title: Aspidofractinine and Eburnane Alkaloids from a North Borneo Kopsia. Ring-Contracted, Additional Ring-Fused, and Paucidactine-Type Aspidofractinine Alkaloids from K. pauciflora.
abstract: Eleven new indole alkaloids (1-11) comprising seven aspidofractinine and four eburnane alkaloids, were isolated from the stem-bark extract of Kopsia pauciflora occurring in Malaysian Borneo. The aspidofractinine alkaloids include a ring-contracted, an additional ring-fused, a paucidactine regioisomer, two paucidactine, and one kopsine alkaloid. The structures of several of these alkaloids were also confirmed by X-ray diffraction analyses. The bisindole alkaloids isolated, norpleiomutine and kopsoffinol, showed in vitro growth inhibitory activity against human PC-3, HCT-116, MCF-7, and A549 cells and moderate effects in reversing multidrug-resistance in vincristine-resistant human KB cells.
authors.forename: Wai-Sum
authors.initials: WS
authors.lastname: Yap
authors.affiliation: University Malaysia of Computer Science and Engineering , Jalan Alamanda 2, Precint 1, 62000 Putrajaya, Malaysia.
authors.forename: Chew-Yan
authors.initials: CY
authors.lastname: Gan
authors.forename: Kae-Shin
authors.initials: KS
authors.lastname: Sim
authors.forename: Siew-Huah
authors.initials: SH
authors.lastname: Lim
authors.forename: Yun-Yee
authors.initials: YY
authors.lastname: Low
authors.forename: Toh-Seok
authors.initials: TS
authors.lastname: Kam
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D029062:Apocynaceae / Q000737:chemistry*; D001893:Borneo; D018360:Crystallography, X-Ray; D018432:Drug Resistance, Multiple / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D026121:Indole Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D007624:KB Cells; D008296:Malaysia; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D024301:Plant Bark / Q000737:chemistry; D014750:Vincristine / Q000494:pharmacology
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D026121:Indole Alkaloids; C552319:aspidofractinine; D014750:Vincristine; C502051:kopsine