13-hydroxy-9-11-octadecadienoic-acid and acetonitrile

The oxidation of linoleic acid produces several products with biological activity including the hydroperoxy fatty acid 13-hydroperoxyoctadecadienoic acid (13-HPODE), the hydroxy fatty acid 13-hydroxyoctadecadienoic acid (13-HODE), and the 2,4-dienone 13-oxooctadecadienoic acid (13-OXO). In the present work, the peroxidase activity of glutathione transferases (GST) A1-1, M1-1, M2-2, and P1-1(Val 105) toward 13-HPODE has been examined. The alpha class enzyme is the most efficient peroxidase while the two enzymes from the mu class exhibit weak peroxidase activity toward 13-HPODE. It was also determined that the conjugated diene 13-HODE is not a substrate for GST from the alpha and mu classes but that 13-HODE does inhibit the GST-catalyzed conjugation of CDNB by enzymes from the alpha, mu, and pi classes. Finally, both 13-HODE and 13-OXO were shown to be inducers of GST activity in HT-29 and HCT-116 colon tumor cells. These data help to clarify the role of GST in the metabolic disposition of linoleic acid oxidation products.

Topics: Acetonitriles; Cell Line, Tumor; Dinitrochlorobenzene; Dose-Response Relationship, Drug; Glutathione; Humans; Kinetics; Linoleic Acid; Linoleic Acids; Linolenic Acids; Lipid Peroxides; Models, Chemical; Oxygen; Peroxidase

A major bioactive metabolite of linoleic acid formed by the action of 15-lipoxygenase-1 is 13(S)-hydroxy-cis-9, trans-11-octadecadienoic acid (13(S)-HODE). 13(S)-HODE is an important intracellular signal agent and is involved in cell proliferation and differentiation in various biological systems. Separation and quantification of 13(S)-HODE from biological materials has previously been achieved only by using radiolabeled linoleic acid as the substrate and two serially connected or two separate HPLC columns to achieve separation of 13(S)-HODE. In the current method, separation and quantification of 13(S)-HODE was achieved by use of a normal-phase HPLC and a solvent system containing hexane/isopropanol/acetonitrile/acetic acid (800/8/30/1, v/v) using isocratic elution with detection at 235 nm. With the currently described method, good separation from unreacted interfering compounds and quantification for 13(S)-HODE were achieved within 35 min with a minimum detection limit of 0.5 ng per injection.

Topics: 2-Propanol; Acetic Acid; Acetonitriles; Animals; Chromatography, High Pressure Liquid; Hexanes; Linoleic Acid; Linoleic Acids; Liver; Lung; Rats; Rats, Sprague-Dawley