title: Amino derivatives of indolone-N-oxide: preparation and antiplasmodial properties.
abstract: There is an urgent need for new antimalarial drugs with novel mechanisms of action on novel targets. Indolone-N-oxides (INODs) display antimalarial properties in vitro and in vivo, but identified leads such as 6-(4-chloro-phenyl)-5-oxy-[1,3]dioxolo[4,5-f]indol-7-one 1, suffer from very poor aqueous solubility. In this study, structural modifications have been made by introducing various amino and bulky groups to produce sufficiently water soluble and active compounds for further pharmacological and pharmacokinetic studies. We report here the preparation of twelve novel amino derivatives and their antiplasmodial activities including those of two other structurally known compounds. The 5-methoxy-2-(4-morpholin-4-yl-phenyl)-1-oxy-indol-3-one, 9, has the highest antiplasmodial activity in vitro (IC₅₀ = 6.5 nM; FcB1 strain) and selectivity index (SI (CC₅₀ MCF7/IC₅₀ FcB1) = 4538.5). The 6-amino-2-(4-chloro-phenyl)-1-oxy-indol-3-one, 14, (IC₅₀ = 183 nM; SI = 60), is an excellent candidate for further mechanistic studies. Indeed, this is structurally the closest analogue to the current lead, 1, bearing an NH2 group at R(2) offering possibilities for functionalization and labeling.
authors.affiliation: Université de Toulouse III, UPS, PHARMA-DEV, UMR 152, 118 Route de Narbonne, F-31062 Toulouse cedex 9, France; IRD, UMR 152, F-31062 Toulouse cedex 9, France. Electronic address: najahimco@yahoo.fr.
authors.forename: Ennaji
authors.initials: E
authors.lastname: Najahi
authors.affiliation: Université de Toulouse III, UPS, PHARMA-DEV, UMR 152, 118 Route de Narbonne, F-31062 Toulouse cedex 9, France; IRD, UMR 152, F-31062 Toulouse cedex 9, France.
authors.forename: Nambinina V
authors.initials: NV
authors.lastname: Rakotoarivelo
authors.affiliation: Université de Toulouse III, UPS, PHARMA-DEV, UMR 152, 118 Route de Narbonne, F-31062 Toulouse cedex 9, France; IRD, UMR 152, F-31062 Toulouse cedex 9, France.
authors.forename: Alexis
authors.initials: A
authors.lastname: Valentin
authors.affiliation: Université de Toulouse III, UPS, PHARMA-DEV, UMR 152, 118 Route de Narbonne, F-31062 Toulouse cedex 9, France; IRD, UMR 152, F-31062 Toulouse cedex 9, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Nepveu
mesh_terms: D000818:Animals; D000962:Antimalarials / Q000737:chemistry / Q000494:pharmacology; D007211:Indoles / Q000737:chemistry* / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010087:Oxides / Q000737:chemistry; D010963:Plasmodium falciparum / Q000187:drug effects*
chemical_list: D000962:Antimalarials; D007211:Indoles; D010087:Oxides
keywords: Amino-indolone-N-oxide derivatives; Antimalarial drugs; Indolone-N-oxide