title: Facile preparation of bioactive seco-guaianolides and guaianolides from Artemisia gorgonum and evaluation of their phytotoxicity.
abstract: Commercially available santonin was used to synthesize seven sesquiterpene lactones using a facile strategy that involved a high-yielding photochemical reaction. Three natural products from Artemisia gorgonum were synthesized in good yields, and in the case of two compounds, absolute configurations were determined from X-ray quality crystals. The structures previously reported for these compounds were revised. Sesquiterpene lactones were tested using the etiolated wheat coleoptile bioassay, and the most active compounds were assayed in standard target species. seco-Guaianolide (4) showed higher phytotoxic activities than the known herbicide Logran. This high activity could be due to the presence of a cyclopentenedione ring. These results suggest that compound 4 should be involved in defense of A. gorgorum, displaying a wide range of activities that allow proposing them as new leads for development of a natural herbicide model with a seco-guaianolide skeleton.
authors.affiliation: Allelopathy Group, Department of Organic Chemistry, School of Sciences, University of Cadiz , C/República Saharaui, s/n, 11510-Puerto Real, Spain.
authors.forename: Francisco A
authors.initials: FA
authors.lastname: Macías
authors.forename: Alejandro
authors.initials: A
authors.lastname: Santana
authors.forename: Azusa
authors.initials: A
authors.lastname: Yamahata
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Varela
authors.forename: Frank R
authors.initials: FR
authors.lastname: Fronczek
authors.forename: José M G
authors.initials: JM
authors.lastname: Molinillo
mesh_terms: D019306:Artemisia / Q000737:chemistry*; D019607:Brassicaceae / Q000187:drug effects; D018360:Crystallography, X-Ray; D006540:Herbicides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry* / Q000494:pharmacology*; D018545:Lactuca / Q000187:drug effects; D018551:Solanum lycopersicum / Q000187:drug effects; D008968:Molecular Conformation; D015394:Molecular Structure; D019697:Onions / Q000187:drug effects; D010963:Plasmodium falciparum / Q000187:drug effects; D045789:Sesquiterpenes, Guaiane / Q000138:chemical synthesis* / Q000737:chemistry* / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014908:Triticum / Q000187:drug effects
chemical_list: D006540:Herbicides; D007783:Lactones; D045789:Sesquiterpenes, Guaiane