Chemical Synthesis and Gas Chromatographic Behaviour of γ‐Stearidonic (18:4n‐6) Acid

γ‐Stearidonic acid, 18:4n‐6, a potential product of β‐oxidation of arachidonic acid (20:4n‐6), was only recently positively identified in a living organism—a thermophilic cyanobacterium Tolypothrix sp., albeit at low levels, whilst some indirect evidence suggests its wider presence, e.g. in a unicellular marine alga. We have prepared 18:4n‐6 using an iodolactonisation chain‐shortening approach from 22:5n‐6 and obtained its ¹H‐, ¹³C‐, COSY‐ and HSQC NMR spectra, with 18:5n‐3 spectra also recorded for a comparison. The GC and GC‐MS behaviour of its methyl ester was also studied. Like another Δ3 polyunsaturated acid, octadecapentaenoic (18:5n‐3), 18:4n‐6 rapidly yields 2‐trans isomer upon formation of dimethyloxazoline derivative. On a polar ionic liquid phase (SLB‐IL100, 200 °C) the methyl ester could be mistaken for 18:3n‐3, while on methylsilicone phase (BP1, 210 °C) it eluted ahead of 18:3n‐6 and 18:4n‐3, suggesting that when present it may be easily misidentified during GC analysis of fatty acids.     

Forms of n‐3 (ALA,C18:3n‐3 or DHA,C22:6n‐3) Fatty Acids Affect Carcass Yield,Blood Lipids,Muscle n‐3 Fatty Acids and Liver Gene Expression in Lambs

The effects of supplementing diets with n‐3 alpha‐linolenic acid (ALA) and docosahexaenoic acid (DHA) on plasma metabolites, carcass yield, muscle n‐3 fatty acids and liver messenger RNA (mRNA) in lambs were investigated. Lambs (n = 120) were stratified to 12 groups based on body weight (35 ± 3.1 kg), and within groups randomly allocated to four dietary treatments: basal diet (BAS), BAS with 10.7 % flaxseed supplement (Flax), BAS with 1.8 % algae supplement (DHA), BAS with Flax and DHA (FlaxDHA). Lambs were fed for 56 days. Blood samples were collected on day 0 and day 56, and plasma analysed for insulin and lipids. Lambs were slaughtered, and carcass traits measured. At 30 min and 24 h, liver and muscle samples, respectively, were collected for determination of mRNA (FADS1, FADS2, CPT1A, ACOX1) and fatty acid composition. Lambs fed Flax had higher plasma triacylglycerol, body weight, body fat and carcass yield compared with the BAS group (P < 0.001). DHA supplementation increased carcass yield and muscle DHA while lowering plasma insulin compared with the BAS diet (P < 0.01). Flax treatment increased (P < 0.001) muscle ALA concentration, while DHA treatment increased (P < 0.001) muscle DHA concentration. Liver mRNA FADS2 was higher and CPT1A lower in the DHA group (P < 0.05). The FlaxDHA diet had additive effects, including higher FADS1 and ACOX1 mRNA than for the Flax or DHA diet. In summary, supplementation with ALA or DHA modulated plasma metabolites, muscle DHA, body fat and liver gene expression differently.     

Profile of (n‐9) and (n‐7) Isomers of Monounsaturated Fatty Acids of Radish (Raphanus sativus L.) seeds

The present study was undertaken to determine the profile of the (n‐9) and (n‐7) isomers for C18:1, C20:1 and C22:1 fatty acids in radish seeds as well as their isomers. Radish (Raphanus sativus L. cvs. ‘Antep, Beyaz, Cherry Belle and Iri K?rm?z?’) seeds were produced in 2003–2005 from different sowing dates (SD). The n‐7 isomers of C18:1, C20:1 and C22:1 ranged from 0.7 to 1.3, 0.1 to 0.3 and 0.4 to 1.1 %, respectively. The average values of C18:1(n‐7) was highest (1 %) amongst the three acids. The ratios of (n‐7)/(n‐9) ranged from 4.5 % (‘Cherry Belle’, SD‐I) to 8.3 % (‘Antep’, SD‐III), 0.8 % (‘Iri K?rm?z?’, SD‐II) to 3 % (‘Iri K?rm?z?’, SD‐I) and 1.6 % (‘Cherry Belle’, SD‐I) to 3.7 % (‘Iri K?rm?z?’, SD‐I) for C18:1, C20:1 and C22:1. Erucic acid was the principal fatty acid with concentrations of nearly 34–39 % in ‘Antep’, 32–34 % in ‘Cherry Belle’, 30–33 % in ‘Beyaz’ and 21–22 % in ‘Ir? K?rm?z?’. The oleic acid content was higher in SD‐I and SD‐II than SD‐III in all cultivars. Correlation studies revealed that palmitoleic acid (C16:1) had a significant relationship between most of the fatty acids of the (n‐7)/(n‐9) family. The results indicated that palmitoleic acid is important in the synthesis of long‐chain fatty acids and that the data for the (n‐7)/(n‐9) ratios for C22:1 could be used as biochemical markers to determine the similarities or differences between radish cultivars.     

Dietary Supplementation of Tetracarpidium conophorum (African Walnut) Seed Enhances Muscle n‐3 Fatty Acids in Broiler Chickens

The influence of dietary Tetracarpidium conophorum (African Walnut) seed meal (TCSM) on fatty acids, productivity parameters, and physicochemical properties of breast and thigh muscles in broiler chickens are assessed. A total of 180, 28‐d‐old Arbor acre broiler chickens are randomly assigned to dietary treatments containing 0% (control), 2.5%, and 5% w/w TCSM, fed for 28 d, and euthanized. Dietary TCSM reduces (p < 0.05) feed intake, body weight gain (BWG), carcass weight, and abdominal fat. Diet does not affect feed efficiency and hematological parameters. The control birds have higher (p < 0.05) serum total cholesterol and triglycerides than do the supplemented birds. Diet has no effect on pH, water holding capacity, carbonyl and malondialdehyde contents, and organoleptic properties of breast and thigh muscles. The 5% TCSM has higher redness in breast muscle than do other treatments. Dietary TCSM improves (p < 0.05) the concentration of C18:3n‐3 (4.80–8.76% vs 1.56%), C20:5n‐3 (0.54–0.79% vs 0.39%), C22:5n‐3 (0.64–0.89% vs 0.18%), and C22:6n‐3 (0.75–0.97% vs 0.19%), and reduces (p <  0.05) the fat content (2.15–2.45% vs 3.15%) in breast and thigh muscles. Dietary TCSM enhances muscle n‐3 fatty acids without instigating oxidative deterioration, but reduces BWG in broiler chickens. Practical Application: Albeit that broiler meat is rich in polyunsaturated fatty acids (PUFA), its omega 6 (n‐6)/omega 3 (n‐3) is >4. Elevated n‐6/n‐3 could have adverse effect on human physiology thereby promoting the pathogenesis of certain diseases. This heightens the need to enhance the n‐3 PUFA content of broiler meat. Dietary TCSM induced up to a fourfold increase in n‐3 PUFA content of the breast and thigh muscles in broiler chickens. Moreover, dietary TCSM induced up to a tenfold decrease in the n‐6/n‐3 of the breast and thigh muscles in broiler chickens. This finding assumes great significance because the health concerns regarding dietary fat are the foremost factors responsible for the bad image suffered by meat. These results provide insights on the potential of TCSM to improve the nutritional quality without compromising the oxidative shelf life, organoleptic traits, and physicochemical properties of broiler meat.     

Dietary n‐3 fatty acids reduce the delayed hypersensitivity reaction and antibody production more than n‐6 fatty acids in broiler birds

The splenocyte fatty acid profile and immune response of broiler chickens were investigated. One hundred and twenty day‐old broiler chicks were fed diets containing conjugated linoleic acid (CLA) (Diet I), sunflower oil (Diet II), flaxseed oil (Diet III) or fish oil (Diet IV). The total lipid content of the diets was 3.5%. Body weight and feed intake was higher (P <0.05) in Diet IV compared to Diets I, II and III. Birds fed Diet III and IV had a higher content of n‐3 fatty acids in splenocytes than those fed Diets I and II. Serum anti‐BSA immunoglobulin content was higher (P <0.05) in birds fed Diets III and IV, compared to those fed Diets I and II. Delayed type hypersensitivity response, measured as the wing web skin swelling reaction (thickness) to Mycobacterium butyricum injection (s.c.), increased (P <0.05) from 0.71 and 0.98 mm in Diets IV and III, respectively, to 1.19 and 1.41 mm in Diets I and II, respectively. The number of CD4⁺ and CD8⁺ blood lymphocytes and CD4⁺, CD8⁺ and IgM⁺ splenocytes did not differ (P >0.05) between treatment groups. N‐3 fatty acids increased production performances and antibody mediated responses, while n‐6 fatty acids and conjugated linoleic acid increased cell mediated responses in broiler birds.     

Stearidonic acid (18:4n‐3): Metabolism,nutritional importance,medical uses and natural sources

Stearidonic acid (SA, 18:4n‐3) is a polyunsaturated fatty acid (PUFA) that constitutes the first metabolite of α‐linolenic acid (ALA, 18:3n‐3) in the metabolic pathway leading to C_20–22 PUFA, such as eicosapentaenoic acid (EPA, 20:5n‐3), and docosahexaenoic acid (DHA, 22:6n‐3), which recently have received much attention because of their various physiological functions in the human body. Recently, several studies indicated that dietary SA increased EPA more efficiently than ALA. Thus, vegetable oils containing SA may become a dietary source of n‐3 fatty acids that is more effective in increasing tissue n‐3 PUFA concentrations than the current ALA‐containing vegetable oils. Nevertheless, few SA sources occur in nature, although there are still a large number of species untested to date. SA has been detected in variable amounts in several species of algae, fungi and animals tissues, but the seeds of some plant families seem to be better sources of SA, especially Echium (Boraginaceae) species. This work reviews the nutritional significance, medical uses and natural occurrence of SA.     

Moonlighting Metals: Insights into Regulation of Cyclization Pathways in Fungal Δ6‐Protoilludene Sesquiterpene Synthases

Fungal 1,11 cyclizing sesquiterpene synthases are product specific under typical reaction conditions. However, in vivo expression of certain Δ⁶‐protoilludene synthases results in dual 1,11 and 1,10 cyclization. To determine the factors regulating this mechanistic variation, in‐depth in vitro characterization of Δ⁶‐protoilludene synthases was conducted. Divalent metal ions determine cyclization specificity and this product variability. Promiscuity in metal binding is mediated by secondary metal‐binding sites away from the conserved D(D/E)XX(D/E) motif in sesquiterpene synthases. Phylogenetic analysis revealed a divergent evolution of Basidiomycota trans‐humulyl cation producing sesquiterpene synthases, results that indicate a wider diversity in function than previously predicted. This study provides key insights into the function and evolution of 1,11 cyclizing fungal sesquiterpene synthases.     

(η6‐N‐alkylcarbazole) (η5‐cyclopentadienyl) iron hexafluorophosphate salts in photoinitiated and thermal epoxy polymerization

(η6‐Carbazole)(η5‐cyclopentadienyl) iron hexafluorophosphate salts (CFS PF₆) are capable of photoinitiating cationic polymerization of epoxy monomers directly upon irradiation with long‐wavelength UV light. To improve the solubility of CFS ferrocenium salts in epoxides, two CFS photoinitiators have been prepared: [cyclopentadiene‐Fe‐N‐buylcarbazole] hexafluorophosphate (C4‐CFS PF₆) and [cyclopentadiene‐Fe‐N‐octylcarbazole] hexafluorophosphate (C8‐CFS PF₆), bearing C4 and C8 alkyl chains, respectively, on the nitrogen atom. Studies with real‐time infrared spectroscopy have shown that C4‐CFS and C8‐CFS photoinitiators exhibit high efficiency in polymerization of 3,4‐epoxycyclohexylmethyl‐3,4‐epoxycyclohexane carboxylate (ERL‐4221) epoxy monomer, but lower efficiency in polymerization of di(2,3‐epoxypropyl)‐3,4‐epoxy‐1,2‐cyclohexanedioate (TDE‐85) epoxy monomer. Benzoyl peroxide (BPO) sensitizer was very effective in improving the photoinitiating activities of CFS in polymerization of both ERL‐4221 and TDE‐85. DSC studies have shown that C4‐CFS and C8‐CFS photoinitiators can also be employed as thermal initiators for the cationic ring‐opening polymerization of epoxides at moderate temperatures. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Incorporation of Alpha‐Linolenic Acid and Enhancement of n‐3 Fatty Acids in Nile Tilapia: a Factorial Design

A 2² factorial design (two factors at two levels, in triplicate) was performed to investigate the influence of factors A (time of treatment, 15 and 30 days) and B (chia oil content in a supplemented diet, at 2.1 and 4.2 %) in three responses of interest referring to: (a) the incorporation of alpha‐linolenic acid (LNA) in lipids of Nile tilapia fillet; (b) the enhancement of n‐3 fatty acids; and (c) the decrease in the omega‐6/omega3 (n‐6/n‐3) ratio in fish. Factors A and B were significant in the three regression models obtained and the interaction AB was a significant contributor to the LNA and n‐6/n‐3 ratio. Analysis of variance suggested three significant and predictive mathematical models. Response surfaces analyses from designs indicated higher LNA and n‐3 contents and a lower n‐6/n‐3 ratio using both factors A and B in the higher levels (30 days of treatment and 4.2 % of chia oil in the diet for fish) chosen for this study.     

13‐Oxo‐9(Z),11(E),15(Z)‐octadecatrienoic Acid Activates Peroxisome Proliferator‐Activated Receptor γ in Adipocytes

Peroxisome proliferator‐activated receptor (PPAR)γ is expressed in adipose tissue and plays a key role in the regulation of adipogenesis. PPARγ activators are known to have potent antihyperglycemic activity and are used to treat insulin resistance associated with diabetes. Therefore, many natural and synthetic agonists of PPARγ are used in the treatment of glucose disorders. In the present study, we found that 13‐oxo‐9(Z),11(E),15(Z)‐octadecatrienoic acid (13‐oxo‐OTA), a linolenic acid derivative, is present in the extract of tomato (Solanum lycopersicum), Mandarin orange (Citrus reticulata), and bitter gourd (Momordica charantia). We also found that 13‐oxo‐OTA activated PPARγ and induced the mRNA expression of PPARγ target genes in adipocytes, thereby promoting differentiation. Furthermore, 13‐oxo‐OTA induced secretion of adiponectin and stimulated glucose uptake in adipocytes. To our knowledge, this is the first study to report that 13‐oxo‐OTA induces adipogenesis through PPARγ activation and to present 13‐oxo‐OTA as a valuable food‐derived compound that may be applied in the management of glucose metabolism disorders.     

Film formation from pigmented latex systems: Drying kinetics and bulk morphologies of ground calcium carbonate/functionalized poly(n‐butyl methacrylate‐co‐n‐butyl acrylate) blend films

The drying kinetics and bulk morphology of pigmented latex films obtained from poly(n‐butyl methacrylate‐co‐n‐butyl acrylate) latex particles functionalized with carboxyl groups and ground calcium carbonate blends were studied. Latex/pigment blends with higher carboxyl group coverage on the latex particle surfaces dried faster than films with few or no carboxyl groups present. The latex/pigment dispersions also dried faster when there was more stabilizer present in the blend system because of the hydrophilic nature of the stabilizer. The net effect of increasing the pigment volume concentration in the blend system was to shorten the drying time. The bulk morphologies of the freeze‐fractured surfaces of the pigmented latex films were studied with scanning electron microscopy. Scanning electron microscopy analysis showed that increased surface coverage of carboxyl groups on the latex particles in the latex/pigment blends resulted in the formation of smaller pigment aggregates with a more uniform size distribution in the blend films. In addition, the use of smaller latex particles in the blends reduced the ground calcium carbonate pigment aggregate size in the resulting films. Scanning electron microscopy analysis also showed that when the initial stabilizer coverage on the latex particles was equal to 18%, smaller aggregates of ground calcium carbonate were distributed within the copolymer matrix of the blend films in comparison with the cases for which the initial stabilizer coverage on the latex particles was 8 or 36%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2267–2277, 2006     

Thermal degradation of poly(3‐hydroxybutyrate) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) as studied by TG,TG–FTIR,and Py–GC/MS

The thermal degradation kinetics of poly(3‐hydroxybutyrate) (PHB) and poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) [poly(HB–HV)] under nitrogen was studied by thermogravimetry (TG). The results show that the thermal degradation temperatures (T_o, T_p, and T_f) increased with an increasing heating rate (B). Poly(HB–HV) was thermally more stable than PHB because its thermal degradation temperatures, T_o(0), T_p(0), and T_f(0)—determined by extrapolation to B = 0°C/min—increased by 13°C–15°C over those of PHB. The thermal degradation mechanism of PHB and poly(HB–HV) under nitrogen were investigated with TG–FTIR and Py–GC/MS. The results show that the degradation products of PHB are mainly propene, 2‐butenoic acid, propenyl‐2‐butenoate and butyric‐2‐butenoate; whereas, those of poly(HB–HV) are mainly propene, 2‐butenoic acid, 2‐pentenoic acid, propenyl‐2‐butenoate, propenyl‐2‐pentenoate, butyric‐2‐butenoate, pentanoic‐2‐pentenoate, and CO₂. The degradation is probably initiated from the chain scission of the ester linkage. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1530–1536, 2003     

Reverse Micellar Encapsulation of d‐ and l‐Enantiomers of Some Aromatic α‐Amino Acids and Nucleobases by Glucose‐Derived Non‐ionic Gemini Surfactants in Neat n‐Hexane

Novel carbohydrate‐based non‐ionic gemini surfactants consisting of two sugar head groups, two hydrophobic tails having chain lengths of C12, C14, and C16 and a flexible –(CH₂)₆– spacer were synthesized and investigated for their reverse micellar encapsulation properties. The head groups of the geminis comprise glucose entities (with reducing function blocked in a cyclic acetal group) connected through C‐6 to tertiary amines. These surfactants were explored for reverse micellar encapsulation of d ‐ and l ‐enantiomers of aromatic α‐amino acids viz. histidine (His), phenylalanine (Phe), tyrosine (Tyr) and tryptophan (Trp) in neat n‐hexane. Similar studies were carried out for encapsulation of nucleobases viz. adenine (Ade), guanine (Gua), thymine (Thy), cytosine (Cyt) and Uracil (Ura). Reverse micellar studies revealed that aromatic α‐amino acids were encapsulated in the sequence His>Tyr>Phe>Trp. In most cases, a difference in the degree of encapsulation of d ‐ and l ‐enantiomers of aromatic amino acids in reverse micellar phases of gemini amphiphiles in neat n‐hexane, was revealed. For Tyr, l ‐enantiomer was better encapsulated than its antipode, i.e., d ‐enantiomer but for Trp, d ‐enantiomer was better encapsulated then l ‐enantiomer. In the case of nucleobases, Ura was found selectively encapsulated by reverse micelles formed by these new amphiphiles.     

Expandable styrene/methyl methacrylate copolymer: Synthesis and determination of VOCs by combined thermogravimetry/differential thermal analysis‐gas chromatography/mass spectrometry

Parts cast of metals using expandable polystyrene foams may have an unacceptable amount of surface defects, such as lustrous carbon. The use of foams made of styrenic/acrylic copolymers can improve the quality of foam molds and metal parts made using such molds. Lost foam copolymer was synthesized by suspension copolymerization of styrene and methyl methacrylate. The polymerization was carried out in the presence of blowing agents. The decomposition products of lost foam beads were studied by a method composed of the thermogravimetry/differential thermal analysis (TG/DTA) and gas chromatography/mass spectrometry (GC/MS). With these systems, the TG/DTA data can be combined with a GC separation and MS identification methods. This combined method improves the analysis of the decomposition products of lost foam beads and enables the precise identification of the amount and the nature of volatile organic compounds (VOCs) trapped during suspension polymerization. The results obtained from the combined method were verified for the nature and amount of VOCs with the results of time‐conversion studies for copolymerization of monomers in the presence of different concentrations of blowing agent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Lower Concentration of n‐3 in the Red Blood Cells and Plasma of Lambs when their Dams were Fed a Diet High Compared with Low in n‐6 Fatty Acids at Joining

Feeding ewes a diet high in n‐6 in late gestation can affect fatty acid concentrations in the newborn lamb. The effect of feeding ewes a high n‐6 diet prior to conception and in early gestation on lamb n‐6 and n‐3 status has not previously been examined. The aim of the current study was to determine whether the concentration of n‐6 was higher and n‐3 was lower in lamb red blood cells (RBC) and plasma when Merino dams were fed a diet high in n‐6 either pre‐conception only or both pre‐conception and in early gestation. Dams were fed a diet low (silage) or high (oats/CSM) in n‐6 for either 6 weeks pre‐mating only or 6 weeks pre‐mating and 17 days post‐mating. The fatty acid status of lamb RBC and plasma was determined following birth and compared with dam fatty acids around parturition. The concentration of lamb RBC and plasma n‐3 was lower (p < 0.05) when dams received the high n‐6 compared with low‐n‐6 diet around mating, independent of the length of time of feeding. The concentration of n‐3 in lamb plasma was also higher when lambs were assessed as being likely rather than unlikely to have suckled prior to blood collection. Lamb RBC and plasma n‐3 fatty acids were lower when dams were fed the high compared with the low n‐6 diet for only a short time around mating. Transfer of fatty acids via the placenta and milk may account for the differences.