One-step isolation of carnosic acid and carnosol from rosemary by centrifugal partition chromatography.

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.