Evaluation of absorption processes of vanadium compounds by ESR

Abstract

Vanadium with insulinomimetic action exists as vanadyl and vanadate species in nature. Recently, vanadyl sulfate (VOSO₄) and sodium vanadate (NaVO₃) have been examined clinically to find whether they improve human diabetes mellitus (DM). In 2001, it was reported that DM has been improved by the treatment of VOSO₄, in which plasma vanadium level during VS treatment was found to correlate with insulinomimetic activity. Therefore, we studied the absorption processes of VOSO₄ and Na VO₃ with respect to total vanadium as well as vanadyl levels in the blood by using electron spin resonance (ESR). Four blood concentration curves for the two compounds exhibited two absorption maxima, indicating that more than two absorption sites of ionic vanadium compounds exist in the gastrointestine. Bioavailability of NaVO₃ was higher than that of VOSO₄, indicating vanadyl is less toxic than vanadate.