The antioxidant effect of some pineal indoles against lipid peroxidation depends on the assay system.

FAGALI, N.; CATALÁ, A.

Potrero de los Funes, San Luis

Congreso; XLVII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2011

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

There is no general agreement yet on the antioxidant effect of pineal indoles against lipid peroxidation. Accordingly, it was the main goal of the present work to study the antioxidant activity of melatonin (MLT), N-acetylserotonin (NAS), 5-HO-tryptophan (5HO-TRP) and 5-methoxytryptamine (5MTP) in two different lipid systems with high content of polyunsaturated fatty acids (PUFAs): triglycerides (20:5 n3, C22:6 n3) dissolved in chloroform and sonicated liposomes (C22:6 n3) made of retinal lipids. In the triglyceride-chloroform-system the peroxidation reaction was initiated by cumen hydroperoxide whereas liposomes were peroxidated with Fe2+. The techniques employed at the present work were: 1) chemiluminescence, 2) TBARS production, 3) DPPH assay, 4) determination of conjugated dienes production and 5) analysis of fatty acid profile by CG-MS. Butilated hydroxitoluene (BHT) was employed as a reference because of its well known antioxidant capacity. Our results showed that MLT and 5MTP were unable to protect PUFAs against lipid peroxidation in both systems, whereas NAS and 5HO-TRPwere better antioxidants that BHT in the triglyceride-system but ineffective in the liposomesystem. We conclude that the antioxidant behaviour of pineal indoles depends not only on their functional groups but also on the assay system.