Abstract
The isolation and structural elucidation of dioncophylline E, a novel naphthylisoquinoline alkaloid from the rare West African liana Dioncophyllum thollonii, is described. The alkaloid displays an unusual 7,3'-linkage between the naphthalene and the isoquinoline portions. Due to the resulting medium degree of steric hindrance exerted by the ortho-substituents next to the biaryl axis, the compound undergoes slow rotation about the axis at room temperature and thus is the first such alkaloid that occurs as a mixture of two configurationally semi-stable atropo-diastereomers. Dioncophylline E exhibits good antimalarial activity against both chloroquine-sensitive and -resistant strains of Plasmodium falciparum while its antitrypanosomal activity against Trypanosoma cruzi is weak and that against T. brucei rhodesiense is moderate. Furthermore, four additional naphthylisoquinoline alkaloids previously known from the related plant species Triphyophyllum peltatum, have been identified in D. thollonii.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Africa
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Alkaloids / pharmacology*
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Animals
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Antiprotozoal Agents / chemistry*
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Antiprotozoal Agents / isolation & purification
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Antiprotozoal Agents / pharmacology*
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Chromatography, High Pressure Liquid / methods
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Circular Dichroism
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Humans
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Inhibitory Concentration 50
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Isoquinolines / chemistry*
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Isoquinolines / isolation & purification
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Isoquinolines / pharmacology*
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Kinetics
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Magnetic Resonance Spectroscopy / methods
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Magnoliopsida / classification
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Magnoliopsida / metabolism*
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Mass Spectrometry / methods
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Muscle, Skeletal / parasitology
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Parasitic Sensitivity Tests
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Plant Extracts / chemistry
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Plant Extracts / isolation & purification
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Plant Extracts / pharmacology
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Plants, Medicinal / chemistry
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Plants, Medicinal / classification
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Plasmodium falciparum / drug effects
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Plasmodium falciparum / growth & development
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Rats
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Spectrophotometry, Infrared
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Stereoisomerism
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Thermodynamics
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Trypanosoma / drug effects
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Trypanosoma / growth & development
Substances
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Alkaloids
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Antiprotozoal Agents
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Isoquinolines
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Plant Extracts
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dioncophylline E