Quantitative Gas Chromatography–Mass Spectrometry Isomer-Specific Measurement of Hydroxy Fatty Acids in Biological Samples and Food as a Marker of Lipid Peroxidation

RESUMEN Epoxidación de ésteres metílicos derivados del aceite de Jatropha: Optimización del estudioSe ha evaluado la optimización de la reacción de epoxidación de ésteres metílicos obtenidos a partir de aceite de Jatropha. Se ha empleado para el diseño experimental una metodología de superficie de respuesta (RSM), basada en un diseño compuesto central giratorio (CCRD). Cuatro variables de la reacción fueron evaluadas: relación molar peróxi-do de hidrógeno/C=C, relación molar ácido fórmico/C=C, temperatura de reacción y tiempo de reacción. Las condiciones óptimas de epoxidación calculadas por el modelo cuadrático fueron 3.12 moles de peróxido de hidrógeno/C=C moles, 0.96 moles de ácido fórmico/C=C moles, una temperatura de reacción de 70.0 °C y un tiempo de reacción de 277 minutos. Una reacción optimizada mediante los parámetros propuestos del proceso proporciona un rendimiento de 92.89 ± 1.29% en peso con un tiempo de reacción relativamente mejorado. La concentración de peróxido de hidrógeno y la temperatura de la reacción fueron las variables más significativas, además la temperatura de la reacción y la concentración de peróxido de hidrógeno mostraron fuertes interacciones. Los ésteres metílicos epoxidados se analizaron mediante FT-IR, 1H RMN y RMN de 13C. Este estudio indica que se requiere una proporción molar relativamente mayor de ácido fórmico que la propuesta en la literatura. PALABRAS CLAVE: Aceite epoxidado de JatrophaCaracterización -Metodología de superficie -Optimización -Respuesta. SUMMARY Epoxidation of methyl esters derived from Jatropha oil: An optimization studyThe optimization of the epoxidation reaction of methyl esters obtained from Jatropha oil was appraised. Response surface methodology (RSM) based on a central composite rotatable design (CCRD) was employed for the experimental design. Four reaction variables namely hydrogen peroxide/ C=C mole ratio, formic acid/C=C mole ratio, reaction temperature and reaction time were evaluated. The optimum epoxidation conditions calculated by the quadratic model were 3.12 moles of hydrogen peroxide/C=C moles, 0.96 moles of formic acid/C=C moles, a reaction temperature of 70.0 °C and a reaction time of 277 minutes. A reaction optimized by the proposed process parameters provided a yield of 92.89 ± 1.29 wt.% with relatively improved reaction time. Hydrogen peroxide concentration and reaction temperature were found to be the most significant variables while reaction temperature and hydrogen peroxide showed strong interactions. The epoxidized methyl esters were analyzed using FT-IR, 1 H NMR and 13 C NMR techniques. This study suggested relatively higher molar ratio of formic acid required than was proposed in the literature.

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“…to 250 °C and maintained at 250 °C for 10 minutes (Wilson et al, 1997). Helium was used as the carrier gas with a flow rate of 0.5 mL min -1 .…”

Section: Characterization Of the Productmentioning

confidence: 99%

Epoxidation of methyl esters derived from Jatropha oil: An optimization study

Mushtaq¹,

Tan²,

Nadeem³

et al. 2013

Grasas y Aceites

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“…Many assays are available to measure lipid peroxidation, such as malonic dialdehyde (MDA) by the thiobarbituric acid (TBA) test and diene conjugation [33][34][35][36][37][38][39]. Recently, ferrous oxidation with Xylenol Orange (FOX) assay coupled with triphenylphosphine has shown to be a reliable marker for determining levels of hydroperoxides (ROOH) in health and disease [33].…”

Section: Which Markers Are Available?mentioning

confidence: 99%

The role of oxidative stress in the onset and progression of diabetes and its complications: asummary of a Congress Series sponsored byUNESCO-MCBN, the American Diabetes Association and the German Diabetes Society

Rösen¹,

Nawroth²,

King

et al. 2001

Diabetes Metab. Res. Rev.

827

513

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SummaryThis review summarises the results and discussions of an UNESCO-MCBN supported symposium on oxidative stress and its role in the onset and progression of diabetes. There is convincing experimental and clinical evidence that the generation of reactive oxygen species (ROI) is increased in both types of diabetes and that the onset of diabetes is closely associated with oxidative stress. Nevertheless there is controversy about which markers of oxidative stress are most reliable and suitable for clinical practice. There are various mechanisms that contribute to the formation of ROI. It is generally accepted that vascular cells and especially the endothelium become one major source of ROI. An important role of oxidative stress for the development of vascular and neurological complications is suggested by experimental and clinical studies. The precise mechanisms by which oxidative stress may accelerate the development of complications in diabetes are only partly known. There is however evidence for a role of protein kinase C, advanced glycation end products (AGE) and activation of transcription factors such as NFkB, but the exact signalling pathways and the interactions with ROI remain a matter of discussion. Additionally, results of very recent studies suggest a role for ROI in the development of insulin resistance. ROI interfere with insulin signalling at various levels and are able to inhibit the translocation of GLUT4 in the plasma membrane. Evidence for a protective effect of antioxidants has been presented in experimental studies, but conclusive evidence from patient studies is missing. Large-scale clinical trials such as the DCCT Study or the UKPDS Study are needed to evaluate the long-term effects of antioxidants in diabetic patients and their potential to reduce the medical and socio-economic burden of diabetes and its complications.

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“…For this purpose, methods such as calorimetry (Wilbur et al, 1949;Erdelmeier et al, 1998;Gerard-Monnier et al, 1998), fluorescence (Chio & Tappel, 1969;Fletcher et al, 1973), luminescence (Nakano et al, 1998), gas chromatography (GC), gas chromatography/ mass spectrometry (Liu et al, 1997;Wilson et al, 1998) and high-performance liquid chromatography (Mawatari & Murakami, 1998) have been used. However, nonspecific correlation with malondialdehyde (MDA) content (Smith et al, 1982) and thiobarbituric acid reagent (TBA)…”

Section: Introductionmentioning

confidence: 99%

Evaluation of lipid peroxidation in red blood cells by monitoring the uptake of sucrose and phenol red

Sawas

Pentyala

2004

J of Applied Toxicology

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Red blood cells (RBCs) are prone to lipid peroxidation by virtue of their function as oxygen carriers, and also because of their lipid composition. Malondialdehyde (MDA) content using thiobarbituric reagent is widely used to quantify lipid peroxidation. In this study we compare MDA assay with a newly developed assay that evaluates the uptake of sucrose and phenol red into RBCs under peroxidative stress. Both sucrose and phenol red uptake show significantly higher correlation with incubation time compared with MDA assay. Furthermore, phenol red uptake into RBCs on treatment with H(2)O(2) has a direct linear proportional relationship, whereas it is hyperbolic with MDA. The assay also clearly shows that uptake of sucrose or phenol red is specific for intact cells (RBCs) prior to hemolysis. Assay validation is carried out by using known lipid peroxidation-causing agents, such as ferrous ions, and also by using peroxidation inhibitors such as alpha-tocopherol. This new method can be applied efficiently to evaluate lipid peroxidation in RBCs as well as other cells and tissues.

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Quantitative Gas Chromatography–Mass Spectrometry Isomer-Specific Measurement of Hydroxy Fatty Acids in Biological Samples and Food as a Marker of Lipid Peroxidation

Cited by 46 publications

References 30 publications

Epoxidation of methyl esters derived from Jatropha oil: An optimization study

Epoxidation of methyl esters derived from Jatropha oil: An optimization study

The role of oxidative stress in the onset and progression of diabetes and its complications: asummary of a Congress Series sponsored byUNESCO-MCBN, the American Diabetes Association and the German Diabetes Society

Evaluation of lipid peroxidation in red blood cells by monitoring the uptake of sucrose and phenol red

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