Quinolones have a large bio-dynamicity. Although they are well known as antibacterials, another important activity has been investigated – quinolones are able to inhibit cancer cell proliferation. In view of the great versatility associated with the synthesis of quinolones, many researchers have spent time and resources on the development of new structurally diversified quinolone derivatives with the purpose of finding new possibilities for cancer treatment. In this review some of the most recent advances in the search for new quinolone anticancer agents are highlighted, with focus on naturally occurring substances, bioactive metal complexes, molecular hybrids, photosensitizers and heterocycle condensed quinolones.

As part of a continuing search for new potential anticancer candidates, we describe the synthesis, cytotoxicity and mechanistic evaluation of a series of 4-oxoquinoline-3-carboxamide derivatives as novel anticancer agents. The inhibitory activity of compounds 10–18 was determined against three cancer cell lines using the MTT colorimetric assay. The screening revealed that derivatives 16b and 17b exhibited significant cytotoxic activity against the gastric cancer cell line but was not active against a normal cell line, in contrast to doxorubicin, a standard chemotherapeutic drug in clinical use. Interestingly, no hemolytical activity was observed when the toxicity of 16b and 17b was tested against blood cells. The in silico and in vitro mechanistic evaluation indicated the potential of 16b as a lead for the development of novel anticancer agents against gastric cancer cells.