Phytotoxic and antioxidant effects of dichloromethane fraction of Smilax Brasiliensis Sprengel.

Dichloromethane (DCM) fraction and sub-fractions obtained from Smilax brasiliensis leaves were examined in order to determine their phytotoxic and antioxidant effects. The dichloromethane fraction was submitted to a preparative layer chromatography leading to seven sub-fractions (DCM1-DCM7). Gas chromatography-mass spectrometry (GC-MS) was performed on the dichloromethane sub-fractions. The DCM sub-fractions presented phytotoxic potential; at a concentration of 125 µg per plate, DCM6 and DCM4 showed the strongest results on Lactuca sativa and Allium cepa, respectively. The DCM fraction and DCM4 sub-fraction were more effective than 2,6-di-tert-butyl-4-methylphenol (BHT) at scavenging the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. Analysis by GC-MS showed the presence of methyl palmitate (33.05%) in DCM4 and methyl palmitate (17.29%) and methyl oleate (50.96%) in DCM6, suggesting that the activities exhibited by the sub-fractions may be attributed, at least partially, to these major compounds. These results indicate that the DCM sub-fractions of S. brasiliensis could be used as natural herbicides and antioxidants.

Evaluation of the bioaccessibility of carotenoid esters from Lycium barbarum L. in nano-emulsions: A kinetic approach.

Lycium barbarum L., known as goji berry, is a rich source of carotenoid esters, which are mainly composed of zeaxanthin dipalmitate (ZDP), lutein palmitate (LP), ß-cryptoxanthin palmitate (ß-CP), zeaxanthin palmitate (ZP), zeaxanthin myristate palmitate (ZMP), and zeaxanthin palmitate stearate (ZPS). Oil-in-water nano-emulsions containing carotenoid esters from L. barbarum L. with olive oil (ON) and soybean oil (SN) were prepared to investigate the liberation and bioaccessibility (BA) of in vitro digestion. The particle sizes of ON and SN were approximately 160 nm stabilized with sucrose esters and monoacylglyceride as emulsifiers. ON presented an equal liberation of each carotenoid ester as SN, except that LP had a high value. Incorporation of carotenoid esters into the micelle were evaluated using a fractional conversion model, containing two phases, namely, a rapid growth rate for the first phase, and then reaching a plateau for the second phase. The kinetic rate was related to the particle size, oil type and carotenoid ester nature. BA at plateau values for ZDP and ZPS were higher than that of the four other carotenoid esters in SN. Considering the great improvement of the liberation and BA, the excipient nano-emulsion prepared in this study is a good delivery system for carotenoid esters from goji berry.

Expression of the Arabidopsis WRINKLED 1 transcription factor leads to higher accumulation of palmitate in soybean seed.

Soybean (Glycine max [L.] Merr.) is a commodity crop highly valued for its protein and oil content. The high percentage of polyunsaturated fatty acids in soybean oil results in low oxidative stability, which is a key parameter for usage in baking, high temperature frying applications, and affects shelf life of packaged products containing soybean oil. Introduction of a seed-specific expression cassette carrying the Arabidopsis transcription factor WRINKLED1 (AtWRI1) into soybean, led to seed oil with levels of palmitate up to approximately 20%. Stacking of the AtWRI1 transgenic allele with a transgenic locus harbouring the mangosteen steroyl-ACP thioesterase (GmFatA) resulted in oil with total saturates up to 30%. The creation of a triple stack in soybean, wherein the AtWRI1 and GmFatA alleles were combined with a FAD2-1 silencing allele led to the synthesis of an oil with 28% saturates and approximately 60% oleate. Constructs were then assembled that carry a dual FAD2-1 silencing element/GmFatA expression cassette, alone or combined with an AtWRI1 cassette. These plasmids are designated pPTN1289 and pPTN1301, respectively. Transgenic events carrying the T-DNA of pPTN1289 displayed an oil with stearate levels between 18% and 25%, and oleate in the upper 60%, with reduced palmitate (<5%). While soybean events harboring transgenic alleles of pPTN1301 had similar levels of stearic and oleate levels as that of the pPTRN1289 events, but with levels of palmitate closer to wild type. The modified fatty acid composition results in an oil with higher oxidative stability, and functionality attributes for end use in baking applications.

Enzymatic lipophilization of epicatechin with free fatty acids and its effect on antioxidative capacity in crude camellia seed oil.

BACKGROUND: Crude camellia seed oil is rich in free fatty acids, which must be removed to produce an oil of acceptable quality. In the present study, we reduced the free fatty acid content of crude camellia seed oil by lipophilization of epicatechin with these free fatty acids in the presence of Candida antarctica lipase B (Novozym 435), and this may enhance the oxidative stability of the oil at the same time. RESULTS: The acid value of crude camellia seed oil reduced from 3.7 to 2.5 mgKOH g-1 after lipophilization. Gas chomatography-mass spectrometry analysis revealed that epicatechin oleate and epicatechin palmitate were synthesized in the lipophilized oil. The peroxide, p-anisidine, and total oxidation values during heating of the lipophilized oil were much lower than that of the crude oil and commercially available camellia seed oil, suggesting that lipophilized epicatechin derivatives could help enhance the oxidative stability of edible oil. CONCLUSION: The enzymatic process to lipophilize epicatechin with the free fatty acids in crude camellia seed oil described in the present study could decrease the acid value to meet the quality standards for commercial camellia seed oil and, at the same time, obtain a new edible camellia seed oil product with good oxidative stability. © 2016 Society of Chemical Industry.

Curation of the Mammalian Palmitoylome Indicates a Pivotal Role for Palmitoylation in Diseases and Disorders of the Nervous System and Cancers.

Palmitoylation involves the reversible posttranslational addition of palmitate to cysteines and promotes membrane binding and subcellular localization. Recent advancements in the detection and identification of palmitoylated proteins have led to multiple palmitoylation proteomics studies but these datasets are contained within large supplemental tables, making downstream analysis and data mining time-consuming and difficult. Consequently, we curated the data from 15 palmitoylation proteomics studies into one compendium containing 1,838 genes encoding palmitoylated proteins; representing approximately 10% of the genome. Enrichment analysis revealed highly significant enrichments for Gene Ontology biological processes, pathway maps, and process networks related to the nervous system. Strikingly, 41% of synaptic genes encode a palmitoylated protein in the compendium. The top disease associations included cancers and diseases and disorders of the nervous system, with Schizophrenia, HD, and pancreatic ductal carcinoma among the top five, suggesting that aberrant palmitoylation may play a pivotal role in the balance of cell death and survival. This compendium provides a much-needed resource for cell biologists and the palmitoylation field, providing new perspectives for cancer and neurodegeneration.

Efficient Separation and Analysis of Triacylglycerols: Quantitation of ß-Palmitate (OPO) in Oils and Infant Formulas.

A high-efficiency, convenient, and reliable method for the separation of structurally similar triacylglycerols is detailed and applied in the quantitative analysis of 1,3-dioleoyl-2-palmitoylglycerol (OPO) in infant formulas and OPO oils. OPO is an important lipid component in "humanized" infant formula. A fast preparative isolation of an OPO-containing fraction from the crude complex mixture, by nonaqueous reversed phase HPLC, followed by Ag(+)-HPLC with detection at 205 nm allowed fine separation and detection of the desired fraction. OPO was quantitated independently of its regioisomer 1,2-dioleoyl-3-palmitoylglycerol (OOP) and isomers of stearoyl-linoleoyl-palmitoyl glycerol that might be present in infant formulas. For samples with low OPO content, an evaporative light-scattering detector (ELSD) was more preferable than UV detection, with a calculated LOD of 0.1 µg of OPO injected and LOQ of 0.3 µg. The method, which showed high reproducibility (RSD < 5%), was suitable for both high OPO content oils and low OPO products such as unenriched infant formula. A number of possible interference issues were considered and dealt with.

Chemical composition and antifungal activity of Matricaria recutita flower essential oil against medically important dermatophytes and soil-borne pathogens.

OBJECTIVE: Fungal infections are potential public health threats all over the world. In the present study, effect of Matricaria recutita flower essential oil (EO) was evaluated against medically important dermatophytes and opportunistic saprophytes using microbioassay technique. MATERIALS AND METHODS: Flower essential oil (EO) of M. recutita prepared by hydrodistillation was analyzed by gas chromatography/mass spectrometry (GC/MS). The effect of plant EO on the growth of pathogenic dermatophytes and opportunistic saprophytes was assessed using microbioassay technique. In the bioassay, fungi were cultured in 6-well flat-bottom microplates in presence of various concentrations of plant EO (2.5-1000µg/mL) for 4-10days at 28°C. RESULTS: A total of 14 compounds were identified in the plant oil by GC/MS accounting for 97.5% of the oil composition. The main compound identified was chamazulene (61.3%) followed by isopropyl hexadecanoate (12.7%), trans-trans-farnesol (6.9%) and E-ß-farnesol (5.2%). Growth inhibition for the dermatophytes exposed to serial two-fold concentrations of plant EO (2.5 to 80µg/mL) was reported in the range of 3.24 to 68.15% for Microsporum gypseum, 24.48 to 100% for M. canis, 11.40 to 96.65% for Trichophyton mentagrophytes, 27.79 to 100% for T. rubrum and 45.73 to 100% for T. tonsurans. M. recutita EO inhibited the growth of opportunistic saprophytes by 3.98 to 64.29% for Aspergillus flavus, 6.38 to 93.62% for A. fumigatus, 3.52 to 89.45% for A. niger, 6.38 to 77.66% for Trichoderma harzianum and 17.41 to 89.41% for Fusarium oxysporum in serial two-fold concentrations of 15.62 to 1000µg/mL. CONCLUSION: Results of the present study indicate that M. recutita could be considered as a potential candidate for designing effective antifungal formulations suitable for treatment of dermatophytosis and other fungal infections.

GC-based analysis of plant stanyl fatty acid esters in enriched foods.

Approaches for the capillary gas chromatographic (GC) based analysis of intact plant stanyl esters in enriched foods were developed. Reference compounds were synthesized by enzyme-catalyzed transesterifications. Their identities were confirmed by means of mass spectrometry. Using a medium polar trifluoropropylmethyl polysiloxane stationary phase, long-chain plant stanyl esters could be separated according to their stanol moieties and their fatty acid chains. Thermal degradation during GC analysis was compensated by determining response factors; calibrations were performed for ten individual plant stanyl esters. For the analysis of low-fat products (skimmed milk drinking yogurts), the GC separation was combined with a "fast extraction" under acidic conditions. For fat-based foods (margarines), online coupled LC-GC offered an elegant and efficient way to avoid time-consuming sample preparation steps. The robust and rapid methods allow conclusions on both, the stanol profiles and the fatty acid moieties, and thus provide a basis for the authentication of this type of functional food ingredients.

A novel functional assay for simultaneous determination of total fatty acid beta-oxidation flux and acylcarnitine profiling in human skin fibroblasts using (2)H(31)-palmitate by isotope ratio mass spectrometry and electrospray tandem mass spectrometry.

BACKGROUND: Two separate and complementary assays, total mitochondrial fatty acid beta-oxidation (FAO) flux rate and acylcarnitine profiling, have been used to establish a definitive diagnosis of FAO defects (FAOD) in cultured cells. We developed a novel functional assay for total FAO rate assay by measurement of deuterated water enrichment and to combine it with the conventional acylcarnitine profiling method into a single tracer incubation experiment. METHODS: Skin fibroblasts were incubated in a medium containing universal deuterium-labeled palmitate ((2)H(31)-palmitate) and l-carnitine without glucose supplementation for 96 h. The culture medium was assayed for deuterated water enrichment using isotope ratio mass spectrometry (IRMS) and acylcarnitine profiling by electrospray-ionization tandem mass spectrometry (ESI/MS/MS). RESULTS: The medians of (2)H(2)O enrichment after 96 h of incubation of (2)H(31)-palmitate of the control, other inherited metabolic diseases and FAOD cell lines were 109.9, 102 and 23.1 ppm/mg protein/96 h, respectively. All fibroblasts with FAOD except carnitine uptake defective, multiple acyl-CoA dehydrogenase and short-chain 3-hydroxyacyl-CoA dehydrogenase deficient cells were well separated from the control (<60% control median, p<0.05) and could be identified by IRMS assay. Accumulations of disease-specific acylcarnitines due to blockage in the carnitine cycle and FAO spiral were also demonstrated by acylcarnitine profiling. CONCLUSIONS: This novel functional assay is less time consuming and relatively simple by comparison to other published methods and can be used to investigate patients suspected to have FAO defects.

Characterization of microemulsion structures in the pseudoternary phase diagram of isopropyl palmitate/water/Brij 97:1-butanol.

This research was aimed to characterize microemulsion systems of isopropyl palmitate (IPP), water, and 2:1 Brij 97 and 1-butanol by different experimental techniques. A pseudoternary phase diagram was constructed using water titration method. At 45% wt/wt surfactant system, microemulsions containing various ratios of water and IPP were prepared and identified by electrical conductivity, viscosity, differential scanning calorimetry (DSC), cryo-field emission scanning electron microscopy (cryo-FESEM) and nuclear magnetic resonance (NMR). The results from conductivity and viscosity suggested a percolation transition from water-in-oil (water/oil) to oil-in-water (oil/water) microemulsions at 30% wt/wt water. From DSC results, the exothermic peak of water and the endothermic peak of IPP indicated that the transition of water/oil to oil/water microemulsions occurred at 30% wt/wt water. Cryo-FESEM photomicrographs revealed globular structures of microemulsions at higher than 15% wt/wt water. In addition, self-diffusion coefficients determined by NMR reflected that the diffusability of water increased at higher than 35% wt/wt water, while that of IPP was in reverse. Therefore, the results from all techniques are in good agreement and indicate that the water/oil and oil/water transition point occurred in the range of 30% to 35% wt/wt water.

[Analysis of constituents of essential oil from the skin of water caltrop].

OBJECTIVE: To analyze the constituents of essential oil from the skin of water caltrop. METHOD: Water steam distillation and GC-MS were used. RESULT: 58 componds were separated respectively. 56 componds being identified which were 96. 5% of the totle essential oil. CONCLUSION: Diethyl phthalate, acetamide, N-acetyl-N, N'-1,2-ethanediylbis-, isopropyl palmitate, hexadecanoic acid, Z-11 and octadecanoic acid are the main component of essential oil from the skin of water caltrop.

Determination of magnesium stearate in capsule- or tablet-type supplements.

A simple method for the determination of magnesium stearate in capsule- or tablet-type supplements was developed. Free stearic acid in the sample was removed by extraction with tetrahydrofuran. The remaining stearate was converted to stearic acid by reaction with a cation-exchange resin. The resulting stearic acid was determined by gas chromatography with a polar column. Esters of stearic acid were not converted to stearic acid and would not cause a positive error in the amount of stearate. The amount of magnesium stearate was calculated based on the stearic acid concentration thus obtained. Magnesium stearate levels in 5 out of 25 supplements exceeded 2500 microg/g, which indicated the possible admixture of magnesium stearate.

An infrared spectroscopic method for quantitative analysis of fatty alcohols and fatty acid esters in machinery oils.

A new infrared spectroscopic method suitable for determining total fatty alcohol and fatty acid ester concentrations in industrial oils has been developed. Oil samples were diluted with toluene (1:3 w/w), the toxicity and volatility of which are relatively low compared with more commonly used IR solvents, like carbon tetrachloride or carbon disulfide. Mixture standards were prepared from dodecanol, tetradecanol, octadecanol, methyl stearate and methyl palmitate. Some analytical and statistical tests were performed on the developed method. The recoveries and the repeatability of the method proved to be sufficient for the quantitative determination of fatty alcohol and fatty acid ester additives in industrial oils. Reproducibility testing in another laboratory also produced satisfactory results. The developed method also proved to be relatively quick and simple. This method was developed to satisfy industry's need to determine the concentrations of these oil additives, and it has already been applied successfully in machinery oil analysis.

Quantification of zeaxanthin dipalmitate and total carotenoids in Lycium fruits (Fructus Lycii).

An HPLC-DAD method has been developed to quantitatively analyze for the content of zeaxanthin dipalmitate, a major carotenoid in Fructus Lycii, in different species of the genus Lycium. Determination was performed using an Alltima C18 column with the mobile phase consisting of acetonitrile and dichloromethane (42:58). The total contents of carotenoids in these samples were also determined by using UV spectrophotometric assay. Total carotenoid concentrations of different Fructus Lycii are within the range of 0.03-0.5%. Zeaxanthin dipalmitate is a predominant carotenoid, comprising 31-56% of the total carotenoids in Fructus Lycii. This study is the first systematic quantification of the carotenoids in the fruits of different Lycium species. The results demonstrated that these methods are reliable and facile techniques for rapid analysis of carotenoids for crude drug and plant-derived food supplements.

Crecimiento, composición del incremento de peso y la absorción de minerales en recién nacidos a término alimentario con una nueva fórmula experimental conteniendo un hidrolizado de proteínas B-Palmitato y prebióticos / Growth, weight gain composition and mineral accretion in term infants fed a new experimental formula containing hydrolysed protein, B-palmitate and prebiotics

Objetivo: La leche materna es la alimentación de referencia para neonatos. Las fórmulas de leche con propiedades funcionales similares a la leche materna deberían ser programadas de modo que garanticen que el desarrollo del crecimiento y de los parámetros metabólicos conseguidos en los lactantes alimentados con fórmulas artificiales, son similares a los de los lactantes alimentados con lactancia materna. En el presente estudio sobre el crecimiento, se analizó en 14 recién nacidos a término alimentados con una fórmula nueva (FN) la composición del incremento de peso, la absorción de minerales y el desarrollo de la flora intestinal. Se compararon los resultados con los datos de los lactantes alimentados con lactancia materna (LM) y con lactantes alimentados con una fórmula estándar (FE).Metodología: Recién nacidos a término alimentados con fórmula reciben NF desde el nacimiento hasta la edad de dos meses. Las sustancias prebióticas en la NF fueron galacto y fructo-oligosacáridos (cantidad total: 0,4 g/100 ml). La NF contiene proteína de trigo parcialmente hidrolizada y B-palmitato (total ácido palmítico 0,6 g/100 ml; 41 por ciento en posición sn-2). La composición de la NF es idéntica a la de Omneo, excepto por la cantidad total de sustancias prebióticas. La tolerancia clínica, la ingesta de fórmula y las muestras de heces fueron obtenidas antes de la salida de la maternidad y a la edad de 3, 6 y 9 semanas. Se efectuaron análisis completos de la composición corporal mediante DEXA después del nacimiento, durante los primeros días de vida y a la edad de 2 meses. Se analizó el porcentaje de bifidobacterias existente en heces mediante "hibridación fluorescente in situ (FISH)".Resultados: 15 recién nacidos fueron enrolados en el estudio, uno de los recién nacidos se retiró debido a reflujo gastroesofágico. Las características antropométricas en el momento del nacimiento fueron: peso corporal 3318 ñ 406 g, longitud 50,0 ñ 1,7 cm, circunferencia craneal: 34,6 ñ 1,3 cm. Los datos de la investigación clínica obtenidos el día 3 ñ 1, día 25 ñ 4, día 45 ñ 4 y día 68 ñ 4 indican un volumen de ingesta y una evolución del peso corporal adecuados y excelente tolerancia a la alimentación. La media del incremento de peso corporal durante el período del estudio fue de 7,8 ñ 1,4 g/kg/d, incremento en la longitud: 0,91 ñ 0,19 cm/sem, circunferencia craneal: 0, 62 ñ 0, 09 cm/sem. La composición del incremento de peso fue 61 por ciento de masa corporal, 37,2 por ciento de masa grasa y 1,5 por ciento de masa mineral ósea. Por lo tanto, entre los días 3 ñ 1 y 68 + 4: la masa de grasa se incrementó de 12,6 a 22,6 por ciento, el contenido de mineral óseo de 56,7 a 90,9 g, y el área ósea de 295 a 430 crn2 mientras que el índice de densidad volumétrica mineral del hueso experimentó un descenso de 11,1 a 10,1. El porcentaje medio de bífidobacteria en las muestras fecales recogidas a la edad de 3 ñ 1 días fue de 21 por ciento. A la edad de 25Iñ 4, 45 ñ 4 y 68 ñ 4 días esta proporción fue 53, 56 y 50 por ciento indicando un rápido efecto bifidogénico de la NF y la capacidad de la NF para mantener una flora bifidobacterial estable. Conclusiones: El crecimiento y la calidad del crecimiento de los lactantes alimentados con la fórmula nueva (FN) fueron similares a los alimentados con lactancia materna (LM) y a los alimentados con fórmulas de inicio estándares (FE). El ligero descenso en la densidad volumétrica del hueso, debido al incremento en el área ósea superior al incremento en la densidad mineral del hueso durante este período de rápido crecimiento, fue similar a nuestros resultados previos en lactantes alimentados con LM y FE (EJP en prensa). La utilización de prebióticos en FN, dio como resultado un incremento rápido y significativo del porcentaje de bifidobacteria endógena y la capacidad de mantener una flora intestinal estable durante los primeros meses de vida (AU)

Bioassays of APONIN-3 and -4 with rabbit erythrocytes.

Rabbit erythrocytes in methanolic phosphate medium were used to bioassay the activity of authentic samples of methyl stearate and methyl palmitate (in 10% methanol:90% water, v/v), which had been identified as apparent oceanic naturally occurring cytolins (APONIN-3 and -4) produced by Nannochloris oculata. The two natural products are notable for cytolytic activity toward the unarmoured dinoflagellate, Gymnodinium breve Davis, an organism responsible for red tides consisting of harmful algal blooms in the Gulf of Mexico and along the eastern coast of the United States. Bioassays were done with heparinized rabbit blood. The absorbance at 540 nm was observed for 15 min in comparison with a sample treated with haemolysing agent. The results indicated that at reasonable concentrations of 1-10 ppm, neither was a haemolysin, although such concentrations caused cytolysis of G. breve cultures.

Effect of dietary lipid on gamma-glutamyl transferase-positive foci during hepatocarcinogenesis in rats.

The effect of dietary lipid on gamma-glutamyl transferase-positive (GGT-positive) foci was investigated. Female Sprague-Dawley rats were dosed with diethylnitrosamine (15 mg/kg) at 24 h of age. After weaning, they were fed nutritionally complete semipurified diets for 3 months. Rats fed 15% corn oil had significantly lower hepatic phospholipid eicosapentaenoate and docosahexaenoate than rats fed 7.5% corn oil plus 7.5% fish oil, 5% corn oil plus 10% fish oil (P < 0.05). However, rats fed 15% corn oil had significantly greater hepatic phospholipid arachidonate than rats fed the other two diets (P < 0.05), suggesting that n-3 polyunsaturated fatty acids were incorporated into hepatic phospholipid at the expense of n-6 polyunsaturated fatty acids. Hepatic PGF2alpha content was significantly greater in rats fed 15% corn oil than in rats fed the other two diets (P < 0.05). Rats fed fish oil had significantly lower hepatic vitamin E content than rats fed corn oil (P < 0.05). Hepatic lipid peroxidation (TBARS) tended to increase with increased dietary fish oil (P < 0.05). Dietary lipid did not influence GGT-positive foci area or number. In conclusion, dietary lipid affected hepatic PGF2alpha production, however, showed no effect on GGT-positive foci area and number. This may suggest that PGF2alpha is not the underlying mechanism for GGT-positive foci during hepatocarcinogenesis.

3 beta-O-palmityl longispinogenin from Trichocereus chilensis.

From the aerial parts of Trichocereus chilensis a new triterpenetriol fatty acid ester was isolated. Its structure was shown to be 3 beta-O-palmityl longispinogenin (olean-12-ene-3 beta,16 beta,28-triol-3-palmitate) [1] by chemical and spectroscopic methods. Compound 1 is inactive in brine shrimp lethality and cytotoxicity bioassays.

Negative ion ammonia chemical ionization and electron impact ionization mass spectrometric analysis of steryl fatty acyl esters.

Synthesis of steryl palmitates, varied in the nature of the steryl moiety, provided model compounds for investigation of the mass spectrometric behavior of steryl long-chain fatty acyl esters. The structure of the steryl moiety was varied according to: (i) position and degree of unsaturation in the steroid nucleus and C-17 side-chain, (ii) position and degree of methylation, (iii) presence or absence of a 9 beta, 19-cyclopropane ring. Compounds were chosen so as to be representative of biochemically important steryl esters. Electron impact (EI) behavior of steryl palmitate esters closely resembles that of their short-chain (e.g. acetate) counterparts. M+.ions were generally weak or absent and the major high mass ions arose from characteristic fragmentations of the steroid nucleus following loss of the acyl moiety ([M-RCO2H]+.). Fragment ions characteristic of the acyl moiety were lacking. Negative ion chemical ionization (NICI) using ammonia as reagent gas, on the other hand, afforded spectra containing characteristic fragment ions [RCO2]-, [RCO2-18]-, and [RCO2-19]- from which the nature of the fatty acyl moiety can be readily deduced. Hence, NICI and EI provide complementary means of ionization for the mass spectrometric determination of structures of steryl esters.