A series of 66 new indolone-N-oxide derivatives was synthesized with three different methods. Compounds were evaluated for in vitro activity against CQ-sensitive (3D7), CQ-resistant (FcB1), and CQ and pyrimethamine cross-resistant (K1) strains of Plasmodium falciparum (P.f.), its well as for cytotoxic concentration (CC50) on MCF7 and KB human tumor Cell lines. Compound 26 (5-methoxy-indolone-N-oxide analogue) had the most potent antiplasmodial activity in vitro (< 3 nM on FcB1 and = 1.7 nM on 3D7) with a very satisfactory selectivity index (CC50 MCF7/IC50 FcB1: 14623; CC50 KB/IC50 3D7: 198823). In in vivo experiments, compound 1 (dioxymethylene derivatives of the indolone-N-oxide) showed the best antiplasmodial activity against Plasmodium berghei, 62% inhibition of the parasitaemia at 30 mg/kg/day.
Pro-oxidant properties of indolone-N-oxides in relation to their antimalarial properties
Indolone-N-oxides (INODs) are bioreducible and possess remarkable anti-malarial activities in the low nanomolar range in vitro against different Plasmodium falciparum (P. falciparum) strains and in vivo. INODs have an original mechanism of action: they damage the host cell membrane without affecting non-parasitized erythrocytes. These molecules produce a redox signal which activates SYK tyrosine kinases and induces a hyperphosphorylation of AE1 (band 3, erythrocyte membrane protein). The present work aimed to understand the early stages of the biochemical interactions of these compounds with some erythrocyte components from which the redox signal could originate. The interactions were studied in a biomimetic model and compared with those of chloroquine and artemisinin. The results showed that INODs i) do not enter the coordination sphere of the metal in the heme iron complex as does chloroquine; ii) do not generate iron-dependent radicals as does artemisinin; iii) generate stable free radical adducts after reduction at one electron; iv) cannot trap free radicals after reduction. These results confirm that the bioactivity of INODs does not lie in their spin-trapping properties but rather in their pro-oxidant character. This property may be the initiator of the redox signal which activates SYK tyrosine kinases. (C) 2013 Elsevier Inc. All rights reserved.
Regioselective Cross-Coupling of Isatogens with Boronic Acids to Construct 2,2-Disubstituted Indolin-3-one Derivatives
作者:Hetao Xu、Mingxing Ye、Kai Yang、Qiuling Song
DOI:10.1021/acs.orglett.1c02808
日期:2021.10.15
Herein we present a transition-metal-free cross-coupling reaction of isatogens with boronic acids through a 1,4-metalate shift of a boron “ate” complex. This coupling reaction provides a feasible method to deliver valuable 2,2-disubstituted indolin-3-one derivatives with excellent regioselectivity, which exhibit operational simplicity, good functional group tolerance, and a broad substrate scope.