Synthesis and antimalarial activity of new 4-aminoquinolines active against drug resistant strains

RSC Advances ◽  
2016 ◽  
Vol 6 (107) ◽  
pp. 105676-105689 ◽  
Author(s):  
Srinivasarao Kondaparla ◽  
Awakash Soni ◽  
Ashan Manhas ◽  
Kumkum Srivastava ◽  
Sunil K. Puri ◽  
...  

In the present study we have synthesized a new class of 4-aminoquinoline derivatives and bioevaluated them for antimalarial activity against theP. falciparum in vitro(3D7 & K1) andP. yoelii in vivo(N-67 strain).

2004 ◽  
Vol 57 (6) ◽  
pp. 400-402 ◽  
Author(s):  
KAZUHIKO OTOGURO ◽  
AKI ISHIYAMA ◽  
MIYUKI KOBAYASHI ◽  
HITOMI SEKIGUCHI ◽  
TAKASHI IZUHARA ◽  
...  

2009 ◽  
Vol 53 (4) ◽  
pp. 1320-1324 ◽  
Author(s):  
M. O. Faruk Khan ◽  
Mark S. Levi ◽  
Babu L. Tekwani ◽  
Shabana I. Khan ◽  
Eiichi Kimura ◽  
...  

ABSTRACT In an attempt to augment the efficacy of 7-chloro 4-aminoquinoline analogs and also to overcome resistance to antimalarial agents, we synthesized three cyclen (1,4,7,10-tetraazacyclododecane) analogs of chloroquine [a bisquinoline derivative, 7-chloro-4-(1,4,7,10-tetraaza-cyclododec-1-yl)-quinoline HBr, and a 7-chloro-4-(1,4,7,10-tetraaza-cyclododec-1-yl)-quinoline-Zn2+ complex]. The bisquinoline displays the most potent in vitro and in vivo antimalarial activities. It displays 50% inhibitory concentrations (IC50s) of 7.5 nM against the D6 (chloroquine-sensitive) clone of Plasmodium falciparum and 19.2 nM against the W2 (chloroquine-resistant) clone, which are comparable to those of artemisinin (10.6 and 5.0 nM, respectively) and lower than those of chloroquine (10.7 and 87.2 nM, respectively), without any evidence of cytotoxicity to mammalian cells, indicating a high selectivity index (>1,333 against D6 clone and >521 against W2 clone). Potent antimalarial activities of the bisquinoline against chloroquine- and mefloquine-resistant strains of P. falciparum were also confirmed by in vitro [3H]hypoxanthine incorporation assay. The in vivo antimalarial activity of the bisquinoline, as determined in P. berghei-infected mice, is comparable to that of chloroquine (50% effective dose, ≤1.1 mg/kg when given orally); no apparent toxicity has been observed up to the highest dose tested (3 × 30 mg/kg). The bisquinoline inhibits in vitro hemozoin (β-hematin) formation with an IC50 of 1.1 μM, which is about 10-fold more potent than chloroquine (IC50 9.5 μM). Overall, this article describes the discovery of a new class of cyclen 4-aminoquinoline analogs as potent antimalarial drugs.


2012 ◽  
Vol 56 (7) ◽  
pp. 3475-3480 ◽  
Author(s):  
Sovitj Pou ◽  
Rolf W. Winter ◽  
Aaron Nilsen ◽  
Jane Xu Kelly ◽  
Yuexin Li ◽  
...  

ABSTRACTSontochin was the original chloroquine replacement drug, arising from research by Hans Andersag 2 years after chloroquine (known as “resochin” at the time) had been shelved due to the mistaken perception that it was too toxic for human use. We were surprised to find that sontochin, i.e., 3-methyl-chloroquine, retains significant activity against chloroquine-resistant strains ofPlasmodium falciparum in vitro. We prepared derivatives of sontochin, “pharmachins,” with alkyl or aryl substituents at the 3 position and with alterations to the 4-position side chain to enhance activity against drug-resistant strains. Modified with an aryl substituent in the 3 position of the 7-chloro-quinoline ring, Pharmachin 203 (PH-203) exhibits low-nanomolar 50% inhibitory concentrations (IC50s) against drug-sensitive and multidrug-resistant strains andin vivoefficacy against patent infections ofPlasmodium yoeliiin mice that is superior to chloroquine. Our findings suggest that novel 3-position aryl pharmachin derivatives have the potential for use in treating drug resistant malaria.


2019 ◽  
Author(s):  
Priyanka Panwar ◽  
Kepa K. Burusco ◽  
Muna Abubaker ◽  
Holly Matthews ◽  
Andrey Gutnov ◽  
...  

AbstractDrug repositioning offers an effective alternative to de novo drug design to tackle the urgent need for novel anti-malarial treatments. The anti-amoebic compound, emetine dihydrochloride, has been identified as a potent in-vitro inhibitor of the multi-drug resistant strain K1 of Plasmodium falciparum (IC50: 47 nM + 2.1 nM). 2,3-dehydroemetine, a synthetic analogue of emetine dihydrochloride has been claimed to have less cardiotoxic effects than emetine. The structures of two diastereoisomers of 2,3-dehydroemetine were modelled on the reported emetine binding site on cryo-EM structure 3J7A and it was found that (-)-R,S-dehydroemetine mimicked the bound pose of emetine more closely than (-)-S,S-dehydroisoemetine. (-)-R,S-dehydroemetine was also found to be highly potent against the multi-drug resistant K1 strain of P. falciparum in comparison with (-)-S,S-dehydroisoemetine, which loses its potency due to the change of configuration at C-1’. In addition to its effect on the asexual erythrocytic stages of P. falciparum, the compounds exhibited gametocidal properties with no cross-resistance against any of the multi-drug resistant strains tested. Drug interaction studies showed (-)-R,S-dehydroemetine to have synergistic antimalarial activity with atovaquone and proguanil. Emetine dihydrochloride, and (-)-R,S-dehydroemetine failed to show any inhibition of the hERG potassium channel and displayed atovoquone-like activity on the mitochondrial membrane potential.


RSC Advances ◽  
2020 ◽  
Vol 10 (58) ◽  
pp. 35516-35530
Author(s):  
Neha Sharma ◽  
Yash Gupta ◽  
Meenakshi Bansal ◽  
Snigdha Singh ◽  
Prateek Pathak ◽  
...  

Malaria, a global threat to the human population, remains a challenge partly due to the fast-growing drug-resistant strains of Plasmodium species.


2019 ◽  
Vol 63 (11) ◽  
Author(s):  
Lloyd Tanner ◽  
Joanna C. Evans ◽  
Ronnett Seldon ◽  
Audrey Jordaan ◽  
Digby F. Warner ◽  
...  

ABSTRACT Mycobacterium tuberculosis, the causative agent of tuberculosis, remains a leading infectious killer globally, demanding the urgent development of faster-acting drugs with novel mechanisms of action. Riminophenazines such as clofazimine are clinically efficacious against both drug-susceptible and drug-resistant strains of M. tuberculosis. We determined the in vitro anti-M. tuberculosis activities, absorption, distribution, metabolism, and excretion properties, and in vivo mouse pharmacokinetics of a series of structurally related phenoxazines. One of these, PhX1, displayed promising drug-like properties and potent in vitro efficacy, supporting its further investigation in an M. tuberculosis-infected animal model.


2004 ◽  
Vol 48 (11) ◽  
pp. 4097-4102 ◽  
Author(s):  
Quinton L. Fivelman ◽  
Ipemida S. Adagu ◽  
David C. Warhurst

ABSTRACT A modified fixed-ratio isobologram method for studying the in vitro interactions between antiplasmodial drugs is described. This method was used to examine the interactions between atovaquone, proguanil, and dihydroartemisinin. The interaction between atovaquone and proguanil was synergistic against atovaquone-sensitive strains K1 and T996; however, there was a loss of synergy against atovaquone-resistant strain NGATV01 isolated after Malarone (the combination of atovaquone and proguanil) treatment failure. While the interaction between atovaquone and dihydroartemisinin was indifferent against isolate NGATV01, the interaction displayed indifference tending toward antagonism against the atovaquone-sensitive strains tested. The relevance of in vitro interactions to in vivo treatment is discussed.


2008 ◽  
Vol 52 (10) ◽  
pp. 3467-3477 ◽  
Author(s):  
Geoffrey S. Dow ◽  
Yufeng Chen ◽  
Katherine T. Andrews ◽  
Diana Caridha ◽  
Lucia Gerena ◽  
...  

ABSTRACT The antimalarial activity and pharmacology of a series of phenylthiazolyl-bearing hydroxamate-based histone deacetylase inhibitors (HDACIs) was evaluated. In in vitro growth inhibition assays approximately 50 analogs were evaluated against four drug resistant strains of Plasmodium falciparum. The range of 50% inhibitory concentrations (IC50s) was 0.0005 to >1 μM. Five analogs exhibited IC50s of <3 nM, and three of these exhibited selectivity indices of >600. The most potent compound, WR301801 (YC-2-88) was shown to cause hyperacetylation of P. falciparum histones, which is a marker for HDAC inhibition in eukaryotic cells. The compound also inhibited malarial and mammalian HDAC activity in functional assays at low nanomolar concentrations. WR301801 did not exhibit cures in P. berghei-infected mice at oral doses as high as 640 mg/kg/day for 3 days or in P. falciparum-infected Aotus lemurinus lemurinus monkeys at oral doses of 32 mg/kg/day for 3 days, despite high relative bioavailability. The failure of monotherapy in mice may be due to a short half-life, since the compound was rapidly hydrolyzed to an inactive acid metabolite by loss of its hydroxamate group in vitro (half-life of 11 min in mouse microsomes) and in vivo (half-life in mice of 3.5 h after a single oral dose of 50 mg/kg). However, WR301801 exhibited cures in P. berghei-infected mice when combined at doses of 52 mg/kg/day orally with subcurative doses of chloroquine. Next-generation HDACIs with greater metabolic stability than WR301801 may be useful as antimalarials if combined appropriately with conventional antimalarial drugs.


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