Efficient separation of similar-polar functional components in Gastrodia elata using modified multiple dual-mode high-speed counter-current chromatography and preparative HPLC.

Gastrodin and parishin compounds alcohol derivatives, the major bioactive components in Gastrodia elata, have attracted significant attention due to their promising potential health benefits. The simultaneous separation of these compounds from crude extracts poses significant challenges due to their structural homology. In this study, a separation method based on modified multiple dual-mode (MDM) high-speed counter-current chromatography was established for the efficient preparation and separation of four polar similar compounds of G.elata. Tert-butyl methyl ether/n-butyl alcohol/acetonitrile/water (acidified with 0.7% trifluoroacetic acid) (2:3:1:5, v/v/v/v) was used as two-phase polar solvent system, four target compounds were simultaneously separated by two cycles in modified MDM mode. Parishin A, gastrodin, parishin B and parishin E were obtained with purities of 90.2%, 98.3%, 87.8% and 93.5%, respectively. The structure of the target compounds was confirmed by ¹H NMR and 13C NMR analysis of the isolated material. Moreover, it provides a novel and scalable technical platform for the efficient isolation of structurally similar compounds from complex natural product matrices.