RESUMO
An inseparable two-sponge association, consisting of a Haliclona sp. and a choristid sponge, yielded two unstable enol sulfates, (1E)-2- (3',4'-dihydroxyphenyl)ethylene sulfate [3] and (1Z)-2-(3',4'-dihydroxyphenyl)ethylene sulfate [4]. Methanolysis converted the enol sulfates into 2-(3',4'-dihydroxyphenyl)-1,1,2-trimethoxyethane [5] by an oxidative mechanism.
Assuntos
Catecóis/isolamento & purificação , Poríferos/química , Ésteres do Ácido Sulfúrico/isolamento & purificação , Animais , Catecóis/química , Espectroscopia de Ressonância Magnética , Ésteres do Ácido Sulfúrico/químicaRESUMO
Bioassay-guided fractionation of the antiprotozoal extract of Geranium niveum led to the isolation of two new A-type proanthocyanidins, epi-afzelechin-(4beta-->8, 2beta-->O-->7)-afzelechin (1) and epi-catechin-(4beta-->8, 2beta-->O-->7)-afzelechin (2). Compounds 1 and 2 were given the trivial names of geranins A and B, respectively. In addition, five known compounds, mahuannin B (3), reynoutrin (4), hyperin (5), methyl gallate (6), and 3-beta-caffeoyl-12-oleanen-28-oic acid (7), were obtained. The structures of the new proanthocyanidins were elucidated by spectroscopic and chemical methods as well as CD measurements. Compounds 1, 2, and 4-7 were tested against axenically grown trophozoites of Giardia lamblia and Entamoeba histolytica.
Assuntos
Antocianinas/farmacologia , Antiprotozoários/farmacologia , Magnoliopsida/química , Proantocianidinas , Animais , Antocianinas/isolamento & purificação , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Antiprotozoários/isolamento & purificação , Ensaios de Seleção de Medicamentos Antitumorais , Entamoeba histolytica/efeitos dos fármacos , Giardia lamblia/efeitos dos fármacos , Humanos , Espectroscopia de Ressonância Magnética , México , Modelos Moleculares , Conformação Molecular , Raízes de Plantas/química , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Células Tumorais CultivadasRESUMO
The hexane extracts of the roots of Stevia connata afforded three new longipinene derivatives, longipinane-7beta,8alpha, 9alpha-triol-1-one 7-angelate-8-methylbutyrate (1), longipin-2-ene-7beta,8alpha,9alpha-triol-1-one 8,9-diangelate (6), and longipin-2-ene-7beta,8alpha,9alpha-triol-1-one 8-angelate-9-methylbutyrate (8), together with the known longipinane-7beta,8alpha,9alpha-triol-1-one 8,9-diangelate (2), longipinane-7beta,8alpha,9alpha-triol-1-one 7,9-diangelate (3), longipinane-7beta,8alpha,9alpha-triol-1-one 7,8-diangelate (4), longipin-2-ene-7beta,8alpha,9alpha-triol-1-one 7,8-diangelate (5), longipin-2-ene-7beta,8alpha,9alpha-triol-1-one 7-angelate-8-methylbutyrate (12), and stigmasterol. The structures of the new compounds were determined by chemical transformations and spectral methods including 2D NMR measurements. Spontaneous intramolecular transesterifications starting from the 8-angelate-9-methylbutyrate 8 provided an equilibrated mixture of the 7-angelate-9-methylbutyrate 10, the 7-angelate-8-methylbutyrate 12 and the starting material when stored in MeOH-H(2)O solution, while the 8,9-diangelate 6 only provided a binary mixture of the 7, 9-diangelate 7 and the starting material under the same conditions. The structures of 6-8, 10, and 12 and those of the nonisolable reaction intermediates 9, 11, and 14 were further evaluated by AM1 semiempirical calculations.
Assuntos
Asteraceae/química , Sesquiterpenos/isolamento & purificação , Esterificação , Modelos Moleculares , Estrutura Molecular , Sesquiterpenos/química , Análise EspectralRESUMO
An in vitro presymbiotic system between mesquite [Prosopis laevigata(Willd.) M.C. Johnst], a semi-arid leguminous plant, and pregerminated spores of Gigaspora rosea Nicol. & Schenck was established. After characteristic hyphal branching, high performance liquid chromatographic analyses of methanol extracts from P. laevigata roots revealed a concentration change in one ultraviolet-detectable product. This product was identified by nuclear magnetic resonance and mass spectrometry as trigonelline, a pyridine alkaloid. The concentration of trigonelline was constant in the aerial parts of the plant with or without G. rosea, but its concentration in the roots increased 1.8-fold when G. roseawas present. Trigonelline may be a regulatory factor during early signal events in the establishment of the arbuscular mycorrhizal symbiosis in P. laevigata.
Assuntos
Alcaloides/análise , Micorrizas/fisiologia , Prosopis/química , Fungos/fisiologia , Raízes de Plantas/química , Raízes de Plantas/microbiologia , Prosopis/microbiologia , Prosopis/fisiologia , Simbiose/fisiologiaRESUMO
The aerial parts of Trixis pallida afforded seven known trixanolides (18-24) together with 17 new trixanolides (1-17). Their structures were determined by 1D and 2D NMR techniques, while the absolute configuration of the trixane skeleton was determined using the Mosher method and turned out to be enantiomeric to that reported using the Horeau method. This result is further discussed from the biosynthetic point of view.
Assuntos
Asteraceae/química , Plantas Medicinais/química , Sesquiterpenos/isolamento & purificação , Argentina , Cromatografia Líquida de Alta Pressão , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Conformação Molecular , Estrutura Molecular , Sesquiterpenos/química , Espectrofotometria Infravermelho , EstereoisomerismoRESUMO
Four new 9R,13R-epoxylabdane diterpenes (1-4) and a known clerodane derivative, 3,4beta-epoxy-5beta,10beta-cis-17alpha, 20alpha-clerod-13(14)-en-15,16-olide, were isolated from the leaves of Stevia subpubescens. The structures, which correspond to the grindelane class of diterpenoids, were elucidated by NMR data, chemical correlation, and single-crystal X-ray diffraction analysis of monoacetate 5. The absolute configuration of 1-4 is based on the optical activity of ketone 3 as compared with data of closely related substances.