Chemistry and Physics of Lipids 132 (2004) 197–208 Relationship between the action of reactive oxygen and nitrogen species on bilayer membranes and antioxidants Vˆ ania Rodrigues de Lima a,b , Marcos Paulo Morfim a , Adriana Teixeira a , Tˆ ania Beatriz Creczynski-Pasa a,∗ a Departamento de Ciˆ encias Farmacˆ euticas, Centro de Ciˆ encias da Sa ´ ude, Universidade Federal de Santa Catarina, Campus Universit´ ario, Trindade, C.P. 476, CEP 88040-900 Florian´ opolis, Brazil b Departamento de Qu´ ımica, Centro de Ciˆ encias F´ ısicas e Matem ´ aticas, Universidade Federal de Santa Catarina, Campus Universit´ ario, Trindade, SC 88040-900 Florian´ opolis, Brazil Received 7 June 2004; received in revised form 8 July 2004; accepted 15 July 2004 Abstract Membrane lipid peroxidation (LPO) induced by hydroxyl ( • OH) and ascorbyl ( • Asc) radicals and by peroxynitrite (ONOO - ) was investigated in asolectin (ASO), egg phosphatidylcholine (PC) and PC/phosphatidic acid mixtures (PC:PA) liposomes and rat liver microsomes (MC). Enthalpy variation (H) of PC:PA at different molar ratios were obtained by differential scanning calorimetry. It was also evaluated the LPO inhibition by quercetin, melatonin and Vitamin B 6 . The oxidant effect power follows the order • OH ≈ • Asc > ONOO - on PC and MC; whilst on ASO liposomes, it follows • Asc > • OH ≈ ONOO - . Increasing amounts of PA in PC liposomes resulted in lower levels of LPO. The H values indicate a more ordered membrane arrangement as a function of PA amount. The results were discussed in order to provide a complete view involving the influence of membranes, oxidants and antioxidants intrinsic behavior on the LPO dynamics. © 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Reactive oxygen species; Reactive nitrogen species; Antioxidants; Lipid peroxidation; Differential scanning calorimetry; Melatonin Abbreviations: • Asc, ascorbyl radical; ASO, asolectin; DG, diacylglicerol; DSC, differential scanning calorimetry; IC50, half inhibition concentration; LPO, lipid peroxidation; MC, rat liver microsomes; O2 •- , superoxide anion; O.D., optical density; • OH, hydroxyl radical; ONOOH, peroxynitrous acid; ONOO - , peroxynitrite; PA, phosphatidic acid; PC, phosphatidylcholine; PE, phosphatidylethanolamine; PI, phosphatidylinositol; PUFAs, polyunsaturated fatty acids; RNS, reactive nitrogen species; ROS, reactive oxygen species; TBARS, thiobarbituric acid reactive substances; H, enthalpy variation ∗ Corresponding author. Tel.: +55 48 3318057; fax: +55 48 3319542. E-mail address: taniac@mbox1.ufsc.br (T.B. Creczynski-Pasa). 0009-3084/$ – see front matter © 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.chemphyslip.2004.07.003