A importância do substituinte orgânico de selênio para a atividade antioxidante de 7-cloro-4-(fenilselanil)quinolina

Abstract

The quinoline-based compounds have been reported for many biological properties, especially as antioxidants. This study investigated the antioxidant effect of 7-chloro- 4-(phenylselanyl)quinoline (PSQ), a quinoline-based compound with organoselenium substituent, against oxidative stress induced by sodium nitroprusside (SNP) in brains of mice. A second objective was to verify the importance of phenylselanyl group in quinoline structure to antioxidant effect of compound. In this context, antioxidant effect of PSQ was compared with a quinoline-based compound without organoseleniun substituent (7-chloro-quinoline [QN]). Male Swiss mice were treated with PSQ or QN at dose of 50 mg/kg (intragastrically). Thirty minutes after these treatments, SNP (0,335 μmol/site) was injected intracerebroventriculary. After 1 hour of NPS administration, animals were sacrificed and the brains were removed for biochemistry analysis. Thiobarbituric acid reactive species (TBARS), protein carbonyl (PC) and non-protein thiol (NPSH) levels, as well as catalase (CAT), glutathione S transferase (GST) and δ –aminolevulinate dehydratase (δ-ALA-D) activities were determined. SNP increased TBARS and PC levels, and reduced the enzymatic (CAT and GST activities) and non-enzymatic (NPSH levels) antioxidant defenses and inhibited the δ-ALA-D activity in the brains of animals. PSQ protected against all biochemical alterations caused by NPS in mouse brain, while the treatment with QN only partially protected the increase on the TBARS levels and did not protected against other changes induced by NPS. In conclusion, these results showed that the PSQ, a quinoline-based compound with organoselenium substituent, presented antioxidant effect against oxidative stress induced by SNP in brains of mice. Moreover, the phenylselanyl group present in quinoline structure is critical for antioxidant activity of PSQ.