Recent studies on rosmarinic acid and its biological and pharmacological activities

Rosmarinic acid (RA), an ester of caffeic acid and 3,4-dihydrophenyllactic acid (Figure 1), is a naturally occurring phenylpropanoid that is commonly found in species of the Boraginaceae family, the subfamily Nepetoideae of the Lamiaceae family, and in lower plants such as ferns and hornworts (Petersen and Simmonds, 2003). RA was first isolated and purified in 1958 from Rosmarinus officinalis by two Italian chemists, Scarpati and Oriente, who then named it according to the plant that they isolated it from (Scarpati and Oriente, 1958). The biosynthesis of RA has been extensively studied, and a biosynthetic pathway was first reported in 1970 by Ellis and Towers. They demonstrated that two aromatic amino acids L-tyrosine and Lphenylalanine are the building blocks of rosmarinic acid (Ellis and Towers, 1970).