title: Resin glycosides from the herbal drug jalap (Ipomoea purga).
abstract: Three new resin glycosides, purginosides I and II (1 and 2) and purgin I (3), were isolated from the aerial parts of Ipomoea purga and purified by preparative-scale recycling HPLC from a chloroform-soluble extract. Their structures were established through NMR spectroscopy and mass spectrometry. Purginosides I and II (1 and 2) are partially acylated branched pentasaccharides derived from operculinic acid A, which is composed of one D-fucose, one D-glucose, and three l-rhamnose units. The site of the aglycon macrolactonization is at C-2 of the second saccharide (rhamnose). In both compounds 1 and 2, three different esterifying residues were located at C-2 of the second rhamnose unit and at C-2 (or C-3) and C-4 on the third rhamnose moiety. The acylating residues were characterized as trans-cinnamic, n-decanoic, and either (+)-(2S)-2-methylbutanoic or n-hexanoic acid. Purgin I (3) was found to be an ester-type dimer of operculinic acid A, acylated by n-dodecanoic, (+)-(2S)-2-methylbutanoic, and trans-cinnamic acids at the same oligosaccharide core positions found in compounds 1 and 2. The site of lactonization by the aglycon in unit A was placed at C-2 of the second saccharide. The position for the ester linkage for the monomeric unit B on the macrocyclic unit A was identified as C-4 of the terminal glucose. This is the first report on the isolation, purification, and structure elucidation of intact individual resin glycoside constituents from the herbal drug jalap.
authors: Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México , Ciudad Universitaria, Mexico City 04510 D.F., Mexico.
authors: Jhon
authors: J
authors: Castañeda-Gómez
authors: Rogelio
authors: R
authors: Pereda-Miranda
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005947:Glucose / Q000737:chemistry; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification*; D027741:Ipomoea / Q000737:chemistry*; D008800:Mexico; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D012116:Resins, Plant / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D006027:Glycosides; D012116:Resins, Plant; C560158:purgin I; C560159:purginoside I; C560160:purginoside II; D005947:Glucose