Supercritical fluids extraction of cinnamic acid derivatives from Brazilian propolis and the effect on growth inhibition of colon cancer cells

This work examined supercritical carbon dioxide (SC-CO2) extractions of an anti-cancer compound, 3,5-diprenyl-4-hydroxycinnamic acid (DHCA) from propolis lumps and studied the inhibitive effect of the SC-CO2 extracts on the growth of two cancer cells. The maximum amount of DHCA, 91.9 mg/g, was obtained by Soxhlet ethyl acetate extraction and the 41.2 wt.% pure DHCA was recovered using SC-CO2 at 20.7 MPa and 323 K with 6 wt.% ethyl acetate addition. The effects of temperature and the addition of ethyl acetate on the DHCA purity, examined using a two factorial central composite response surface methodology, indicated that both factors were significant. A normal phase column adsorption approach was directly employed to purify the DHCA, and the purity was increased to 95 wt.%. The cell concentrations following growth inhibition ranged from 10 μg/mL to 500 μg/mL, indicating that the SC-CO2 extracts and 95 wt.% DHCA effectively inhibited the growth of human leukemia (HL-60) and colon (colo 205) cancer cells, but did not suppress the growth of two human normal cells.