Green Fluids Extraction and Purification of Bioactive Compounds from Natural Materials

This article introduces green solvent extraction and purification of few marker compounds from propolis and rice bran using supercritical carbon dioxide (SC-CO2). The purity (41.2 wt%) of 3,5-diprenyl-4-hydroxycinnamic acid (DHCA) was recovered from propolis using SC-CO2 at 207 bar and 323 K with ethyl acetate (6 wt%) addition. The addition of a normal-phase column adsorption approach was directly employed to obtain purified product containing 95 DHCA by weight. SC-CO2 antisolvent micronization at 200 bar and 328 K generated the submicron particulates containing DHCA (35.2 wt%) from the solution of Brazilian propolis extracts, and the enhancement factor for DHCA concentration reached to 1.61. The DHCA effectively inhibited the growth of human leukemia, colon as well as breast cancer cells, and the human serum low-density lipid oxidation in bioassay. This work also elucidates SC-CO2 extraction of rice bran oil at 300 bar and 313 K from 1.03-kg powdered rice bran. The total yield of oil was 15.7% with a free fatty acid (FFA) content of 3.75%, obtained from 20.5 kg of carbon dioxide. An oil retention efficiency of 82.2% and an FFA removal efficiency of 97.8% were achieved by using SC-CO2 deacidification at 250 bar and 353 K with 2,700 g of carbon dioxide consumed. Besides, the two purest γ-oryzanols (>98 wt%) were isolated by preparative reverse-phase high-performance liquid chromatography (HPLC). Furthermore, the central composite response surface methodology (RSM) was applied to predict the optimal operating conditions and to examine the significance of experimental parameters by a statistic analysis.