Abstract

STUDY ON THE INTERACTION OF LOSARTAN POTASSIUM AND BOVINE SERUM ALBUMIN IN THE PRESENCE OF RUTIN AND BAICALIN

Mingyan Sun, Ming Su, and Hanwen Sun*

ABSTRACT

The interaction of losartan potassium (LP) with bovine serum albumin (BSA) was studied by fluorescence quenching in combination with UV–Vis spectroscopic method under near physiological conditions. The fluorescence quenching rate constants and binding constants for BSA–LP system were determined at different temperatures. The fluorescence quenching of BSA by LP is due to static quenching and energy transfer. The distance between LP and a tryptophane unit was estimated in the absence and presence of rutin and baicalin based on the Förster resonance energy transfer theory. The binding constant (Ka) of BSA–LP at 298K was 1.932×104 L mol‒1. In the presence of rutin or baicalin, the Ka value decreased, and the increase of concentration of free losartan could enhance the effect of medicine. Synchronous fluorescence and three-dimensional fluorescence studies showed that the presence of LP, rutin, and baicalin could change the conformation of BSA during the binding process. The results are of great importance in pharmacy, pharmacology and biochemistry. Uniterms: Bovine serum albumin, losartan potassium, rutin, baicalin fluorescence quenching, binding constant, conformation change.

Keywords: .