title: Separation and characterization of phenolic compounds and triterpenoid saponins in licorice (Glycyrrhiza uralensis) using mobile phase-dependent reversed-phase×reversed-phase comprehensive two-dimensional liquid chromatography coupled with mass spectrometry.
abstract: Licorice is one of the most popular herbal medicines worldwide. It contains a big array of phenolic compounds (flavonoids, coumarins, and diphenylethanones). Due to high structural diversity, low abundance, and co-elution with licorice saponins, these phenolic compounds are difficult to be separated by conventional chromatography. In this study, a mobile phase-dependent reversed-phase×reversed phase comprehensive two-dimensional liquid chromatography (RP×RP 2DLC) method was established to separate phenolic compounds in licorice (the roots of Glycyrrhiza uralensis). Organic solvents in the mobile phase were optimized to improve orthogonality of the first and second dimensions, and a synchronized gradient mode was used to improve chromatographic resolution. Finally, licorice extracts were eluted with methanol/water/formic acid in the first dimension (Acquity CSH C18 column), and acetonitrile/water/formic acid in the second dimension (Poroshell Phenyl-Hexyl column). By using this 2DLC system, a total of 311 compounds were detected within 40min. The practical and effective peak capacity was 1329 and 524, respectively, and the orthogonality was 79.8%. The structures of 21 selected unknown compounds were tentatively characterized by mass spectrometry, and 8 of them were discovered from G. uralensis for the first time. The mobile phase-dependent 2DLC/MS system could benefit the separation and characterization of natural products in complicated herbal extracts.
authors.affiliation: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Qiao
authors.affiliation: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Song
authors.affiliation: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Ji
authors.affiliation: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China; State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China.
authors.forename: De-an
authors.initials: DA
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China; State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China. Electronic address: yemin@bjmu.edu.cn.
authors.forename: Min
authors.initials: M
authors.lastname: Ye
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D002623:Chemistry Techniques, Analytical; D002851:Chromatography, High Pressure Liquid; D056148:Chromatography, Reverse-Phase; D003374:Coumarins / Q000032:analysis; D005419:Flavonoids / Q000032:analysis; D006035:Glycyrrhiza / Q000737:chemistry*; D029882:Glycyrrhiza uralensis / Q000737:chemistry; D013058:Mass Spectrometry; D010636:Phenols / Q000032:analysis* / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D012503:Saponins / Q000032:analysis* / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D003374:Coumarins; D005419:Flavonoids; D010636:Phenols; D012503:Saponins; C032159:acetonitrile
keywords: 2DLC; Glycyrrhiza uralensis; Licorice; Phenolic compounds; Triterpenoid saponins