Synthesis of arylated tetrahydrobenzo[H]quinoline-3-carbonitrile derivatives as potential hits for treatment of diabetes.

Aim: Quinoline scaffolds are serving as the core structure for numerous antifungal, analgesic, antipyretic, anti-inflammatory drugs as well as have also been investigated for their potential antidiabetic properties. Though further exploration is required in this area as the current antidiabetic agents, such as acarbose, miglitol and voglibose, are associated with several adverse side effects. In this context, arylated tetrahydrobenzo[H]quinoline-3-carbonitrile derivatives were designed and evaluated as potential antidiabetic agents.Materials & methods: A one-pot multicomponent reaction of 6-methoxy-1-tetralone with ethyl cyanoacetate, ammonium acetate and varying aldehydes yielded a range of new arylated tetrahydrobenzo[h]quinoline-3-carbonitrile molecules 1-36.Results: Compounds 2-5, 12, 13, 19 and 32-34 showed excellent inhibition against α-amylase (IC50 = 3.42-15.14 μM) and α-glucosidase (IC50 = 0.65-9.23 μM) enzymes in comparison to the standard acarbose (IC50 = 14.35 μM). In addition, all compounds revealed significant to moderate DPPH radical scavenging activity (SC50 = 21.30-138.30 μM) compared with BHT (SC50 = 64.40 μM). Kinetic studies confirmed competitive inhibition mode, while molecular docking studies comprehend ligands' interaction with enzyme's active sites and absorption, distribution, metabolism, and excretion analysis confirms that all synthetic derivatives are nontoxic.Conclusion: This research offers a range of lead candidates to become antidiabetic agents after further advanced study.