Supercritical CO2 Extraction and HPLC Quantification of Carnosic Acid from the leaves of Rosemary Officinalis: A Green Approach to Bioactive Compound Purification

Abstract

This study explores the extraction and purification of carnosic acid, a potent antioxidant found in rosemary (Rosmarinus officinalis), using a green and sustainable method involving supercritical CO₂. The extraction was conducted at 45°C and 350 bar, with three cycles lasting 45 minutes each. The process resulted in the collection of 75 grams of oleoresin from 1 kg of dried rosemary leaves which is an optimal yield. The oleoresin underwent further purification via hexane precipitation, yielding a carnosic acid powder with a purity of 40% as determined by Gradient elution of Mobile phase A: Methanol: Water + Phosphoric acid solution, Mobile phase B: Methanol: Acetonitrile + Phosphoric acid solution by high-performance liquid chromatography (HPLC). Comparisons with a 60% purity standard highlight the potential of supercritical CO₂ extraction in obtaining bioactive compounds, though additional optimization is necessary to achieve higher purity.