RESUMEN
In addition to the known sterols and ketosteroids beta-sitosterol (24 alpha-ethylcholest-5-en-3 beta-ol), stigmasterol (24 alpha-ethylcholesta-5,22-dien-3 beta-ol), campesterol (24 alpha-methylcholest-5-en-3 beta-ol), beta-sitostenone (stigmast-4-en-3-one, 24 alpha-ethylcholest-4-en-3-one), stigmastenone (stigmasta-4,22-dien-3-one, 24 alpha-ethylcholesta-4,22-dien-3-one), campestenone (24 alpha-methylcholest-4-en-3-one), and stigmasta-3,5-dien-7-one (24 alpha-ethylcholesta-3,5-dien-7-one), the new steroids stigmasta-3,5,22-trien-7-one (24 alpha-ethylcholesta-3,5,22-trien-7-one), and campesta-3,5-dien-7-one (24 alpha-methylcholesta-3,5-dien-7-one) were isolated from the stem bark of Harrisonia abyssinica and identified by NMR and mass spectrometry.
Asunto(s)
Plantas Medicinales/química , Esteroides/aislamiento & purificación , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Estructura Molecular , Esteroides/químicaRESUMEN
Six new homologous triterpenoid saponins were isolated from the methanol extract of the leaves of Maesa lanceolata and characterized as 3 beta-O-[alpha-L-rhamnopyranosyl(1 --> 2)-beta-D-galactopyranosyl (1 --> 3)]-[beta-D-galactopyranosyl(1 --> 2)]-beta-D-glucuronopyranosides alpha-diol, 22 alpha-angeloyloxy-16 alpha-butanoyloxy-13 beta,28-oxydoolean-21 beta,28 alpha-diol, 16 alpha,22 alpha-diangeloyloxy-13 beta,28-oxydoolean-21 beta,-28 alpha-diol, 22 alpha-angeloyloxy-13 beta,28-oxydo-16 alpha-(2-methyl-butanoyloxy)-olean-21 beta,28 alpha-diol, 21 beta-acetoxy-22 alpha-angeloyloxy-13 beta,28-oxydo-16 alpha-propanoyloxyolean-28 alpha-ol, 21 beta-acetoxy-22 alpha-angeloyloxy-16 alpha-butanoyloxy-13 beta,28-oxydoolean-28 alpha-01. The structures were established on the basis of chemical and spectral evidence.
Asunto(s)
Plantas Medicinales , Saponinas/química , Árboles , Triterpenos/química , Conformación de Carbohidratos , Secuencia de Carbohidratos , Espectroscopía de Resonancia Magnética , Datos de Secuencia Molecular , Estructura Molecular , Extractos Vegetales , Hojas de la Planta , Rwanda , Saponinas/aislamiento & purificación , Espectrometría de Masa Bombardeada por Átomos Veloces , Triterpenos/aislamiento & purificaciónRESUMEN
The four major C-glycosidic flavonoids isolated from Passiflora incarnata were identified as schaftoside, isoschaftoside, isovetexin-2''-O-glucopyranoside and isoorientin-2''-O-glucopyranoside on the basis of mass spectral and 13C NMR data. The daughter ion spectra of [M + H]+ ions of schaftoside and isoschaftoside showed differences for the [M + H - 104]+ ions, which could be rationalized by hydrogen bonding effects. In the negative-ion mode, pronounced differences were found for the [M - H - 90]- and [M - H - 120]- ions, formed by prevalent fragmentation in the C-6-linked sugar moiety. With respect to isovitexin-2''-O-beta-glucopyranoside and isoorientin-2''-O-beta-glucopyranoside, the daughter ion spectra of both the [M + H]+ and [M - H]- ions provided evidence for a 1----2 linkage in the diglucosidic moiety. Support for C-6 glucosylation was obtained by recording the daughter ion spectra of [M - H - 162]- ions, which were in good agreement with that obtained for [M - H]- ions of isovitexin.