Supercritical fluid extractions were performed using a laboratory-scale supercritical extraction unit equipped with two intelligent HPLC pumps(ModelPU-1580,Jasco Corporation,Japan): a CO2 pump, and a co-solvent pump. Liquid CO2 contained in the cylinder was cooled using a cooling jacket attached to the intelligent HPLC pump. For all runs,the 50mL stainless steel extractor(ModelEV 3,Jasco Corporation,Japan) was charged with a mixture of 1:1(v/v) milled P.nigrum L. seeds (5g) and glass beads (1.00 mm in diameter), and the extraction vessel was placed in a column oven (modelCO-1560,Jasco Corporation,Japan) at preferred temperature.