ABSTRACT
<p><b>OBJECTIVE</b>The optimum conditions of SFE-CO2 extraction of Plantaginis Semen oil (SPO), the composition of SPO and its antioxidant activities of SPO were all investigated in this paper.</p><p><b>METHOD</b>Response surface method (RSM) was used to establish the mathematical model of SFE-CO2 extraction of SPO to obtain the optimum conditions based on Single factor experiments. Fatty acid compositions and contents of SPO were tested by GC-MS, and antioxidant activities of SPO were studied by DPPH and ABTS free radical elimination method.</p><p><b>RESULT</b>The optimum conditions obtained through RSM analysis were as follows: extraction tempreture 70 degrees C, extraction pressure 30 MPa, extraction time 120 min and flow rate 30 L x h(-1). Under the optimal condition, predicted value was 35.91%, while the experimental value was 35.07%. The experimental values agree with the predicted from the regression model with a relative error less than 5%. The main components of SPO were 9,12,15-octadecatrienoic acid, 8,11-octadecadienoic acid, octadecanoic acid and hexadecanoic acid. Most of the fatty acids were polyunsaturated fatty ones, whose quantities were obtained more than 88%. The IC50DPPH and IC50ABTS were 1.13, 3.57 g x L(-1) respectively in DPPH and ABTS assay.</p><p><b>CONCLUSION</b>Optimization of the extraction process by RSM of SPO is convenient and feasible. SPO has good antioxidant activity and is worth to develop for application.</p>