The Ability of Melatonin to Counteract Lipid Peroxidation in Biological Membranes

Abstract

This paper reviews recent data relevant to the antioxidant effects of melatonin with special emphasis on the changes produced in polyunsaturated fatty acids located in the phospholipids of biological membranes. The onset of lipid peroxidation within cellular membranes is associated with changes in their physicochemical properties and with the impairment of protein functions located in the membrane environment. All cellular membranes are especially vulnerable to oxidation due to their high concentration of polyunsaturated fatty acids. These processes combine to produce changes in the biophysical properties of membranes that can have profound effects on the activity of membrane-bound proteins. This review deals with aspects for lipid peroxidation of biological membranes in general, but with some emphasis on changes of polyunsaturated fatty acids, which arise most prominently in membranes and have been studied extensively in our laboratory. The article provides current information on the effect of melatonin on biological membranes, changes in fluidity, fatty acid composition and lipid-protein modifications during the lipid peroxidation process of photoreceptor membranes and modulation of gene expression by the hormone and its preventive effects on adriamycin-induced lipid peroxidation in rat liver. Simple model systems have often been employed to measure the activity of antioxidants. Although such studies are important and essential to understand the mechanisms and kinetics of antioxidant action, it should be noted that the results of simple in vitro model experiments cannot be directly extrapolated to in vivo systems. For example, the antioxidant capacity of melatonin, one of the important physiological lipophilic antioxidants, in solution of pure triglycerides enriched in omega-3 polyunsaturated fatty acids is considerably different from that in subcellular membranes.

Effects of clothianidin exposure on sperm quality, testicular apoptosis and fatty acid composition in developing male rats

“…Cholesterol is the main precursor for steroidogenesis and it is produced mostly in the liver from LDL and HDL (Catala 2007;Walsh et al 2000;Wang et al 2002). The increase of cholesterol level in the testicular tissue may result from its non-utilization for production of testosterone.…”

Lipid peroxidation of membrane phospholipids generates hydroxy-alkenals and oxidized phospholipids active in physiological and/or pathological conditions

“…This complex process is believed to contribute to human aging and disease by disrupting the structural conformation, the packing of lipid components and, ultimately, the function of biological membranes (Catalá, 2007). The polyunsaturated fatty acids of membrane phospholipids are particularly susceptible to peroxidation and undergo significant modifications, including the rearrangement or loss of double bonds and, in some cases, the reductive degradation of lipid acyl side chains (Leibowitz and Johnson, 1971;Gardner, 1975;Buege and Aust, 1978).…”

“…aconitase) that include iron-sulfur centers, releasing ferrous iron, which catalyzes production of hydroxyl radicals ( • OH) from the H 2 O 2 by the Fenton reaction. The hydroxyl and hydroperoxyl radicals can both remove hydrogen atoms from polyunsaturated fatty acyl chains (linoleic, ␣-linolenic, arachidonic, docosahexaenoic, others) of membrane phospholipids, generating carbon-centered fatty acyl radicals that react with oxygen to form peroxyl radicals (Catalá, 2007). These propagate lipid peroxidation cascades that produce a complex mixture of species including, reactive alkenals such as 4-hydroxy-2-nonenal (see Fig.…”

Действие Мелатонина На Активность Аконитатгидратазы, Содержание Продуктов Липопероксидации И Некоторых Неферментативных Антиоксидантов В Крови Больных Сахарным Диабетом 2 Типа, Осложненным Стеатогепатитом

“…1). Î÷åâèäíî, ýòî ñâÿçàíî ñ òåì, ÷òî ìåëàòîíèí, âõîäÿùèé â ñîñòàâ äàííîãî ïðåïàðàòà, ÿâëÿÿñü àìôèôèëüíûì âåùåñòâîì, ìîaeåò äåéñòâîâàòü êàê ýôôåêòèâíûé àíòèîêñèäàíò, ÷òî ïðîÿâëÿåòñÿ, â ÷à-ñòíîñòè, â îáðûâå ðåàêöèé ÏÎË â ôîñôîëèïèäíîì ñëîå áèîìåìáðàí [14].…”