REVIEW ARTICLE; ANTICANCER ACTIVITIES OF SOME FUSED HETEROCYCLIC MOIETIES CONTAINING NITROGEN AND/OR SULFUR HETEROATOMS

Cancer cells often have a high demand for antiapoptotic proteins in order to resist programmed cell death. Heterocyclic compounds present themselves as a fundamental division of organic chemistry. Most clinically effective antitumor agents are inhibitors of DNA, RNA or protein synthesis, enzyme inhibition and/or interfere with the metabolism of other cell components, frequently lacking or displaying poor selective antitumor activity. The majority of heterocycle compounds and typically common heterocycle fragments present in most pharmaceuticals currently marketed, alongside with their intrinsic versatility and unique physicochemical properties have poised them as true cornerstones of medicinal chemistry. The S-heterocyclic core (Thiophene) has been reported to possess significant importance in various fields from medicinal chemistry. Many diverse biologically active products were prepared, several of which exhibited antimicrobial, analgesic, anti-inflammatory, antioxidant, antitumor, local anesthetic, anticoagulant and antithrombotic activities. Many N-heterocyclic compounds that are broadly distributed in Nature, possess physiological and pharmacological properties and are constituents of many biologically important molecules, including many vitamins, nucleic acids, pharmaceuticals, antibiotics, dyes and agrochemicals, amongst many others. The base pairs of DNA and RNA (Guanine, cytosine, adenine, and thymine) are also made up of N-heterocyclic compounds, namely purines, pyrimidines, etc. These nitrogen-containing heterocyclic molecules with distinct characteristics and applications have gained prominence in the rapidly expanding fields of organic and medicinal chemistry and the pharmaceutical industry. Finally, many of these compounds have higher activity against cancer cells using the standard MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)assay.