A review on pharmacological potentials of phenolic diterpenes carnosic acid and carnosol obtained from Rosmarinus officinalis L. and modern extraction methods implicated in their recovery

Rosmarinus officinalis L. is a perennial herb, known for culinary as well as medicinal properties. It has been shown that bioactive compounds like rosmarinic acid, carnosic acid, and carnosol are responsible for the medicinal properties of this plant species. Carnosic acid is a phenolic diterpene synthesized in young leaves of rosemary, whereas carnosol is produced after the oxidation of carnosic acid. Several studies have confirmed their antiangiogenic, anti-inflammatory, antimicrobial, antidiabetic, antioxidant, antitumor, neuroprotective, and gastroprotective properties. Ethanol, a mixture of ethanol-acetone, and hexane have been recommended as the best solvents for the extraction of carnosic acid, but advanced extraction techniques such as microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE), etc. have been used to extract these phenolic antioxidant compounds in higher yield. This report is a kind of first study that emphasizes the recent research on the pharmacological potentials of carnosic acid and carnosol and summarizes the studies on modern extraction procedures.