Screening of α-glucosidase inhibitors in tea by amino-functionalized mesoporous SBA-15 immobilized α-glucosidase microreactor

Abstract

NH2-SBA-15 was prepared as an enzyme loading microreactor by modifying SBA-15 with 3-aminopropyltriethoxysilane as the functionalizing reagent. After modification, α-glucosidase (α-Glu) can be easily and fast immobilized on the surface and inner wall of the two-dimensional pores of NH2-SBA-15 by electrostatic adsorption in phosphate buffered saline (PBS, pH 7.4). The quantity of immobilized α-Glu by NH2-SBA-15 under the optimum conditions was 39.93 μg mg−1 which was much higher than unmodified SBA-15 (15.92 μg mg−1), and the enzyme activity still retained 76.1% after 7 cycles. In addition, due to the restricted conformational change of the immobilized enzyme in the 2D pore structure, which had some protective effect on the enzyme, the immobilized enzyme had good acid and alkali resistance, and high temperature resistance. The results showed that the relative activity of the immobilized enzyme fluctuated less in the same pH range, and still retained more than 90% of the activity after standing at 40 °C and 60 °C for 24 h. Finally, the NH2-SBA-15-α-Glu microreactors were co-incubated with the tea extract, and the α-Glu inhibitory active components were screened by HPLC. Several chemical components were successfully screened out, verifying the feasibility of the microreactor.