α-Glucosidase inhibitory derivatives of protocetraric acid.

Lichen-derived depsidones have been a successful source for alpha-glucosidase inhibitory agents with numerous advantages. In this article, derivatives of protocetraric acids were designed and synthesised. Diels-Alder reaction, esterification, and Friedel-Crafts alkylation of protocetraric acid with different reagents under Lewis acid were performed. Eleven products were prepared, including 10 new compounds and parmosidone A. Among them, compounds and had the novel skeletons. The newly synthetic products were evaluated for alpha-glucosidase inhibition. Among tested compounds, showed the strongest activity, with an IC value of 5.9 µM. The molecular docking model indicated the consistency between and data of alpha-glucosidase inhibition.