Synthesis, Antimalarial Activity Evaluation and Drug-likeness Study of Some New Quinoline-Lawsone Hybrids

In the present study, a new series of quinoline-lawsone hybrid compounds were synthesized and evaluated in vitro for their antimalarial effectiveness. Several aliphatic and aromatic/heteroaromatic diamines were used as connecting/bridge moiety between the 7-chloro-4-aminoquinoline and 3-amino-1, 4-naphthoquinone pharmacophoric scaffolds. The molecular properties of hybrid compounds were also studied in silico for drug-likeness assessment based on Lipinski's rule of five. Results of antimalarial activity reveal that all the tested compounds showed activity against both chloroquine sensitive (RKL-2) and chloroquine resistant (RKL-9) strains of Plasmodium falciparum which was considerably less as compared to the standard drug, chloroquine. All the compounds exhibited same degree of activity at the tested dose against sensitive strain with IC50 values 0.391-1.033 mu g/ml. Furthermore, four compounds which were additionally tested against resistant strain also showed activity with IC50 values from 0.684 to 1.778 mu g/ml at the same dose. The IC50 values for CQ against sensitive and resistant strains of P. falciparum were found to be 0.0391 mu g/ml and 0.305 mu g/ml, respectively. From results it is apparent that the compound with a small alkyl bridge moiety diaminoethyl possesses better activity profile against both sensitive and resistant strains (IC50=0.391 and 0.684 mu g/ml, respectively) than rest of the synthesized analogues. The results of drug-likeness studies showed that all newly designed quinoline-lawsone hybrids possess good drug-like properties, indicating their drug-likeness behaviour is favourable for optimal antimalarial action. Assessment of drug-likeness score further implies the suitability of hybrid derivatives as drug-like molecules.