Action of the novel antioxidants 4GBE43 and 2BBE43 against lipid peroxidation

The action and the effect of the newly synthesized compounds 4GBE43 [N-(1,2 -diethyltetrahydro-1H-pyrazol-4-yl)-4-[(2E)-3,7-diethyl-2,6-octadienyl]oxyb enzamide] and 2BBE43 [2-(benzyloxy)-N-(1,2-diethyltetrahydro-1H-pyrazol-4-y l)benzamide] against lipid peroxidation were studied. 4GBE43 and 2BBE43 que nched the ESR signal of diphenylpicrylhydrazyl(DPPH), suggesting that 4GBE4 3 and 2BBE43 act as scavengers of free radicals and that each compound quen ched 6 free radical molecules. These compounds suppressed the oxidation of methyl linoleate emulsions and soybean phosphatidylcholine liposomes by a f ree radical initiator, suggesting that these compounds quench the lipid per oxyl radical. 4GBE43 and 2BBE43 also suppressed the spontaneous oxidation o f rat brain homogenates. The inhibitory effect of 2BBE43 was of the same or der of magnitude (IC50) as that of probucol. The IC50 of 4GBE43 was on the same order of magnitude as that of alpha -tocopherol. However, 4GBE43 at 10 (-4)-10(-5) M completely inhibited peroxidation, showing it to be more effe ctive than cr-tocopherol, These results suggest that 4GBE43 and 2BBE43 act as antioxidants by quenching the lipid peroxyl radical. (C) 2001 Elsevier S cience Inc. All rights reserved.