Xanthones as potential α-glucosidase non-competition inhibitors: Synthesis, inhibitory activities, and in silico studies.

α-glucosidase inhibitors (AGIs) were commonly used in clinical for the treatment of type 2 diabetes. Xanthones were naturally occurring antioxidants, and they may also be potential AGIs. In this study, eleven 1,6- and 1,3-substituted xanthone compounds were designed and synthesized, of which four were new compounds. Their α-glucosidase inhibitory activities in vitro and in silico were evaluated. Five xanthone compounds with higher activity than acarbose were screened out, and the xanthones substituted at the 1,6-positions were more likely to be potential α-glucosidase non-competitive inhibitors. The binding mode of xanthones with α-glucosidase was further studied by molecular docking method, and the results showed that the inhibitory effect of non-competitive inhibitors on site 1 of α-glucosidase may be related to the hydrogen bonds formed by the compounds with amino acid residues ASN165, HIS209, TRY207, ASP243, and SER104. This study provided a theoretical basis of the rapid discovery and structural modification of non-competitive xanthone inhibitors of α-glucosidase.