The Evaluation of Metal Co-ordinating Bis-Thiosemicarbazones as Potential Anti-malarial Agents

2019 ◽  
Vol 15 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Fady N. Akladios ◽  
Scott D. Andrew ◽  
Samantha J. Boog ◽  
Carmen de Kock ◽  
Richard K. Haynes ◽  
...  

Background:The emergence of resistance to the artemisinins which are the current mainstays for antimalarial chemotheraphy has created an environment where the development of new drugs acting in a mechanistally discrete manner is a priority.Objective:The goal of this work was to synthesize ane evaluate bis-thiosemicarbazones as potential antimalarial agents. </P><P> Methods: Fifteen compounds were generated using two condensation protocols and evaluated in vitro against the NF54 (CQ sensitive) strain of Plasmodium falciparum. A preliminary assessment of the potential for human toxicity was conducted in vitro against the MRC5 human lung fibroblast line.Results:The activity of the bis-thiosemicarbazones was highly dependent on the nature of the arene at the core of the structure. The inclusion of a non-coordinating benzene core resulted in inactive compounds, while the inclusion of a pyridyl core resulted in compounds of moderate or potent antimalarial activity (4 compounds showing IC50 < 250 nM).Conclusion:Bis-thiosemicarbazones containing a central pyridyl core display potent antimalarial activity in vitro. Sequestration and activation of ferric iron appears to play a significant role in this activity. Ongoing studies are aimed at further development of this series as potential antimalarials.

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.


2009 ◽  
Vol 81 (4) ◽  
pp. 715-740 ◽  
Author(s):  
Alaíde B. Oliveira ◽  
Maria Fâni Dolabela ◽  
Fernão C. Braga ◽  
Rose L.R.P. Jácome ◽  
Fernando P. Varotti ◽  
...  

Malaria remains one of the most serious world health problem and the major cause of mortality and morbidity in the endemic regions. Brazil is among the 30 high-burden countries and most of the cases occur in the Legal Amazonian Region. New chemotherapeutical agents are needed for the treatment of malaria. Many plant species are used in traditional medicines of malarious countries and a relatively few number of these have been investigated for evaluation of their antimalarial effect. Still lower is the number of those that have had the active natural compounds isolated and the toxicity determined. This area is, then, of great research interest. discovery project of antimalarial natural products from plants traditionally used to treat malaria must include in vitro and in vivo assays as well as bioguided isolation of active compounds. The final products would be antimalarial chemical entities, potential new drugs or templates for new drugs development, and/or standardized antimalarial extracts which are required for pre-clinical and clinical studies when the aim is the development of effective and safe phythomedicines. This review discusses these two approaches, presents briefly the screening methodologies for evaluation of antimalarial activity and focuses the activity of alkaloids belonging to different structural classes as well as its importance as new antimalarial drugs or leads and chemical markers for phytomedicines.


2020 ◽  
Vol 16 ◽  
Author(s):  
Haicheng Liu ◽  
Yushi Futamura ◽  
Honghai Wu ◽  
Aki Ishiyama ◽  
Taotao Zhang ◽  
...  

Background: Malaria is one of the most devastating parasitic diseases, yet the discovery of antimalarial agents remains profoundly challenging. Very few new antimalarials have been developed in the past 50 years, while the emergence of drug-resistance continues to appear. Objective: This study focuses on the discovery, design, synthesis, and antimalarial evaluation of 3-cinnamamido-N-substituted benzamides. Method: In this study, a screening of our compound library was carried out against the multidrug-sensitive Plasmodium falciparum 3D7 strain. Derivatives of the hit were designed, synthesized and tested against P. falciparum 3D7 and the in vivo antimalarial activity of the most active compounds was evaluated using the method of Peters’ 4-day suppressive test. Results: The retrieved hit compound 1 containing a 3-cinnamamido-N-substituted benzamide skeleton showed moderate antimalarial activity (IC50 = 1.20 µM) for the first time. A series of derivatives were then synthesized through a simple four-step workflow, and half of them exhibited slightly better antimalarial effect than the precursor 1 during the subsequent in vitro assays. Additionally, compounds 11, 23, 30 and 31 displayed potent activity with IC50 values of approximately 0.1 µM, and weak cytotoxicity against mammalian cells. However, in vivo antimalarial activity is not effective which might be ascribed to the poor solubility of these compounds. Conclusion: In this study, phenotypic screen of our compound library resulted in the first report of 3-cinnamamide framework with antimalarial activity and 40 derivatives were then designed and synthesized. Subsequent structure-activity studies showed that compounds 11, 23, 30 and 31 exhibited the most potent and selective activity against P. falciparum 3D7 strain with IC50 values around 0.1 µM. Our work herein sets another example of phenotypic screen-based drug discovery, leading to potentially promising candidates of novel antimalarial agents once given further optimization.


Author(s):  
Mehul Zaveri ◽  
Neha Kawathekar

Objective: Current therapies to treat P. falciparum malaria are heavily reliant on artemisinin-based combinations. However, resistance to artemisinin has recently been identified, and resistance to key artemisinin partner drugs is already widespread. Therefore, there is an urgent need for new antimalarial drugs with improved attributes over older therapies. The objective of this research work is to synthesize new antimalarial agents more effective against clinically relevant malarial strains.Methods: In present work, a series of ten 3-phenyl-2-thioxothiazolidin-4-one (MF1-MF10) derivatives, were synthesized by Knoevenagel condensation of N-phenyl rhodanine (I1) with substituted aromatic or hetro aromatic aldehydes using microwave irradiation. N-phenyl rhodanine (I1) was synthesized by a conventional reaction involving methyl-2-mercaptoacetate (1) and phenyl Isothiocyanates in presence of triethylamine. All the synthesized compounds were characterized by various spectroscopic techniques and evaluated for in-vitro antimalarial activity by microdilution technique against resistance strains of Plasmodium falciparum.Results: The antimalarial activity data showed that six compounds (MF1, MF3, MF4, MF5, MF7 and MF8) exhibited IC50 values ranging from 1.0-1.30 µg/ml, three compounds (MF2, MF6 and MF10) displayed IC50 values in the range of 0.9-1.0 µg/ml. Compound MF9 showed most significant result with maximum activity (IC50 = 0.85µg/ml).Conclusion: The antimalarial activity results revealed that compound MF9 possess potent activity and could be identified as a promising lead for further investigation.


Author(s):  
Saiful Arefeen Sazed ◽  
Ohedul Islam ◽  
Sarah L. Bliese ◽  
Muhammad Riadul Haque Hossainey ◽  
Jakaria Shawon ◽  
...  

The exploration of alternative antimalarial therapeutics is a requisite for the emergence of resistance against Artemisinin. Considering the required cost and time length of classical small molecule drug discovery process, phytochemical screening of traditionally used medicinal plant which are repertoire of active compounds with antimalarial activity has become popular. To investigate the antimalarial property of traditionally used medicinal plants, a number of Erythrina spp have been reviewed systematically where less studied E. fusca has been selected for further analysis. Phytochemical investigation yielded five compounds namely; Phaseolin, Phytol, &beta;-amyrin, Lupeol, and Stigmasterol. In-vitro antimalarial drug sensitivity HRP-II ELISA was carried out against chloroquine (CQ) sensitive 3D7 and CQ-resistant Dd2 strains. Extracts showed significant antimalarial activity against 3D7 and Dd2 strains (IC50 4.94 &ndash; 22 &micro;g/mL) and these compounds have been reported here for the first time. Molecular docking analysis showed high binding energy (&minus;9.0 &plusmn; 0.32 kcal/mole) indicating high degree of interaction between Phaseolin and 14 clinically important Plasmodium falciparum proteins at the active site. Stable interaction was also observed between ligand and protein from molecular dynamics simulation analysis with high free energy (&minus;75.156 &plusmn; 11.459) that substantiates the potential of Phaseolin as an antimalarial drug candidate.


2013 ◽  
Vol 57 (7) ◽  
pp. 3131-3136 ◽  
Author(s):  
Michael P. Draper ◽  
Beena Bhatia ◽  
Haregewein Assefa ◽  
Laura Honeyman ◽  
Lynne K. Garrity-Ryan ◽  
...  

ABSTRACTWith increasing resistance to existing antimalarials, there is an urgent need to discover new drugs at affordable prices for countries in which malaria is endemic. One approach to the development of new antimalarial drugs is to improve upon existing antimalarial agents, such as the tetracyclines. Tetracyclines exhibit potent, albeit relatively slow, action against malaria parasites, and doxycycline is used for both treatment (with other agents) and prevention of malaria. We synthesized 18 novel 7-position modified tetracycline derivatives and screened them for activity against cultured malaria parasites. Compounds with potentin vitroactivity and other favorable drug properties were further tested in a rodent malaria model. Ten compounds inhibited the development of culturedPlasmodium falciparumwith a 50% inhibitory concentration (IC50) after 96 h of incubation of <30 nM, demonstrating activity markedly superior to that of doxycycline (IC50at 96 h of 320 nM). Most compounds showed little mammalian cell cytotoxicity and no evidence ofin vitrophototoxicity. In a murinePlasmodium bergheimodel, 13 compounds demonstrated improved activity relative to that of doxycycline. In summary, 7-position modified tetracyclines offer improved activity against malaria parasites compared to doxycycline. Optimized compounds may allow lower doses for treatment and chemoprophylaxis. If safety margins are adequate, dosing in children, the group at greatest risk for malaria in countries in which it is endemic, may be feasible.


2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Dina Coertzen ◽  
Janette Reader ◽  
Mariëtte van der Watt ◽  
Sindisiwe H. Nondaba ◽  
Liezl Gibhard ◽  
...  

ABSTRACT The emergence of resistance toward artemisinin combination therapies (ACTs) by the malaria parasite Plasmodium falciparum has the potential to severely compromise malaria control. Therefore, the development of new artemisinins in combination with new drugs that impart activities toward both intraerythrocytic proliferative asexual and transmissible gametocyte stages, in particular, those of resistant parasites, is urgently required. We define artemisinins as oxidant drugs through their ability to oxidize reduced flavin cofactors of flavin disulfide reductases critical for maintaining redox homeostasis in the malaria parasite. Here we compare the activities of 10-amino artemisinin derivatives toward the asexual and gametocyte stages of P. falciparum parasites. Of these, artemisone and artemiside inhibited asexual and gametocyte stages, particularly stage V gametocytes, in the low-nanomolar range. Further, treatment of both early and late gametocyte stages with artemisone or artemiside combined with the pro-oxidant redox partner methylene blue displayed notable synergism. These data suggest that modulation of redox homeostasis is likely an important druggable process, particularly in gametocytes, and this finding thereby enhances the prospect of using combinations of oxidant and redox drugs for malaria control.


2019 ◽  
Vol 24 ◽  
pp. 2515690X1988532 ◽  
Author(s):  
Dagninet Derebe ◽  
Muluken Wubetu

Failure of the efficacy of antimalarial drugs is recognized in different classes of medicines for treating malaria, which urges the need for new drugs. This study tried to check the in vivo antimalarial activity of the root extracts of Acanthus polystachyus Delile against Plasmodium berghei–infected mice. The study revealed that the methanolic crude extract of the root of Acanthus polystachyus Delile showed significant ( P < .01) parasitemia suppressive activities in both models compared with the negative control. Parasitemia suppressive activities were 25.26%, 33.46%, and 51.48% in a 4-day suppressive test and 23.31%, 31.20%, and 43.54% in prophylaxis test at 100, 200, and 400 mg/kg of the extract, respectively, as compared to the negative control. Besides, the extract increases mean survival time significantly in all tested doses in a 4-day suppressive test, but in the prophylaxis model, only mice treated with 200 and 400 mg/kg significantly lived longer. Based on this finding, the root of Acanthus polystachyus Delile has strong antimalarial activity, which may be a good candidate for new antimalarial agents.


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.


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.


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