Abstract
Two new monoterpenoid indole alkaloids, alstoscholactine (1) and alstolaxepine (2), were isolated from Alstonia scholaris. Compound 1 represents a rearranged stemmadenine alkaloid with an unprecedented C-6-C-19 connectivity, whereas compound 2 represents a 6,7- seco-angustilobine B-type alkaloid incorporating a rare γ-lactone-bridged oxepane ring system. Their structures and absolute configurations were determined by spectroscopic analyses. Compound 1 was successfully semisynthesized from 19 E-vallesamine. Compound 2 induced marked vasorelaxation in rat isolated aortic rings precontracted with phenylephrine.
MeSH terms
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Alstonia / chemistry*
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Animals
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Aorta / drug effects
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Cell Line, Tumor
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Crystallography, X-Ray
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Cycloheptanes / chemistry
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Cycloheptanes / isolation & purification
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Cycloheptanes / pharmacology*
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Dose-Response Relationship, Drug
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Heterocyclic Compounds, 4 or More Rings / chemistry
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Heterocyclic Compounds, 4 or More Rings / isolation & purification
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Heterocyclic Compounds, 4 or More Rings / pharmacology*
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Humans
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Indoles / chemistry
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Indoles / isolation & purification
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Indoles / pharmacology*
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Lactones / chemistry
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Lactones / isolation & purification
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Lactones / pharmacology*
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Male
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Models, Molecular
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Molecular Conformation
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Oxepins / chemistry
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Oxepins / isolation & purification
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Oxepins / pharmacology*
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Rats
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Secologanin Tryptamine Alkaloids / chemistry
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Secologanin Tryptamine Alkaloids / isolation & purification
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Secologanin Tryptamine Alkaloids / pharmacology*
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Structure-Activity Relationship
Substances
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Cycloheptanes
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Heterocyclic Compounds, 4 or More Rings
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Indoles
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Lactones
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Oxepins
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Secologanin Tryptamine Alkaloids
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alstoscholarine