The interaction between phenylboronic acid derivatives and active ingredients with diphenol structure of traditional Chinese medicine

Abstract

Many active ingredients of traditional Chinese medicine with important pharmacological effects always have glycol or diphenol structure, which lays a foundation for the combination with phenylboronic acid (PBA) derivatives to form cyclic boronic esters compounds. Herein, four important pharmacological active ingredients, namely baicalein, baicalin, gallic acid and protocatechuic acid, were chosen to study the interaction with PBA derivatives. Five PBA derivatives of 3-aminophenylboronic acid monohydrate (APBA), 3-acrylaminophenylboronic acid (AAPBA), poly(3-acrylaminophenylboronic acid) (PAAPBA), poly([poly(ethylene glycol) methacrylate-block-3-acrylaminophenylboronic acid]) (PEbPB), and poly[poly(ethylene glycol) methacrylate-random-3-acrylaminophenylboronic acid] (PErPB) were used. The interactions between five PBA derivatives and four active ingredients were explored by fluorescent spectrophotometer using the alizarin red (ARS) method. The fluorescent intensity of PBA derivative-ARS-active ingredient mixture was decreasing with the increasing concentrations of active ingredients. In comparison, the fluorescent intensity of PAAPBA, PEbPB, and PErPB showed an obviously decrease after active ingredients were added, while the fluorescent intensity of APBA and AAPBA showed a gradually decrease after active ingredients were added. These results indicated a stronger interaction between PBA polymers and active ingredients than that of APBA and AAPBA. Simultaneously, PEbPB and PErPB could enhance cellular uptake of baicalin in A549 cells. This research provided new strategies for improving the bioavailability and water solubility, extending the circulation time, and wider application of the active ingredients of traditional Chinese medicine in the prevention and therapy of diseases.