title: Unusual amino acids and monofluoroacetate from Dichapetalum michelsonii (Umutambasha), a toxic plant from Rwanda.
abstract: In the course of our investigations on Umutambasha in order to identify its convulsant principles, small quantities of monofluoroacetate were observed in stem bark, leaves, and fruits of this plant newly identified as Dichapetalum michelsonii Hauman. Conclusive evidence for a monofluoroacetate presence came from its isolation from the freeze-dried extract of stem bark. Three free unusual amino acids, named N-methyl-α-alanine, N-methyl-β-alanine, and 2,7-diaminooctan-1,8-dioic acid, described for the first time in a plant, and known trigonelline were also isolated from the stem bark of D. michelsonii. Structure elucidations were mainly achieved by spectroscopic methods (1H-NMR, 2D-NMR, MS) and by comparison with authentic references. These unusual amino acids were detected by a fast, reliable TLC analysis in all our batches of Umutambasha, suggesting that they could be used for identification purposes in case of human or livestock intoxications. Finally, EEG recordings and behavioural observations performed in mice suggested that the convulsive patterns produced by Umutambasha are the consequence of monofluoroacetate presence in D. michelsonii.
authors: Laboratory of Pharmacognosy, Centre Interfacultaire de Recherche du Médicament (CIRM), Department of Pharmacy, University of Liège, Liège, Belgium. virginie.esters@ulg.ac.be
authors: Virginie
authors: V
authors: Esters
authors: Charles
authors: C
authors: Karangwa
authors: Monique
authors: M
authors: Tits
authors: Pierre
authors: P
authors: Francotte
authors: Bernard
authors: B
authors: Pirotte
authors: Anne-Catherine
authors: AC
authors: Servais
authors: Marianne
authors: M
authors: Fillet
authors: Jacques
authors: J
authors: Crommen
authors: Elmar
authors: E
authors: Robbrecht
authors: Arlette
authors: A
authors: Minet
authors: Thierry
authors: T
authors: Grisar
authors: Luc
authors: L
authors: Angenot
authors: Michel
authors: M
authors: Frederich
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D005463:Fluoroacetates / Q000032:analysis*; D019684:Magnoliopsida / Q000737:chemistry* / Q000633:toxicity; D051379:Mice; D012432:Rwanda; D018675:Toxicity Tests; D014197:Trees / Q000737:chemistry* / Q000633:toxicity
chemical_list: D000596:Amino Acids; D005463:Fluoroacetates; C014815:fluoroacetic acid