Flavanols oligomeric

Flavanols consist of catechin and epicatechin monomers together with oligomeric tannins, which comprise the most abundant class of flavonoids in the... 

He, J., Santos-Buelga, C., Silva A.M.S., Mateus N., De Freitas, V. (2006a). Isolation and qualification of oligomeric pyranoanthocyanin-flavanol pigments from red wines by combination of column chromatographic techniques. /. Chromatog. A 1134, 215-225. 

The polyphenols are a series of phytochemicals synthesized by plants. They include the bioflavonoids anthocyanins, coumestanes, flavonoids, isoflavonoids, and stil-benes (Figure 4.1). Each bioflavanoid class is subdivided into other groups, e.g., flavones, flavans, flavanols, flavonols, and flavanones (Figure 4.2). Another class of polyphenol is the oligomeric polyphenols, such as the proanthocyanidins, found in the grape and various berries (black currant, blueberry, etc.). 

Figure 1. Chemical structures of flavanols and a cocoa (-)-epicatechin dimer. Higher molecular weight procyanidins typically oligomerize through the 4 -8 bond.

Oligomeric procyanidins correspond to polymers formed from three to ten flavanol units, linked by C4-C8 or C4-C6 bonds. An infinite number of isomers are possible, which explains why it is so difficult to separate these molecules. Condensed procyanidins (Figure 6.17) have more than ten flavan units and a molecular weight greater than 3000. 

Monomeric flavanols yield dimeric, higher oligomeric and polymeric procyanidins (proanthocyanidins) of several types. The link between the monomeric units is usually in position C-4 of the... 

Condensed tannins or proanthocyanidins are oligomeric to polymeric compounds formed from the condensation of flavanols or flavandiols, with degrees of... 

Flavan-3-ols, often referred to as flavanols, are the most complex class of the flavonoids because they range from simple monomers (catechin and its isomer epicatechin) to the oligomeric and polymeric proanthocyanidins, which are also known as... 

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