Abstract: | Carnosic acid and carnosol are the main bioactive components responsible for the significant antioxidant activity of Rosmarinus officinalis . Nevertheless, they are known for their instability in solutions. Separation of both compounds from crude rosemary extract was successfully achieved by one‐step centrifugal partition chromatography without any degradation. A two‐phase solvent system, hexane/ethyl acetate/methanol/water (3:2:3:2 v/v) was run on a preparative scale applying the elution–extrusion technique in descending mode. A 900 mg quantity of the crude extract containing 39.7% carnosic acid and 12.3% carnosol was loaded onto a 500 mL column, rotating at 1800 rpm. Carnosic acid and carnosol were obtained at purities of 96.1 ± 1% and 94.4 ± 0.9%, with recoveries of 94.3 ± 4.4% and 94.8 ± 2.3%, respectively. The compounds were identified by mass spectrometry, tandem mass spectrometry, and comparison with authentic standards. |