1-palmitoyl-2-linoleoylphosphatidylcholine and methyl-linoleate

With increasing evidence suggesting the involvement of oxidative stress in various disorders and diseases, the role of antioxidants in vivo has received much attention. 2,3-Dihydro-5-hydroxy-2,2-dipentyl-4,6-di-tert-butylbenzofuran (BO-653) was designed, synthesized and has been evaluated as a novel antiatherogenic drug. In order to further understand the action of BO-653 and also radical-scavenging antioxidants in general, the dynamics of inhibition of oxidation by BO-653 were compared with those of the related compounds, 2,3-dihydro-5-hydroxy-2,2-dimethyl-4,6-di-tert-butylbenzofuran (BOB), 2,3-dihydro-5-hydroxy-2,2,4,6-tetramethylbenzofuran (BOM), alpha-tocopherol and 2,2,5,7,8-pentamethyl-6-chromanol (PMC), aiming specifically at elucidating the effects of substituents and side chain length of the phenolic antioxidants. These five antioxidants exerted substantially the same reactivities toward radicals and antioxidant capacities against lipid peroxidation in organic solution. When compared with di-methyl side chains, the di-pentyl side chains of BO-653 reduced its inter-membrane mobility but exerted less significant effect than the phytyl side chain of alpha-tocopherol on the efficacy of radical scavenging within the membranes. Di-tert-butyl groups at both ortho-positions made BO-653 and BOB more lipophilic than di-methyl substituents and reduced markedly the reactivity toward Cu(II) and also the synergistic interaction with ascorbate. The results of the present study together with those of the previous work on the effect of substituents on the stabilities of aryloxyl radicals suggest that tert-butyl group is more favorable than methyl group as the substituent at the ortho-positions and that di-pentyl side chains may be superior to a phytyl side chain.

Topics: alpha-Tocopherol; Antioxidants; Ascorbic Acid; Benzhydryl Compounds; Benzofurans; Copper; Electron Spin Resonance Spectroscopy; Free Radical Scavengers; Iron; Linoleic Acids; Lipid Peroxidation; Lipid Peroxides; Liposomes; Oxidation-Reduction; Phenols; Phosphatidylcholines; Vitamin E

The hydroperoxides of methyl linoleate, 1-palmitoyl-2-linoleoyl-phosphatidylcholine and trilinolein each produced similar fluorescent substances through reaction with amino compounds after decomposition by heme methyl ester. Fluorescent substances formed from methyl linoleate with 1-aminopentane revealed characteristic fluorescence peaks on HPLC, while those obtained from 1-palmitoyl-2-linoleoyl-phosphatidylcholine and trilinolein were not eluted under the same conditions. However, when both of these fluorescent substances were transesterified to methyl ester, the same fluorescence peaks were observed. This result suggests that fluorescent substances formed from oxidized membrane lipids with amino compounds remain attached to phospholipids without being released from their glycerol backbone.

Topics: Amines; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Linoleic Acids; Lipid Peroxides; Phosphatidylcholines; Spectrometry, Fluorescence; Triglycerides