Assessment of Stability and Degradation Kinetics of Carnosic and Rosmarinic Acid in Edible Oil and Its Effectiveness as an Extraction Medium Compared to Other Solvents

The aim of this study was to compare the effectiveness of edible oil (as an extractant) for the extraction of CA (carnosic acid), C (carnosol), and RA (rosmarinic acid) from sage with popular solvents (methanol, ethanol, 70% methanol, 70% ethanol, and water), as well as to assess the stability and fit the kinetic reaction model to the course of CA and RA degradation in oil macerate and various extracts. The degradation rate constant and half-life of CA and RA were also estimated and compared. CA was most efficiently extracted from sage using ethanol and methanol (9.3-10.1 mg/g of sage), followed by oil (7.10 mg/g). For C and RA, the most suitable solvents were 70% ethanol and 70% methanol (C: 3.08-4.01 mg/g; RA: 19.16-20.24 mg/g). CA was most stable in oil, followed by ethanol > methanol > 70% ethanol > 70% methanol. CA degradation followed a first-order kinetic model. RA was very stable in all extracts, except water, where the kinetics of RA degradation most closely followed a second-order model. Although oil extracts smaller amounts of phytochemicals from sage than solvents, CA in oil was the most stable, and the maceration of sage in oil is safe and consistent with the concept of sustainable development.