, and influence of external factors like pH, salts, etc. have been found to have impact on anthocyanin colors. ... 

Checklist of all natural anthocyanidins (in bold) and anthocyanins. Anthocyanidins found in plants without sugar are labeled with numbers. For anthocyanins found after 1992 the numbers in italic correspond to the numbers in the reference list. 

On the other hand, anthocyanins, i.e. the glycosylated anthocyanidins, are an important group of water-soluble pigments occuring in 27 families of food plants (mainly red fruits and vegetables), Fig. (11) [53]. Table 15 shows the most common anthocyanidins and anthocyanins. 

Table 15. Structure of the most common anthocyanidins and anthocyanins...

H and l3C NMR spectral data for various anthocyanins are given in Tables FI.4.4 and FI.4.5. Typical1 H- H coupling constants for common anthocyanidins and their monosaccharides are given in Tables FI.4.6 and FI.4.7. 

HPLC is the main separation technique for quantification of water-soluble, nonvolatile, thermally labile anthocyanins (Table 3.4). The columns most commonly used are reversed-phase C18. The pH of mobile phase is generally kept acidic with either formic, acetic, or trifluoroacetic acid. The order of elution follows the decreasing polarity of the anthocyanidins and is as follows delphinidin, cyanidin, petunidin, pelargonidin, peonidin, and malvidin. Disaccharide moieties in the C-3 position influence polarity less than the presence of the same two monosaccharides in C-3 and C-5 positions. Anthocyanins absorb visible light at 510-528 nm and UV light at 270-280 nm. DAD is the most common technique used for detection and quantification of anthocyanins, with the quantification occurring around the absorption... 

Anthocyanins are composed of anthocyanidines and their sugar molecules. Anthocyanins are one of the most typical phy to chemicals in the pigments of the plant kingdom with various colors such as carotenoids. Surprisingly, the anthocyanins of over 150 flavonoids are highly antioxidative. To date, it is thought that more than 4000 flavonoids have been identified [7]. 

Cyanidin inhibits epidermal growth factor receptor tyrosine kinase (EGF-RTK), a-glycosidase and COX-1 and COX-2. Delphinidin (3,5,7,3, 4, 5 -hexahydroxyflavylium) also inhibits EGF-RTK. Anthocyanidins and anthocyanins can be anti-inflammatory antioxidants by acting as free radical scavengers. Thus, nasunin (delphinidin-3-(j6-coumaroylrutinoside)-5-glucoside) scavenges OH (hydroxyl), 02 (superoxide) and lipid peroxyl radicals and inhibits lipid peroxidation. 

Flavanol oligomers and polymers are also called condensed tannins or proan-thocyanidins. The term tannin refers to their capacity to interact or react with proteins and precipitate them out. When heated under acidic conditions, these molecules release red anthocyanidin pigments, hence the term proanthocyanidins. The term leucoanthocyanidin, also referring to this particular property, is sometimes encountered in the literature. However, this should be restricted to another group of compounds, flavan 3,4-diols, which are intermediates in the biosynthetic pathway leading to flavanols and anthocyanins (Stafford and Lester 1984 Nakajima et al. 2001 Abrahams et al. 2003) but have never been isolated from grapes, presumably due to their instability. 

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