Mudududdla R, Mohanakrishnan D, Bharate SS, Vishwakarma RA, Sahal D, Bharate SB. Orally Effective Aminoalkyl 10H-Indolo[3,2-b]quinoline-11-carboxamide Kills the Malaria Parasite by Inhibiting Host Hemoglobin Uptake.
ChemMedChem 2018;
13:2581-2598. [PMID:
30358112 DOI:
10.1002/cmdc.201800579]
[Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/10/2018] [Indexed: 12/26/2022]
Abstract
A series of indolo[3,2-b]quinoline-C11-carboxamides were synthesized by incorporation of aminoalkyl side chains into the core of indolo[3,2-b]quinoline-C11-carboxylic acid. Their in vitro antiplasmodial evaluation against Plasmodium falciparum led to the identification of a 2-(piperidin-1-yl)ethanamine-linked analogue {2-bromo-N-[2-(piperidin-1-yl)ethyl]-10H-indolo[3,2-b]quinoline-11-carboxamide (3 g)} (IC50 =1.3 μm) as the most promising compound exhibiting good selectivity indices against mammalian cell lines. The kill kinetics on erythrocytic-stage parasites revealed that 3 g caused complete killing of only the trophozoite-stage parasites. Mechanistic studies showed that 3 g targets the food vacuole of the parasite and inhibits hemoglobin uptake, β-hematin formation, and the basic endocytic processes of the parasite. Analogue 3 g was found to be orally bioavailable, and its curative antimalarial studies at 50 mg per kg p.o. against a Plasmodium berghei (ANKA)-infected mouse model revealed that mice treated with 3 g showed 27-35 % suppression of parasitemia with an increase in life span relative to untreated, control mice. Thus, the present work demonstrated a proof of concept for the oral efficacy of indolo[3,2-b]quinoline-C11-carboxamides.
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