are organic compounds
that are hydroxy
derivatives of cinnamic acid
. There are three isomers
-coumaric acid, m
-coumaric acid, and p
-coumaric acid, that differ by the position of the hydroxy substitution of the phenyl group. p
-Coumaric acid is the most abundant isomer in nature.
Together with sinapyl alcohol and coniferyl alcohols, p-coumaric acid is a major component of lignocellulose. It is biosynthesized from cinnamic acid by the action of the P450-dependent enzyme 4-cinnamic acid hydroxylase.
p-Coumaric acid can be found in a wide variety of edible plants such as peanuts, tomatoes, carrots, and garlic. It is a crystalline solid that is slightly soluble in water, but well soluble in ethanol and diethyl ether.
p-Coumaric acid has antioxidant properties and is believed to reduce the risk of stomach cancer by reducing the formation of carcinogenic nitrosamines.