3-(3,4-dihydroxyphenyl)-2-[(2E)-3-(3,4-dihydroxyphenyl)prop-2-enoyloxy]propanoic acid
Rosmarinic acid is the 1-carboxy-2-(2,4-dihydroxyphenyl)ethyl ester of trans-caffeic acid. It has a role as a non-steroidal anti-inflammatory drug, an antioxidant, a serine proteinase inhibitor, a peripheral nervous system drug, an EC 1.1.1.21 (aldehyde reductase) inhibitor and a plant metabolite. It is a polyphenol, a phenylpropanoid, a carboxylic ester and a monocarboxylic acid. It is functionally related to a trans-caffeic acid. It is a conjugate acid of a rosmarinate.