Taste sensor for detecting non-charged bitter substances: Xanthine derivatives of pharmaceutical applications

Novel taste sensors utilizing an allosteric mechanism for potentiometric measurement have demonstrated the ability to detect non -charged bitter substances, including caffeine. In this study, three xanthine derivatives commonly found in pharmaceuticals (i.e., etofylline, proxyphylline, and diprophylline) were detected by the sensor modified with 3-bromo-2,6-dihydroxybenzoic acid (3-Br-2,6-DHBA). The concentration -dependent experiments and selectivity tests revealed that the sensor exhibited remarkable sensitivity and selectivity for these materials. The sensory test results demonstrated a linear correlation with the measurements of the 3-Br-2,6DHBA-modified taste sensor, particularly within the sample concentration range of 1 mM to 30 mM. Thus, this study provided an effective method to evaluate the bitterness of chemical substances with xanthine scaffold.