Heterocyclic Compounds: Importance in Anticancer Drug Discovery.

Cancer, a crucial global health problem, is characterized by abnormal cell division and uncontrolled growth. According to WHO, cancer is the second leading cause of global deaths and accounted for approximately 9.6 million deaths or one in six deaths in 2018. The National Cancer Registry Programme Report 2020, released by the ICMRIndia, estimated that there would be 13,90,000 cases of cancer in India in 2020 and that this number is likely to rise to 15,70,000 by 2025. In spite of several anti-cancer drugs, cancer cannot be cured completely, especially at late stages. In the current era, almost every person is suffering from some kind of disease. Thus, it is the necessity of time to develop novel, potent bioactive molecules. Many researchers are working on the development of new lead molecules or finding a new biological target for the betterment of human beings. However, heterocycles are constantly being used for the discovery of new lead molecules. Many of the clinically approved drugs contain the heterocyclic core as these molecules show exhilarating pharmaceutical properties, including anti-cancer agents such as methotrexate, vinblastine, vincristine, daunorubicin, 5-fluorouracil, doxorubicin, etc. Thus, heterocyclic compounds provide a fascinating research area for the design and development of anti-cancer drug(s). Herein, we focused on the natural as well as synthetic anti-cancer heterocyclic compounds. Furthermore, efforts have been made toward the mechanism of action of selected heterocyclic anti-cancer compounds.