Coumaryl-sulfonamide moiety: Unraveling their synthetic strategy and specificity toward hCA IX/XII, facilitating anticancer drug development.

Currently, cancer is the most grieving threat to society. The cancer-related death rate has had an ascending trend, despite the implementation of numerous treatment strategies or the discovery of an array of potent molecules against several pathways of cancer growth. The need of the hour is to prevent the multidrug resistance toll, and the current efforts have been bestowed upon a versatile small molecule scaffold, coumarin (benz[α]pyrone), a natural compound possessing interesting affinity toward the cancer target human carbonic anhydrase (hCA), focusing on hCA I, II, IX, and XII. Along with coumarin, the age-old known antibacterial drug sulfonamide, when conjugated at positions 3, 7, and 8 of coumarin either with a linker group or as a single entity, has been reported to enhance the affinity of coumarin toward the overexpressed enzymes in tumor cell lines. The sulfonamides have been listed as obsolete drugs due to the severe side effects caused by them; however, their affinity toward the hCA-zinc-binding core has attracted the attention of researchers. Hence, in the process of drug development, coumarin and sulfonamides have remained the choice of last resort. To unveil the synthetic strategy of coumarin-sulfonamide conjugation, their rationale for inhibiting cancer cells/enzymes, and their affinity toward various types of carcinoma have been the sole goal of the researchers. This review specifically focuses on the mechanism of action and the structure-activity relationship through synthetic strategies and the binding affinity of coumaryl-sulfonamide conjugates with the anticancer targets possessing the highest enzyme affinity, since 2008.