Determination of ubiquinone in serum and liver by high-speed liquid chromatography.

Abstract

SummaryTwo kinds of high-speed liquid chromatographic methods using either ultraviolet or a fluorometric detector (HSLC-UV and HSLC fluorometric methods) are described for the determination of ubiquinones (UQ). HSLC-UV method: Serum or liver was saponified with methanolic alkaline solution containing pyrogallol as an antioxidant and 2, 3, 6 trimethyl-5-nonaprenyl-l, 4-benzoquinone as an internal standard and then extracted with n-hexane. The extract was evaporated and then dissolved in dioxane. The resulting solution was applied to a HSLC system using a Permaphase ODS column, ethanol-water (80:20) as a mobile phase and a high sensitivity UV detector (275nm). HSLC-fluorometric metho: Serum was deproteinized with ethanol and then extracted with n-hexane. The resulting extract was reacted with alkaline ethylcyanoacetate (ECA) reagent to give fluorescence. The reacted solution was applied to a HSLC system using a Permaphase ODS column, ethanol-water (75: 25) as a mobile phase and a spectrofluorometer (Ex. 430nm, Em. 530nm). Neither of the proposed HSLC methods were affected by other fat-soluble substances and seemed to be more simple, sensitive and specific than other conventional determination methods.It is well known that ubiquinones (UQ) play an important role in the mitochondrial electron transport chain of respiration . These compounds are also used for the therapy of human diseases. In order to investigate the role of UQ in animals and human beings, it is necessary to establish a simple and precise method for the determination of these compounds in biological materials .

Coenzymes Q9and Q10: Contents in Foods and Dietary Intake

“…Coenzymes Q and Q have been extracted from food and biological tissues using either direct ethanol}n-hexane extraction (Ikenoya et al, 1981;Lang et al, 1986;Lang and Packer, 1987;Okamoto et al, 1988;Weber et al, 1997) or saponi"cation before solvent extraction (Abe et al, 1978;Kamei et al, 1986). Direct ethanol}n-hexane extraction was employed for most of the samples in this study because it was simple to perform and e$cient for tissue samples (Ikenoya et al, 1981).…”

Higher Serum Retinol-Binding Protein Concentration in Indonesian Neonates in Surabaya than Japanese Neonates in Kobe

“…This free, uncomplexed protein is metabo lized principally by the kidney [ 1 ]. The lower molar ratio in Indonesian neonates may be a reflection of lower glomerular filtration [5], A poorer correlation between cord PA and RBP level in premature neonates than in term infants has been demonstrated [12]. The concentration of RBP was strongly cor related with the concentration of PA in adults [6].…”

“…Readings were done at 48 h by one investigator (I.S.M.). The vitamin-A concentration was determined by using the method described before [5]. To minimize interlabo ratory variation, all the measurements were done at Kobe University, Kobe, Japan.…”

Role of Free Radical Reactions in Myelodysplastic Syndrome

“…Enzyme activities were expressed as pmol of NADP reduced or NADPH oxidized per min per g of hemoglobin (Hb). The plasma levels of riboflavin and its derivatives, and those of CoQ10 were estimated by high-performance liquid chromatography methods [9,10]. The values of lipid peroxides in plasma were obtained by the method of Ohishi et al [11].…”