title: Cytotoxic triterpenoid alkaloids from Buxus microphylla.
abstract: Five new triterpenoid alkaloids, buxmicrophyllines E-I (1-5), and six known ones (6-11) were isolated from the leaves and stems of Buxus microphylla. The structures of compounds 1-5 were elucidated by NMR and MS spectroscopic analysis, and the relative stereochemistry of 5 was determined by single-crystal X-ray crystallography. Compounds 3 and 9 were cytotoxic against HepG2 cells, with IC(50) values of 0.89 and 0.78 microM, and compounds 2, 3, 7, 8, and 9 were cytotoxic against K562 cells, with IC(50) values of 2.95, 4.44, 1.70, 5.61, and 0.37 microM, respectively.
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, Yunnan, People's Republic of China.
authors.forename: Yu-Xin
authors.initials: YX
authors.lastname: Yan
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Hu
authors.forename: Jian-Chao
authors.initials: JC
authors.lastname: Chen
authors.forename: Yun
authors.initials: Y
authors.lastname: Sun
authors.forename: Xian-Min
authors.initials: XM
authors.lastname: Zhang
authors.forename: Chen
authors.initials: C
authors.lastname: Qing
authors.forename: Ming-Hua
authors.initials: MH
authors.lastname: Qiu
mesh_terms: D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D031235:Buxus / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004354:Drug Screening Assays, Antitumor; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D056945:Hep G2 Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D020014:K562 Cells; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*
chemical_list: D000470:Alkaloids; D000972:Antineoplastic Agents, Phytogenic; D004365:Drugs, Chinese Herbal; D014315:Triterpenes