title: The Joint Action of Sesquiterpene Lactones from Leaves as an Explanation for the Activity of Cynara cardunculus.
abstract: The work described herein is a continuation of a previous study centered on the bioprospect of cardoon (Cynara cardunculus) leaf extracts through the isolation of secondary metabolites with phytotoxic activity. Chromatographic fractionations of the ethyl acetate extract and spectroscopic analysis showed that the majority of the components were sesquiterpene lactones. Of these compounds, aguerin B, grosheimin, and cynaropicrin were very active on etiolated wheat coleoptile, standard target species, and weed growth. The joint action of binary mixtures of these three active sesquiterpene lactones and one nonactive compound (11,13-dihydroxy-8-desoxygrosheimin) was studied. The activities of fixed-ratio mixtures were assessed on wheat coleoptile. The results can be interpreted with respect to a reference model by considering dose-response analyses and isobolograms with linear regression analyses. A total of 17 binary mixtures at different levels of inhibition (ED25, ED50, and ED75) were studied, and predominantly they responded additively (25). Deviations from additivity included seven synergistic responses and two antagonistic responses. The joint action of major sesquiterpene lactones isolated from C. cardunculus can explain the activities observed in extracts and fractions. The results reported here reiterate the utility of the wheat coleoptile bioassay as a quick tool to detect potential synergistic effects in binary mixtures.
authors.affiliation: Allelopathy Group, Department of Organic Chemistry, Institute of Biomolecules (INBIO), Campus de Excelencia Internacional (ceiA3), School of Science, University of Cadiz , C/República Saharaui 7, 11510 Puerto Real, Cadiz, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Rial
authors.affiliation: Allelopathy Group, Department of Organic Chemistry, Institute of Biomolecules (INBIO), Campus de Excelencia Internacional (ceiA3), School of Science, University of Cadiz , C/República Saharaui 7, 11510 Puerto Real, Cadiz, Spain.
authors.forename: Benito F
authors.initials: BF
authors.lastname: García
authors.affiliation: Allelopathy Group, Department of Organic Chemistry, Institute of Biomolecules (INBIO), Campus de Excelencia Internacional (ceiA3), School of Science, University of Cadiz , C/República Saharaui 7, 11510 Puerto Real, Cadiz, Spain.
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Varela
authors.affiliation: Allelopathy Group, Department of Organic Chemistry, Institute of Biomolecules (INBIO), Campus de Excelencia Internacional (ceiA3), School of Science, University of Cadiz , C/República Saharaui 7, 11510 Puerto Real, Cadiz, Spain.
authors.forename: Ascensión
authors.initials: A
authors.lastname: Torres
authors.affiliation: Allelopathy Group, Department of Organic Chemistry, Institute of Biomolecules (INBIO), Campus de Excelencia Internacional (ceiA3), School of Science, University of Cadiz , C/República Saharaui 7, 11510 Puerto Real, Cadiz, Spain.
authors.forename: José M G
authors.initials: JM
authors.lastname: Molinillo
authors.affiliation: Allelopathy Group, Department of Organic Chemistry, Institute of Biomolecules (INBIO), Campus de Excelencia Internacional (ceiA3), School of Science, University of Cadiz , C/República Saharaui 7, 11510 Puerto Real, Cadiz, Spain.
authors.forename: Francisco A
authors.initials: FA
authors.lastname: Macías
mesh_terms: D018548:Cotyledon / Q000187:drug effects; D031942:Cynara / Q000737:chemistry*; D007783:Lactones / Q000737:chemistry*; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D012717:Sesquiterpenes / Q000737:chemistry*; D014908:Triticum / Q000187:drug effects
chemical_list: D007783:Lactones; D010936:Plant Extracts; D012717:Sesquiterpenes; C000598116:aguerin B; C075687:cynaropicrin; C007887:grosheimin
keywords: additive; antagonist; binary mixtures; cytotoxicity bioassays; isobole; sesquiterpene lactones; synergism