Lipid peroxidation as measured by chromatographic determination of malondialdehyde. Human plasma reference values in health and disease.

Free radicals and oxidants are involved in physiological signaling pathways, although an imbalance between pro-oxidant and anti-oxidant systems in favor of the former leads to major biomolecular damage. This is the so-called oxidative stress, a complex process that affects us all and is responsible for the development of many diseases. Lipids are very sensitive to oxidant attack and to-date, malondialdehyde (MDA), 4-hydroxy-2-nonenal (4-HNE) and F2-isoprostane are the main biomarkers for lipid peroxidation assessment. They all derive from polyunsaturated fatty acids (PUFAs) either by enzyme-catalyzed reactions (physiological) or by non-enzyme reactions (pathological). The profile of PUFAs present in the tissue will determine the proportion of each biomarker. In this review we aim to discuss the proper method for MDA determination using HPLC. We also offer reference MDA values in humans in physiological and pathological conditions.

Values of sperm thiobarbituric acid-reactive substance in fertile men.

BACKGROUND: The objective of this study was to establish for the first time reference levels of sperm malondialdehyde, a stable lipid peroxidation product, in a cohort of fertile men. METHODS: Sperm malondialdehyde, a thiobarbituric acid-reactive substance, was assayed using the 2-thiobarbituric acid method. RESULTS: Sperm malondialdehyde levels, expressed in nM/10(8) spermatozoa, were normally distributed in our cohort of fertile men and averaged 0.0287 +/- 0.0162 (mean +/- S.D.). CONCLUSIONS: Given the impact of lipid peroxidation on spermatozoa and thereby on male fertility, the assay of sperm membrane thiobarbituric acid-reactive substance is clearly of interest. Malondialdehyde levels found in our study form a basis for normal values of sperm thiobarbituric acid-reactive substance observed in the semen of fertile men.

Subpicogram determination of malondialdehyde by gas-liquid chromatography with nitrogen phosphorus detector. I. Standardization.

A method for the measurement of malondialdehyde (MDA) using GLC with a nitrogen phosphorus detector (GLC/NPD) is described and evaluated. The method uses 2-hydrazinobenzothiazole (HBT) which forms condensation derivatives with MDA, acetoacetaldehyde, and acetylacetone (AA). GC/MS and 13C NMR studies of the three derivatives obtained showed that they are 2-(pyrazol-1'-yl)benzothiazoles and that they can be separated by GLC/NPD. Any one of these derivatives can be used as an internal standard for the measurement of the other two. The optimal conditions for the measurement of MDA were studied. At pH 2.5 and 70 degrees C, the condensation derivative is quantitatively formed in 30 min. Its extraction is obtained by a mixture of n-hexane/isoamyl alcohol 98/2 (v/v) containing HBT-AA as internal standard. The GLC detection limit is 0.04 pmol. Inter- and intrassay coefficients of variation were 2.9 and an average of 4.0%, respectively. The method is specific, and there was no interference from other carbonyl compounds. The artifactual formation of MDA from carbohydrates during the derivatization reaction is negligible. The method is proposed as a reference method for the standardization of working solutions of MDA or MDA-generating solutions.