RESUMO
Two new cyclopeptides, named discarene C (1) and discarene D (2), have been isolated from the bark of Discaria americana, along with seven known cyclopeptide alkaloids. The structures of the new compounds were determined by spectroscopic methods, mainly NMR. The stereochemistry of the ring amino acid residues have been assigned by gas chromatography employing modified cyclodextrins as chiral stationary phases.
Assuntos
Alcaloides/isolamento & purificação , Peptídeos Cíclicos/isolamento & purificação , Plantas Medicinais/química , Alcaloides/química , Brasil , Cromatografia Gasosa , Cromatografia em Camada Fina , Leucina/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Peptídeos Cíclicos/química , Fenilalanina/química , Raízes de Plantas/química , Espectrofotometria Infravermelho , EstereoisomerismoRESUMO
Two diterpenoids, humirianthol and acrenol, as well as the known annonalide, were isolated from Humirianthera ampla. Humirianthol and acrenol were determined by 1D and 2D NMR spectroscopic techniques to be 3 beta,20:14 beta,16-diepoxy-3 alpha, 15 alpha-dihydroxy-7-pimaren-19,6 beta-olide and 3 beta,20-epoxy-3 alpha,15,16-trihydroxy-7-pimaren-19,6 beta-olide, respectively.