Investigation of intermediate oxidation products of Genistein and Luteolin generated in aerobic conditions

Unstable intermediate oxidation products in the solution of Luteolin [L] and Genistein [G] were discovered by HPLC-MS-ESI(-) in aerobic conditions at pH=8. These covalently bonded compounds of [2L-H2] and [L+G-H2] compositions, as well as trimeric [L+2G-2H2], can be separated by the HPLC, but easily undergo further destruction. Possibly, such compounds are products of initial radical oxygenation. In trimeric conjugate Luteolin, as a more potent reducing agent, binds two Genistein molecules together.