Bis-alkylamine Indolo[3,2-b]quinolines as hemozoin ligands: implications for antimalarial cytostatic and cytocidal activities

Alexandra Paulo, Marta Figueiras, Marta Machado, Catarina Charneira, João Lavrado, Sofia A. Santos, D Lopes, Jiri Gut, Philip J. Rosenthal, F Nogueira, Rui Moreira

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

To get insight into the relevance of targeting hemozoin (Hz) crystals, two isomeric series, N5,N10-bis-alkylamine (2a-k) and N10,O11-bis-alkylamine (3a-k) indolo[3,2-b]quinolines, were evaluated for their in vitro activity against chloroquine (CQ)-resistant and sensitive strains of Plasmodium falciparum. In general, compounds of series 3 were more active than isomers 2, with IC50/LD50 ranging from 25/233 nM (3i) to 1.3 (3a)/10.7 (3b) μM. SAR analyses showed that lipophilicity and chlorine substitution at C3 increased both cytostatic and cytocidal activities. Both series bound to hematin monomer, inhibited β-hematin formation in vitro, delayed intraerythrocytic parasite development with apparent inhibition of Hz biocrystallization, and showed higher cytocidal activity against schizonts. In addition, cytostatic and cytocidal activities of series 3, but not those of isomers 2, correlated with calculated vacuole accumulation ratios, suggesting different capacities of 2 and 3 to bind to the Hz crystal face {001} exposed on the vacuole aqueous medium and different mechanisms of cytocidal potency.
Original languageEnglish
Pages (from-to)3295-3313
Number of pages18
JournalJournal of Chemotherapy
Volume57
Issue number8
DOIs
Publication statusPublished - 24 Apr 2014

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