title: Macrocyclic pyrrolizidine alkaloids from Senecio anonymus. Separation of a complex alkaloid extract using droplet counter-current chromatography.
abstract: Ten 12-membered macrocyclic pyrrolizidine alkaloids, all of them esters of the necines, retronecine or otonecine, have been isolated from Senecio anonymus. The separation, carried out by droplet counter-current chromatography, afforded senecionine [1], integerrimine [2], retrorsine [3], senkirkine [5], neosenkirkine [6], otosenine [10], hydroxysenkirkine [7], and a new alkaloid given the trivial name anonamine [9]. Traces of usaramine [4] and another new alkaloid, hydroxyneosenkirkine [8], were detected by 1H nmr. In addition, the previously unreported 3a beta-hydroxy-4-ethoxy-2,6-perhydroindoledione [11] was isolated. X-ray structures were obtained for neosenkirkine [6], hydroxysenkirkine [7], anonamine [9], and [11]. 1H-13C heteronuclear shift correlated nmr (HETCOR) provided unambiguous chemical shift assignments for 13C-nmr data. Antitumor activity was assayed using the A204-rhabdomyosarcoma cell line in soft agarose.
authors.affiliation: School of Chemistry, Georgia Institute of Technology, Atlanta 30332.
authors.forename: L H
authors.initials: LH
authors.lastname: Zalkow
authors.forename: C F
authors.initials: CF
authors.lastname: Asibal
authors.forename: J A
authors.initials: JA
authors.lastname: Glinski
authors.forename: S J
authors.initials: SJ
authors.lastname: Bonetti
authors.forename: L T
authors.initials: LT
authors.lastname: Gelbaum
authors.forename: D
authors.initials: D
authors.lastname: VanDerveer
authors.forename: G
authors.initials: G
authors.lastname: Powis
mesh_terms: D000972:Antineoplastic Agents, Phytogenic; D003377:Countercurrent Distribution; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D010947:Plants, Toxic; D011763:Pyrrolizidine Alkaloids / Q000302:isolation & purification* / Q000494:pharmacology; D012208:Rhabdomyosarcoma / Q000473:pathology; D012674:Senecio / Q000032:analysis*; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D011763:Pyrrolizidine Alkaloids