Indoles as therapeutics of interest in medicinal chemistry: Bird's eye view

Indoles constitute extensively explored heterocyclic ring systems with wide range of applications in pathophysiological conditions that is, cancer, microbial and viral infections, inflammation, depression, migraine, emesis, hypertension, etc. Presence of indole nucleus in amino acid tryptophan makes it prominent in phytoconstituents such as perfumes, neurotransmitters, auxins (plant hormones), indole alkaloids etc. The interesting molecular architecture of indole makes them suitable candidates for the drug development. This review article provides an overview of the chemistry, biology, and toxicology of indoles focusing on their application as drugs. Our effort is to corroborate the information available on the natural indole alkaloids, indole based FDA approved drugs and clinical trial candidates having diverse therapeutic implementations. This compiled information may serve as a benchmark for the alteration of existing ligands to design novel potent molecules with lesser side effects.