11‐selenadodecylglyceryl‐1‐ether in lipid autoxidation

Abstract

The effect of 11-selenadodecylglyceryl-1-ether (11-SeDGE) at concentrations of 5 × 10 −4 and 1 × 10 −2 M on the autoxidation of sunflower oil with a natural content of 0.06% tocopherols at 100°C and at room temperature in the dark and of pure triacylglycerols of sunflower oil (TGSO) at 100°C was studied. The process was followed by peroxide concentration (peroxide value) determination and by ultraviolet (UV) spectroscopy. It was found that 11-SeDGE acted synergistically with the tocopherols in sunflower oil in a dose-dependent manner to delay oxidation at 100°C. The results from the UV spectra indicated that 11-SeDGE decomposed the initiators of the process, the hydroperoxides, into inactive products. During oxidation of pure TGSO (i.e., depleted of tocopherols) at 100°C, 11-SeDGE retarded the process without a pronounced induction period. At room temperature, 11-SeDGE showed a slight prooxidative effect on sunflower oil oxidation. Taking into account the established prooxidative effect of the two hydroxy groups in a molecule such as 11-SeDGE, it was recommended to study the lipid autoxidation in the presence of selenium compounds that do not contain such prooxidative groups.Paper no. J9693 in JAOCS 78, 691-696 (July 2001).Selenium (Se) is an essential micronutrient that has important biological activities (1-5). It is considered to strengthen the immune system (6) and to be a protective agent against cancer (7-15),human immunodeficiency virus (14,16), and heart diseases (17-19). Therefore, Se-containing compounds are valuable food constituents (5,19-23) and are included as active components in pharmaceuticals (3,4,24,25) and cosmetics (9,26). The concentration of selenium and its biological activity are closely related to the reactive oxygen species (27). That is, the higher the concentration of selenium, the greater its biological activity and the lower the concentration of the reactive oxygen species.Sodium selenate, sodium selenite, selenourea, and selenomethionine display an interesting antioxidant capacity because these derivatives catalyze the disproportionation of the superoxide ion (28). Selenium is a part of the antioxidative enzyme selenoglutathione oxidase, which inactivates free radicals and other oxidants, particularly hydrogen peroxide (29). The biological activity of selenium compounds is related to their antioxidant properties in lipid oxidation in membranes in vitro and in vivo (2)(3)(4)12,18,20,(30)(31)(32)(33)(34)(35)(36). A synergistic antioxidative effect of selenium with vitamin E has been established (23,37). Vitamin E and selenium show different and complementary antioxidative activities in the living cell (38).In general, the organoselenium compounds are more biologically active and less toxic than inorganic selenium (39). Already 50 yr ago, Denison and Condit (40) reported on the good antioxidant effectiveness of fatty alcohol selenides, especially didodecyl selenide, in lubricating oils.Data concerning the effect of selenium compounds on the autoxidation of lipids in vitro are sparse. ...

Action of 1‐(11‐selenadodecyl)‐glycerol and 1‐(11‐selenadodecyl)‐3‐trolox‐glycerol against lipid peroxidation

“…This may explain why SeG did not spare α-TOH in rat plasma but spared it in an MLV system when oxidized by the hydrophilic initiators AAPH or the lipophilic AMVN or MeO-AMVN. It was found previously that SeG reacts synergistically with tocopherols in sunflower oil (10). The presence of two hydroxyl groups in SeG may have an undesirable prooxidative effect (10).…”

“…It was found previously that SeG reacts synergistically with tocopherols in sunflower oil (10). The presence of two hydroxyl groups in SeG may have an undesirable prooxidative effect (10). It is also possible that SeG has lower mobility in the membranes due to hydrogen bonding between the hydroxyl groups and the water (32).…”

“…Selenium compounds act as antioxidants by reducing lipid hydroperoxides. Hydroperoxide formation in sunflower oil was retarded by SeG (10). Ebselen, which exerts glutathione-peroxidase activity, also acts as antioxidant by reducing FA and lipid hydroperoxides (7,8).…”

“…Sodium selenate, sodium selenite, selenourea, and selenomethionine (5), ebselen (6)(7)(8), tetradecylselenoacetic acid (9), the monoglyceride 1-(11-selenadodecyl)-glycerol (SeG) (10), and the triglyceride 1-(β-apo-8′-carotenoyl)-2-(7selenaoctanoyl)-3-(6-hydroxy-2,5,7,8-tetramethylchroman-2acyl)-glycerol (11) show antioxidant capacity. Selenoproteins and organoselenium compounds protect against pro-oxidants and peroxynitrite (12).…”

Heavy Atom Detergent/Lipid Combined X-ray Crystallography for Elucidating the Structure-Function Relationships of Membrane Proteins

“…Selenium is an essential trace element and a source of the antioxidant selenoproteins. Ether-type lipids bearing a selenomethyl moiety at the terminus of a hydrocarbon chain were synthesized to gain antioxidant activity [56,57]. Interestingly, seleno fatty acids were also developed as antimicrobial agents [58].…”