Docosahexaenoic Acid-rich Oil Research Articles

Diet to Stop Hypertension: Should Fats be Included?

International guidelines emphasize advice to incorporate dietary measures for the prevention and in the management of hypertension. Current data show that modest reductions in weight can have an impact on blood pressure. Reducing salt and marine oils have also shown consistent benefit in reducing blood pressure. Whether other dietary constituents, in particular the amount and type of fat that play important roles in cardiovascular prevention, influence blood pressure sufficiently to be included in the management of hypertension is less certain. In this review, we provide a summary of the most recent findings, with a focus on dietary patterns, fats and other nutrients and their impact on blood pressure and hypertension. Since reducing salt consumption is an established recommendation only corollary dietary advice is subject to the current review. Population studies that have included reliable evaluation of fat intake have indicated almost consistently blood pressure lowering with consumption of marine oils and fats. Results with vegetable oils are inconclusive. However dietary patterns that included total fat reduction and changes in the nature of vegetable fats/oils have suggested beneficial effects on blood pressure. Plant-based foods, dairy foods and yoghurt particularly, may also lower blood pressure irrespective of fat content. Total fat consumption is not directly associated with blood pressure except when it is part of a weight loss diet. Consumption of marine oils has mostly shown moderate blood pressure lowering and possibly greatest effect with docosahexaenoic acid-rich oil.

A randomized double-blind trial to measure the absorption characteristics of eicosapentaenoic acid and docosahexaenoic acid rich oil blend with natural lipid-based delivery system.

A randomized, double-blinded trial with 65 subjects was conducted to compare the pharmacokinetics between PhytoMarineCelle (PM) that consists of eicosapentaenoic acid and docosahexaenoic acid (EPA + DHA) plus a self-emulsifying drug delivery system (SEDDS), and a standard EPA + DHA ethyl ester (SEE) that does not contain SEDDS. PM showed 1.6-fold greater plasma area under the curve (AUC) than SEE at 300 mg, although no significant difference was observed. PM showed a 3.1 and 3.2-fold (p < 0.05) greater plasma AUC than SEE at 500 mg and 1000 mg respectively. The concentration max (Cmax) of EPA + DHA did not change between PM and SEE at 300 mg. Cmax of PM was twofold greater than SEE at 500 mg and 1000 mg respectively. The Cmax of EPA + DHA achieved significant difference (p < 0.05) only with the 500 mg dose. The PM formulation increased the bioavailability of EPA + DHA by threefold compared to SEE at 500 and 1000 mg.

Efficient biotransformation of docosahexaenoic acid-rich oils into the lipid mediator resolvin D5 by cells expressing 15S-lipoxygenase using a bioreactor

Resolvin D5 (RvD5), 7S,17S-dihydroxy-4Z,8E,10Z,13Z,15E,19Z-docosahexaenoic acid (DHA) is a specialized pro-resolving mediator (SPM) generated in human macrophages. It is implicated in the resolution of inflammation and synthesized using an inefficient chemical process. Here, DHA-enriched oil hydrolysate was prepared from oils by lipase with resin treatment and solvent extraction. The reaction factors on the biotransformation of oil hydrolysate into RvD5 were optimized using Escherichia coli expressing arachidonate double-oxygenating 15S-lipoxygenase. After optimization, the cells converted 5.0 mM (1.64 g/L) DHA in oil hydrolysate into 4.0 mM (1.44 g/L) RvD5 in a bioreactor for 3.0 h, which was 15-fold higher than that in a flask before optimization, and RvD5 with a purity of > 97% was prepared from reaction solution by treatments of resins. This is the first trial for the production of C22-dihydroxy fatty acid using a bioreactor. This study will contribute to the large-scale production of SPMs from oils.

Extraction of a Docosahexaenoic Acid-Rich Oil from Thraustochytrium sp. Using a Hydrophobic Ionic Liquid

Thraustochytrium sp. (T18) is a marine heterokont that exhibits a fast growth rate and accumulates a high proportion of polyunsaturated fatty acids (PUFAs), particularly docosahexaenoic acid (DHA), as essential compounds for health. The extraction of DHA-rich oil from marine microorganisms is challenging due to the difficulty in the substantial cost of lyophilization, the incompatibility of solvents with wet biomass, and the large volumes of organic solvents required by traditional extraction techniques. To address these concerns, ionic liquids (ILs) have been used to improve the oil yield from a wet oleaginous microorganism under mild conditions. In this study, a novel hydrophobic IL, 1-decyl-3-methyl-imidazolium bis(2,4,4-trimethylpentyl)phosphinate ([C10mim][(iC8)2PO2]) was first applied as pretreatment to aid in the extraction of DHA-rich oil from T18 biomass in the aqueous phase. A central composite design and response surface methodology were used to study the effect of different extraction variables on the oil yield (temperature, pH, and the mass ratio of IL to dried T18). The extraction conditions were numerically optimized to maximize the oil yield [69.4 ± 0.5% (w/w)] within the experimental range (the temperature of 76 °C, pH of 5.0, and mass ratio of 4.2). In addition, the extraction efficiency was up to 97.4 ± 0.4% of the total lipid content. The extracted oil contained 44.7 ± 0.2% DHA under 1 h of the pretreatment process. In this work, the proposed approach was found to be efficient and sustainable for the water-compatible recovery of a DHA-rich oil recovery process.

Harvesting Aurantiochytrium sp. SW1 using organic flocculants and characteristics of the extracted oil

The use of microalgae as an alternative source of biofuel production has become an emerging topic of interest in recent years. However, the main challenge in the microalgae downstream process lies in the separation of microalgae from the growth media (harvesting process). This study proposed the use of different organic flocculants, namely, cationic guar gum, gum arabic and okra gum, to harvest the microalga Aurantiochytrium sp. SW1 for subsequent extraction of docosahexaenoic acid-rich oil from the microalgae. The physicochemical properties and bioactivities of the cell and extracted oil were studied. The results showed that cationic guar gum at 0.5% w/v and gum arabic at 0.1% w/v were the optimum concentrations for cell harvesting. The highest cell recovery was achieved using cationic guar gum with up to 12.8 g/L culture, which was 3.8-fold higher than that of the control method, probably due to the cationic charge of the cationic guar gum, which exhibited a greater efficiency in coagulating the negatively charged surface of microalgae. Overall, the different flocculants used during harvesting affect the extraction efficiency of lipids and other phytochemicals in the cells. Cationic guar gum significantly produced the highest (p ≤ 0.05) oil yield extracted from the culture, which was up to 25.06% w/w biomass. Interestingly, the significantly highest (p ≤ 0.05) total phenolic content (0.23 ± 0.01 mg gallic acid equivalent/mL) and carotene content (1.67 ± 0.42 mg/mL) were observed in microalgae oil flocculated with okra gum, signifying that the type of flocculant affected the determination of phytochemical content of the extracted oil. The oil obtained from okra gum flocculant also exhibited the highest 2,2-diphenyl-1-picrylhydrazyl scavenging activity (0.89 ± 0.01 mg Trolox equivalent/mL) and ferric reducing antioxidant powder (26.77 ± 1.52 mg Trolox equivalent/mL), which was attributed to the higher concentrations of phenolic compounds and carotene content. This work reveals the potential usage of okra gum as a flocculant with enhanced phytochemical contents and bioactivities.

CaCl2 supplementation of hydrophobised whey proteins: Assessment of protein particles and consequent emulsions

Hydrophobised whey protein particles were prepared through successive acetylation and heat treatment practices, and the particle characteristics were modulated by CaCl2 supplementation. Then, the usefulness of the hydrophobised protein particles for emulsification of a docosahexaenoic acid-rich oil was compared with that of heat-denatured whey protein. Addition of CaCl2 into hydrophobised whey protein resulted in smaller protein particles and lower ζ-potential and interfacial tension values. It also decreased the creaming stability of the consequent emulsions. It was argued that besides Ca2+-protein charge interactions, Cl– anions bind to the hydrophobised particles, and the Pickering stabilisation of oil does not rely on interfacial tension reduction. Compared with heat-denatured whey protein, hydrophobised whey protein afforded a lower protection to oil against oxidation; the peroxide value of the oil emulsified using hydrophobised protein was higher during storage.

Separation of microalgal docosahexaenoic acid-rich oils using a microwave-assisted three-phase partitioning system

A novel and efficient microwave-assisted three-phase partitioning system (MA-TPPS) was developed to separate and purify docosapentaenoic acid (DPA) and docosahexaenoic acid-rich oils from protein, carbohydrate, flavonoids and other raw components in cultivation broths of microalgae Schizocytrium limacinium SR21. The MA-TPPS was optimized by a three-level four independent factor central composite design (CCD) to create response surfaces using response surface methodology (RSM). The optimized parameters were concentrations (w/w, %) of n-hexane (37.5%) potassium acetate (13.33%), and cultivation broths (33.33%), as well as microwave power duration (650 W for 25 s) and pH (7.2). The corresponding yields obtained under optimized conditions are 96.97 ± 1.22% of β-carotene, 94.88 ± 0.93% of astaxanthin, 98.90 ± 0.89% of DHA, and 98.36 ± 1.11% of total fatty acids (TFAs) in oils, respectively, as well as 99.18 ± 0.98% of oils in the n-hexane phase. While 94.79 ± 0.96% protein was recovered in the middle solid interface and 93.29 ± 1.25% total flavonoids in the bottom salt-phase. The validated model system was scaled-up at the laboratory level from 15 g to 50 g. The recovery yields of all components in scale-up experiments were the same. The extracted DHA-oil was purified by semi-preparative high performance liquid chromatography (HPLC) and analyzed by nuclear magnetic resonance (NMR). The purification yield of DHA was comparable to that of the conventional method. These facts, along with higher product yield in a short time and easily scalable characteristics, enable us to use MA-TPPS for separation and purification of DPA & DHA-rich oils from microalgae biomass.

Enhanced production of carotenoids using a Thraustochytrid microalgal strain containing high levels of docosahexaenoic acid-rich oil.

Results to date suggest that microalgal Thraustochytrids family strains can be used to produce high-functional omega-3 rich oil (~ 30-70% of dry cell weight) and carotenoid-based antioxidant pigments simultaneously with value-added bioactive potential. In the present study, we describe the isolation and characterization of a new Thraustochytrid Schizochytrium sp. from the west coastal area of Korea. This newly isolated Thraustochytrid, identified as Schizochytrium sp. through 18S rRNA analysis and named SH104, simultaneously produces high levels of DHA and carotenoid-based antioxidant pigments. An improved Schizochytrium mutant, named SHG104, was obtained from the original host strain by γ-irradiation-induced mutagenesis. Under combined temperature-shift cultivation conditions employing white-light LEDs (light-emitting diodes), Schizochytrium sp. SHG104 yielded 10.8g L-1 of biomass comprising 45.8% total lipids (32.1% DHA) and 4.6mg L-1 of astaxanthin. In addition to DHA, the main fatty acids produced by Schizochytrium sp. SHG104 were palmitic acid and a trace of other long-chain fatty acids. The carotenoid profile of SH104 and SHG104 was β-carotene, astaxanthin, canthaxanthin, pheonicoxanthin and echinenone, which analyzed by HPLC and LC/APCI-MS. Furthermore, genomic analysis of Schizochytrium and Aurantiochytrium microalgae confirmed that the presence of carotenogenesis pathway enzymes and genes including geranylgeranyl diphosphate, phytoene synthase, lycopene cyclase, and cytochrome P450 hydroxylase that necessary for the production of antioxidants via a complete biosynthetic KEGG synthesis pathway. This newly isolated Schizochytrium microalga potentially have wide application as a source of antioxidants for astaxanthin-containing pigments, commercial omega-3 lipids and feed additives, such as nutritional supplements for aquaculture.

Transcriptomic Analysis of the Regulation of Lipid Fraction Migration and Fatty Acid Biosynthesis in Schizochytrium sp.

Schizochytrium sp. is the main source of docosahexaenoic acid-rich oil, which is widely used in food additive and pharmaceutical industry. In this study, using RNA-seq, comparative transcriptomic analyses were performed at four stages of DHA fermentation by Schizochytrium sp to get potential genes related to cell transition from cell growth to lipid accumulation and then to lipid turnover. 1406, 385, 1384 differently expressed genes were identified by comparisons in pairs of S2 vs S1, S3 vs S2 and S4 vs S3. Functional analysis revealed that binding and single-organism process might be involve in the cell transition from cell growth to lipid accumulation while oxidation-reduction process played an important role in the transition from lipid accumulation to lipid turnover. pfaC in the PKS pathway showed higher sensitivity to the environmental change, which might be the key regulator for enhancing PUFA biosynthesis in the future. Some other genes in signal transduction and cell transport were revealed to be related to lipid turnover, which would enrich the current knowledge regarding lipid metabolism and help to enhance the DHA production and enrich different lipid fractions by Schizochytrium in the future.

Oxidation in EPA‐ and DHA‐rich oils: an overview

Oxidation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) rich omega-3 oils (hereafter referred to as either EPA and DHA or omega-3) is a complicated topic, but an important one to understand. A significant number of consumers cite fishy burp and/or taste, thought to be the result of oxidation, as one of the main reasons they do not consume EPA and DHA rich oils. In addition, consumers note that some articles have raised concerns about the potential for adverse effects associated with consumption of oxidized oils. Measuring oxidation in omega-3 oils is complicated due to the differences in chemical and physical characteristics of many commercially available products, which means not all methods to determine quality are appropriate for all types of oils. A number of consumer advocacy groups, product quality seal programs and academic groups have published data on levels of oxidation in omega-3 oils. Overall, this data shows that commercially available omega-3 supplements are low in oxidation. If consumers have a poor sensory experience with their omega-3 product, they should try another product as an alternative.

Combination of grape seed proanthocyanidin extract and docosahexaenoic acid-rich oil increases the hepatic detoxification by GST mediated GSH conjugation in a lipidic postprandial state

The ingestion of dietary lipids leads to oxidative stress. This postprandial oxidative stress may potentiate the adverse effects of postprandial hyperlipidaemia. Proanthocyanidins have been shown to alleviate oxidative stress and hypertriglyceridaemia associated with the postprandial state. Additionally, omega-3 polyunsaturated fatty acids (PUFAs) also have beneficial effects on lipoprotein metabolism and oxidative stress. The present study was designed to investigate the possible additive effects in liver of an acute dose of grape seed proanthocyanidins extract (GSPE) and oil rich in docosahexaenoic acid (DHA-OR) on lipidic postprandial oxidative stress in Wistar rats. GSPE+DHA-OR modifies the hepatic antioxidant enzymatic activities (GST and GPx), clearly showing that this combination increases the detoxification of postprandial xenobiotics via the GST action mediated hepatic GSH conjugation. In conclusion, this study provides evidence that the combination of GSPE and DHA-OR ameliorate the transient imbalance between the lipid hydroperoxide level and antioxidant status related to a lipidic postprandial state.

The influence of feeding linoleic, gamma-linolenic and docosahexaenoic acid rich oils on rat brain tumor fatty acids composition and fatty acid binding protein 7 mRNA expression

BackgroundExperimental studies indicate that gamma linolenic acid (GLA) and docosahexaenoic acid (DHA) may inhibit glioma cells growth but effects of oral consumption of these fatty acids on brain tumor fatty acid composition have not been determined in vivo.MethodsGLA oil (GLAO; 72% GLA), DHA oil (DHAO; 73% DHA) were fed to adult wistar rats (1 mL/rat/day) starting one week prior to C6 glioma cells implantation and continued for two weeks after implantation. Control group were fed same amount of high linoleic acid safflower oil (74–77% linoleic acid). Fatty acid composition of tumor samples was determined in a set of 8–12 animals in each group and serum fatty acid in 6 animals per each group. Gene expression of tumor fatty acid binding protein 7 (FABP7), epidermal growth factor receptor (EGFR), peroxisome proliferator activated receptor γ (PPAR-γ) and retinoid × receptor-α (RXR-α) were determined in a set of 18 animals per group.ResultsDHAO feeding increased EPA of brain tumors and decreased ratio of n-6/n-3 fatty acids. Serum levels of EPA were also increased in DHAO group. A similar trend in serum and tumor levels of DHA were observed in DHAO group but it did not achieve statistical significance. GLAO increased serum concentration of GLA but had no significant effect on tumor GLA or dihomo-gamma linolenic acid (DGLA) concentrations. Gene expression of FABP7 was up-regulated in tumors of DHAO group but no other significant effects were observed on EGFR, PPAR-γ or RXR-α expression, and expression of these genes in tumors of GLAO were not different from SFO group.ConclusionDietary supplementation of DHA containing oil could be an effective way to increase levels of long chain n-3 fatty acids in brain tumors and this increase may be mediated partly by up-regulation of FABP7 expression.

The effect of PUFA enriched Artemia on growth, survival and lipid composition of western rock lobster, Panulirus cygnus, phyllosoma

Western rock lobster, Panulirus cygnus, phyllosoma were grown from hatching to stage IV. Larvae were fed with Artemia enriched with a (i) base enrichment (Base) containing 520 g kg−1 squid oil or tailor made enrichments in which oils high in polyunsaturated fatty acid (PUFA) have been added at the expense of squid oil. These treatments were (ii) base enrichment supplemented with docosahexaenoic acid (DHA) rich oil, (iii) base enrichment supplemented with arachidonic acid (AA) rich oil, or (iv) base enrichment supplemented with DHA and AA (D + A) rich oils. Total survival of phyllosoma to stage IV was high, with no significant difference between treatments (range 12.3–17.5%). By stage IV, the larvae fed the DHA or AA enriched Artemia were significantly larger (3.33 mm length) than larvae fed the Base or D + A enriched Artemia (3.18–3.24 mm length). Phyllosoma were sampled at stages II and III for biochemical analysis. The major lipid class (LC) in all phyllosoma was polar lipid (PL) (88.9–92.4%), followed by sterol (ST) (6.2–9.7%). Triacylglycerol (TAG), free fatty acid (FFA) and hydrocarbon/wax ester were minor components (≤1%) in all phyllosoma samples. In contrast, the major LC in all enrichments and enriched Artemia was TAG (76.3–85.1% and 53.4–60.2%, respectively), followed by PL (11.4–14.8% and 30.6–38.1% respectively). The main fatty acids (FA) in phyllosoma were 16:0, 18:1n-9, 18:1n-7, 18:0, AA, eicosapentaenoic acid (EPA) and DHA. Addition of AA, and to a lesser extent DHA, to enrichments resulted in increased levels of those FA in Artemia and phyllosoma compared with the Base enrichment. This was particularly evident for stage III larvae. Comparatively, elevated growth for phyllosoma to stage IV was achieved with DHA and AA enriched diets. Our findings highlight the importance of lipids and in particular essential long-chain PUFA, as nutritional components for phyllosoma diets.

Transcription Profiling in Rat Liver in Response to Dietary Docosahexaenoic Acid Implicates Stearoyl-Coenzyme A Desaturase as a Nutritional Target for Lipid Lowering

The gene expression profile in response to dietary docosahexaenoic acid rich oil for 6 wk was analyzed in the livers of male Sprague-Dawley rats to identify genes whose expression was regulated by dietary modification and correlated with serum lipid changes. Such genes may represent targets for intervention into cardiovascular health using nutraceuticals. High density glass microarrays containing approximately 7800 cloned expressed sequences from rat were used to identify those genes that responded to dietary long chain (n-3) fatty acids. In general, dietary long chain (n-3) fatty acids exhibited statistically significant lipid-lowering effects similar to a pharmaceutical alternative, fenofibrate, but showed narrower effects on the transcription of most of the genes assayed. The transcription patterns confirmed that the expression of several key genes involved in cholesterol metabolism, fatty acid beta-oxidation and lipogenesis was affected. These analyses indicated that stearoyl-coenzyme A (Delta9) desaturase, a key enzyme involved in the regulation of triglyceride biosynthesis and secretion, is a potential target for nutritional intervention for hyperlipidemia and cardiovascular health. In addition these results suggested that regulation of the farnesoid X receptor may be a key nutritionally regulated mediator of serum lipid changes. A nutritional product concept based on a convenient dietary aid demonstrated comparable efficacy with less spurious gene regulation than a pharmaceutical alternative.

Methyl Esterification of Waste Fatty Acids with Immobilized Candida antarctica Lipase.

Enzymatic production of a docosahexaenoic acid-rich oil from tuna oil creates considerable amounts of free fatty acids (FFA), which are treated as an industrial waste but the handling is difficult because of their solid state. We thus attempted to convert the waste FFA (Tuna-FFA) to their methyl esters through an organic solvent-free enzymatic process. When waste Tuna-FFA were esterified at 30°C with two molar equivalents of methanol (MeOH) using 1.0 wt% immobilized Candida antarctica lipase, the esterification degree reached 95% after 24 h. The reaction was recycled by transferring the enzyme into a fresh substrate mixture every 24 h, but the esterification degree maintained 95% during 45 cycles. To further increase the esterification degree, the esterification was repeated with 5 molar equivalents of MeOH against the remaining FFA after dehydration of the mixture obtained by the single reaction. The repeated reaction increased the esterification degree to 97-98%.

Hemostatic factors and platelet aggregation after a fish-enriched diet or fish oil or docosahexaenoic acid supplementation

The effects of a fish-enriched diet or dietary supplements consisting of either fish oil or a docosahexaenoic acid-rich oil (DHA-oil) on platelet aggregation and hemostatic factors were studied in healthy male students. After an experimental period of 15 weeks, the levels of tissue factor pathway inhibitor, prothrombin fragment 1+2 and fibrinogen as well as factor VII activity were not changed. Factor X activity was slightly decreased by the fish diet ( P < 0.05). Collagen but not ADP-induced maximum platelet aggregation decreased in the fish diet and the fish oil groups ( P < 0.05 in both). In the DHA-oil group there was a slight, statistically insignificant, increase of platelet aggregation which correlated significantly with the decrease of plasma triglycerides. Platelet aggregation measured 4 h after a standardized fat meal was lower than in the fasting state and this decrease correlated with the increase of plasma triglycerides. These results show that a fish diet and fish oil, but not DHA-oil, inhibit in vitro platelet aggregation and that hemostatic factors are not affected by moderate n-3 fatty acid supplementation.