Nonflavonoids stilbenes

Phenols include several hundred compounds that are broadly grouped as flavonoids and nonflavonoids. The former include anthocyanins, cate-chins, and tannins the latter include stilbenes and other compounds derived from benzoic, caffeic, and cinnamic acids. 

Nonflavonoid compounds comprise simple phenols, phenolic acids, coumarins, xanthones, stilbenes, lignins, and lignans. Phenolic acids are further divided into benzoic acid derivatives, based on a C6-C1 skeleton and cinnamic acid derivatives, which are based on a C6-C3 skeleton [6], The conmarins are phenolic acid derivatives composed of a benzene ring fnsed with an oxygen heterocycle. Xanthones consist of a C6-C1-C6 basic structure, and stilbenes are composed of a C6-C2-C6 skeleton with various hydroxylation patterns [13], Lignins are polymers of C6-C3 units, whereas lignans are made up of two phenylpropane units [13]. The structures of each of these classes are shown in Table 16.1. 

The nonflavonoid polyphenols include the phenolic acids or hydroxybenzoates (basic chemical structure C6-C1), hydroxycinammates (basic chemical structure C6-C3), and polyphenolic stilbenes (basic chemical structure C6-C2-C6). 

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