rosmarinic

Rosmarinic acid is a polyphenolic ester formed from caffeic acid and 3,4-dihydroxyphenyllactic acid. It is a prominent natural antioxidant found in many culinary herbs and medicinal plants, especially within the Lamiaceae family. In particular, rosemary (Rosmarinus officinalis), sage (Salvia officinalis), lemon balm (Melissa officinalis), marjoram, peppermint, and basil contain notable amounts of rosmarinic acid.

The compound is primarily located in plant aerial parts and is commonly extracted from leaves and herbs using polar solvents for use in foods, cosmetics, and research. Its content can vary with species, plant part, cultivation conditions, and harvest time. Rosmarinic acid is often quantified in plant extracts by high-performance liquid chromatography (HPLC).

Biosynthetically, rosmarinic acid arises from the phenylpropanoid pathway. It is formed by condensation of caffeic acid derivatives with hydroxyphenyllactic acid, a reaction catalyzed by specific enzymes such as rosmarinic acid synthase in many plant species.

Chemically, rosmarinic acid is hydrophilic and soluble in polar solvents like methanol and water. It is noted for potent radical-scavenging activity and the ability to chelate metal ions, contributing to its antioxidant properties. It also exhibits anti-inflammatory, antimicrobial, and potential antiviral effects in various in vitro and some in vivo studies, though clinical evidence remains limited.

Applications include use as a natural antioxidant additive in foods and cosmetics and as a standard reference compound in polyphenol research. Safety data generally support dietary use from common culinary herbs; higher-dose therapeutic implications require further study.