|Yokoyama, Wallace - Wally|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/14/2010
Publication Date: 5/18/2010
Citation: Langhorst, M., Hastings, M.J., Yokoyama, W.H., Hung, S., Young, S.A., Cellar, N., Kuppannan, K. 2010. Determination of F2-isoprostanes, biomarkers of oxidative stress in hamster urine samples by on-line solid phase extract. Journal of Agricultural and Food Chemistry. 58 (11), pp 6614–6620. DOI: 10.1021/jf101146q.
Interpretive Summary: Free radical damage, a form of oxidative stress, is believed to be the root cause of many dietary-related chronic diseases. Free radical oxidation of certain fatty acids to isoprostanes are believed to measure free radical oxidative stress. Isoprostanes are similar in structure to natural lipid signaling agents and isoprostane determination has been tedious and complex. This method simplifies the sample cleanup and uses modern mass spectroscopic instrumentation for accurate and sensitive determination of this oxidative stress biomarker. Hamster urine was used as the source of isoprostanes in this study.
Technical Abstract: F2-isoprostanes are a unique class of prostaglandin-like compounds formed in vivo from the free radical-initiated peroxidation of arachidonic acid independent of the cyclooxygenase enzyme. F2-isoprostanes are initially generated esterified to phospholipids and then released in free-acid form possessing biological activity. They represent good biomarkers of lipid peroxidation in both animal and human models of oxidative stress despite challenges to accurately quantify the multiple forms of F2-isoprostanes. Existing immunoassay methods do not enable a separate quantification of various species of isoprostanes. Existing chromatography/mass spectrometry procedures often involve extensive sample preparation schemes prior to analysis. Hence a quantitative analytical method was developed for the determination of F2-isoprostanes, biomarkers of oxidative stress, in urine samples by on-line solid phase extraction (SPE) with liquid chromatography and tandem mass spectrometry (LC/MS/MS). The on-line SPE LC/MS/MS procedure has significant advantages over alternative, published methods with respect to simplicity, speed, and sensitivity. The present assay enables the quantification of iPF2a-VI, iPF2a-III, and iPF2a-IV over the concentration range from 0.5-50 ng/mL in hamster urine samples with quantitation limits of 0.3 ng/mL.