RESUMO
Bioassay-guided fractionation of Eschweilera coriacea collected in the lowland wet forest of Suriname yielded the new but only weakly active ellagic acid derivative eschweilenol A (1) and the two new but inactive ellagic acid derivatives eschweilenol B (2) and eschweilenol C (3). The four known compounds, sucrose, ellagic acid, 3-O-galloylepigallocatechin, and epigallocatechin, were also isolated. The structures of the three new compounds were determined by spectrometric methods, primarily from the HMQC, HMBC, NOESY, and ROESY NMR techniques, and chemical methods, including methylation and triethylsilylation. The location of a hydroxyl group in one ellagic acid derivative was determined by a new technique involving an NOE correlation of the protons of a triethylsilyl derivative with a proton on a neighboring aromatic ring.
Assuntos
Ácido Elágico/análogos & derivados , Epiderme Vegetal/química , Plantas Medicinais/química , Antifúngicos/farmacologia , Sequência de Carboidratos , Cromatografia em Camada Fina , Ácido Elágico/isolamento & purificação , Ácido Elágico/farmacologia , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Espectrofotometria Ultravioleta , Suriname , Leveduras/efeitos dos fármacosRESUMO
Bioassay-guided fractionation of the EtOAc extract of both Allamanda cathartica and Himatanthus fallax (Apocynaceae) using the Sc-7 yeast strain resulted in the isolation of the weakly cytotoxic isoplumericin and plumericin. In addition, the new lignan 7(R)-methoxy-8-epi-matairesional and three known compounds, plumieride, matairesinol, and pinoresinol, were isolated from H. fallax.