Recent advances in the therapeutic potential of quinoline-piperazine hybrids.

This review summarizes the therapeutic potential of quinoline-piperazine hybrid molecules having no spacer/linker in between highlighting their potential therapeutic applications in various diseases that include viral infections, tuberculosis, malaria, fungal infections, microbial diseases, cancer, inflammatory disorders, and diabetes. The C-2 position of the quinoline ring is most frequently explored site for piperazine substitution, in comparison, substitutions at the C-4 and C-7 positions have been moderately investigated, whereas C-3 substitution remains relatively less explored and structure activity relationships associated with these hybrids have been explored broadly identifying key factors that influence their biological efficacy. Additionally, the electronic nature of the functional groups (i.e. electron donating or withdrawing) significantly influences the biological activity of the resulting molecules. Pharmacokinetic properties of the most potent quinoline-piperazine hybrids have been discussed. This review gives an insight into the designing and optimization of quinoline-piperazine hybrids as promising therapeutic agents.