ABSTRACT
High-affinity α-glucosidase inhibitors were screened from Cichorium glundulosum Boiss.et Hout seed (CGS) extract by ultra-filtration affinity-liquid chromatography-mass spectrometry (UF-LC-MS) and molecular docking.By taking 4-nitrobenzene-α-D-glucopyranoside (PNPG) as substrate and acarbose as positive control to evaluate the inhibitory activity of CGS extract, IC50 of acarbose and CGS extract were 0.003 mg/mL and 0.447 mg/mL, respectively.Meanwhile, 4 compounds from CGS extract by UF-LC-MS were screened and identified.Then by using autodock software, the compounds that combined with α-glucosidase were well screened out, including chlorogenic acid and isochlorogenic acid A.The inhibitory activity of chlorogenic acid and chlorogenic acid A against α-glucosidase was verified in vitro.The results showed that the inhibitory activity of the compounds toward α-glucosidase presented the sequence of acarbose>isochlorogenic acid A>chlorogenic acid.The inhibition rate of isochlorogenic acid A was close to acarbose.The experimental results illustrated that UF-LC-MS and molecular docking could be used to screen high affinity enzyme inhibitors from CGS.