title: Thirteen novel cycloartane-type triterpenes from Combretum quadrangulare.
abstract: Thirteen novel cycloartane-type triterpenes were isolated from Combretum quadrangulare, a Vietnamese medicinal plant. The structures of the novel triterpenes were determined by spectroscopic methods as well as by chemical transformations. Among those compounds, quadrangularic acids F (1), G (2), and H (4) and 24-epiquadrangularic acid G (3) are the first examples of cycloartane-type triterpenes bearing carboxylic acid groups at both C-4 and C-20. Furthermore, norquadrangularic acid A (13) is the first example of a trinorcycloartane-type triterpene isolated from the genus Combretum.
authors.affiliation: Institute of Natural Medicine, Toyama Medical and Pharmaceutical University, 2630-Sugitani, Toyama 930-0194, Japan.
authors.forename: A H
authors.initials: AH
authors.lastname: Banskota
authors.forename: Y
authors.initials: Y
authors.lastname: Tezuka
authors.forename: K Q
authors.initials: KQ
authors.lastname: Tran
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: I
authors.initials: I
authors.lastname: Saiki
authors.forename: S
authors.initials: S
authors.lastname: Kadota
mesh_terms: D010946:Plants, Medicinal / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry*; D013057:Spectrum Analysis; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D012503:Saponins; D014315:Triterpenes; C085352:cycloartane