Insights into the structure activity relationship of nitrogen-containing heterocyclics for the development of antidepressant compounds: An updated review

Abstract

According to the World Health Organization (WHO), depression is a common mental disorder and includes complex interaction between social and psychological behaviour affecting 264 million people worldwide. The review aims to highlight the role and importance of nitrogen-based heterocyclics in the development of antidepressant compounds. Many research groups have attempted to design drug candidates capable of binding within the receptors. The commonest drug design strategy includes the incorporation of different structural features widely recognized as an antidepressant in the synthesized derivatives to enhance their CNS antidepressant effects. In this review, we have shed light on nitrogenous heterocyclic moieties such as quinazoline, pyridine, pyrimidine, pyrrolidine, imidazole, pyrazole, piperidine, oxadiazole, benzimidazole, benzothiazole, piperazine, triazine, purine, benzoxazole, and isoxazole as core nucleus and/or in combination as an antidepressant compound. These molecules with different structural features were noted to exert their antidepressant effects by multiple mechanisms viz., selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase (MAO) inhibitors, and Catechol-O-methyltransferase (COMT) inhibitors. The review focuses on the selection of these heterocyclic moieties for the further design and development of promising antidepressants by taking a clue from the earlier reported potent antidepressant compounds or from the marketed products. The results have been correlated with their structural activity relationship (SAR) to identify the substituents for the potency and selectivity within the receptors. This review might help the researchers working in the antidepressant field to develop more novel molecules that could fill the gap by improving potency and reducing toxicity.