Supercritical fluids extraction of Ginkgo ginkgolides and flavonoids

This study investigated the feasibility of extracting three major terpene lactones and flavonoids from Ginkgo leaves by using supercritical carbon dioxide, nitrous oxide and R134a. A semi-batch extraction and absorption process was employed to collect and sequentially dissolve solutes precipitated from supercritical fluids. The extraction conditions ranged from 24.2 to 31.2 MPa and from 333 to 393 K. A reverse-phase HPLC system coupled with RI and UV detectors was also used to individually quantify the level of terpene lactones and flavonoid aglycones in the extracts. Experimental data showed that Soxhlet ethanol extraction had the best performance on total yield and the amount of terpene lactones and flavonoids. Our results further indicated that three dry supercritical fluids, individually at the density of 0.84, 0.83 and 1.13 g/ml, could not extract terpene lactones and flavonoids. However, when ethanol was added to supercritical fluid extraction, the extracted amount of terpene lactones increased with the mole fraction of ethanol addition. In doing so, supercritical carbon-dioxide (SC-CO2) could extract more terpene lactones than the other two fluids.