Affiliation:
1. Organic Synthesis and Process Chemistry Division CSIR-Indian Institute of Chemical Technology Hyderabad 500007 Telangana India
2. Malaria Drug Discovery Laboratory International Centre For Genetic Engineering and Biotechnology New Delhi 110067 India
3. Department of Biochemistry and Chemical Synthesis Core Facility Albert Einstein College of Medicine 1300 Morris Park Avenue NY-10461 Bronx USA
Abstract
AbstractGuided by Structural Activity Relationship (SAR), a series of synthetic tri‐ and tetra‐substituted imidazoles were studied for in vitro antiplasmodial activities against erythrocytic stages of chloroquine sensitive and resistant strains of Plasmodium falciparum using SYBR green I assay. This led to the identification of three potent (IC50 μM) derivatives : Im2 (0.75), Im5 (0.75) and Im22 (0.5). These three lead molecules present unique structural features with a common molecular architecture. Thus, Im2 and Im22 have phenyl rings at positions 4 and 5 of imidazole ring along with n‐hexyl at N3 position, and differ in the C2 substituent (3‐cyclopentyloxy‐4‐methoxy phenyl for Im2) versus naphthyl for Im22. In contrast, positions 4 and 5 in Im5 have pyridyl rings, with unsubstituted N3. Further, curative antimalarial studies with Im2 and Im5 in a Plasmodium berghei (ANKA) infected mouse model of malaria, revealed an increase in average survival time to 28.6±4.2 and 27.4±4 days respectively, as compared to 20.2±2.3 days for untreated control mice. Results of in vitro combination (Im22+Artemisinin) with ΣFIC50: 0.34–0.79, indicated promising synergy and prospects for the use of Im22 as a new constituent in Artemisinin combination therapy (ACT).