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 1H NMR, 13C NMR, and HR–ESI–MS.
The synthesized products were tested for their α-glucosidase
inhibitory activity where compounds 11 (IC50
= 0.56 ± 0.01 μM), 10 (IC50
= 0.94 ± 0.01 μM), 4 (IC50
= 1.47 ± 0.01 μM), 2 (IC50
= 2.20 ± 0.03 μM), 6 (IC50
= 2.20 ± 0.03 μM), 12 (IC50
= 2.22 ± 0.07 μM), 7 (IC50
= 2.76 ± 0.04 μM), 9 (IC50
= 2.78 ± 0.03 μM),
and 3 (IC50
= 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 IC50 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”
(IC50 = 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.