Keiichi Suto

Three flavonol glycosides from Epimedium koreanum

Abstract Three new flavonol glycosides: 4′-methoxy-5-hydroxy-8-3,3-dimethylallylflavone 3-glycosyl(1→2)rhamnoside-7-glucoside, 3-xylosyl(1→2)rhamnoside-7-glucoside and 3-rhamnosyl(1→2)rhamnoside-7-glucoside and icariin were characterized from the aerial parts of Epimedium koreanum .

Determination of berberine and palmatine in Phellodendri Cortex using ion-pair supercritical fluid chromatography on-line coupled with ion-pair supercritical fluid extraction by on-column trapping

An assay of berberine and palmatine in Phellodendri Cortex was established using ion-pair supercritical fluid chromatography (IP-SFC) on-line coupled with ion-pair supercritical fluid extraction (IP-SFE). The on-column method was employed to successfully perform on-line SFE-SFC. With a silica-gel column as a trapping and separation column, berberine and palmatine were extracted and focused at the column head, even if 10% methanol containing dioctyl sodium sulfosuccinate (DSS) was added to the supercritical carbon dioxide as an entrainer. After consecutive extraction and adsorption, berberine and palmatine were desorped and SFC was performed increasing the concentration of DSS methanol solution to 15%. The addition of DSS improved the efficiency of extraction of alkaloids, and the recovery of the analytes of interest was almost the same as that obtained with solvent extraction. Determination of the analytes in Phellodendri Cortex was achieved with only a few mg of crude sample. SFE was completed within ca. 10 min, and SFC was also achieved within ca. 10 min. The consecutive procedures of extraction, concentration and analysis were thus completed within ca. 20 min. Commercial Phellodendri Cortex was tested for determination of the analytes, and results confirmed that our on-line SFE-SFC method can be used for rapid convenient assay of berberine and palmatine in Phellodendri Cortex.

Determination of magnolol and honokiol in Magnoliae Cortex using supercritical fluid chromatography on-line coupled with supercritical fluid extraction by on-column trapping

Abstract An assay of magnolol and honokiol in Magnoliae Cortex was established by on-line supercritical fluid chromatography (SFC) coupled with supercritical fluid extraction (SFE). With an amino column as the trapping and separation column, magnolol and honokiol were extracted and focused at the column head as a narrow band, even if 5% methanol was added to the supercritical carbon dioxide as an entrainer. Addition of the entrainer improved extract efficiency, and recovery of the analytes was almost the same as for solvent extraction. Determination of analytes of interest in Magnoliae Cortex was achieved with only a few mg of sample. SFE was completed within ca. 1 min, and SFC was achieved within ca. 3 min. The consecutive procedures of extraction, concentration and analysis were completed within ca. 5 min.

Determination of atractylon in Atractylodes rhizome using supercritical fluid chromatography on-line coupled with supercritical fluid extraction by the direct induction method

Abstract Atractylon was extracted from Atractylodes rhizome within 15 s with supercritical carbon dioxide. The extraction was so rapid that SFE extracts could be transported directly into an SFC column and analyzed. Atractylon was eluted and separated in ca. 5 min. Analyte recovery was 30% higher than when using solvent extraction. Determination of atractylon in Atractylodes rhizome was achieved with only a few mg of crude drug sample. Atractylon is unstable due to oxidation and is easily transformed to atractylenolides. Loss of analytes during the procedures was also minimal with this on-line SFE–SFC system.