Polyphenols biosynthetic pathways

The biosynthetic pathway (Figure 10.5) of polyphenols, including phenolic acids is well known. Phenylalanine formed in plants via the shikimate pathway is a common precursor for most of the phenolic compounds. Forming hydroxycinnamic acids from phenylalanine requires hydroxylation and methylation steps. The formation of hydroxybenzoic acids is simple and they can directly be formed from the corresponding hydroxycinnamic acids with the loss of acetate or with an alternate path stemming from an intermediate in the phenylpropanoid pathway [69,77,78]. 

Plants - Lignin, tannins, and pigments, flavor components of spices (cinnamon oil, wintergreen oil, bitter almond, nutmeg, cayenne pepper, vanilla bean, clove, and ginger) are derived from coniferyl alcohol. Coniferyl alcohol, in turn, is derived from phenylalanine and tyrosine. Phenylalanine is also a precursor of plant pigments and related polyphenolic compounds called flavonoids. The biosynthetic scheme leads to a class of flavonoids called anthocyanins, which are common flower pigments.. An offshoot of this pathway leads to the synthesis of cocaine. 

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