Structure-based Drug Design and Synthesis of PARP Inhibitors

Poly(ADP-ribose)polymerase (PARP) is a chromatin bound nuclear enzyme which gets activated by DNA breaks, uses NAD as substrate and catalyses the poly-ADP ribosylation of a variety of proteins. The enzyme PARP is considered as a suitable target for anti-cancer activity as it is involved in a variety of physiological functions like cellular proliferation, differentiation, apoptosis and DNA replication. Based on the literature, pharmacophoric templates and bio-isosteric replacement approach, quinazolinone and phthalazinone derivatives were selected to design molecules to calculate binding affinity and visualize binding conformations and interactions at the active pocket of target PARP-1 protein. For preliminary evaluation, in silico potential compounds were selected to synthesize, purified by column chromatography, characterized by HNMR and Mass Spectral studies and carried out for in vitro cytotoxicity. Molecular docking and preliminary experimental data helped to investigate Structure Activity Relationship for design of safe and potential PARP-1 inhibitors for cancer therapy.