Chiral thioureas containing naphthalene moiety as selective butyrylcholinesterase inhibitors: Design, synthesis, cholinesterase inhibition activity and molecular docking studies

Butyrylcholinesterase (BChE), which plays a role in the regulation of acetylcholine (ACh) as well as cholinergic type neurotransmission, also has non-cholinergic functions such as differentiation, proliferation and apoptosis. The strategy of increasing ACh levels without the typical undesirable effects of AChE inhibitors used in treatment with selective inhibition of BChE may be an effective approach to delay the progression of Alzheimer's disease (AD). Based on this approach, twenty derivatives of chiral thioureas containing the naphthalene moiety (1a 1a-10a and 1b-10b) ) in both enantiomeric forms were designed, synthesized with good yields (up to 90 %), in this study. Also, their AChE and BChE inhibition activities and antioxidant profiles were tested. All chiral thioureas except compound 5b showed excellent inhibitory activity against BChE but lower inhibitory activity against AChE compared to galantamine. The activity results on BChE revealed that compound 1b (S-enantiomer) S-enantiomer) had the strongest inhibitory effect on BChE (IC50 50 = 10.18 +/- 1.02 mu M) with a selectivity index of 7.27 among all compounds. In terms of antioxidant activity, compound 7a (R R-isomer) exhibited the overall highest antioxidant profile in the series of chiral thioureas. Molecular docking studies were used to reveal the interactions of the most active compounds with target enzymes. Besides, an estimation of the drug-likeness and pharmacokinetic properties of all chiral thioureas was performed.