Extractive derivatization of the 12-lipoxygenase products, hepoxilins, and related compounds into fluorescent anthryl esters for their complete high-performance liquid chromatography profiling in biological systems.

Facile methods for the detection of intact hepoxilins, monohydroxy-epoxide derivatives of arachidonic acid formed through the 12-lipoxygenase pathway, are unavailable because (i) an absence in these compounds of an appropriate chromophore for sensitive detection by uv exists, (ii) these compounds are sensitive to the acidic workup leading to varying degrees of decomposition, and (iii) they decompose to the derivatization procedures required for their analysis by gas chromatography mass spectrometry. Herein we apply a method which introduces a fluorescent ester chromophore to the carboxylic group of the hepoxilins under conditions which do not require acidification leading to stabilization of the derivative which is extracted into an organic solvent in situ. This procedure quantitatively derivatizes hepoxilins in a biological sample, permitting the detection of hepoxilins after a TLC purification with a limit of 50 pg/sample. This method permits the profiling of 12-HETE, hepoxilins A3 and B3, as well as the corresponding epoxide hydrolase products, trioxilins A3 and B3, in a biological sample by reverse-phase HPLC with fluorescent detection. We also report on the fluorescent and mass spectral properties of these derivatives using a liquid chromatography mass spectrometry LCMS interface with thermospray ionization.