scholarly journals New Active Drugs against Liver Stages of Plasmodium Predicted by Molecular Topology

2008 ◽  
Vol 52 (4) ◽  
pp. 1215-1220 ◽  
Author(s):  
Nassira Mahmoudi ◽  
Ramon Garcia-Domenech ◽  
Jorge Galvez ◽  
Khemais Farhati ◽  
Jean-François Franetich ◽  
...  

ABSTRACT We conducted a quantitative structure-activity relationship (QSAR) study based on a database of 127 compounds previously tested against the liver stage of Plasmodium yoelii in order to develop a model capable of predicting the in vitro antimalarial activities of new compounds. Topological indices were used as structural descriptors, and their relation to antimalarial activity was determined by using linear discriminant analysis. A topological model consisting of two discriminant functions was created. The first function discriminated between active and inactive compounds, and the second identified the most active among the active compounds. The model was then applied sequentially to a large database of compounds with unknown activity against liver stages of Plasmodium. Seventeen drugs that were predicted to be active or inactive were selected for testing against the hepatic stage of P. yoelii in vitro. Antiretroviral, antifungal, and cardiotonic drugs were found to be highly active (nanomolar 50% inhibitory concentration values), and two ionophores completely inhibited parasite development. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed on hepatocyte cultures for all compounds, and none of these compounds were toxic in vitro. For both ionophores, the same in vitro assay as those for P. yoelii has confirmed their in vitro activities on Plasmodium falciparum. A similar topological model was used to estimate the octanol/water partition of each compound. These results demonstrate the utility of the QSAR and molecular topology approaches for identifying new drugs that are active against the hepatic stage of malaria parasites. We also show the remarkable efficacy of some drugs that were not previously reported to have antiparasitic activity.

2020 ◽  
Author(s):  
Awet Alem Teklemichael ◽  
Shusaku Mizukami ◽  
Kazufumi Toume ◽  
Farhana Mosaddeque ◽  
Mohamed Gomaa Kamel ◽  
...  

Abstract Background: The herbal medicine has been a rich source of new drugs exemplified by quinine and artemisinin. In this study, examined a variety of Japanese traditional herbal medicine (Kampo) for their potential antimalarial activities. Methods: We designed a comprehensive screening to identify novel antimalarial drugs from a library of Kampo herbal extracts (n = 120) and related compounds (n=96). The antimalarial activity was initially evaluated in vitro against chloroquine/mefloquine-sensitive (3D7) and -resistant (Dd2) strains of Plasmodium falciparum . The cytotoxicity was also evaluated using primary Adult Mouse Brain cells. After being selected through the first in vitro assay, positive extracts and compounds were examined for possible in vivo antimalarial activity. Results: Out of 120 herbal extracts, Coptis Rhizome showed the highest antimalarial activity (IC 50 1.9 µg/mL of 3D7 and 4.85 µg/mL of Dd2) with a high selectivity index (SI) > 263 (3D7) and > 103 (Dd2). Three major chlorinated compounds (coptisine, berberine, and palmatine) related to Coptis Rhizome also showed antimalarial activities with IC 50 1.1, 2.6, and 6.0 µM (against 3D7) and 3.1, 6.3, and 11.8 µM (against Dd2), respectively. Among them, coptisine chloride exhibited the highest antimalarial activity (IC 50 1.1 µM against 3D7 and 3.1 µM against Dd2) with SI of 37.8 and 13.2, respectively. . Finally, the herbal extract of Coptis Rhizome and its major active compound coptisine chloride exhibited significant antimalarial activity in mice infected with P. yoelii 17X strain with respect to its activity on parasite suppression consistently from day 3 to day 7 post-challenge. The effect ranged from 50.38 to 72.13% (P <.05) for Coptis Rhizome and from 81 to 89% (P <.01) for coptisine chloride. Conclusion: Coptis Rhizome and its major active compound coptisine chloride showed promising antimalarial activity against chloroquine-sensitive (3D7) and -resistant (Dd2) strains in vitro as well as in vivo mouse malaria model. Thus Kampo herbal medicine is a potential natural resource for novel antipathogenic agents.


Blood ◽  
1990 ◽  
Vol 76 (6) ◽  
pp. 1250-1255 ◽  
Author(s):  
S Whitehead ◽  
TE Peto

Abstract Deferoxamine (DF) has antimalarial activity that can be demonstrated in vitro and in vivo. This study is designed to examine the speed of onset and stage dependency of growth inhibition by DF and to determine whether its antimalarial activity is cytostatic or cytocidal. Growth inhibition was assessed by suppression of hypoxanthine incorporation and differences in morphologic appearance between treated and control parasites. Using synchronized in vitro cultures of Plasmodium falciparum, growth inhibition by DF was detected within a single parasite cycle. Ring and nonpigmented trophozoite stages were sensitive to the inhibitory effect of DF but cytostatic antimalarial activity was suggested by evidence of parasite recovery in later cycles. However, profound growth inhibition, with no evidence of subsequent recovery, occurred when pigmented trophozoites and early schizonts were exposed to DF. At this stage in parasite development, the activity of DF was cytocidal and furthermore, the critical period of exposure may be as short as 6 hours. These observations suggest that iron chelators may have a role in the treatment of clinical malaria.


2020 ◽  
Vol 64 (9) ◽  
Author(s):  
Letícia Tiburcio Ferreira ◽  
Juliana Rodrigues ◽  
Gustavo Capatti Cassiano ◽  
Tatyana Almeida Tavella ◽  
Kaira Cristina Peralis Tomaz ◽  
...  

ABSTRACT Widespread resistance against antimalarial drugs thwarts current efforts for controlling the disease and urges the discovery of new effective treatments. Drug repositioning is increasingly becoming an attractive strategy since it can reduce costs, risks, and time-to-market. Herein, we have used this strategy to identify novel antimalarial hits. We used a comparative in silico chemogenomics approach to select Plasmodium falciparum and Plasmodium vivax proteins as potential drug targets and analyzed them using a computer-assisted drug repositioning pipeline to identify approved drugs with potential antimalarial activity. Among the seven drugs identified as promising antimalarial candidates, the anthracycline epirubicin was selected for further experimental validation. Epirubicin was shown to be potent in vitro against sensitive and multidrug-resistant P. falciparum strains and P. vivax field isolates in the nanomolar range, as well as being effective against an in vivo murine model of Plasmodium yoelii. Transmission-blocking activity was observed for epirubicin in vitro and in vivo. Finally, using yeast-based haploinsufficiency chemical genomic profiling, we aimed to get insights into the mechanism of action of epirubicin. Beyond the target predicted in silico (a DNA gyrase in the apicoplast), functional assays suggested a GlcNac-1-P-transferase (GPT) enzyme as a potential target. Docking calculations predicted the binding mode of epirubicin with DNA gyrase and GPT proteins. Epirubicin is originally an antitumoral agent and presents associated toxicity. However, its antiplasmodial activity against not only P. falciparum but also P. vivax in different stages of the parasite life cycle supports the use of this drug as a scaffold for hit-to-lead optimization in malaria drug discovery.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
M. O. Falade ◽  
D. O. Akinboye ◽  
G. O. Gbotosho ◽  
E. O. Ajaiyeoba ◽  
T. C. Happi ◽  
...  

Drug resistance inPlasmodium falciparumrequires that new drugs must be developed. Plants are a potential source for drug discovery and development. Two plants that used to treat febrile illnesses in Nigeria were tested forin vitroandin vivoantimalarial activity and cytotoxicity in cancer cell lines. Methanol, hexane, and ethyl acetate leaf extracts ofFicus thonningiiandLophira alatawere active inin vitroassays againstP. falciparumNF54 (sensitive) and K1 (multiresistant) strains. Hexane extracts ofF. thonningiiandL. alatawere the most effective extracts inin vitroassays with IC50of2.7±1.6 μg/mL and2.5±0.3 μg/mL for NF54 and10.4±1.6 μg/mL and2.5±2.1 μg/mL for K1 strain. All extracts were nontoxic in cytotoxicity assays against KB human cell line with IC50of over 20 μg/mL, demonstrating selectivity againstP. falciparum.In vivoanalysis shows that hexane extracts of both plants reduced parasitaemia. At the maximum dose tested,L. alatahad a 74.4% reduction of parasitaemia whileF. thonningiihad a reduction of 84.5%, both extracts prolonged animal survival in mice infected withP. bergheiNK65 when compared with vehicle treated controls. The antiplasmodial activity observed justifies the use of both plants in treating febrile conditions.


Parasitology ◽  
2005 ◽  
Vol 131 (3) ◽  
pp. 295-301 ◽  
Author(s):  
R. TRIPATHI ◽  
S. DHAWAN ◽  
G. P. DUTTA

Many different drug-resistant lines of rodent malaria are available as screening models. It is obligatory to screen new compounds for antimalarial activity against a series of resistant lines in order to identify a compound with potential for the treatment of multi-drug resistant (MDR) malaria infections. Instead of using a battery of resistant lines, a single MDR Plasmodium yoelii nigeriensis strain that shows a wide spectrum of drug resistance to high doses of chloroquine, mepacrine, amodiaquine, mefloquine, quinine, quinidine, halofantrine as well as tetracyclines, fluoroquinolines and erythromycin, was used to assess the blood schizontocidal efficacy of a new macrolide azithromycin and other antibiotics. The present study shows that only azithromycin has the potential to control an MDR P. y. nigeriensis infection in Swiss mice, provided the treatment with a dose of 50–100 mg/kg/day by oral route is continued for a period of 7 days. Tetracycline, oxytetracycline, doxycyline, erythromycin, ciprofloxacin and norfloxacin, although active in vitro, failed to protect the mice. Tetracycline, ciprofloxacin and norfloxacin combinations with chloroquine did not control the infection. Additionally, the antimalarial efficacy of azithromycin can be potentiated with the addition of arteether, which is an ethyl ether derivative of artemisinin. A total (100%) curative effect has been obtained with a shorter regimen of 4 days only.


2021 ◽  
Vol 14 (8) ◽  
pp. 791
Author(s):  
Irving Balbuena-Rebolledo ◽  
Itzia Irene Padilla-Martínez ◽  
Martha Cecilia Rosales-Hernández ◽  
Martiniano Bello

Repurposing studies have identified several FDA-approved compounds as potential inhibitors of the intracellular domain of epidermal growth factor receptor 1 (EGFR) and human epidermal receptor 2 (HER2). EGFR and HER2 represent important targets for the design of new drugs against different types of cancer, and recently, differences in affinity depending on active or inactive states of EGFR or HER2 have been identified. In this study, we first identified FDA-approved compounds with similar structures in the DrugBank to lapatinib and gefitinib, two known inhibitors of EGFR and HER2. The selected compounds were submitted to docking and molecular dynamics MD simulations with the molecular mechanics generalized Born surface area approach to discover the conformational and thermodynamic basis for the recognition of these compounds on EGFR and HER2. These theoretical studies showed that compounds reached the ligand-binding site of EGFR and HER2, and some of the repurposed compounds did not interact with residues involved in drug resistance. An in vitro assay performed on two different breast cancer cell lines, MCF-7, and MDA-MB-23, showed growth inhibitory activity for these repurposed compounds on tumorigenic cells at micromolar concentrations. These repurposed compounds open up the possibility of generating new anticancer treatments by targeting HER2 and EGFR.


BMC Biology ◽  
2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Amy L. Burns ◽  
Brad E. Sleebs ◽  
Ghizal Siddiqui ◽  
Amanda E. De Paoli ◽  
Dovile Anderson ◽  
...  

Abstract Background Resistance to front-line antimalarials (artemisinin combination therapies) is spreading, and development of new drug treatment strategies to rapidly kill Plasmodium spp. malaria parasites is urgently needed. Azithromycin is a clinically used macrolide antibiotic proposed as a partner drug for combination therapy in malaria, which has also been tested as monotherapy. However, its slow-killing ‘delayed-death’ activity against the parasite’s apicoplast organelle and suboptimal activity as monotherapy limit its application as a potential malaria treatment. Here, we explore a panel of azithromycin analogues and demonstrate that chemical modifications can be used to greatly improve the speed and potency of antimalarial action. Results Investigation of 84 azithromycin analogues revealed nanomolar quick-killing potency directed against the very earliest stage of parasite development within red blood cells. Indeed, the best analogue exhibited 1600-fold higher potency than azithromycin with less than 48 hrs treatment in vitro. Analogues were effective against zoonotic Plasmodium knowlesi malaria parasites and against both multi-drug and artemisinin-resistant Plasmodium falciparum lines. Metabolomic profiles of azithromycin analogue-treated parasites suggested activity in the parasite food vacuole and mitochondria were disrupted. Moreover, unlike the food vacuole-targeting drug chloroquine, azithromycin and analogues were active across blood-stage development, including merozoite invasion, suggesting that these macrolides have a multi-factorial mechanism of quick-killing activity. The positioning of functional groups added to azithromycin and its quick-killing analogues altered their activity against bacterial-like ribosomes but had minimal change on ‘quick-killing’ activity. Apicoplast minus parasites remained susceptible to both azithromycin and its analogues, further demonstrating that quick-killing is independent of apicoplast-targeting, delayed-death activity. Conclusion We show that azithromycin and analogues can rapidly kill malaria parasite asexual blood stages via a fast action mechanism. Development of azithromycin and analogues as antimalarials offers the possibility of targeting parasites through both a quick-killing and delayed-death mechanism of action in a single, multifactorial chemotype.


Author(s):  
WAHYU FITRIANA ◽  
ARRY YANUAR ◽  
ADE ARSIANTI ◽  
HIROKI TANIMOTO ◽  
KIYOMI KAKIUCHI

Objective: The emergence of malaria as a global health problem over the past few decades, accompanied by the rise of chemoresistant strains ofPlasmodium falciparum, has emphasized the need for the discovery of new therapeutic drugs against this disease. In this study, enantiomericallyenriched (enantioenriched) analogs of triclosan were synthesized and evaluated for antimalarial activity against P. falciparum cultures.Methods: Enantioselective dihydroxylation of the olefin in amide seven was performed efficiently using chiral quinine ligand (DHQ)2PHAL to yieldenantioenriched dihydroxy propionamide derivative (+)-1 in moderate yields. In a similar way, the chiral quinidine ligand (DHQD)2PHAL was used asstereoselectivity agent yielded the desired enantioenriched (−)-1. The enantioenriched products were used for further in vitro assay, and accordingly thepercent enantiomeric excess (% ee) was not determined. The structures of compounds were proven by spectral data (1H NMR, 13C NMR, and mass spectra).Results: The phenol moiety at the C1 position of triclosan was chemically substituted with a methoxy group, in conjunction with an introducedstereocenter in a 2,3-dihydroxy-propionamide group at C2’ position. Unmodified triclosan inhibited the P. falciparum cultures with an IC50 value of27.2 μM. By contrast, the triclosan analogs, compounds (+)-1 and (−)-1, inhibited the P. falciparum cultures with IC50 values of 0.034 and 0.028 μM,respectively.Conclusion: Collectively, our preliminary in vitro results suggest that these triclosan analogs have potent antimalarial activity and represent apromising new treatment strategy on further development.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Dejen Nureye ◽  
Solomon Assefa ◽  
Teshome Nedi ◽  
Ephrem Engidawork

Background. Evolution of antimalarial drug resistance makes the development of new drugs a necessity. Important source in search of such drugs is medicinal plants.Gardenia ternifoliaplant is used in Ethiopian traditional medicine for the treatment of malaria and is endowed within vitroantimalarial activity. Herein, thein vivoantimalarial activity of the plant was investigated.Methods. Acute toxicity was carried out using a standard procedure. A 4-day suppressive test was employed to evaluate the antimalarial effect of methanolic crude extract and solvent fractions of the plant. The curative and prophylactic effect of crude extract was further tested by Ranes’s test and residual infection procedure, respectively, usingPlasmodium berghei(ANKA strain) in Swiss albino mice.Results. The chemosuppressive effect exerted by the crude extract and fractions ranged between 30-59% and 14-51%, respectively. Curative and prophylactic effects of the crude extract were in the range of 36-63% and 24-37%, respectively. All dose levels of the crude extract prevented loss of weight, reduction in temperature, and anemia on early and established infection. Butanol and chloroform fractions also did reverse reduction in temperature, body weight, and packed cell volume.Conclusions. The results indicated that the plant has a promising antiplasmodial activity and it could be considered as a potential source to develop new antimalarial agents.


2016 ◽  
Vol 60 (7) ◽  
pp. 4217-4228 ◽  
Author(s):  
Souvik Sarkar ◽  
Asim A. Siddiqui ◽  
Shubhra J. Saha ◽  
Rudranil De ◽  
Somnath Mazumder ◽  
...  

ABSTRACTWe synthesized a new series of conjugated hydrazones that were found to be active against malaria parasitein vitro, as well asin vivoin a murine model. These hydrazones concentration-dependently chelated free iron and offered antimalarial activity. Upon screening of the synthesized hydrazones, compound 5f was found to be the most active iron chelator, as well as antiplasmodial. Compound 5f also interacted with free heme (KD[equilibrium dissociation constant] = 1.17 ± 0.8 μM), an iron-containing tetrapyrrole released after hemoglobin digestion by the parasite, and inhibited heme polymerization by parasite lysate. Structure-activity relationship studies indicated that a nitrogen- and sulfur-substituted five-membered aromatic ring present within the benzothiazole hydrazones might be responsible for their antimalarial activity. The dose-dependent antimalarial and heme polymerization inhibitory activities of the lead compound 5f were further validated by following [3H]hypoxanthine incorporation and hemozoin formation in parasite, respectively. It is worth mentioning that compound 5f exhibited antiplasmodial activityin vitroagainst a chloroquine/pyrimethamine-resistant strain ofPlasmodium falciparum(K1). We also evaluatedin vivoantimalarial activity of compound 5f in a murine model where a lethal multiple-drug-resistant strain ofPlasmodium yoeliiwas used to infect Swiss albino mice. Compound 5f significantly suppressed the growth of parasite, and the infected mice experienced longer life spans upon treatment with this compound. Duringin vitroandin vivotoxicity assays, compound 5f showed minimal alteration in biochemical and hematological parameters compared to control. In conclusion, we identified a new class of hydrazone with therapeutic potential against malaria.


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