title: Biologically active aspidofractinine, rhazinilam, akuammiline, and vincorine alkaloids from Kopsia.
abstract: Eleven new indole alkaloids, in addition to the previously reported rhazinal (1), and 14 other known alkaloids, were obtained from the Malayan Kopsia singapurensis, viz., kopsiloscines A-F (2-7), 16-epikopsinine (8), kopsilongine- N-oxide (9), 16-epiakuammiline (10), aspidophylline A (11), and vincophylline (12). The structures of these alkaloids were determined using NMR and MS analyses. Rhazinal (1), rhazinilam (17), and rhazinicine (18) showed appreciable cytotoxicity toward drug-sensitive as well as vincristine-resistant KB cells, while kopsiloscines A (2), B (3), and D (5) and aspidophylline A (11) were found to reverse drug-resistance in drug-resistant KB cells.
authors.affiliation: Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: G
authors.initials: G
authors.lastname: Subramaniam
authors.forename: Osamu
authors.initials: O
authors.lastname: Hiraku
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hayashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Koyano
authors.forename: Kanki
authors.initials: K
authors.lastname: Komiyama
authors.forename: Toh-Seok
authors.initials: TS
authors.lastname: Kam
mesh_terms: D000470:Alkaloids / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification* / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D018432:Drug Resistance, Multiple / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D007212:Indolizines / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D007624:KB Cells; D007769:Lactams / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D008296:Malaysia; D015394:Molecular Structure; D010946:Plants, Medicinal / Q000737:chemistry*
chemical_list: D000470:Alkaloids; D000972:Antineoplastic Agents, Phytogenic; D007212:Indolizines; D007769:Lactams; C009170:rhazinilam