Isolation and purification of 3,5-diprenyl-4-hydroxycinnamic acid (artepillin C) in Brazilian propolis by supercritical fluid extractions

This study individually investigated organic solvents and supercritical carbon dioxide (SC-CO2) extractions to recover 3,5-diprenyl-4-hydroxycinnamic acid (DHCA) from Brazilian propolis. An experimental design was applied to show the effect of two independent operational parameters on the recovery and purity of DHCA for these SC-CO2 extractions. Our experimental results indicated that temperature and addition ratio of ethyl-acetate are two major factors to influence the recovery and purity of DHCA in the extracts. A design point at 50 °C (323 K) and 4 wt.% ethyl-acetate addition ratio subsequently responded that DHCA recoveries were substantially enhanced from 3.7 wt.% (no adding) to 13.9 wt.% (6 wt.% adding) and DHCA purities in the SC-CO2 extracts were all over 40 wt.%, much better than that of Soxhlet ethyl-acetate extraction (16.9 wt.%). A further purification of the SC-CO2 extract using a normal phase Silica-gel 60 resin column chromatography without two solvent partitions could yield a purified product containing 95 wt.% DHCA. The total DHCA recovery was twice higher than that when the solvent partition was used. Finally, the inhibition of human serum low density lipid revealed a positive relationship between the DHCA purity in the SC-CO2 extracts and the anti-oxidative ability.