Phytochemical and larvicidal studies on Stemona curtisii: structure of a new pyrido[1,2-a]azepine Stemona alkaloid

• Published in: Journal of natural products (Washington, D.C.) D.C.), 2004-04, Vol.67 (4), p.675-677
• Main Authors: Mungkornasawakul, P, Pyne, S.G, Jatisatienr, A, Supyen, D, Jatisatienr, C, Lie, W, Ung, A.T, Skelton, B.W, White, A.H
• Format: Article
• Language: English
• Subjects: Alkaloids - chemistry; Alkaloids - isolation & purification; Alkaloids - pharmacology; Animals; Anopheles - drug effects; Azepines - chemistry; Azepines - isolation & purification; Azepines - pharmacology; Biological and medical sciences; Crystallography, X-Ray; Fundamental and applied biological sciences. Psychology; Furans - chemistry; Furans - isolation & purification; Furans - pharmacology; Inhibitory Concentration 50; Larva - drug effects; Medically important nuisances and vectors, pests of stored products and materials: population survey and control; Molecular Structure; Stemonaceae - chemistry; Thailand; Vectors. Intermediate hosts
• ISSN: 0163-3864; 1520-6025
• DOI: 10.1021/np034066u

A new pentacyclic Stemona alkaloid, stemocurtisinol (3), with a pyrido[1,2-a]azepine A,B-ring system, and the known pyrrolo[1,2-a]azepine alkaloid oxyprotostemonine (4) have been isolated from a root extract of S. curtisii. The structure and relative stereochemistry of stemocurtisinol was determined by spectral data interpretation and X-ray crystallography. This compound is a diastereoisomer of oxystemokerrin and has the opposite configuration at C-4 and C-19. The individual alkaloid components showed significant larvicidal activity (IC(50) 4-39 ppm) on mosquito larvae (Anopheles minimus HO).