title: Pyrrolizidine alkaloids from Lithospermum canescens Lehm.
abstract: Seven pyrrolizidine alkaloids (PAs) have been isolated from Lithospermum canescens and their structures determined by spectroscopical methods. Besides the known lycopsamine, O7-acetyl-lycopsamine and O7-acetylintermedine four new PAs were found. Their structures are O7-(3-hydroxy-3-methyl-butanoyl)-O9-(+)-trachelanthoyl-heliotridine (= O7-(3-hydroxy-3-methyl-butanoyl)-rinderine = canescine), O7-(3-hydroxy-3-methyl-butanoyl)-O9-(-)-viridifloryl-heliotridine (= O7-(3-hydroxy-3-methyl-butanoyl)-echinatine = canescenine and their O13-acetyl-derivatives (= acetylcanescine; acetylcanescenine).
authors.affiliation: Pharmazeutisches Institut der Universität, An der Immenburg 4, D-53121 Bonn, F. R. G. wiedenfeld@uni-bonn.de
authors.forename: Helmut
authors.initials: H
authors.lastname: Wiedenfeld
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Pietrosiuk
authors.forename: Miroslava
authors.initials: M
authors.lastname: Furmanowa
authors.forename: Erhard
authors.initials: E
authors.lastname: Roeder
mesh_terms: D000470:Alkaloids / Q000737:chemistry* / Q000302:isolation & purification; D029684:Lithospermum / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure; D035261:Plant Components, Aerial / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry*
chemical_list: D000470:Alkaloids