Cathepsin B inhibitor screening in traditional Chinese medicines by electrophoretically mediated microanalysis

Abstract

A new method based on capillary electrophoresis for the screening of cathepsin B inhibitors in traditional Chinese medicine was developed. This method integrated longitudinal diffusion and transverse diffusion of laminar flow profiles to achieve mixing different reactants with high efficiency. Taking advantage of the difference in electrophoretic mobility, enzyme reaction, separation and detection can be carried out in the same capillary by injecting reactants successively. The conditions were optimized, including pH, enzyme concentration, incubation time and methanol concentration. Under the optimal conditions, the kinetic constant was tested and the inhibition activity of twelve potential candidates from traditional Chinese medicine was screened. It has been found that dauricine (80 μM) showed inhibitory activity with an inhibitory percentage of 17%. This work provides a significant approach for the initial screening of cathepsin B inhibitors by capillary electrophoresis.