Methyl Docosanoate Research Articles

The vaporization enthalpies and vapor pressures of Vescepa® and related unsaturated marine FAME by correlation gas chromatography

This article combines data from two previous reports together with new data dealing with the vaporization enthalpies and vapor pressures of a series of saturated and unsaturated fatty acid methyl ester(s) (FAME) by correlation gas chromatography. The work updates earlier results using newly proposed vaporization enthalpies for the saturated FAME used as standards in previous work. This update also provides some insight into the requirements necessary for appropriate column and standard selection for experiments using correlation gas chromatography. Vaporization enthalpies and vapor pressures for saturated FAME methyl heneicosanoate, methyl docosanoate, and methyl tetracosanoate are re-evaluated and together with proposed literature values for methyl tetradecanoate to methyl eicosanoate, are used to evaluate similar properties for a series of unsaturated fatty acid esters. Updated results on the vaporization enthalpies and vapor pressures of a number of unsaturated fatty acid methyl esters (FAME) found in marine oil are reported including several relatively reactive omega-3-polyunsaturated esters. Omega-3-FAME include methyl (9,12,15)Z-octadecatrienoate, methyl (5,8,11,14,17)Z-eicosapentaenoate, and methyl (4,7,10,13,16,19)Z-docosahexenoate among other unsaturated methyl esters. Also included in the study of the omega-3-unsaturated esters is the drug Vescepa®, ethyl (5,8,11,14,17)Z-eicosapentaenoate, a drug used to lower triglyceride levels.

High-pressure phase equilibrium data for the carbon dioxide + methyl esters homologous series and SAFT-VR Mie modelling

High-pressure phase transition data measured using a visual static synthetic method are presented for various CO2 + saturated fatty acid methyl ester systems in the range 308–358 K and up to 27.5 MPa. The newly measured data cover methyl esters between methyl decanoate and methyl docosanoate in the liquid-like, mixture critical and vapour-like regions, and complement previously published data. The systems studied do not suggest three-phase behaviour, liquid-liquid immiscibility or temperature inversions in the temperature range considered. An increase in temperature and molecular mass of the methyl ester leads to an increase in the phase transition pressure. The SAFT-VR Mie equation of state was able to correlate the data well with decreasing performance at higher methyl ester molecular masses and lower temperatures.

Phase equilibria of methyl esters in supercritical propane

High pressure phase equilibria measurements using a static synthetic view cell for methyl decanoate, methyl dodecanoate, methyl hexadecanoate, methyl octadecaonate and methyl docosanoate in supercritical propane were conducted between 376.6 and 412.4K at methyl ester mass fractions between 0.0178 and 0.660. The data show a linear increase in phase transition pressure with an increase in temperature at constant composition and, within the experimental range, total solubility was achieved below 8.1MPa for all systems. Comparing the various data sets, an increase in phase transition pressure with increasing hydrocarbon backbone is noted, indicating that propane is able to fractionate a mixture of methyl esters.

Chemical constituents and antioxidant activity of n-hexane extract of Impatiens bicolor

Plants belonging to the genus Impatiens (Balsaminaceae) are rich in organic acids, anthraquinones, and flavonoids [1–3]. It is well known that these classes of aromatic compounds possess widespread pharmacological activities. Previous investigations showed that various plant extracts of Impatiens bicolor Royle display antimicrobial and antifungal activity [4, 5], as well as acetylcholinesterase inhibition and antioxidant activities [6]. Thus, there is a considerable research interest in the assay of composition and/or antioxidant properties of various extracts of I. bicolor. This study presents the very first investigation on the chemical composition of plant extracts of I. bicolor, as well as their antioxidant activities, and it can provide a broad base for the possibility of further detailed pharmacological studies on this species. The sub-extracted samples of the n-hexane fraction of I. bicolor were subjected to detailed GC and GC/MS analysis in order to determine the impact of chemical composition on their antioxidant activity. About 42 compounds were identified in eight samples, representing 56.64–93.85% in total. The percentage compositions of the samples were computed in each case from GC peak areas and are shown in Table 1. In general, all investigated samples can be characterized as mixtures of aliphatic compounds (20.11–93.85%), with oxygenated aliphatic compounds as the most abundant (5.97–89.38%). The fatty acid esters (FAEs) were found to be major components of the investigated subfractions of the n-hexane extract, comprising trans-methyl 13-octadecenoate (2.44–47.29%), methyl heptadecanoate (8.76–18.82%), methyl octadecanoate (4.96–16.49%), methyl docosanoate (3.14–12.64%), methyl tetracosanoate (1.04–11.23%), and methyl eicosanoate (3.83–10.93%). These compounds were mainly found in samples eluted with solvents with relatively low polarity (MQ-1 to MQ-5), while samples eluted with higher polarity (MQ-6 to MQ-8) contained significant amounts of aromatic compounds and shorter-chain oxygenated aliphatic compounds. The antioxidant activity of sub-extracted samples of the n-hexane fraction of I. bicolor were evaluated by DPPH radical-scavenging test. Assessed samples were able to reduce the stable violet DPPH radical to the yellow DPPH-H, reaching 50% of reduction with IC 50 values ranging from 23.22 0.75 g/mL for sample MQ1 to 59.00 2.01 g/mL for sample MQ8 (Table 2). Those values are comparable to ascorbic acid (IC 50 = 7.80 0.14 g/mL), whose antioxidant properties are already known [7, 8]. Despite the fact that major natural antioxidants belong to the class of phenolic compounds, such as thymol and carvacrol [9, 10], the investigated samples, rich in FAEs, showed radical scavenging activity. The IC 50 values presented in the Table 2 are comparable with the content of FAEs in the investigated sample. However, the percentage of these esters decreases from sample MQ1 to sample MQ8, and due to the polarity of eluent, the antioxidant activity decreases. Sample MQ1 was the exception, with a content of FAEs of 58.33%, which is much lower than in the next sample, MQ2, but sample MQ1 showed uniqueness in the content of 2-(1-naphthyl)acetophenone, a member of a class of already known natural antioxidants [11, 12].

Influence of Fatty Acid Methyl Esters on Fuel properties of Biodiesel Produced from the Seeds Oil of <i>Curcubita pepo</i>

Oil extracted from the seeds of Curcubita pepo was transesterified using potassium hydroxide in methanol. Fatty acid methyl esters (FAME) profile of the produced diesel was analyzed using Gas chromatograph coupled with mass spectrophotometer (GC-MS). The results indicate the presence of methyl (12E)-octadecenotate as the dominant ester with approximate percentage by composition of 82.90%. Other esters detected were methyl tetradecanoate (0.4%), methyl eicosonoate (2.48%), methyl docosanoate (0.97%) methyl teracosanoate (0.47%). Some critical fuel parameters like oxidation stability, cetane number, iodine value and viscosity were correlated with the methyl ester composition and structural configuration. It was found that the cetane number and oxidation stability of the produced biodiesel is a function of the degree of unsaturation and long chain saturated factor. The profile of methyl esters in the biodiesel produced indicates its likelihood to be a viable fuel source for internal combustion engines.

Phase behaviour of high molecular mass methyl esters in supercritical ethane

High pressure phase equilibria measurements of long chain saturated methyl esters (methyl decanoate, methyl dodecanoate, methyl tetradecanoate, methyl hexadecanoate, methyl octadecanoate and methyl docosanoate) in supercritical ethane have been measured for temperatures between 312 K and 355 K and for methyl ester mass fractions from 0.65 to 0.018. The results show a generally linear relationship between the phase equilibria pressure and the temperature with complete mutual solubility above 17 MPa. No three-phase regions or temperature inversions (change in sign of gradient of temperature–pressure relationship at constant composition) were observed while maxima in the phase transition pressures were found for methyl ester mass fractions usually between 0.2 and 0.3. When the phase transition pressure is plotted as a function of carbon number at constant temperature and mass fraction methyl ester, a linear relationship is realised. This linear relationship can be used to determine the solubility of any saturated methyl ester with between 10 and 22 carbon atoms, with limited extrapolation being possible. Thermodynamic modelling of the measured phase equilibria with the sPC-SAFT and Peng Robinson equations of state showed that, even with the use of an interaction parameter, these equations of state are not able to model the phase behaviour and the linear pressure–carbon numbers provide more accurate predictions.

Identification, FT-IR, NMR (1H and 13C) and GC/MS studies of fatty acid methyl esters in biodiesel from rocket seed oil

Biodiesel was synthesized from rocket seed oil by base-catalyzed transesterification with methanol. The synthesis of biodiesel was confirmed by FT-IR and NMR (1H and 13C) spectroscopy. Various fuel properties of the synthesized biodiesel were determined using ASTM methods and discussed accordingly. A total of eleven fatty acid methyl esters (FAMEs) were identified in rocket seed oil biodiesel (RSOB) by the retention time and the fragmentation pattern data of GC/MS analysis. The identified FAMEs were, methyl 9-hexadecenoate (C16:1), 14-methyl pentadecanoate (C16:0), methyl 9,12-octadecadienoate (C18:2), methyl 9-octadecenoate (C18:1), methyl octadecanoate (C18:0), methyl 11-eicosenoate (C20:1), methyl eicosanoate (C20:0), methyl 13-docosenoate (C22:1), methyl docosanoate (C22:0), methyl 15-tetracosenoate (24:1) and methyl tetracosanoate (C24:0). The percentage conversion of triglycerides to corresponding methyl esters determined by 1H NMR was 88.49%.

Phytochemical examination of <i> Prosopis cineraria</i> L.(druce) leaves

The phytochemical studies on the leaves of Prosopis cineraria resulted in isolation of methyl docosanoate, diisopropyl-9,10-dihydroxyicosane-1,20-dioate, tricosan-1-ol and 7,24-tirucalladien-3-one. While diisopropyl-10,11-dihydroxyicosane-1,20-dioate is a hitherto unreported compound, methyl docosanoate, tricosan-1-ol and 7,24-tirucalladien-3-one are being reported for the first time from P. cineraria . These compounds have been characterized on the basis of spectral and other data.

Sensitive and accurate quantitation of monoepoxy fatty acids in thermoxidized oils by gas-liquid chromatography.

A sensitive and accurate methodology for quantitation of monoepoxy fatty acid methyl esters (FAME) by gas-liquid chromatography is proposed. Analytical problems of interfering compounds, ie, methyl monoester of azelaic acid and methyl docosanoate, were solved by a second methylation step with diazomethane and by elimination of nonpolar FAME by adsorption chromatography, respectively. Six monoepoxy FAME were identified and quantitated in olive and sunflower oils heated at 180 degrees C for 15 h: trans-9,10- and cis-9,10-epoxystearate coming from oleate and trans-12,13-, trans-9,10-, cis-12,13- and cis-9,10-epoxyoleate coming from linoleate. Results demonstrated total recovery of monoepoxy compounds after nonpolar FAME elimination with the additional advantage of sample concentration, which allowed quantitation of monoepoxy FAME in the initial oils. Also, repeatability was excellent as relative standard deviations ranged from 2.2 to 5.1% for on-column injection and from 0.1 to 2.0% for automatic split injection.

Steric Considerations in the Covalent Binding of Myoglobin to Thin Films

Myoglobin is shown to bind to mixed thin films of docosyl mesylate and methyl docosanoate. Myoglobin can be attached to films containing docosyl mesylate; however, films containing only methyl docosanoate exhibit only minimal myoglobin attachment. This indicates that myoglobin is specifically attached to the docosyl mesylate sites on the film surface. Surface coverage of myoglobin is dependent on the percentage of docosyl mesylate in the film. A maximum myoglobin coverage of approximately 1.2 × 1012 myoglobin/cm2 is estimated for films composed of between 22% and 30% docosyl mesylate.

Honey bee, , nestmate discrimination: hydrocarbon effects and the evolutionary implications of comb choice

Comb wax in honey bee colonies serves as a source and medium for transmission of recognition cues. Worker honey bees learn the identity of their primary nesting material, the wax comb, within an hour of emergence. In an olfactometer, bees discriminate between combs on the basis of odour; they prefer the odours of previously learned combs. Representatives of three of the most common compound classes in bee's wax were surveyed for effects on nestmate discrimination behaviour. Hexadecane, octadecane, tetracosanoic acid and methyl docosanoate make worker honey bees less acceptable to their untreated sisters. Other similar compounds did not have this effect. These findings support the hypothesis that nestmate recognition in honey bees is mediated by many different compounds, including some related to those found in comb wax.

Honey bee, Apis mellifera, nestmate discrimination: hydrocarbon effects and the evolutionary implications of comb choice

Comb wax in honey bee colonies serves as a source and medium for transmission of recognition cues. Worker honey bees learn the identity of their primary nesting material, the wax comb, within an hour of emergence. In an olfactometer, bees discriminate between combs on the basis of odour; they prefer the odours of previously learned combs. Representatives of three of the most common compound classes in bee's wax were surveyed for effects on nestmate discrimination behaviour. Hexadecane, octadecane, tetracosanoic acid and methyl docosanoate make worker honey bees less acceptable to their untreated sisters. Other similar compounds did not have this effect. These findings support the hypothesis that nestmate recognition in honey bees is mediated by many different compounds, including some related to those found in comb wax.

Some Aliphatic Methyl Esters from Aralia elata Seemann (Araliaceae)

Abstract The dried bark of Aralia elata Seemann was extracted with n-hexane. Methyl pentadecanoate, methyl hexadecanoate, methyl octadecanoate, methyl eicosanoate, methyl docosanoate, methyl tetracosanoate, methyl hexacosanoate, and 1-hexacosene were identified from the extract by means of GC-Mass spectrometer.