Design, synthesis and in vitro antiplasmodial activity of some bisquinolines against chloroquine-resistant strain

A series of novel bisquinoline compounds comprising N-1-(7-chloroquinolin-4-yl) ethane-1,2-diamine and 7-chloro-N-(2-(piperazin-1-yl) ethyl) quinolin-4-amine connected with 7-chloro-4-aminoquinoline containing various amino acids is described. We have bio-evaluated the compounds against both chloroquine-sensitive (3D7) and chloroquine-resistant (K1) strains of Plasmodium falciparum in vitro. Among the series, compounds 4 and 7 exhibited 1.8- and 10.6-fold superior activity as compared to chloroquine (CQ; IC50 = 0.255 +/- 0.049 mu m) against the K1 strain with IC50 values 0.137 +/- 0.014 and 0.026 +/- 0.007 mu m, respectively. Furthermore, compound 7 also displayed promising activity against the 3D7 strain (IC50 = 0.024 +/- 0.003 mu m) of P. falciparum when compared to CQ. All the compounds in the series displayed resistance factor between 0.57 and 4.71 as against 51 for CQ. These results suggest that bisquinolines can be explored for further development as new antimalarial agents active against chloroquine-resistant P. falciparum.