Supercritical fluid extraction of quercetin and rutin from Hyperici herba

An analytical-scale method using supercritical carbon dioxide for extraction of flavonoidal compounds from Hyperici herba has been developed. Carbon dioxide pressure, temperature, flow, percentage of methanol as organic modifier, and trapping conditions were optimized using an experimental design. Quercetin and rutin were the compounds detected in the HPLC chromatogram of each extract. Recovery and the reproducibility of both compounds were calculated. Under optimized conditions recovery was estimated to be 92% and 76% for quercetin and rutin, respectively, with RSD values equal to 6.4% and 5.2%. Results from the supercritical fluid extraction method were compared with results obtained via a sonication method, using a methanol-water extraction system.