STEREOCHEMICAL STUDIES OF EPOXIDES FORMED BY LIPOXYGENASE-CATALYZED CO-OXIDATION OF RETINOL, BETA-IONONE, AND 4-HYDROXY-BETA-IONONE

摘要

High-pressure liquid chromatographic (HPLC) analysis of the products formed during co-oxidation of retinol (1), beta-ionone (2), and 4-hydroxy-beta-ionone (3) by purified soybean lipoxygenase isoenzymes (LOX-1/LOX-2) revealed 5,6-epoxides as major transformation products; with 1, also the 5,8-epoxy derivative was found. The epoxides were characterized by comparison of their chromatographic and spectroscopic data with those of synthesized reference compounds. Using chiral phases, multidimensional gas chromatography and HPLC analyses showed the occurrence of racemic mixtures of the epoxides. The assignment of their stereochemistry and chromatographic order of elution was performed by circular dichroism spectroscopy. The observed lack of selectivity of product formation during co-oxidation supports the hypothesis of a free peroxyl radical mechanism.