Nowadays traditional medicine, a source of several bioactive molecules for therapeutic purposes, has become a cure for various diseases. In fact, the evaluation of plant exploitation has become progressively significant and this for their therapeutic effects of many traditional medicines may be due to the immense presence of natural antioxidants. In this respect, Retama reatam was chosen among six herbal Tunisian plants traditionally known for their therapeutic virtues, as the best source of total polyphenol content (1122,927g GEA/g extract) with an important extraction yield as ethanol is the solvent. The Soxhlet extraction always has the lowest value in total polyphenol content (164,857 GEA/g extract) for such solvent. The total flavonoid content of the different extracts is not significantly different from each other. However, the yield extraction remains higher for ethanolic extraction exceeding a value of 26.7%. Concerning antioxidant activity of Retama reatam, results suggest that supercritical CO 2 extraction can be used as an efficient alternative for pre-treatment to eliminate fatty compounds and therefore evaluating oxygen radical absorbance capacity values.

In this work, the Supercritical AntiSolvent process has been used to generate micronized crystals of Retama raetam. The process was performed using ethanol and CO2 as solvent and antisolvent, respectively. Recrystallization was made at various temperatures (30–50 °C) and pressures (8–12 MPa) using a constant flow rate of supercritical CO2 (2 kg/h). We have been also varied the solution flow rate and its volume to identify conditions leading to spheroidal powder morphology. Size and morphology have been characterized by scanning electron microscopy and ImageJ software. The spraying of the supercritical solution directing the flow towards the precipitator results in the deposition of fine particles with uniform morphology at the bottom, and of a porous film adhering to the precipitator wall. For that reason, thermodynamic and hydrodynamic aspects are discussed so as to rationalize the powder and spongious film characteristics and provide a new way to control the SAS process applied to plant derivatives.