RESUMO
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
The antibacterial activity of the hexane, ethyl acetate and methanol extracts of the flowers, leaves and stems of Gnaphalium oxyphyllum var. oxyphyllum, G. liebmannii var. monticola and G. viscosum was investigated. The hexane extracts showed in all cases the higher inhibitions, G. oxyphyllum flower extract exhibiting the wider spectrum of activity.
Assuntos
Antibacterianos/farmacologia , Asteraceae , Bactérias/efeitos dos fármacos , Extratos Vegetais/farmacologia , Diterpenos/farmacologia , Flavonoides/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Folhas de Planta/química , Caules de Planta/químicaRESUMO
The aerial parts of an Argentinian collection of Acanthospermum hispidum afforded 26 sesquiterpene lactones, including the two guaianolides (1 and 2) having a novel oxygen bridge between C-4 and C-14, three new cis,cis-germacranolides (4, 7, and 8), and two new melampolides (25 and 26). Guaianolides 1 and 2 seem to derive biosynthetically from the germacranolide 27 having the (1)D(14, 15)D(5) conformation. The structures were elucidated using extensive spectroscopic analysis.
Assuntos
Ésteres/isolamento & purificação , Furanos/isolamento & purificação , Lactonas/isolamento & purificação , Magnoliopsida/química , Argentina , Ésteres/química , Furanos/química , Lactonas/química , Espectroscopia de Ressonância MagnéticaRESUMO
The flowers of Hyaloseris salicifolia afforded known ivasperin, while the leaves afforded ivasperin and 2-O-(6'-O-acetyl-beta-D-glucopyranosyl)-ivasperin, whose structure was determined by spectroscopic methods.
Assuntos
Asteraceae/química , Glucosídeos/isolamento & purificação , Sesquiterpenos/isolamento & purificação , Asteraceae/classificação , Cromatografia Líquida de Alta Pressão , Glucosídeos/química , Espectroscopia de Ressonância Magnética , Sesquiterpenos/químicaRESUMO
The roots of Croton sarcopetalus afforded three new diterpenoids (2-4) with a novel carbon skeleton that seems to be derived biosynthetically from a pimarane precursor. The essential oil of the roots gave trans-methylisoeugenol as the main constituent, along with 22 further compounds.
Assuntos
Diterpenos/química , Euphorbiaceae/química , Cromatografia Líquida de Alta Pressão , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância Magnética , Peso Molecular , Raízes de Plantas/química , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Espectrofotometria Infravermelho , Espectrofotometria UltravioletaRESUMO
A series of tryptamine analogues has been prepared and tested for their 5-HT1 receptor agonist properties. The incorporation of an alkoxy group at the C-5 position of the indole nucleus resulted in a short-lived and dose-dependent immediate antihypertensive and bradycardic response in anaesthetized spontaneously hypertensive rats (SHR). In addition, a carbomethoxy function at the beta-position of the side-chain of the tryptamines significantly increased the mean resting arterial blood pressure (MAP) in pithed rats and also produced contraction of the canine basilar artery in a dose-dependent fashion. Structure-activity relationships (SAR) suggest that the 5-alkoxy group is an important pharmacophore in the production of the antihypertensive effect and that the introduction of a hydroxymethylene group on the side-chain, instead of the carbomethoxy group, changed the receptor affinity profile.