Conjugated Diene Production Research Articles

Oxidative stability of milk and expression of oxidative stress response, lipogenic-related, and IGF-1 genes in early-lactation cows supplemented with peanut and sunflower oils

Context Feeding dairy cows with plant oils rich in unsaturated fatty acids is a recommended strategy for increasing the proportion of polyunsaturated fatty acids in milk for human consumption. Aims We evaluated the effects of supplementation with peanut oil (high oleic acid content) and sunflower oil (high linoleic acid content) on the fatty acid profile and oxidative stability of milk and the expression of oxidative stress response, lipogenic-related and insulin-like growth factor 1 (IGF-1) genes in pasture-fed Jersey cows in early lactation. Methods Twenty-four cows were distributed in a randomised block design. Treatments were four dietary supplements of concentrate alone, or concentrate plus oil (59.6 g/kg dry matter): peanut oil, sunflower oil, or a 1:1 (v/v) mixture of peanut and sunflower oils. Analyses were performed at 30 and 60 days in milk. Key results Both peanut oil and mixed oil diets increased the hypocholesterolemic/hypercholesterolemic ratio (P < 0.001) and health-promoting index (P < 0.001) of milk. The sunflower oil diet increased the thrombogenicity index (P = 0.005) and conjugated diene production (P < 0.001). mRNA abundance of fatty acid synthase (P = 0.003), acetyl-CoA carboxylase alpha (P = 0.001), and stearoyl-CoA desaturase (P < 0.001) decreased with the sunflower oil diet. mRNA abundance of superoxide dismutase decreased (P = 0.01) with sunflower oil and mixed oil diets. The control diet tended (P = 0.08) to reduce IGF-1 mRNA abundance. Conclusions and implications Supplementation with peanut oil increases the health-promoting index of milk, whereas supplementation with sunflower oil increases susceptibility to lipid peroxidation. Supplementation with sunflower oil reduces the expression of lipogenic and antioxidant enzyme genes, and supplementation with unsaturated fats may reduce IGF-1 gene expression in early-lactation cows. The relatively small sample size means that more studies are needed.

Ene-Yne Metathesis of Allylphosphonates and Allylphosphates: Synthesis of Phosphorus-Containing 1,3-Dienes.

A variety of ene-yne cross metathesis reactions were performed using unsaturated phosphonate and phosphate reagents, affording the corresponding phosphorylated 1,3-diene products in good to excellent yields. These difficult ene-yne metatheses employed a Grubbs catalyst bearing a cyclic amino alkyl carbene ligand. A variety of terminal alkynes of varying substitution underwent the reaction, and different phosphorus-containing alkenes were found to give the conjugated diene products in high yields. The resulting dienes were further transformed by Horner-type Wittig reactions and a Diels-Alder cycloaddition.

The Effect of Quail Egg and Hen Egg Consumption on Low-Density Lipoprotein Oxidation and Small Dense Low-Density Lipoprotein

Objective: The aim of the study was to investigate the effect of quail egg and hen egg supplements on lipoprotein profiles, low-density lipoprotein (LDL) oxidation and small dense LDL cholesterol (sd-LDL-C) in young healthy people, compared with hen eggs. Material and Methods: Twenty-three healthy volunteers (11 men and 12 women) were randomly assigned to consume 3 whole hen eggs per day (hen group, n=11) (total cholesterol 633 mg) or 9 quail eggs per day (quail group, n=12) (total cholesterol 459 mg) for 30 days. The plasma cholesterol and plasma triglyceride concentrations and lipoprotein fractions (Triglyceride-rich lipoprotein; TRL, LDL and high-density lipoprotein; HDL) were determined at baseline and after the 30-day period of egg consumption. The LDL oxidation (lag time) was measured by the increase of conjugated diene production. Sd-LDL-C was calculated from the major lipid and lipoprotein parameters. Results: In the quail group, plasma triglyceride (TG) and LDL-TG were significantly decreased, whereas the plasma cholesterol and HDL-C were unchanged. There was no alteration in lipoprotein profiles in the hen group. The LDL lag time of the quail group was longer than at baseline. There were no significant changes in sd-LDL-C levels in both groups during the study.Conclusion: Quail egg and hen egg consumptions for 30 days did not change the lipoprotein profiles, sd-LDL as well as the LDL-oxidation, which not modified the cardiovascular disease risk factor.

Selective Synthesis of 3-O-Palmitoyl-Silybin, a New-to-Nature Flavonolignan with Increased Protective Action against Oxidative Damages in Lipophilic Media.

A selective acylation protocol using cerium chloride (CeCl3) as catalyst was applied to functionalize silybinin (1), a natural antioxidant flavonolignan from milk thistle fruit, in order to increase its solubility in lipophilic media while retaining its strong antioxidant activity. The selective esterification of 1 at the position 3-OH with a palmitate acyl chain leading to the formation of the 3-O-palmitoyl-silybin (2) was confirmed by both mass spectroscopy (MS) and nuclear magnetic resonance (NMR) analyses. The antioxidant activity of 1 was at least retained and even increased with the CUPRAC assay designed to estimate the antioxidant activity of both hydrophilic and lipophilic compounds. Finally, the 3-O-palmitoylation of 1, resulting in the formation of 2, also increased its anti-lipoperoxidant activity (i.e., inhibition of conjugated diene production) in two different lipophilic media (bulk oil and o/w emulsion) subjected to accelerated storage test.

Palladium-Catalyzed Decarboxylative γ-Olefination of 2,5-Cyclohexadiene-1-carboxylic Acid Derivatives with Vinyl Halides.

This study explores a Pd-catalyzed decarboxylative Heck-type Csp3-Csp2 coupling reaction of 2,5-cyclohexadiene-1-carboxylic acid derivatives with vinyl halides to provide γ-olefination products. The olefinated 1,3-cyclohexadienes can be further oxidized to produce meta-alkylated stilbene derivatives. Additionally, the conjugated diene products can also undergo a Diels-Alder reaction to produce a bicyclo[2.2.2]octadiene framework.

Oxidative status of dairy cows fed flax meal and infused with sunflower oil in the abomasum

Flax products increase concentration of antioxidants in milk and plasma of dairy cows, which may reduce oxidative damage resulting from lipoperoxidation of polyunsaturated fatty acids. The aim of this study was to investigate the effects of flax meal on the antioxidant status of dairy cows infused with sunflower oil (SO), a source of omega-6 fatty acids (FA), in the abomasum. Eight rumen fistulated lactating Holstein cows were assigned to a double 4×4 Latin square design with a 2×2 factorial arrangement of treatments: (1) control diet with no flax meal and no infusion of SO (CO); (2) diet containing 137g/kg flax meal (FM); (3) CO and infusion of 250g SO/d; and (4) FM and infusion of 250g SO/d. Dry matter intake and milk production were similar among diets. Flax meal increased milk fat concentration. Dietary FM supplementation increased plasma concentration of saturated fatty acids, and tended to reduce the polyunsaturated to saturated FA ratio. The plasma peroxidizability index was not affected by FM supplementation or SO infusion. Infusion of SO increased antioxidant capacity and rate of diene production, and decreased the time to reach maximal amount of conjugated diene production in plasma. Production of thiobarbituric reactive substances (TBARS) in ruminal fluid was reduced by dietary FM. Milk and plasma TBARS production were not affected by FM supplementation. Sunflower oil had no effect on TBARS production in ruminal contents, milk and plasma. In conclusion, feeding FM to dairy cows receiving a source of omega-6 FA (250g/d) that bypasses the rumen did not protect cows and milk from lipoperoxidation.

Capsaicin protects endothelial cells and macrophage against oxidized low-density lipoprotein-induced injury by direct antioxidant action

Atherosclerosis is a chronic inflammatory vascular disease. It is characterized by endothelial dysfunction, lipid accumulation, leukocyte activation, and the production of inflammatory mediators and reactive oxygen species (ROS). Capsaicin, a biologically active compound of the red pepper and chili pepper, has several anti-oxidant, anti-inflammatory, anti-cancer, and hypolipidemic biological effects. However, its protective effects on foam cell formation and endothelial injury induced by oxidized low-density lipoprotein (oxLDL) remain unclear. In this study, we evaluated the anti-oxidative activity of capsaicin, and determined the mechanism by which capsaicin rescues human umbilical vein endothelial cells (HUVECs) from oxLDL-mediated dysfunction. The anti-oxidative activity of capsaicin was defined by Apo B fragmentation and conjugated diene production of the copper-mediated oxidation of LDL. Capsaicin repressed ROS generation, as well as subsequent mitochondrial membrane potential collapse, cytochrome c expression, chromosome condensation, and caspase-3 activation induced by oxLDL in HUVECs. Capsaicin also protected foam cell formation in macrophage RAW 264.7 cells. Our results suggest that capsaicin may prevent oxLDL-induced cellular dysfunction and protect RAW 264.7 cells from LDL oxidation.

Koelreuteria formosana extract impedes in vitro human LDL and prevents oxidised LDL-induced apoptosis in human umbilical vein endothelial cells

Koelreuteria formosana ethanol extract (KFEE) is obtained from natural plants that are endemic in Taiwan. A study showed that KFEE has antioxidant activity in DPPH assay. In the current study, the antioxidative activity of KFEE, which contains polyphenols including gallic acid and caffeic acid, was evaluated. The manner by which KFEE protects human umbilical vein endothelial cells (HUVECs) from oxidised LDL (oxLDL)-mediated dysfunction in vitro was investigated as well. The results indicate that the antioxidative activity of KFEE is defined by the relative electrophoretic mobility of oxLDL, the fragmentation of ApoB, conjugated diene production, and malondialdehyde production through Cu2+-mediated oxidation of LDL. KFEE also inhibited ROS generation as well as the subsequent mitochondrial membrane potential collapse, chromosome condensation, cytochrome C release, and caspase-3 activation induced by oxLDL in HUVECs. Our results also indicate that KFEE may protect LDL oxidation and prevent oxLDL-induced cellular dysfunction in HUVECs.

Antioxidant properties of 3-deoxyanthocyanidins and polyphenolic extracts from Côte d’Ivoire’s red and white sorghums assessed by ORAC and in vitro LDL oxidisability tests

Red sorghum is a source of phenolic compounds (PCs), including 3-deoxyanthocyanidins that may protect against oxidative stress related disease such as atherosclerosis. HPLC was used to characterise and quantify PCs extracted from red or white sorghum whole grain flour. Antioxidant activity was measured by an oxygen radical absorbance capacity assay and against LDL-oxidisability, and further compared to that of synthesised 3-deoxyanthocyanidins (i.e., luteolinidin and apigeninidin). Phenolic content of red and white sorghums was evaluated as 3.90±0.01 and 0.07±0.01mmol gallic acid equivalents L−1, respectively. Luteolinidin and apigeninidin were mainly found in red sorghum. Red sorghum had almost 3 and 10 times greater specific antioxidant activity compared to luteolinidin and apigeninidin, respectively. Red sorghum PCs and the two 3-deoxyanthocyanidins were also effective at preventing LDL vitamin E depletion and conjugated diene production. Red sorghum flour exhibits antioxidant capacity suggesting that it may be a valuable health-promoting food.

The Antioxidant Activity of the Essential Oil of Different Parts of Juniperus foetidissima Willd. in Lipid System

It is believed that the cell damages caused by free radicals are playing a major role in the ageing process and other human diseases. The free radicals can stabilize or deactivating by antioxidants before they attack cells. Synthetic antioxidants have been suspected to cause or promote negative health effects. Therefore finding new and safe effective natural antioxidants is needed as alternatives of commercial antioxidants. The activity of the essential oils and their main compounds has been investigated as natural antioxidants. In this study the essential oils of leaves of male and female and fruits of Juniperus foetidissima as well as their main components were examined for their antioxidant activities using lipid systems. GC and GC-MS were employed to study the compositions of the essential oils. The antioxidant activity of the essential oils of leaves of male and female and fruits of J. foetidissima and their major components were tested using TBARS (thiobarbituric acid reactive species) test and linoleic acid-derived conjugated dienes production inhibition test. Vitamin E was used as positive control in both tests. The test samples showed a very wide range of activity. Within the tested compounds α-pinene was the weakest of all. Generally the essential oils obtained from fruits and leaves of male and female trees of J. foetidissima showed a good antioxidant activity in high concentration when compared with the activity of vitamin E. Among the tested essential oils, the oil of the male leaves of J. foetidissima showed the highest antioxidant activity while the oil of the leaves of the female plant showed the lowest activity. However the nature of compounds and their solubility in aqueous and organic phases in the applied test systems may affects the observed results of antioxidant activity determination.

Pioglitazone protects HDL2&3 against oxidation in overweight and obese men

The worldwide epidemic of obesity is a major public health concern and is persuasively linked to the rising prevalence of diabetes and cardiovascular disease. Obesity is often associated with an abnormal lipoprotein profile, which may be partly negated by pioglitazone intervention, as this can influence the composition and oxidation characteristics of low-density lipoprotein (LDL). However, as pioglitazone's impact on these parameters within high-density lipoprotein (HDL), specifically HDL(2&3), is absent from the literature, this study was performed to address this shortcoming. Twenty men were randomized to placebo or pioglitazone (30 mg/day) for 12 weeks. HDL(2&3) were isolated by rapid-ultracentrifugation. HDL(2&3)-cholesterol and phospholipid content were assessed by enzymatic assays and apolipoprotein AI (apoAI) content by single-radial immunodiffusion. HDL(2&3) oxidation characteristics were assessed by monitoring conjugated diene production and paraoxonase-1 activity by spectrophotometric assays. Compared with the placebo group, pioglitazone influenced the composition and oxidation potential of HDL(2&3). Specifically, total cholesterol (P < 0.05), phospholipid (P < 0.001) and apoAI (P < 0.001) were enriched within HDL(2). Furthermore, the resistance of HDL(2&3) to oxidation (P < 0.05) and the activity of paroxonase-1 were also increased (P < 0.001). Overall, these findings indicate that pioglitazone treatment induced antiatherogenic changes within HDL(2&3), which may help reduce the incidence of premature cardiovascular disease linked with obesity.

The antioxidant behaviour of melatonin and structural analogues during lipid peroxidation depends not only on their functional groups but also on the assay system

There is no general agreement yet on the antioxidant effect of pineal indoles against lipid peroxidation. Accordingly, the main goal of the present work was 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 (rich in 20:5 n-3, 22:6 n-3) dissolved in chloroform and sonicated liposomes made of retinal lipids (rich in 22:6 n-3). In the triglyceride–chloroform-system the peroxidation reaction was initiated by cumene hydroperoxide (CHP) whereas liposomes were peroxidized with Fe2+. The techniques employed at the present work were: (1) TBARS production, (2) DPPH assay, (3) determination of conjugated dienes production and (4) analysis of fatty acid profile by GC–MS. Butylated hydroxytoluene (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-TRP were better antioxidants that BHT in the triglyceride-system but ineffective in the liposome-system. We conclude that the antioxidant behaviour of pineal indoles depends not only on their functional groups but also on the assay system and could be explained by the polar paradox theory.

Polyphenol input to the antioxidant activity of yerba mate (Ilex paraguariensis) extracts

Industrial processing modified the polyphenol content, composition and antioxidant activity of the yerba mate extracts. Pre-dried leaves were the most appropriate raw material combining maximum activity with high polyphenol content. Chlorogenic acid and its derivatives were the major components of the phenolic fraction but we also identified caffeic, rutin and quercetin.Yerba mate extracts inhibited malonedialdehyde formation in sunflower oil (20 μmol/kg) and conjugated dienes production in oil/water emulsions (60 μmol/kg). Enhancing the dose to 60 μmol/kg reduced 27.8% the extract’s activity in oil.The relationship between polyphenol composition and antioxidant activity of a mixture of caffeic, chlorogenic, kaempferol, quercetin and rutin was satisfactorily predicted with a polynomial model. Results showed that quercetin was the highest contributor to the linear term followed by kaempferol and caffeic acid while rutin and chlorogenic acid inputs were the lowest. The model detected five synergistic and six antagonistic effects.

Free radical scavenging and antiatherogenic activities of Sesamum indicum seed extracts in chemical and biological model systems

An emerging consensus underscores the importance of oxidative events in vascular disease including excess production of reactive oxygen/nitrogen species (ROS/RNS), in addition to lipoprotein oxidation. Sesamum indicum has long been used extensively as a traditional food. The aim of present study was to evaluate antioxidant action of aqueous and ethanolic seed extracts from S. indicum using various in vitro ROS/RNS generated chemical and biological models. Results demonstrated that the graded-dose (25–1000 μg/ml) of aqueous and ethanolic extracts markedly scavenged the nitric oxide, superoxide, hydroxyl, 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals and, showed metal chelating ability as well as reducing capacity in Fe 3+/ferricyanide complex and ferric reducing antioxidant power assays. In biological models, both extracts were found to inhibit metal-induced lipid peroxidation in mitochondrial fractions, human serum and LDL oxidation models. In lipoprotein kinetics study, both extracts significantly ( P < 0.05) increased lag phase time along with reduced oxidation rate and conjugated dienes production. Ethanolic extract of S. indicum showed higher amounts of total polyphenol and flavonoid content as compared to their counterpart. The IC 50 values of both extracts were compared with respective antioxidant standards. Overall, ethanolic extract of S. indicum possess strong antioxidant capacity and offering effective protection against LDL oxidation susceptibility.

Dietary polyunsaturated fatty acids and adaptation to chronic hypoxia alter acyl composition of serum and heart lipids

The effects of dietary supplementation with fat of different fatty acid profile and chronic intermittent hypoxia (CIH) on the fatty acid composition of serum and heart lipids were analysed. Adult male Wistar rats were fed a standard non-fat diet enriched with 10 % of lard, fish oil (n-3 PUFA) or maize oil (n-6 PUFA) for 10 weeks. After 4 weeks on the diets, each group was divided in two subgroups, either exposed to CIH in a barochamber (7000 m, twenty-five exposures) or kept at normoxia. In normoxic rats, the fish oil diet increased the level of conjugated dienes. The n-6:n-3 PUFA ratio in serum TAG, phospholipids (PL), cholesteryl esters (CE) and heart TAG, PL and diacylglycerols (DAG) followed the ratio in the fed diet (in the sequence maize oil>lard>fish oil). In heart TAG, PL and DAG, 20 : 4n-6 and 18 : 2n-6 were replaced by 22 : 6n-3 in the fish oil group. The main fatty acid in CE was 20 : 4n-6 in the lard and maize oil groups whereas in the fish oil group, half of 20 : 4n-6 was replaced by 20 : 5n-3. CIH further increased 20 : 5n-3 in CE in the fish oil group. CIH decreased the n-6:n-3 PUFA ratio in serum CE, heart TAG, PL and DAG in all dietary groups and stimulated the activity of catalase in the maize and fish oil groups. In conclusion, PUFA diets and CIH, both interventions considered to be cardioprotective, distinctly modified the fatty acid profile in serum and heart lipids with specific effects on conjugated diene production and catalase activity.

Substituent effects on regioselectivity in the autoxidation of nonconjugated dienes.

Free radical oxidation of several 1,4-dienes was carried out in the presence of variable concentrations of alpha-tocopherol to investigate the effect of diene structure on product distribution. Oxidations carried out at low tocopherol concentration gave only C-1 and C-5 conjugated diene hydroperoxides, while higher concentrations of the antioxidant resulted in formation of substantial amounts of the nonconjugated C-3 diene hydroperoxide. Increasing size of the substituents at C-1 and C-5 of the diene favors kinetic products arising from oxygen addition at the nonconjugated position, C-3, of the pentadienyl radical intermediate. Substituents at C-1 or C-5 of the pentadienyl radical also have a significant effect on the regioselectivity of the conjugated diene hydroperoxides formed, larger substituents directing oxygen addition to the pentadienyl radical at the site of least steric hindrance. This trend is also observed in oxidations of omega-3 and omega-6 linolenate fatty acid esters. Groups at C-1 and C-5 of the diene can influence product distribution based upon (a) steric demand in the oxygen-radical reaction and (b) the influence of substituents on the rearrangement of the C-3 peroxyl radical to give conjugated diene products.

In Vitro antioxidant and anti-inflammatory activities of Jaceosidin from Artemisia princeps Pampanini cv. Sajabal

Oxidized low-density lipoprotein (oxLDL) plays a key role in the inflammatory processes of atherosclerosis. Jaceosidin isolated from the methanolic extracts of the aerial parts of Artemisia princeps Pampanini cv. Sajabal was tested for antioxidant and anti-inflammatory activities. Jaceosidin inhibited the Cu(2+)-mediated LDL oxidation with IC(50) values of 10.2 microM in the thiobarbituric acid-reactive substances (TBARS) assay as well as the macrophage-mediated LDL oxidation. The antioxidant activities of jaceosidin were exhibited in the conjugated diene production, relative electrophoretic mobility, and apoB-100 fragmentation on copper-mediated LDL oxidation. Jaceosidin also inhibited the generation of reactive oxygen species (ROS) concerning in regulation of NF-kappaB signaling. And jaceosidin inhibited nuclear factor-kappa B (NF-kappaB) activity, nitric oxide (NO) production, and suppressed expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-induced RAW264.7 macrophages.

Inhibition of Low-Density Lipoprotein Oxidation and Oxidative Burst in Polymorphonuclear Neutrophils by Caffeic Acid and Hispidin Derivatives Isolated from Sword Brake Fern (Pteris ensiformis Burm.)

Several antioxidant compounds have been previously identified from sword brake fern (Pteris ensiformis Burm.) by DPPH bleaching and Trolox equivalent antioxidant capacity (TEAC) analyses. Among the isolates, 7-O-caffeoylhydroxymaltol 3-O-beta-D-glucopyranoside and hispidin 4-O-beta- D-glucopyranoside [6-(3,4-dihydroxystyryl)-4-O-beta-D-glucopyranoside-2-pyrone] were two new compounds. The aim of this study is to elucidate the possible effect of the aqueous extract of sword brake fern (SBF) and these two compounds in preventing atherosclerosis. The results demonstrated that SBF and these two compounds strongly inhibited Cu2+-mediated low-density lipoprotein (LDL) oxidation measured by thiobarbituric acid-reactive substances assay (TBARS), conjugated diene production, and relative electrophoretic mobility. The commercial antioxidant dl-alpha-tocopherol showed lower antioxidant activity than these two compounds at the same molecular concentration. SBF and these two compounds also suppressed N-formylmethionyl-leucylphenylalanine (fMLP)-stimulated reactive oxygen species (ROS) production in human polymorphonuclear neutrophils (PMN). These findings indicate that sword brake fern may prevent atherosclerosis via inhibition of both LDL oxidation and ROS production.

Antioxidant Activities of Abietane Diterpenoids Isolated from Torreya nucifera Leaves

Investigation on antioxidant compounds from the ethanolic extracts of Torreya nucifera leaves resulted in the isolation of abietane diterpenoids, a known 18-methylesterferruginol (1) and a new 18-dimethoxyferruginol (2). The structures of compounds 1 and 2 were elucidated on the basis of their spectroscopic analyses. Compounds 1 and 2 inhibited the Cu2+-mediated, 2,2'-azobis(2-amidinopropane)hydrochloride-mediated and 3-morpholinosydnonimine-1-mediated low-density lipoprotein (LDL) oxidation in the thiobarbituric acid-reactive substances assay as well as the macrophage-mediated LDL oxidation. Compounds 1 and 2 exhibited the potent antioxidant activities in the conjugated diene production, relative electrophoretic mobility, and apoB-100 fragmentation on copper-mediated LDL oxidation. Compound 1 also suppressed nitric oxide production and inducible nitric oxide synthase expression in lipopolysaccharide-stimulated RAW264.7 cells.

A one-step method of 10,17-dihydro(pero)xydocosahexa-4Z,7Z,11E,13Z,15E,19Z-enoic acid synthesis by soybean lipoxygenase

A product of lipoxygenase (LOX) oxidation of docosahexaenoic acid (DHA), 10,17-dihydro(pero)xydocosahexa-4Z,7Z,11E,13Z,15E,19Z-enoic acid [10,17(S)-diH(P)DHA] was obtained through various reaction pathways that involved DHA, 17(S)-hydro(pero)xydocosahexa-4Z,7Z,11Z,13Z,15E,19Z-enoic acid [17(S)-H(P)DHA], soybean lipoxygenase (sLOX), and potato tuber lipoxygenase (ptLOX) in various combinations. The structure of the product was confirmed by HPLC, ultraviolet (UV) light spectrometry, GC-MS, tandem MS, and NMR spectroscopy. It has been found that 10,17(S)-diH(P)DHA formed by sLOX through direct oxidation of either DHA or 17(S)-H(P)DHA was apparently identical to the product of ptLOX oxidation of the latter. The sLOX- and ptLOX-derived samples of 10,17-diHDHAs coeluted under the conditions of normal, reverse, and chiral phase HPLC analyses, displayed identical UV absorption spectra with maxima at 260, 270, and 280 nm, and had similar one-dimensional and two-dimensional proton NMR spectra. Analysis of their NMR spectra led to the conclusion that 10,17-diHDHA formed by sLOX had solely 11E,13Z,15E configuration of the conjugated triene fragment, which was identical to the previously published structure of its ptLOX-derived counterpart. Based on the cis,trans geometry of the reaction products, the conclusion is made that in the tested conditions sLOX catalyzed direct double dioxygenation of DHA. Compared with the previously described two-enzyme method that involved sLOX and ptLOX, the current simplified one-enzyme procedure uses only sLOX as the catalyst of both dioxygenation steps.