title: Phytotoxic potential of Onopordum acanthium L. (Asteraceae).
abstract: Onopordum acanthium L. (Asteraceae) is a plant native to southern Europe and southwestern Asia, but it is invasive in disturbed areas and agricultural fields around the world, causing many agronomic problems by interfering with crops or preventing animals from grazing on pastures. Allelopathy could be one of the reasons that this plant has spread over different continents. The aim of the present study was to bioprospect O. acanthium leaf extracts through the isolation and purification of allelopathic secondary metabolites with phytotoxicity to explain their invasive behavior. Phytotoxic activity was tested using etiolated wheat coleoptiles. The most active extract was selected to perform a bioassay-guided isolation of two flavonoids, pectolarigenin (1) and scutellarein 4'-methyl ether (2), and two sesquiterpene lactones, elemanolide 11(13)-dehydromelitensin β-hydroxyisobutyrate (3) and acanthiolide (4). All compounds were isolated for the first time from O. acanthium, and acanthiolide (4) is described for the first time. Compound 3 strongly inhibited the growth of wheat coleoptiles and 1 showed an intermediate effect. The results indicate that these compounds could contribute to the invasion of O. acanthium in ecological systems and agricultural fields.
authors.affiliation: Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Paula
authors.initials: P
authors.lastname: Novaes
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Varela
authors.forename: José M G
authors.initials: JM
authors.lastname: Molinillo
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kato-Noguchi
authors.forename: Francisco A
authors.initials: FA
authors.lastname: Macías
mesh_terms: D064089:Allelopathy; D047310:Apigenin / Q000302:isolation & purification / Q000633:toxicity; D002867:Chromones / Q000302:isolation & purification / Q000494:pharmacology; D044950:Flavanones / Q000302:isolation & purification / Q000633:toxicity; D058865:Introduced Species; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D031183:Onopordum / Q000737:chemistry* / Q000378:metabolism*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology / Q000633:toxicity*; D018515:Plant Leaves / Q000737:chemistry; D064210:Secondary Metabolism; D012717:Sesquiterpenes / Q000302:isolation & purification / Q000633:toxicity; D014908:Triticum / Q000187:drug effects
chemical_list: D002867:Chromones; D044950:Flavanones; D010936:Plant Extracts; D012717:Sesquiterpenes; C528671:pectolinarigenin; C583906:scutellarein tetramethyl ether; D047310:Apigenin
keywords: Invasive plants; Onopordum acanthium; Scotch thistle; Sesquiterpene lactones