Vladimir Ferreira Cabral

Comparing conventional and supercritical extraction of (-)-mammea A/BB and the antioxidant activity of Calophyllum brasiliense extracts.

Calophyllum brasiliense is a rich source of bioactive coumarins, xanthones and biflavonoids. The aim of the study was to compare the phenol contents and the antioxidant activity of C. brasiliense extracts obtained by conventional and supercritical fluid extraction (SFE) methods, as well as the quantification of crude extracts and (−)-mammea A/BB yields. Dichloromethane and hexane were used as solvents for the conventional extractions and SFE was developed using supercritical CO2; the kinetic curves were modeled using a second-order empirical model. The dichloromethane extract presented the best total yield, although it showed the lowest content of (−)-mammea A/BB. The concentration of the coumarin was considerably higher in extracts obtained by the supercritical fluid method and a higher antioxidant activity was assigned to extracts obtained by this technique. Concerning the total phenolic contents, both the dichloro-methane and the supercritical extractions produced satisfactory amounts. The SFE method proved to be more promising than conventional methods.

Phase Behavior at High Pressure of the Ternary System: CO2, Ionic Liquid and Disperse Dye

High pressure phase behavior experimental data have been measured for the systems carbon dioxide (CO2)

Dyeing of polyethylene terephthalate fibers with a disperse dye in supercritical carbon dioxide

A 24 factorial design of experiments complemented with a central point was performed to examine the influence of operating factors on color strength and color fastness of polyethylene terephthalate (PET) fibers dyed with the Disperse Orange 30 dye in supercritical CO2. The effects of temperature, pressure, dyeing time and mass ratio between the dye and PET introduced in the dyeing chamber (α ratio) were considered. An additional set of kinetic results of color strength was obtained at the optimum condition in terms of pressure at the already presented temperatures and α ratios. A significant statistical effect of all the investigated factors on the color was observed, but except for the temperature, the influence of the same variables on wash fastness was negligible (p < 0.05). The color results expressed in terms of K/S from 2.4 to 21.8 revealed that the use of supercritical CO2 as a solvent for the dye is a rapid and reliable alternative procedure for dyeing of PET fibers with the Disperse Orange 30 dye. The results of wash fastness currently obtained (i.e. 4.69 ± 0.18) support the use of ScCO2.

Evaluation of antifungal activity of extracts of Piper regnellii obtained by supercritical fluid extraction.

The antifungal activity of extracts obtained from Piper regnellii with supercritical carbon dioxide was tested against yeast and filamentous fungi. The most active extract was obtained from leaves extracts of P. regnellii at 40°C and 25 MPa, featuring a minimal inhibitory concentration of 3.9 μg/mL against Trichophyton mentagrophytes. Neolignans eupomatenoid-3, eupomatenoid-5, eupomatenoid-6 and conocarpan were present in all extracts. The results indicate the possibility of further studies on the use of extracts of P. regnellii obtained by supercritical extraction, as potential sources of bioactive compounds for use in medicine.