ubiquinone and formic-acid

A UPLC-MS method for determining Coenzyme Q(10) (CoQ(10)) levels in rat serum was developed. CoQ(10) was quantitatively extracted into 2-propanol using a fast extraction procedure. The separation of CoQ(10) was performed on a Waters Acquity UPLCtrade mark BEH C(18) column (1.7 microm, 1.0 mm x 50 mm) with the mobile phase containing acetonitrile, 2-propanol, and formic acid (90:10:0.1) over 5 min. The sensitivity of this method allows for the quantitation of 50 ng/mL CoQ(10) in serum (S/N=10). The linearity of this method was found to be from 50 to 20,000 ng/mL. The precision was less than 10% (intra- and inter-day), and the average extraction recovery was between 90 and 105%. This procedure provides a precise, sensitive and direct assay method for the determination of CoQ(10) in rat serum after oral administration. This method could be applied to further pharmacokinetic studies of CoQ(10).

Topics: 2-Propanol; Acetates; Acetic Acid; Acetonitriles; Administration, Oral; Ammonium Hydroxide; Animals; Area Under Curve; Chromatography, Liquid; Coenzymes; Formates; Hydroxides; Linear Models; Mass Spectrometry; Metabolic Clearance Rate; Rats; Rats, Sprague-Dawley; Reproducibility of Results; Solvents; Ubiquinone

A HPLC-method was developed for the simultaneous detection of the lipophilic antioxidants ubiquinol-10, ubiquinone-10, alpha-tocopherol, and gamma-tocopherol in plasma macrosamples (100 microl) as well as microsamples (10 microl) using electrochemical detection with internal standardization (gamma-tocotrienol, ubiquinol-9, ubiquinone-9). The use of a mobile phase containing ammonium formate instead of lithium perchlorate as conductivity salt and the use of a PEEK column instead of a steel column improved the reproducibility of the method. The components were separated on a RP C18 column. The detection limits for all components were between 1 and 28 fmol. The within-day precision varied between 3 and 13% for all measured substances. The analytical recovery was between 93 and 109%. The plasma levels from 10 healthy donors were determined in microsamples and macrosamples taken by micropuncture or venous puncture, respectively. A good correlation of the antioxidant levels for both methods strengthened the reliability and the transferability of the results. The present method can be used to assess the role of these antioxidants in diseases associated with oxidative damage in childhood.

Topics: Antioxidants; Benzophenones; Chromatography, High Pressure Liquid; Electrochemistry; Formates; Humans; Ketones; Oxidative Stress; Polyethylene Glycols; Polymers; Reference Standards; Sensitivity and Specificity; Temperature; Ubiquinone; Vitamin E

Free radical formation in aqueous solutions of ubiquinone (coenzyme Qo) induced by ultrasound was studied by EPR and spin trapping with 3,5-dibromo-4-nitrosobenzene sulphonate. When aqueous solutions of ubiquinone were sonicated with 50-kHz ultrasound in the presence of argon or nitrogen, radicals formed by addition of.OH or.H to the double bonds of the ubiquinone ring and methyl radicals were observed as the major spin adducts. The methyl radicals were formed by pyrolysis of ubiquinone. These radicals led to the degradation of ubiquinone. The reduced from of ubiquinone, ubiquinol, was formed by sonication in the presence of argon, and its formation was prevented by addition of native but not of denatured superoxide dismutase. Sodium formate, which scavenges .OH to form CO2-., enhanced ubiquinol formation but partially inhibited the degradation of the ubiquinone ring. No ubiquinol was formed in nitrogen- or oxygen-saturated solutions under our conditions. These results indicate that ubiquinol was formed by reduction of ubiquinone by O2-., which was generated by the sonolysis of argon-saturated water.

Topics: Benzenesulfonates; Electron Spin Resonance Spectroscopy; Formates; Gases; Nitroso Compounds; Reactive Oxygen Species; Solutions; Spectrophotometry, Ultraviolet; Spin Labels; Spin Trapping; Superoxide Dismutase; Ubiquinone; Ultrasonics; Water