NMR and Molecular Mechanics Study of Pyrethrins I and II

• Published in: Journal of agricultural and food chemistry Vol. 47; no. 8; pp. 3402 - 3410
• Main Authors: Rugutt, Joseph K, Henry, Charles W, Franzblau, Scott G, Warner, Isiah M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.08.1999
• Subjects: Agronomy. Soil science and plant productions; Antibacterial agents; antibacterial properties; Antibiotics. Antiinfectious agents. Antiparasitic agents; Biological and medical sciences; Chemical constitution; Chrysanthemum cinerariifolium; Computer Simulation; Economic plant physiology; esters; Fundamental and applied biological sciences. Psychology; Insecticides - chemistry; Insecticides - isolation & purification; Magnetic Resonance Spectroscopy; Medical sciences; Models, Molecular; Molecular Conformation; Mycobacterium tuberculosis; nuclear magnetic resonance spectroscopy; Pharmacology. Drug treatments; Plant Extracts - chemistry; pyrethrin i; pyrethrin ii; pyrethrins; Pyrethrins - chemistry; Pyrethrins - isolation & purification; spectral analysis; Tanacetum cinerariifolium; Pyrethrins; Molecular structure; NMR spectrometry; Compositae; Experimental study; Pesticide crop; Antibiotic; Tanacetum cinerariifolium; Mycobacterium tuberculosis; Structure activity relation; Mycobacteriales; Dicotyledones; Angiospermae; Molecular model; Mycobacteriaceae; Bacteria; Actinomycetes; Spermatophyta; Antibacterial agent; Structural analysis
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf980660b

Bioassay-directed fractionation of the organic extract of the Kenyan pyrethrum flowers (Chrysanthemum cinerariaefolium Vissiani) resulted in the isolation of two natural pyrethrin esters, pyrethrin I (PI) and pyrethrin II (PII) as the major constituents. These esters elicited inhibition of the multiple drug resistant (MDR) Mycobacterium tuberculosis. The high-field 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of PI and PII were unequivocally assigned using modern two-dimensional (2D) proton-detected heteronuclear multiple-quantum coherence (HMQC) and heteronuclear multiple-bond correlation (HMBC) experiments. The conformations of both esters were deduced from 1H−1H vicinal coupling constants and confirmed by 2D nuclear Overhauser effect spectroscopy (NOESY). Computer molecular modeling (MM) studies revealed that PI and PII molecules adopt a “love-seat” conformation in chloroform (CDCl3) solution. Keywords: Pyrethrum; Chrysanthemum cinerariaefolium; pyrethrins; vacuum−liquid chromatography; antimycobacteria; Mycobacterium tuberculosis; M. avium; nuclear magnetic resonance spectroscopy; molecular modeling; conformations