Dihydroxydocosahexaenoic acids of the neuroprotectin D family: synthesis, structure, and inhibition of human 5-lipoxygenase.
During aerobic oxidation of docosahexaenoic acid (DHA), soybean lipoxygenase (sLOX) has been shown to form 7,17(S)-dihydro(pero)xydocosahexaenoic acid [7,17(S)-diH(P)DHA] along with its previously described positional isomer, 10,17(S)-dihydro(pero)xydocosahexa-4Z,7Z,11E,13Z,15E,19Z-enoic acid. 7,17(S)-diH(P)DHA was also obtained via sLOX-catalyzed oxidation of either 17(S)-hydroperoxydocosahexaenoic acid [17(S)-HPDHA] or 17(S)-hydroxydocosahexaenoic acid [17(S)-HDHA]. The structures of the products were elucidated by normal-phase, reverse-phase, and chiral-phase HPLC analyses and by ultraviolet, NMR, and tandem mass spectroscopy and GC-MS. 7,17(S)-diH(P)DHA was shown to have 4Z,8E,10Z,13Z,15E,19Z geometry of the double bonds. In addition, a compound apparently identical to the sLOX-derived 7,17(S)-diH(P)DHA was produced by another enzyme, potato tuber LOX, in the reactions of oxygenation of either 17(S)-HPDHA or 17(S)-HDHA. All of the dihydroxydocosahexaenoic acids (diHDHAs) formed by either of the enzymes were clearly produced through double lipoxygenation of the corresponding substrate. 7,17(S)-diHDHA inhibited human recombinant 5-lipoxygenase in the reaction of arachidonic acid (AA) oxidation. In standard conditions with 100 microM AA as substrate, the IC(50) value for 7,17(S)-diHDHA was found to be 7 microM, whereas IC(50) for 10,17(S)-DiHDHA was 15 microM. Similar inhibition by the diHDHAs was observed with sLOX, a quintessential 15LOX, although the strongest inhibition was produced by 10,17(S)-diHDHA (IC(50) = 4 microM). Inhibition of sLOX by 7,17(S)-diHDHA was slightly less potent, with an IC(50) value of 9 microM. These findings suggest that 7,17(S)-diHDHA along with its 10,17(S) counterpart might have anti-inflammatory and anticancer activities, which could be exerted, at least in part, through direct inhibition of 5LOX and 15LOX.
Butovich
Igor A
IA
Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA. igor.butovich@utsouthwestern.edu
Lukyanova
Svetlana M
SM
Bachmann
Carl
C
D002626:Chemistry, Pharmaceutical / Q000379:methods; D002851:Chromatography, High Pressure Liquid; D004281:Docosahexaenoic Acids / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D020128:Inhibitory Concentration 50; D008084:Lipoxygenase / Q000737:chemistry; D016859:Lipoxygenase Inhibitors; D009682:Magnetic Resonance Spectroscopy; D010100:Oxygen / Q000378:metabolism; D013025:Glycine max / Q000201:enzymology
D004791:Enzyme Inhibitors; D016859:Lipoxygenase Inhibitors; C487679:protectin D1; D004281:Docosahexaenoic Acids; D008084:Lipoxygenase; D010100:Oxygen