Supercritical fluid extraction of Bidens pilosa L. oil: Kinetics evaluation and antitumor activity

Abstract

Different plants have been used, around the world, in the treatment of primary diseases as an alternative or popular medicine. In Brazil, the Health Minister introduced a national politic for the phytotherapy use in the Single Health System (SUS). Due to that, Bidenspilosa L. (Asteraceae) was chosen because it is one of the medicinal plants present in the Single Health System list, called RENISUS. Bidens pilosa L. is a popular plant used in the treatment of different diseases (malaria, cancer tumors, fever, diabetes, infections, inflammations, angina, etc.) and is widely disseminated throughout the tropical and subtropical regions of the world. The biological activities of the plant are attributed to the presence of flavonoids, polyacetylenes and terpenes. Therefore, this study evaluated the biological activities of the oil extraction using supercritical CO₂ at different pressure and temperature conditions, due to the scarcity of studies comparing supercritical fluid extraction to conventional techniques (Soxhlet and maceration). The experimental procedure used 8 g of previously dried and milled leaves at different conditions according to an experimental design (150 bar - 60 °C; 179 bar - 46 °C; 179 bar - 74 °C; 250 bar - 40 °C; 250 bar - 80 °C; 321 bar - 46 °C; 321 bar - 74 °C, 350 bar - 60 °C, 250 bar - 60 °C). According to the results, the best yield was 0.082 % (6.6 mg) at 321 bar and 74 °C. The analyses of the experiments done at 321 bar at 74 °C and 250 bar at 40 °C, showed ultraviolet spectra characteristic of terpenes. The extracts analyzed showed promising inhibition in the two tumor cell lines: melanoma, SK-MEL-28 (68 %) and leukemia K562 (90 %), both at a concentration of 150 μg/mL. The results suggested the importance of the bioactive components from Bidens pilosa to contribute to a new anticancer drug using supercritical technology.