INVESTIGATION OF SUPERCRITICAL FLUID EXTRACTION OF PUERARIN FROM PUERARIA LOBATA

ABSTRACT Puerarin, which is the most abundant isoflavone in Pueraria lobata , has many pharmacological effects. In this study, supercritical carbon dioxide extraction was employed as a novel and efficient technique to extract puerarin from Pueraria lobata. Effects of four variables (pressure, temperature, time and co‐solvent amount) on the puerarin yield of Pueraria lobata were investigated. Up to a certain value, the puerarin yield increased with increasing pressure; thereafter, puerarin yield decreased as pressure increased. A similar effect of temperature was also found. When the temperature was at 50C or the pressure was at 20 MPa, the highest puerarin yield obtained was 5.8 ± 0.3 mg/g. Positive effects of time and co‐solvent amount were observed on the puerarin yield. However, when the time was longer than 100 min or the co‐solvent amount was greater than 120 g, no significant improvement was detected in the puerarin yield. It was therefore important to define the level of each variable for an efficient preparation of puerarin. From the results obtained, supercritical carbon dioxide extraction was proved to be an efficient technique for extraction of puerarin from Pueraria lobata. PRACTICAL APPLICATIONS Pueraria lobata is a famous Chinese traditional medicinal herb which has been consumed by many people all over the world. Puerarin is the most abundant isoflavone in this herb, and it has been proven to have some important pharmacological properties. In this study, a novel technique called supercritical carbon dioxide extraction was employed to prepare puerarin from Pueraria lobata . Effects of pressure, temperature, time and co‐solvent amount on the puerarin yield were evaluated. The results were helpful in understanding the extraction process of puerarin and could give evidence for further developments on this special medicinal herb.