Quinoxaline 1,4-dioxide: a versatile scaffold endowed with manifold activities.

Since 1940s, Quinoxaline 1,4-dioxides (QdNO's) are known as potent antibacterial agents, and subtherapeutic levels have been used to promote growth and improve efficiency of feed conversion in animal feed. They have also shown a selective cytotoxicity against hypoxic cells present in solid tumours. Furthermore, recent studies have put in evidence that QdNO's are endowed with antitubercular, antiprotozoal and anticandida activities. On the other hand, several authors have reported about photoallergic and mutagenic effects of some derivatives. QdNO's may also cause the development of antibiotic-resistant bacteria and influence the horizontal transfer of virulence genes between bacteria. In this review article we report the biological properties, the mode of action and Structure Activity Relationship (SAR) studies of the QdNO derivatives. Furthermore, some cytogenetic and genotoxic effects, classical and more recent method of synthesis, the quinoxaline 1,4-dioxides, and some of their most important reactions, were also reported.