title: Purification of amide alkaloids from Piper longum L. using preparative two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography.
abstract: A comprehensive off-line two-dimensional liquid chromatography (2D-LC) method coupling normal phase liquid chromatography (NPLC) and reversed phase liquid chromatography (RPLC) was developed for separation and purification of amide alkaloids from Piper longum L. In the first dimension, the crude alkaloid fractions were separated in NPLC mode and 20 fractions were collected. Then fractions 5-20 were selected for further purification in RPLC mode in the second dimension. The purities of RPLC fractions with similar structures were all identified accurately by ultra performance liquid chromatography (UPLC). In total, 28 compounds with high purity were obtained and their structures were comprehensively characterized by electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) spectroscopy. The results demonstrate that this 2D NPLC × RPLC method with good orthogonality (58.3%) was effective for the preparative separation and purification of amide alkaloids from Piper longum L.
authors.affiliation: Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
authors.forename: Kuiyong
authors.initials: K
authors.lastname: Li
authors.forename: Wenya
authors.initials: W
authors.lastname: Zhu
authors.forename: Qing
authors.initials: Q
authors.lastname: Fu
authors.forename: Yanxiong
authors.initials: Y
authors.lastname: Ke
authors.forename: Yu
authors.initials: Y
authors.lastname: Jin
authors.forename: Xinmiao
authors.initials: X
authors.lastname: Liang
mesh_terms: D000470:Alkaloids / Q000737:chemistry* / Q000302:isolation & purification*; D000577:Amides / Q000737:chemistry*; D056148:Chromatography, Reverse-Phase / Q000379:methods*; D008970:Molecular Weight; D031701:Piper / Q000737:chemistry*
chemical_list: D000470:Alkaloids; D000577:Amides