hydroxycinnamates

Hydroxycinnamates are a group of phenylpropanoid-derived compounds consisting of hydroxycinnamic acids (notably p-coumaric, caffeic, ferulic, and sinapic acids) and their esters or conjugates. They occur widely in plants as free acids or as esters with sugars, phenolic alcohols, or cell-wall polymers. Common examples include chlorogenic acid (caffeoylquinic acid) and feruloyl-, caffeoyl-, or p-coumaroyl-esters of various acceptors.

In plants, hydroxycinnamates are produced via the phenylpropanoid pathway from phenylalanine. They participate in structural roles such as cross-linking of cell-wall polysaccharides and lignin formation, particularly in grasses where ferulic acid cross-links polysaccharides. They also contribute to UV protection and plant defense responses.

In foods and the diet, hydroxycinnamates contribute to antioxidant capacity and may influence flavor and color. They are present in fruits, vegetables, coffee, whole grains, and many processed plant foods. The bioavailability of hydroxycinnamates depends on their form; bound forms may be released during digestion or microbial metabolism in the colon, contributing to systemic exposure.

Analytically, hydroxycinnamates are quantified by chromatography, often after hydrolysis or during targeted extraction of caffeic, ferulic, and p-coumaric acids and their esters.