Asunto(s)
Técnicas de Química Analítica/métodos , Glicósidos/sangre , Hiperlipidemias/sangre , Extracción en Fase Sólida/métodos , Esteroides/sangre , Acetonitrilos/química , Animales , Cromatografía Líquida de Alta Presión/métodos , Gentianaceae/química , Humanos , Extracción Líquido-Líquido/métodos , Metanol/química , Éteres Metílicos/química , Ratones , Fosfolípidos/sangre , Extractos Vegetales/química , Conejos , Ratas , Espectrometría de Masas en Tándem/métodosRESUMEN
Hoodia gordonii extract contains steroid glycosides, fatty acids, plant sterols and polar organic material. Certain steroid glycosides show appetite suppressant activities following oral ingestion. This study describes the validation of a bioanalytical method for the quantification of one of the steroid glycosides, H.g.-12 (≈ 10% (w/w) of the extract), in mouse, rat, rabbit and human plasma. The method utilises a liquid-liquid extraction with methyl-tert-butyl ether followed by chromatographic separation on a 2.1 × 50 mm C(18) Genesis high performance liquid chromatography (HPLC) column and detection on a triple quadrupole mass spectrometer. Detection of H.g.-12 and its stable isotope internal standards is performed using positive TurboIonspray™ ionisation in multiple reaction monitoring mode. The validation procedure demonstrated assay sensitivity, linearity, accuracy, precision and selectivity over the calibration range of 0.5-150 ng/mL in human plasma (500 µL sample volume), 1.0-100 ng/mL in rat and rabbit plasma (150 µL sample volume) and 1.0-250 ng/mL in mouse plasma (150 µL sample volume) with good recoveries (≥ 77%). H.g.-12 was stable in plasma for ≥ 6 months at -20°C, for up to 4h at ambient temperature (ca22°C) and after 3 freeze-thaw cycles. Plasma extracts were stable for up to 24h at ambient temperature.
Asunto(s)
Apocynaceae/química , Depresores del Apetito/química , Glicósidos/sangre , Animales , Fraccionamiento Químico , Cromatografía Líquida de Alta Presión , Glicósidos/análisis , Humanos , Límite de Detección , Ratones , Extractos Vegetales/sangre , Extractos Vegetales/química , Conejos , Ratas , Reproducibilidad de los Resultados , Espectrometría de Masa por Ionización de Electrospray/métodos , Espectrometría de Masas en TándemRESUMEN
Deuterated choline-d(9) labelling of IMR-32 cells enabled comparison of the molecular specificities of whole cell and endonuclear phosphatidylcholine synthesis after 96 h polyunsaturated fatty acid supplementation. Surprisingly, while cell phosphatidylcholine synthesis and remodelling reflected a pattern of polyunsaturated fatty acid accretion, the saturated endonuclear phosphatidylcholine pool was only transiently labelled with polyunsaturates. Periodic endonuclear accumulations of the lipid second messenger diacylglycerol, mobilised from unsaturated phosphatidylinositol or saturated phosphatidylcholine, accompany cell proliferation. Non-specific incorporation into endonuclear phosphatidylcholine and selective removal or remodelling of unsaturated molecular species may form part of a single 'off switch' recycling all endonuclear diacylglycerol accumulations.