Quinoline and quinolone dimers and their biological activities: An overview.

Quinoline and quinolone motifs which act as structural subunits of more complex natural products are ubiquitous in nature, and they are useful pharmacophores which play a pivotal role in drug development. Compared with the corresponding monomeric compounds, the dimers usually exhibited some unique properties, so dimers have caused great interests in recent years. Quinline and quinolone dimers possess various biological properties such as antibacterial, anticancer, antimalarial and antitubercular activities, and some of them which are exemplified by piperaquine have already used in clinical practice. Numerous quinline and quinolone dimers have been synthesized and screened for their in vitro and in vivo biological activities, and some of them exhibited promising potency. Therefore, quinline and quinolone dimers have the potential for clinical deployment in the control and eradication of various diseases. This review covers the recent advances of quinline and quinolone dimers as bioactive substances. The structure-activity relationship was also discussed to provide an insight for rational designs of more active quinline and quinolone dimers.