RESUMO
Objective To develop a systematic chromatography separation method for flavonoids from Glycyrrhiza uralensis Fisch. (GU). Methods A new method for the separation of effective parts and monomers of flavonoids from GU by two-dimensional reversed-phase liquid chromatography was developed using the self-developed preparation chromatography plant system with independent intellectual property rights. Flavonoids compounds were enriched with specific adsorption materials. The separation conditions of the chromatography were optimized by the chromatographic separation expert system software, and the loading weight of samples and the enrichment times of a separation were investigated. Results The process of chromatography separation of flavonoids from GU had good precision and reproducibility with C18 as separation and enrichment solid phase and the methanol/water and acetonitrile/water as mobile phase of one-dimensional and two-dimensional chromatography system. The dilution solution which used for one-dimensional and two-dimensional enrichment chromatography was water. The flow rate of gradient elution and dilution enrichment solution was 21 mL/min. The sample loading amount of chromatography separation was 300 mg each time. A total of 16 flavonoids parts contained stable chemical composition were obtained by the repeatable separation method after three times of enrichment. Nine pure compounds were obtained and identified by NMR and MS, which were liquiritin, liquiritigenin, formononetin, echinatin, 7,4'-dihydroxyflavone, 4'-O-[β-D-apio-D-furanosyl-(1→2)-β-D-glucopyranosyl] liquiritigenin, isoliquiritigenin, glycyrol, and glycycoumarin. Conclusion The study can provide a certain reference value for the systematic separation and cognition for flavonoids from GU.