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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Alkaloids / chemistry
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Alkaloids / isolation & purification*
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Alkaloids / pharmacology
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Antineoplastic Agents, Phytogenic / chemistry
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Antineoplastic Agents, Phytogenic / isolation & purification*
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Antineoplastic Agents, Phytogenic / pharmacology
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Apocynaceae / chemistry*
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Azepines / chemistry
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Crystallography, X-Ray
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Drug Resistance, Neoplasm / drug effects
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Drug Screening Assays, Antitumor
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Heterocyclic Compounds, 4 or More Rings / chemistry
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Humans
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Indolizines / chemistry
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KB Cells
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Lactams / chemistry
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Malaysia
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Molecular Conformation
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Molecular Structure
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Nuclear Magnetic Resonance, Biomolecular
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Plant Bark / chemistry
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Vincristine / pharmacology
Substances
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Alkaloids
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Antineoplastic Agents, Phytogenic
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Azepines
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Heterocyclic Compounds, 4 or More Rings
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Indolizines
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Lactams
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rhazinicine
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rhazinilam
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Vincristine
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leuconolam