Recent Advances in Various Heterocyclic Compounds as Anticancer Agents and Their Applications

Abstract

The World Health Organization (WHO) estimates that there will be approximately 22 million new cases of cancer by 2030, making it one of the leading causes of death globally. The urgent need for efficient prevention, diagnosis, and treatment methods is highlighted by this increasing incidence. Medicinal chemistry, one of the many fields involved in the search for anticancer drugs, is essential in creating compounds that minimize toxicity while specifically targeting cancer cells. Because of their structural diversity, distinctive physicochemical characteristics, and wide range of biological activity, heterocyclic compounds which are defined by ring structures containing heteroatoms like nitrogen, oxygen, or sulfur are especially valuable in this context. Heterocyclic scaffolds form the foundation of many approved anticancer drugs, interacting with important biological targets such as DNA, enzymes, and cellular receptors to modulate multiple disrupted pathways in cancer cells (e.g., cell proliferation, apoptosis, DNA replication, tumor signaling). Nitrogen, sulfur, and oxygencontaining heterocycles represent an important tool for targeting these pathways due to the ability to provide these interactions, thus contributing significantly to drug discovery. Although promising, heterocyclic compounds pose significant challenges because of their poor solubility, limited bioavailability, off-target toxicity, and drug resistance. Structure-activity relationship (SAR) studies are used to provide guidance on rational changes for improved selectivity and reductions of adverse events. Advances in nanotechnology represent new opportunities for overcoming these issues. The use of nanocarrier drug delivery systems, i.e., nanoparticles, liposomes, or polymers, has been shown to enhance solubility, circulation lifetime, and accumulation of drug at the targeted tumor through multiple mechanisms, including the enhanced permeability and retention (EPR) effect through improving pharmacokinetic and pharmacodynamic parameters. The review emphasizes the role of heterocyclics in treatment of cancer including their function, mechanisms of action in cancer treatment, potential uses in medicine, their challenges for development, and potential new methods of drug delivery (such as nanoparticles). The first-half of the review summarizes what is known from current studies and gives an example of a rational design process that has produced better efficacy; selectivity; and safety for future heterocyclic antitumor drugs.