Study of factors influencing pressurised solvent extraction of polar steroids from plant material. Application to the recovery of withanolides

Pressurised solvent extraction was applied to the extraction of three witha nolides from the leaves of lochroma gesnerioides. A study was carried out o f the influence of various parameters on the extraction efficiency and kine tic parameters; these included the nature of the extracting solvent, its fl ow rate, the pressure and temperature, as well as the particle size of the plant material. The pressurised solvent extraction method compared to a con ventional Soxhlet extraction showed similar recoveries and extraction selec tivity but the total handling time and solvent volume were dramatically red uced.