Rosmarinic acid is a polyphenolic compound belonging to the class of phenolic acids, commonly found in herbs of the Lamiaceae family such as rosemary, sage, and oregano. It exhibits strong antioxidant, anti-inflammatory, and antimicrobial properties due to its catechol moieties and conjugated double bond system. This compound is widely studied for its potential health benefits including neuroprotective effects and use as a natural food preservative. It is biosynthesized from caffeic acid and 3,4-dihydroxyphenyllactic acid. In food applications, it contributes to the stability of oils and meats by scavenging free radicals. Chemically, it is an ester of caffeic acid and danshensu, with a molecular structure allowing for metal chelation and radical stabilization.