Background:
Alzheimer’s disease (AD), a neurological disorder, is the most common cause of senile dementia.
Butyrylcholinesterase (BuChE) enzyme plays a vital role to regulatethe brain acetylcholine (ACh) neurotransmitter, but in
the case of Alzheimer’s disease (AD), BuChE activity gradually increases in patients with a decrease intheacetylcholine
(ACh) concentration via hydrolysis. ACh plays an essential role in regulating learning and memory as the cortex originates
from the basal forebrain, and thus, is involved in memory consolidation in these sites.
Methods:
In this work, we have developed partial least squares (PLS)-regression based two dimensional quantitative structure-activity relationship (2D-QSAR) models using 1130 diverse chemical classes of compounds with defined activity
against the BuChE enzyme. Keeping in mind the strict Organization for Economic Co-operation and Development (OECD)
guidelines, we have tried to select significant descriptors from the large initial pool of descriptors using multi-layered variable selection strategy using stepwise regression followed by genetic algorithm (GA) followed by again stepwise regression
technique and at the end best subset selection prior to development of final model thus reducing noise in the input. Partial
least squares (PLS) regression technique was employed for the development of the final model while model validation was
performed using various stringent validation criteria.
Results:
The results obtained from the QSAR model suggested that the quality of the model is acceptable in terms of both
internal (R2= 0.664, Q2= 0.650) and external (R2Pred= 0.657) validation parameters. The QSAR studies were analyzed, and
the structural features (hydrophobic, ring aromatic and hydrogen bond acceptor/donor) responsible for enhancement of the
activity were identified. The developed model further suggests that the presence of hydrophobic features like long carbon
chain would increase the BuChE inhibitory activity and presence of amino group and hydrazine fragment promoting the hydrogen bond interactions would be important for increasing the inhibitory activity against BuChE enzyme.
Conclusion:
Furthermore, molecular docking studies have been carried out to understand the molecular interactions between the ligand and receptor, and the results are then correlated with the structural features obtained from the QSAR models. The information obtained from the QSAR models are well corroborated with the results of the docking study.