title: Rhazinilam-Leuconolam-Leuconoxine Alkaloids from Leuconotis griffithii.
abstract: Eight new indole alkaloids (1-8) belonging to the rhazinilam-leuconolam-leuconoxine group, in addition to 52 other alkaloids, were isolated from the stem-bark extract of Leuconotis griffithii, viz., nor-rhazinicine (1), 5,21-dihydrorhazinilam-N-oxide (2), 3,14-dehydroleuconolam (3), and leuconodines A-E (4-8). The structures of these alkaloids were determined using NMR and MS analyses and in some instances confirmed by X-ray diffraction analyses. Alkaloids 1, 5, and 7 showed only moderate to weak cytotoxicity toward KB cells (IC50 12-18 μg/mL), while 8 showed moderate activity in reversing MDR in vincristine-resistant KB cells.
authors: Department of Chemistry, University of Malaya, Kuala Lumpur, Malaysia.
authors: Chew-Yan
authors: CY
authors: Gan
authors: Yun-Yee
authors: YY
authors: Low
authors: Noel F
authors: NF
authors: Thomas
authors: Toh-Seok
authors: TS
authors: Kam
mesh_terms: D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D029062:Apocynaceae / Q000737:chemistry*; D001381:Azepines / Q000737:chemistry; D018360:Crystallography, X-Ray; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D006576:Heterocyclic Compounds, 4 or More Rings / Q000737:chemistry; D006801:Humans; D007212:Indolizines / Q000737:chemistry; D007624:KB Cells; D007769:Lactams / Q000737:chemistry; D008296:Malaysia; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D024301:Plant Bark / Q000737:chemistry; D014750:Vincristine / Q000494:pharmacology
chemical_list: D000470:Alkaloids; D000972:Antineoplastic Agents, Phytogenic; D001381:Azepines; D006576:Heterocyclic Compounds, 4 or More Rings; D007212:Indolizines; D007769:Lactams; C529483:rhazinicine; C009170:rhazinilam; D014750:Vincristine; C062173:leuconolam