Development of an on-line immobilized α-glucosidase microreactor coupled to liquid chromatography for screening of α-glucosidase inhibitors.

In order to rapidly screen α-glucosidase (α-GLU) inhibitors from Chinese herbs extract, an online screening method was developed by using enzymatic microreactors in combination with HPLC. A type of dodecahedral and porous material (ZIF-90) was synthesized at room temperature and employed as supports to construct enzymatic microreactor. The amount of α-glucosidase immobilized on ZIF-90 was 58.65 μg per mg carrier under the optimized conditions. In the online screening process, the eluent of 30 s was selected for detection. For the application of this on-line screening system, three α-glucosidase inhibitors with known structure (2,4-dimethoxy-6,7-dihydroxyphenanthrene, batatasin I, 3,5-dimethoxy-2'-hydroxyaiaryl) were selectively extracted from Dioscorea opposita Thunb. Three compounds screened from honeysuckle leaves were isochlorogenic acid B, 1,5-dicaffeoylquinic acid and isochlorogenic acid C, respectively. Two compounds including (+)-catechin and (-)-epigallocatechin gallate were screened from Xinyang Maojian tea. Three unknown ingredients were also screened out from Radix Rehmanniae Praeparata. The nanomaterials in the microreactor can be conveniently replaced. The screening flow rate and elution time can be easily adjusted and controlled by microinjection pump. Considering the specificity of enzyme binding and convenience of online screening system, this method has great potential for fast real-time fishing of α-glucosidase inhibitors from Chinese herbal medicines.