Showing papers by "Guillermo Díaz-Araya published in 1998"
TL;DR: All the tested nitroso aryl derivatives were more potent inhibitors of lipid peroxidation than were the parent nitro compounds, and the rank order of antioxidant potency for these derivatives can be established as: ortho-nitrosotoluene>NTP>nitrosobenzene.
Abstract: 1. Lipid peroxidation in rat brain slices was induced by Fe+3/ascorbate. 2. Brain lipid peroxidation, as measured by malondialdehyde formation, was inhibited by all the tested nitro aryl 1,4-dihydropyridine derivatives over a wide range of concentrations. The time-course antioxidant effects of the most representative agents were assessed. On the basis of both time-course and IC50 experiments the tentative order of antioxidant activity on rat brain slices could be: nicardipine>nisoldipine> (R,S/S,R)-furnidipine > (R,R/S,S)-furnidipine>nitrendipine>nimodipine> nifedipine. 3. 1,4-Dihydropyridine derivatives that lack of a nitro group in the molecule (isradipine, amlodipine) also inhibited lipid peroxidation in rat brain slices but at higher concentrations than that of nitro-substituted derivatives. 4. All the tested nitroso aryl derivatives [2,6-dimethyl-4-(2-nitrosophenyl)-3,5-pyridinedicar. boxylic acid dimethyl ester (NTP), nitrosotoluene, nitrosobenzene] were more potent inhibitors of lipid peroxidation than were the parent nitro compounds. In conclusion, on the basis of the IC50 values determined, the rank order of antioxidant potency for these derivatives can be established as: ortho-nitrosotoluene>NTP>nitrosobenzene.
50 citations
TL;DR: The present findings indicate that the trypanocide effects exerted by isradipine and lacidipine are not related with a disruption of the calcium homeostasis of the parasite.
Abstract: 1. Isradipine and lacidipine, two new drugs that are members of the nitro-aryl-1,4-dihydropyridine family, produced inhibition of both growth cultures and oxygen consumption on epimastigotes of Trypanosoma cruzi Tulahuen strain, at micromolar concentrations. 2. Isradipine was found to be the most potent derivative in both, in growth cultures (I50 = 20.8 microM) and in vivo oxygen uptake (I50 = 31.1 microM). 3. Diltiazem and verapamil, two well-known calcium channel antagonists, lacked inhibitory activity, even at a 100 microM concentration. 4. The present findings indicate that the trypanocide effects exerted by isradipine and lacidipine are not related with a disruption of the calcium homeostasis of the parasite.
19 citations
TL;DR: Electrochemical and EPR data indicated that all the tested thiols scavenged the nitro radical anion from nisoldipine, significantly higher than the natural decay of the radical in mixed medium.
Abstract: Purpose. To determine the formation of the one-electron reduction product from nisoldipine and its reactivity with relevant thiols in mixed medium.
7 citations