Optimization of accelerated solvent extraction, ultrasound assisted and supercritical fluid extraction to obtain carnosol, carnosic acid and rosmarinic acid from rosemary

Antioxidant activities of rosemary (Rosmarinus officinalis L.) are related to the amount of phenolic compounds, mainly carnosol (C), carnosic acid (CA) and rosmarinic acid (RA). In this study, it was aimed to optimize the process conditions of accelerated solvent extraction (ASE), ultrasound assisted extraction (UAE), supercritical CO2 extraction (SFE) of rosemary to obtain the high amount of total C and CA in extract. A Box-Behnken design was applied to investigate and optimize the process variables. De -oiled rosemary by hydrodistillation, was used in the extractions. The amounts of C+CA were 18.92 mg/100 mg for ASE, 17.63 mg/100 mg for UAE, and 26.96 mg/100 mg for SFE at optimum conditions, respectively. The extract yields were 13.98% for ASE, 13.73% for UAE and %19.40 for SFE at optimum conditions. The results of antioxidant activity tests were almost the same for ASE and UAE, these were almost 2 fold higher for SFE than that of ASE and UAE. ASE, UAE and SFE were clean and environmentally friendly, green extraction techniques for extraction of C+CA in rosemary.