Linoleic peroxide

Antioxidant capacities of common individual curcuminoids were determined in vitro by phosphomolybdenum and linoleic acid peroxidation methods. Antioxidant capacities expressed as ascorbic acid equivalents (pmol/g) were 3099 for curcumin, 2833 for demethoxycurcumin, and 2677 for bisdemethoxycurcumin at concentrations of 50 ppm. The same order of antioxidant activity (curcumin > demethoxycurcumin > bisdemethoxycurcumin) was observed when compared with BHT (buty-lated hydroxyl toluene) in linoleic peroxidation tests. The antioxidant activity of curcumin in the presence of ethyl linoleate was demonstrated and six reaction products were identified and structurally characterized. The mechanism proposed for this activity consisted of an oxidative coupling reaction at the 3 position of the curcumin with the lipid and a subsequent intramolecular Diels-Alder reaction. ... 

Liu, H. P. (1970a). Catalysts of lipid peroxidation in meats. 1. Linoleate peroxidation catalyzed by MetMb or Fe(ll)-EDTA. 7. Food Sci. 35, 590-592. 

Values (fimol I 1) of Flavonoids for Iron-Induced Linoleate Peroxidation (I) and Autoxidation of Rat Cerebral Membranes (II) and Log Capacity factor log k ... 

Carcinogenic aminoazo dyes were previously found to increase the latent period of linoleate peroxidation and that DAB was a more effective antioxidant than MAB (13). Furthermore, as autoxidation of the linoleic acid proceeded, N-demethylation of DAB and MAB occurred. Demethylation of DAB also occurred in vitro when DAB is dissolved in cottonseed oil and mixed with ground brown rice (14). Our results clearly indicate that a linoleic acid hydroperoxide-hematin system readily N-demethylates DAB to MAB and MAB to AB. Previously, it was found that in this system, HCHO formation by N-demethylation of DAB was faster than that obtained with MAB (15). Similar results are now reported during the H202 peroxidase catalyzed oxidation of DAB and MAB. Peroxidase and H2O2 have previously been reported to catalyze the N-dealkylation of other arylamines (16, 17). 

Pio. 2. Inhibition of linoleate peroxidation by high-protein tissue fractions from... 

Fio. 3. Inhibition of linoleate peroxidation in presence of antioxidant and prooxidant by selenium-tissue fractions. Initial antioxidant addition was 5 X 10 M a-tocopherol. Prooxidant added at 4 hours was 1 X 10 M hemoglobin. 

Tallman, K. A., D. A. Pratt, and N. A. Porter. 2001. Kinetic products of linoleate peroxidation Rapid P-fragmentation of nonconjugated peroxyls. 

The first stage of autoxidation of a pure oil is easily traceable by applying conventional wet chemistry, for example determination of the peroxide value. Peroxides are known to be heat labile compounds, which undergo breakdown at elevated temperatures to form simple hydrocarbons. Thus ethane and pentane are the predominant breakdown products of linolenate and linoleate peroxides, respectively (Evans et al., 1967). Scholz and Ptak (1966) and Evans et al. (1969) proposed a gas chromatographic method to measure rancidity in edible oils whereby the undiluted oil is injected directly into the hot injector (250°C). At these temperatures lipid peroxides are... 

Sevanian et al. (1994) applied GLC and LC/TS/MS for the analysis of plasma cholesterol-7-hydroperoxides and 7-ketocholesterol. Analysis of human and rabbit plasma identified the commonly occurring oxidation products, yet dramatic increases in 7-ketocholesterol and cholesterol-5p, 6P-epoxide were observed. The study failed to reveal the presence of choles-terol-7-hydroperoxides, which were either too unstable for isolation, metabolized or further decomposed. The principal ions of cholesterol oxides monitored by LC/TS/MS were m/z 438 (cholestane triol) m/z 401 (cholesterol-7-hydroperoxide) m/z 401 (7-ketocholesterol) m/z 367 (7a-hydroxycholesterol) m/z 399 (cholesta-3,5-dien-7-one) and m/z 385 (choles-terol-5a,6a-epoxide). The major ions were supported by minor ions consistent with the steroid structure. Kamido et al. (1992a, b) synthesized the cholesteryl 5-oxovaleroyl and 9-oxononanoyl esters as stable secondary oxidation products of cholesteryl arachidonate and linoleate, respectively. These compounds were identified as the 3,5-dinitrophenylhydrazone (DNPH) derivatives by reversed-phase LC/NICI/MS. These standards were used to identify cholesteryl and 7-ketocholesteryl 5-oxovaleroyl and 9-oxononanoyl esters as major components of the cholesteryl ester core aldehydes generated by copper-catalysed peroxidation of low-density lipoprotein (LDL). In addition to 9-oxoalkanoate (major product), minor amounts of the 8, 9, 10, 11 and 12 oxo-alkanoates were also identified among the peroxidation products of cholesteryl linoleate. Peroxidation of cholesteryl arachidonate yielded the 4, 6, 7, 8, 9 and 10 oxo-alkanoates of cholesterol as minor products. The oxysterols resulting from the peroxidation of the steroid ring were mainly 7-keto, 7a-hydroxy and 7P-... 

Addition of quercetin to culture cell medium enhanced the rate of growth of baby hamster kidney (BHK-21) cells and also diminished levels of Upid peroxidation breakdown products [214]. Furtoermore, quercetin and three other flavonoids, hesperetin, naringenin, rutin, were found to be effective inhibitors of lipid oxidation in two different in vitro experimental models (1) Fe( )-induced linoleate peroxidation, by detection of conjugated dienes, and (2) auto-oxidation... 

Sodium dodecyl sulfate and hydrogen dodecyl sulfate have been used as catalysts in the denitrosation iV-nitroso-iV-methyl-p-toluenesulfonamide [138]. The kinetics of condensation of benzidine and p-anisidine with p-dimethylamino-benzaldehyde was studied by spectrophotometry in the presence of micelles of sodium dodecyl sulfate, with the result that the surfactant increases the rate of reaction [188]. The kinetics of reversible complexation of Ni(II) and Fe(III) with oxalatopentaaminecobalt(III) has been investigated in aqueous micellar medium of sodium dodecyl sulfate. The reaction occurs exclusively on the micellar surface [189]. Vitamin E reacts rapidly with the peroxidized linoleic acid present in linoleic acid in micellar sodium dodecyl sulfate solutions, whereas no significant reaction occurs in ethanol solution [190]. 

Oleic acid, linolic acid, ricinolic acid, and 2-bromostearic acid methyl ester as well are reacting with diethyl phosphite in the presence of benzoyl peroxide to the corresponding phosphono fatty acid esters [156-158]. 

JiAZ s,ZHOU B, YANG L, wu L M and LIN z L (1998) Autioxidant synergism of tea polyphenols and a-tocopherol against free radical induced peroxidation of linoleic acid in solution, J Chem Soc Perkin Trans, II, 911-15. 

PEDRiELLi p and SKIBSTED L H (2002) Antioxidant syneigy and regeneration effect of quercetin, (-)epicatechin, and (+)-catechin on a-tocopherol in homogeneous solutions of peroxidating methyl linoleate, JAgric Food Chem, 50, 7138-44. 

ROGINSKY v A, BARSUKOVA T K, REMOROVA A A and BORS w (1996) Moderate antioxidative efficiencies of flavonoids during peroxidation of methyl linoleate in homogeneous and micellar solutions, J Am Oil Chem, Ti, 777-86. 

With the above procedure, dienoic fatty acid peroxidation products yield a conjugated triene chromophore with second-derivative absorption minima iocated at 258, 269.5 and 281 nm, whilst trienoic fatty-acid peroxidation products give rise to a conjugated tetraene chromophore with minima at 278, 289, 303 and 318 nm. The arrows in (c) denote second-derivative absorption minima corresponding to the conjugated triene adduct arising from linoleate-derived peroxidation products (conjugated hydroperoxydienes, hydroxydienes and oxodienes). 

Galaris, D., Sevanian, A., Caelenas, E. and Hochstein, P. (1990). Ferrylmyoglobin catalysed linoleic acid peroxidation. Arch. Biochem. Biophys. 281, 163-169. 

Guyan et al. 1990) have used several markers of lipid peroxidation (9-cis-, 11-tmns-isomer of linoleic acid, conjugated dienes and ultraviolet fluorescent products) to demonstrate significant increases in the duodenal aspirate after secretin stimulation in patients with acute and clinic pancreatitis. They interpreted this as indicating induction of hepatic and pancreatic drug-metabolizing enzymes in the face of a shortfidl of antioxidant defences, more marked in chronic pancreatitis. Subsequent studies in patients with chronic pancreatitis have confirmed decreased serum concentrations of selenium, -carotene and vitamin E compared with healthy controls (Uden et al., 1992). Basso aol. (1990) have measured increases in lipid peroxides in the sera of patients with chronic... 

Probucol, another di-r-butyl phenol, is an anti-atherosclerotic agent that can suppress the oxidation of low-density lipoprotein (LDL) in addition to lowering cholesterol levels. The antioxidant activity of probucol was measured, using EPR, with oxidation of methyl linoleate that was encapsulated in liposomal membranes or dissolved in hexane. Probucol suppressed ffee-radical-mediated oxidation. Its antioxidant activity was 17-fold less than that of tocopherol. This difference was less in liposomes than in hexane solution. Probucol suppressed the oxidation of LDL as efficiently as tocopherol. This work implies that physical factors as well as chemical reactivity are important in determining overall lipid peroxidation inhibition activity (Gotoh et al., 1992). 

Vulcain, E. et al. (2005). Inhibition of the metmyoglobin-induced peroxidation of linoleic acid by dietary antioxidants Action in the aqueous vs. lipid phase. Free Rad. Res. 39(5) 547-563. 

Yamauchi, R. et al. (1998). Oxidation products of beta-carotene during the peroxidation of methyl linoleate in the bulk phase. Biosci. Biotechnol. Biochem. 62(7) 1301-1306. 

Dopamine, a strong water-soluble antioxidant, was identified in banana fruit (Musa cavendishii) by Kanazawa and Sakakibara (2000). Banana fruit contained high levels in the pulp and peel 2.5-10 mg/100 g and 80-560 mg/100 g, respectively. A banana water extract was reported to suppress the autoxidation of linoleic acid by 65-70% after a 5-day incubation in an emulsion system, as determined from peroxide value and thiobarbituric acid reactivity (Kanazawa and Sakakibara 2000). 

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