Preparation of Curcuma longa L. Extract Nanoparticles Using Supercritical Solution Expansion.

Nanoparticles of Curcuma longa Linn (turmeric) rhizome extract were prepared using supercritical carbon dioxide (SC-CO2 ). The SC-CO2 was used for sample pretreatment, including lipophilic compounds removal and extraction as well as particle production. The particle formation process was based on the expansion of supercritical solution (ESS) of plant extract into a secondary chamber. In the course of the ESS process, the herbal extract changed from dissolved mode at higher pressures to precipitated mode at lower pressures, as long as the pressures were higher than critical pressure. The particle growth via coagulation was limited by a large number of unsuccessful collisions between CO2 molecules and primary nuclei due to the presence of pressurized CO2 molecules where the particle formation occurs. The presence of curcumin derivatives in nanoparticles was confirmed by Liquid Chromatography-Mass Spectrometry (LC-MS) results. Irregular to quasi-spherical particles with average diameter of 47 ± 20 nm (n = 300) were prepared at a pre-expansion pressure of 35 MPa, pressure drop of 24 MPa, temperature of 50°C, equilibration time of 30 min, collection time of 60 min, extract volume of 30 μL, and feeding solution concentration of 2 mg mL-1 .