Role of pyridines as enzyme inhibitors in medicinal chemistry

Medicinal chemists are investigating new methods for the synthesis of alternative scaffolds that can be used as chemotherapeutic agents in the field of medicinal chemistry. Nitrogen-containing heterocycles are well known for their numerous biological activities and play a pivotal role in current drug design and discovery. Among them, pyridine and pyridine-based molecules are privileged pharmacophores that are present in numerous natural products and are tremendously important in biological systems. This electron-deficient heterocycle is present in the important vitamins and in the marketed drugs such as nexium, takepron, actos, etc. Substituted pyridines are reported as anticancer, anti-inflammatory, antifungal, antiproliferative, antitumor, antimicrobial, antitubercular, anti-HIV, and enzyme inhibitors. Inhibition of enzymes is a promising therapeutic strategy to improve a metabolic imbalance or kill a pathogen. Enzyme inhibitors interact with enzymes in a way (temporary or permanent) that prevent the enzymes from functioning normally and decrease the rate of an enzyme-catalyzed reaction. Many of the pyridine drugs are enzyme inhibitors such as indinavir, milrinone, and nevirapine. Promising results with the pyridinyl moiety open up the door for the development of a new generation of inhibitors. This chapter aims to review the progress in enzyme inhibition by pyridine-heterocyclic systems. Due to numerous bioactivities of pyridine-based compounds, they are involved in the drug designing and development process for screening them against diversified therapeutic targets. Among them, several classes of pyridine-based molecules inhibit a variety of clinically important enzymes.