title: Phytotoxicity of constituents of glandular trichomes and the leaf surface of camphorweed, Heterotheca subaxillaris.
abstract: Camphorweed, Heterotheca subaxillaris (Lam.) Britt. & Rusby, has a camphor-like odor, and its leaf surfaces contain glandular trichomes of the type shown to contain high levels of isoprenoids in other species. Borneol (1), the phytotoxic calamenene-type sesquiterpenes (2-5, 9-11), and methylated flavones (12-15) were isolated from the dichloromethane rinsate of camphorweed aerial tissues. The strongest plant growth inhibitor against Agrostis stolonifera and Lactuca sativa seedlings, as well as duckweed (Lemna pausicostata), was 2-methoxy-calamenene-14-carboxylic acid (2). Esterification of calamenene carboxylic acids decreased their biological activity.
authors.affiliation: USDA-ARS, Natural Products Utilization Research Unit, Box 8048, University, MS 38677, USA. masanori@nara.kindai.ac.jp
authors.forename: Masanori
authors.initials: M
authors.lastname: Morimoto
authors.forename: Charles L
authors.initials: CL
authors.lastname: Cantrell
authors.forename: Lynn
authors.initials: L
authors.lastname: Libous-Bailey
authors.forename: Stephen O
authors.initials: SO
authors.lastname: Duke
mesh_terms: D031703:Agrostis / Q000187:drug effects; D019659:Asteraceae / Q000737:chemistry* / Q000648:ultrastructure; D001892:Camphanes / Q000737:chemistry* / Q000494:pharmacology; D047309:Flavones / Q000737:chemistry* / Q000494:pharmacology; D006540:Herbicides / Q000737:chemistry / Q000494:pharmacology; D018545:Lactuca / Q000187:drug effects; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry* / Q000648:ultrastructure; D036226:Seedlings / Q000187:drug effects; D012717:Sesquiterpenes / Q000737:chemistry* / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: D001892:Camphanes; D047309:Flavones; D006540:Herbicides; D012717:Sesquiterpenes; C022871:isoborneol