Synthesis of aminoquinoline-based aminoalcohols and oxazolidinones and their antiplasmodial activity

Antimalarial Activities of (Z)-2-(Nitroheteroarylmethylene)-3(2H)-Benzofuranone Derivatives: In Vitro and In Vivo Assessment and β-Hematin Formation Inhibition Activity

A series of (Z)-2-(nitroheteroarylmethylene)-3(2H)-benzofuranones possessing nitroheteroaryl groups of nitroimidazole, nitrofuran, and nitrothiophene moieties was screened for antiplasmodium activity against a drug-sensitive strain (3D7 strain) and a multidrug-resistant (chloroquine [CQ] and pyrimethamine) strain (K1 strain) of Plasmodium falciparum. 5-Nitroimidazole and 4-nitroimidazole analogs were highly selective and active against resistant parasites, while 5-nitrofuran and 5-nitrothiophene derivatives were more potent against the 3D7 strain than against the K1 strain. Among the synthetic analogues, (Z)-6-chloro-2-(1-methyl-5-nitroimidazol-2-ylmethylene)-3(2H)-benzofuranone (compound 5h) exhibited the highest activity (50% inhibitory concentration [IC₅₀], 0.654 nM) against the K1 strain and (Z)-7-methoxy-2-(5-nitrothiophen-2-ylmethylene)-3(2H)-benzofuranone (10g) showed the highest activity (IC₅₀, 0.28 μM) against the 3D7 strain in comparison with the activities of CQ (IC₅₀s of 3.13 and 206.3 nM against 3D7 and K1 strains, respectively). The more active compounds, with IC₅₀s lower than 5 μg/ml (∼20 μM), were further studied for their cytotoxicity responses using KB cells. From these studies, 5-nitroimidazole, 4-nitroimidazole, and 5-nitrofuran analogues were shown to be cytotoxic against KB cells, while 5-nitrothiophene analogues were shown to have the least cytotoxic effects. To gain some insight into their potential contributing mechanisms of action, three derivatives, 10e, 10g, and 10h (from the nitrothiophene subgroup, possessing 6-methoxy, 7-methoxy, and 6,7-dimethoxy substituents, respectively, on their benzofuranone moieties), showing the least toxicity and highest selectivity indices were assessed for their β-hematin formation inhibition activity. Compound 10g demonstrated the highest inhibition activity (IC₅₀, 10.78 μM) in comparison with that of CQ (IC₅₀, 2.63 μM) as the reference drug. Finally, these three analogues (10e, 10g, and 10h) were further evaluated for their in vivo activities against the Plasmodium berghei/albino mouse model (Peter's test). The tested analogues were shown to be active, reducing the percentages of erythrocytes that contained parasites by 53.4, 48.8, and 32.4%, respectively.

Exploring the scope of new arylamino alcohol derivatives: Synthesis, antimalarial evaluation, toxicological studies, and target exploration

Synthesis of new 1-aryl-3-substituted propanol derivatives followed by structure-activity relationship, in silico drug-likeness, cytotoxicity, genotoxicity, in silico metabolism, in silico pharmacophore modeling, and in vivo studies led to the identification of compounds 22 and 23 with significant in vitro antiplasmodial activity against drug sensitive (D6 IC₅₀ ≤ 0.19 μM) and multidrug resistant (FCR-3 IC₅₀ ≤ 0.40 μM and C235 IC₅₀ ≤ 0.28 μM) strains of Plasmodium falciparum. Adequate selectivity index and absence of genotoxicity was also observed. Notably, compound 22 displays excellent parasitemia reduction (98 ± 1%), and complete cure with all treated mice surviving through the entire period with no signs of toxicity. One important factor is the agreement between in vitro potency and in vivo studies. Target exploration was performed; this chemotype series exhibits an alternative antimalarial mechanism.

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New aryl-substituted propanol derivatives (APD) show promising antimalarial activity.

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γ-amino alcohol moiety is significant antimalarial chemotype.

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Compound 22 displays excellent in vivo parasitemia reduction (98%) and complete cure.

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APD are active against drug sensitive and multidrug resistant strains.

4-Aminoquinoline-hybridization en route towards the development of rationally designed antimalarial agents

Recent developments in 4-aminoquinoline-hybridization, as an attractive strategy for averting and delaying the drug resistance along with improvement in efficacy of new antimalarials, are described.

Reemergence of chloroquine (CQ) analogs as multi-targeting antimalarial agents: a review

Amongst several communicable diseases (CDs), malaria is one of the deadliest parasitic disease all over the world, particularly in African and Asian countries. To curb this menace, numbers of antimalarial agents are being sold as over the counter (OTC) drugs. Chloroquine (CQ) is one of them and is one of the oldest, cheapest, and easily available synthetic agents used to curb malaria. Unfortunately, after the reports of CQ-resistance against different strains of malarial parasite strains worldwide, scientist are continuously modifying the core structure of CQ to get an efficient drug. Interestingly, several new drugs have been emerged in due course having unique and enhanced properties (like dual stage inhibitors, resistance reversing ability etc.) and are ready to enter into the clinical trial. In this course, some new agents have also been discovered which are; though inactive against CQS strain, highly active against CQR strains. The present article describes the role of modification of the core structure of CQ and its effects on the biological activities. Moreover, the attempt has also been made to predict the future prospects of such drugs to reemerge as antimalarial agents.