First QSAR report on FSH receptor antagonistic activity: Quantitative investigations on physico-chemical and structural features among 6-amino-4-phenyltetrahydroquinoline derivatives

A quantitative attempt has been made to correlate the structure–activity relationship (SAR) among the recently reported 6-amino-4-phenyltetrahydroquinoline derivatives as antagonists for the Gs-protein-coupled human follicle-stimulating hormone (FSH) receptor. The compounds used for the present study have been reported to show high antagonistic efficacy in vitro using a CHO-hFSHR(luc) assay. Our QSAR investigations revealed a hydrophobic type of interactions between these ligands and the FSH receptor, hence confirming the presence of a lipophilic pocket on the active site of the target structure. The positive coefficient of C log P variable in our derived QSAR model suggests that more hydrophobic ligands are crucial for their FSH receptor antagonistic efficacy. In exploring the structural requirements among these congeners, we found an amide linkage as conducive to their FSH receptor antagonistic activity. Also, an unsubstituted 4-phenyl ring of the tetrahydroquinoline scaffold is favorable for their FSH receptor antagonistic activity. The results discussed herein could be useful in understanding the nature of interactions of these newly identified ligands as FSH receptor antagonists and in designing more potent ligands based on this novel 6-amino-4-phenyltetrahydroquinoline scaffold.