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Forsythoside A and suspensaside A were isolated and purified fromForsythia suspensaby one step of high-speed counter-current chromatography for the first time using a solvent system of ethyl acetate-n-butanol-methanol-water (4:0.5:0.5:5,v/v). The purities of the two compounds were 98.19% and 98.05%, respectively, as determined by HPLC. Their structures were identified by MS, UV, and NMR analysis. Such a simple and effective method was fairly useful to prepare pure compounds as reference substances for related study onForsythia suspensa. [ABSTRACT FROM PUBLISHER]

An effective high–speed counter–current chromatography (HSCCC) method was established for semi-preparative isolation and purification of bioactive chemical constituents from the Tibetan medicinal plantPedicularis longifloravar.tubiformis(Klotzsch) P. C. Tsoong. With a two-phase solvent system composed of chloroform–methanol–water (8:4:5, v/v), 40 mg of extract was separated to yield luteolin (12.5 mg), apigenin (9.6 mg), and chrysoeriol (4.8 mg), with purities of 99.3, 98.2, and 98.6%, respectively, as determined by high-performance liquid chromatography (HPLC). The chemical structures of these three components were identified by1H NMR and13C NMR. [ABSTRACT FROM PUBLISHER]

The detrimental effect of heterogeneity on the efficiency of particle packed columns has been a long standing issue in chromatographic separations. This heterogeneity arises from the difference in packing density between the wall and central regions of the chromatographic bed and imparts radial variance in mobile phase velocity through the column. In conjunction with the uneven distribution of the sample band through frits and distributors at the head of the column, the resultant effect is a decrease in efficiency due to the formation of a parabolic-“like” sample band. We introduce the concept of “Active Flow Management” to counteract the effects of column heterogeneity via the separation of the flow eluting from the center of the column from that of the flow eluting near the peripheral wall region. The flow streams from the two aforementioned regions are separated by the use of a specialized column outlet fitting. By varying the ratio of flow eluting from the center to the peripheral region it was possible to increase the efficiency of a 100 × 21 mm column by up to 57% compared to a column operated in the conventional manner. [ABSTRACT FROM AUTHOR]