title: Four new triterpenoid saponins from Conyza blinii.
abstract: Three new bisdesmosidic saponins named conyzasaponins A, B, and C (1-3) and one new monodesmosidic saponin, conyzasaponin G (4), were isolated from the aerial parts of Conyza blinii. Their structures were elucidated on the basis of extensive NMR (DEPT, DQF-COSY, HOHAHA, HMQC, HMBC, and NOESY) and MS studies. Compounds 1-3 share a common prosapogenin, bayogenin 3-O-beta-D-xylopyranosyl-(1-->3)-beta-D-glucopyranoside, which is identical with conyzasaponin G (4), and differ in the structures of the ester-linked sugar moieties at C-28. Conyzasaponin A (1) is the 28-O-beta-D-apiofuranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl ester, conyzasaponin B (2), the 28-O-beta-D-apiofurano- syl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->3)]-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl ester, and conyzasaponin C (3), the 28-O-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-[beta-D-apiofuranosyl-(1-->3)]-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl ester of the prosapogenin, respectively.
authors.affiliation: School of Pharmaceutical Sciences, Peking University, Beijing 100083, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Su
authors.forename: D
authors.initials: D
authors.lastname: Guo
authors.forename: H
authors.initials: H
authors.lastname: Guo
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Zheng
authors.forename: K
authors.initials: K
authors.lastname: Koike
authors.forename: T
authors.initials: T
authors.lastname: Nikaido
mesh_terms: D002240:Carbohydrate Sequence; D002681:China; D002855:Chromatography, Thin Layer; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry* / Q000302:isolation & purification; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014315:Triterpenes / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D012503:Saponins; D014315:Triterpenes