Process Optimization for Supercritical Carbon Dioxide Extraction of Total Flavonoids from Praecox Leaves in Northern Areas

Supercritical CO2 fluid extraction technique was explored to extract total flavonoids from praecox leaves in northern areas of China.Single-factor design was used to determine main variables that influence extraction rate of total flavonoids.The optimal extraction conditions were achieved to be extraction temperature of 36 ℃,ethanol concentration of 50%,extraction pressure of 35 MPa,entrainer(absolute ethanol) amount of 1:15,entrainer amount 9% and extraction time of 40 min.Under the optimal extraction conditions,the extraction rate of total flavonoids was 23.24 mg/g.The supercritical fluid CO2 extraction can be used for the extraction of total flavonoids from praecox leaves with high extraction efficiency.