Bio-Oriented Synthesis of Novel Polyhydroquinoline Derivatives as α-Glucosidase Inhibitor for Management of Diabetes.

Polyhydroquinoline derivatives ( 1-15 ) were synthesized through an unsymmetrical Hantzsch reaction in excellent yields by treating 3,5-dibromo-4-hydroxybenzaldehyde, dimedone, ammonium acetate, and ethyl acetoacetate in ethanol solvent. The structures of the synthesized compounds ( 1-15 ) were deduced through different spectroscopic techniques such as 1 H NMR, 13 C NMR, and HR-ESI-MS. The synthesized products were tested for their α-glucosidase inhibitory activity where compounds 11 (IC 50 = 0.56 ± 0.01 μM), 10 (IC 50 = 0.94 ± 0.01 μM), 4 (IC 50 = 1.47 ± 0.01 μM), 2 (IC 50 = 2.20 ± 0.03 μM), 6 (IC 50 = 2.20 ± 0.03 μM), 12 (IC 50 = 2.22 ± 0.07 μM), 7 (IC 50 = 2.76 ± 0.04 μM), 9 (IC 50 = 2.78 ± 0.03 μM), and 3 (IC 50 = 2.88 ± 0.05 μM) exhibited high potential for the inhibition of α-glucosidase, while the rest of the compounds ( 8 , 5 , 14 , 15 , and 13 ) showed significant α-glucosidase inhibitory potential with IC 50 values of 3.13 ± 0.10, 3.34 ± 0.06, 4.27 ± 0.13, 6.34 ± 0.15, and 21.37 ± 0.61 μM, respectively. Among the synthesized series, two compounds, i.e., 11 and 10 , showed potent α-glucosidase inhibitory potential higher than the standard. All the compounds were compared with standard drug "acarbose" (IC 50 = 873.34 ± 1.67 μM). An in silico method was used to predict their mode of binding within the active site of enzyme to understand their mechanism of inhibition. Our in silico observation complements with the experimental results.