New Molecules of Diterpene Origin with Inhibitory Properties toward α-Glucosidase.

The incidence of diabetes mellitus (DM), one of the most common chronic metabolic disorders, has increased dramatically over the past decade and has resulted in higher rates of morbidity and mortality worldwide. The enzyme, α-Glucosidase (α-GLy), is considered a therapeutic target for the treatment of type 2 DM. Herein, we synthesized arylidene, heterocyclic, cyanoetoxy- and propargylated derivatives of quinopimaric acid (levopimaric acid diene adduct with -benzoquinone) - and, first, evaluated their ability to inhibit α-GLy. Among the tested compounds, quinopimaric acid , 2,3-dihydroquinopimaric acid and its amide and heterocyclic derivatives , , , , , with IC values of 35.57-65.98 μM, emerged as being good inhibitors of α-GLy. Arylidene 1β-hydroxy and 1β,13α-epoxy methyl dihydroquinopimarate derivatives , , -, thiadiazole , 1a,4a-dehydroquinopimaric acid and its indole, nitrile and propargyl hybrids -, , , , and showed excellent inhibitory activities. The most active compounds , , , and displayed IC values of 0.15 to 0.68 μM, being 1206 to 266 more active than acarbose (IC of 181.02 μM). Kinetic analysis revealed the most active diterpene indole with an alkyne substituent as a competitive inhibitor with of 50.45 μM. Molecular modeling supported this finding and suggested that the indole core plays a key role in the binding. Compound also has favorable pharmacokinetic and safety properties, according to the computational ADMET profiling. The results suggested that quinopimaric acid derivatives should be considered as potential candidates for novel alternative therapies in the treatment of type 2 diabetes.