RESUMEN
Five flavonol 3- O-glycosides were isolated from the leaves of MOGHANIA FAGINEA O. Ktze. Their structures were elucidated as quercetin-3-O-rhamnoside (quercitrin), myricetin-3-O-rhamnoside (myricitrin), quercetin-3-O-xyloxyl(1-->2)rhamnoside, myricetin-3-O-xylosyl(1-->2)rhamnoside and kaempferol-3-O-xylosyl (1-->2)rhamnoside by chromatographic methods (TLC, HPLC) and UV, IR, (1)H-NMR, (13)C-NMR and FAB-mass spectroscopy. These substances are described for the first time in MOGHANIA FAGINEA and some of them are new.
RESUMEN
1. Both after ingestion of benzyl isothiocyanate (BITC), a compound with antibacterial properties, and after consumption of garden cress known to contain BITC, the metabolite N-acetyl-S-(N-benzylthiocarbamoyl)-L-cysteine was identified in the urine of volunteers by comparative chromatography. 2. The chemical structure of the metabolite was confirmed by elemental analysis and by comparison of the i.r. and 1H-n.m.r. spectra with those of the synthetic product. 3. On average 53.7% of the dose of BITC was excreted as this metabolite by the renal route. 4. The metabolite was excreted rapidly, appearing with maximum concentrations some 2-6 h after dosing and being essentially complete 10-12 h after administration.
Asunto(s)
Isotiocianatos , Tiocianatos/farmacocinética , Adulto , Anciano , Cromatografía en Capa Delgada , Humanos , Riñón/metabolismo , Magnoliopsida , Masculino , Tasa de Depuración Metabólica , Persona de Mediana Edad , Tiocianatos/orinaRESUMEN
In addition to 2,3-dicaffeoyltartaric acid 2-caffeoyl-3-feruoyltartaric acid, three further caffeic acid derivatives were isolated for the first time from the epigeous parts of E. PURPUREA. Their structures were established on the basis of total hydrolysis and spectroscopic methods.
RESUMEN
The metabolism of methyl, ethyl, butyl and allyl isothiocyanate, which occur as glucosinolates in a number of plants, was studied. Oral administration of the substances to the rat was followed by their renal excretion as mercapturic acids, which were isolated as dicyclohexylamine salts. Chemical structure was determined by synthesis and 1H-n.m.r. spectra. The mercapturic acids were very labile dithiocarbamidic acid esters, formed by the addition of the isothiocyanate group to the SH group of the cysteine component.
Asunto(s)
Isotiocianatos , Tiocianatos/metabolismo , Acetilcisteína/orina , Animales , Masculino , Ratas , Ratas Endogámicas , Tiocarbamatos/orinaRESUMEN
1. Following oral administration of benzyl isothiocyanate or its cysteine conjugate the major metabolite isolated from urine of guinea-pigs and rabbits was a cyclic mercaptopyruvate conjugate, 4-hydroxy-4-carboxy-3-benzylthiazolidin-2-thione. 2. Renal excretion of the metabolite after oral administration of benzyl isothiocyanate or its cysteine conjugate to guinea-pigs amounted to 23% and 33% respectively. The corresponding N-acetylcysteine conjugate of benzyl isothiocyanate (a mercapturic acid) was present as a minor metabolite. 3. After oral or i.v. administration of the glutathione, cysteinylglycine, cysteine or N-acetylcysteine conjugates of benzyl isothiocyanate to guinea-pigs, the major metabolite in urine was 4-hydroxy-4-carboxy-3-benzylthiazolidin-2-thione, with the N-acetylcysteine conjugate of benzyl isothiocyanate present in traces only. 4. It is concluded that during formation of the cyclic mercaptopyruvate conjugate, the cysteine conjugate predominantly undergoes transamination, and only a small proportion undergoes N-acetylation.
Asunto(s)
Cisteína/análogos & derivados , Isotiocianatos , Tiocianatos/metabolismo , Animales , Fenómenos Químicos , Química , Cromatografía en Capa Delgada , Cisteína/metabolismo , Cobayas , Espectroscopía de Resonancia Magnética , Masculino , Conejos , Tiazoles/orina , TiazolidinasRESUMEN
1. The corresponding cysteine conjugate was formed when the GSH (reduced glutathione) or cysteinylglycine conjugates of benzyl isothiocyanate were incubated with rat liver or kidney homogenates. When the cysteine conjugate of benzyl isothiocyanate was similarly incubated in the presence of acetyl-CoA, the corresponding N-acetylcysteine conjugate (mercapturic acid) was formed. 2. The non-enzymic reaction of GSH with benzyl isothiocyanate was rapid and was catalysed by rat liver cytosol. 3. The mercapturic acid was excreted in the urine of rats dosed with benzyl isothiocyanate or its GSH, cysteinyl-glycine or cysteine conjugate, and was isolated as the dicyclohexylamine salt. 4. An oral dose of the cysteine conjugate of [14C]benzyl isothiocyanate was rapidly absorbed and excreted by rats and dogs. After 3 days, rats had excreted a mean of 92.4 and 5.6% of the dose in the urine and faeces respectively, and dogs had excreted a mean of 86.3 and 13.2% respectively. 5. After an oral dose of the cystein conjugate of [C]benzyl isothiocyanate, the major 14C-labelled metabolite in rat urine was the corresponding mercapturic acid (62% of the dose), whereas in dog urine it was hippuric acid (40% of the dose). 5. Mercapturic acid biosynthesis may be an important route of metabolism of certain isothiocyanates in some mammalian species.