grows along stream banks and in moist areas. It prefers full sun, but will tolerate light shade. An active principle, galegine, was first isolated from this plant by Tanret and recognized as a guanidine derivate, (3-methylbut-2-en-ethyl) guanidine, by Sp?th and Perkop. The preliminary studies claim galegine can increase milk production in sheep. Additionally, there are some more studies in which the effect of water extraction of G. officinalis L. on human platelet aggregation in vitro and body weight were examined. As an alternative technique in pharmaceutical processing in contrast to chemical reaction, the supercritical fluid extraction of galegine from G. officinalis L. was investigated in this study. In comparison to conventional liquid solvent extraction, the quality of extracted components by supercritical fluids is more suitable and preferable for pharmaceutical industry. Thus, for separation of essential oil from G. officinalis L., supercritical CO 2 extraction was carried out on a laboratory scale under the following operating conditions: 40-50?C; 15-25 Mpa; 1-2 ml/min (CO 2 flow rate); 60-120 min (extraction dynamic time). The constant static time of 20 min was applied for all extraction runs. Liquid chromatography-mass spectrometry (LC-MS) was applied to identify and quantify galegine in each extracted sample. In order to obtain maximum galegine yield as the objective function of this research, the effective extraction parameters were optimized using statistical techniques, response surface methodology and analysis of variance. Response surface methodology (RSM), defined as the statistical method that uses quantitative data from an appropriate experimental design to determine and simultaneously solve multivariate equations, is an effective and powerful statistical method for optimizing experimental conditions and investigation of critical processes while reducing the number of experimental trials. Most RSM applications come from areas such as chemical or engineering processes, industrial research, and biological investigations The optimum conditions were found to be the extraction dynamic time of 150 min, 23 Mpa, 42.3?C and 1.15 ml/min to achieve galegine yield of 3.398 mg/g. Response surface analysis showed that the data were adequately fitted to second-order polynomial model and The statistical analysis also showed that the linear terms of pressure, temperature, and extractio dynamic time, the quadratic terms of pressure, extraction dynamic time, and CO 2 flow rate, as well as the interactions of pressure and temperature, and temperature and flow rate, have considerable effects on the yield. A general mathematical model for supercritical CO 2 extraction was developed. Its results showed that extraction vessel had some non-ideality due to channeling across .
