scholarly journals Computational approach to identify potential antileishmanial activity of reported inhibitor, E5700 and two natural alkaloids against Leishmania donovani Squalene Synthase

2020 ◽  
Vol 1 ◽  
Author(s):  
Padmika Wadanambi

AbstractLeishmania species are the causative agents for Leishmaniasis which is one of the neglected tropical diseases causing 70,000 deaths worldwide each year. Squalene synthase enzyme plays a vital role in sterol metabolism which is essential for Leishmania parasite viability. Therefore squalene synthase of Leishmania donovani is a therapeutic target to inhibit growth of parasite. The 3D model of Leishmania donovani Squalene Synthase (LdSQS) was generated by homology modeling and validated through PROCHECK, ERRAT, VERIFY3D and PROSA tools. Virtual screening of the protein was performed by AutoDock with reported inhibitor, E5700 and two natural alkaloids. Molecular interactions were explored to understand the nature of intermolecular bonds between active ligand and the protein binding site residues using UCSF Chimera and PLIP server. The reported inhibitor showed the best binding affinity (-9.75 kcal/mol) closely followed by Ancistrotanzanine B (-9.55 kcal/mol) and Holamine (-8.79 kcal/mol). Ancistrotanzanine B showed low binding energy and permissible ADMET properties. Based on the present study, homology model of LdSQS and Ancistrotanzanine B can be used to design inhibitors with antileishmanial activity.


2020 ◽  
Vol 35 (1) ◽  
pp. 51-58
Author(s):  
Tamirat Tekassa ◽  
Yitagesu Tewabe ◽  
Daniel Bisrat ◽  
Asrat Hailu ◽  
Kaleab Asres

Aloe ghibensis Sebsebe & Friis is traditionally used in Ethiopia for the treatment of various ailments including skin problem, wounds and malaria. Phytochemical constituents and antileshimanial properties of the leaf latex of A. ghibensis have not been reported. The objective of this study was, therefore, to determine the phytochemical constituents and in vitro antileishmanial activities of the leaf latex of A. ghibensis and its major compounds against two Leishmania species. Preparative TLC was used to isolate compounds from the leaf latex of A. ghibensis and spectroscopic techniques including 1D- and 2D-NMR as well as ESI-MS were employed to elucidate structures of the isolated compounds. In vitro antileishmanial activity was performed against promastigotes and axenically cultured amastigotes of Leishmania aethiopica and Leishmania donovani clinical isolates using Alamar Blue assay. Phytochemical investigation led to the isolation of two major anthrones, identified as aloin A/B and 7-hydroxyaloin A/B. Both the leaf latex of A. ghibensis and isolated compounds showed antileishmanial activity with IC50 values ranging from 1.6 ± 0.43 to 3.64 ± 0.09 µg/ml and 1.87 ± 0.21 to 3.72 ± 0.12 against promastigotes and axenically cultured amastigotes of L. aethopica and L. donovani, respectively. Moreover, the test substances were found to be less toxic (LC50 = 145 ± 0.72 to 156 ± 0.08 µg/ml) than amphotericin B (LC50 = 12.11 ± 0.51 µg/ml) towards human monocytic cell line (THP-1). The present study revealed that the latex and pure compounds possess genuine antileishmanial activity with high selectivity indices (SIs). Therefore, the isolated compounds can be used as a scaffold for the development of effective drugs for leishmaniasis.  



2009 ◽  
Vol 58 (10) ◽  
pp. 1298-1302 ◽  
Author(s):  
Ursula Fürnkranz ◽  
Markus Nagl ◽  
Waldemar Gottardi ◽  
Ulrich Matt ◽  
Horst Aspöck ◽  
...  

Protozoan parasites of the genus Leishmania are the causative agents of life-threatening visceral as well as cutaneous and mucocutaneous leishmaniasis. First-line drugs are antimonials, but toxicity and resistance in some endemic areas cause serious problems. In the current study, the antileishmanial activity of the weak oxidant N-chlorotaurine (NCT) was investigated. NCT is a derivative of the amino acid taurine produced by granulocytes and monocytes during oxidative burst, but can also be synthesized chemically and used topically as an antiseptic at a concentration of 1 % (55 mM) in vivo. NCT susceptibility tests were performed in vitro with promastigotes and amastigotes of Leishmania infantum and Leishmania donovani. As NH4Cl is known to increase the activity of NCT by the formation of monochloramine (NH2Cl), co-treatment assays were included in the study. Mean EC50 values after 1 h of treatment were 5.94 mM for L. infantum and 9.8 mM for L. donovani promastigotes. Co-treatment with 5.5 mM NCT plus 19 mM NH4Cl led to complete killing of promastigotes of both strains within 15 min. Amastigotes were inactivated by treatment with 2 mM NCT alone. The results of this study indicate a high potential of NCT against Leishmania species.



2020 ◽  
Vol 26 ◽  
Author(s):  
Luíza Dantas-Pereira ◽  
Edézio F. Cunha-Junior ◽  
Valter V. Andrade-Neto ◽  
John F. Bower ◽  
Guilherme A. M. Jardim ◽  
...  

: Chagas disease, Sleeping sickness and Leishmaniasis, caused by trypanosomatids Trypanosoma cruzi, Trypanosoma brucei and Leishmania spp., respectively, are considered neglected tropical diseases, and they especially affect impoverished populations in the developing world. The available chemotherapies are very limited and a search for alternatives is still necessary. In folk medicine, natural naphthoquinones have been employed for the treatment of a great variety of illnesses, including parasitic infections. This review is focused on the anti-trypanosomatid activity and mechanistic analysis of naphthoquinones and derivatives. Among all the series of derivatives tested in vitro, naphthoquinone-derived 1,2,3-triazoles were very active on T. cruzi infective forms in blood bank conditions, as well as in amastigotes of Leishmania spp. naphthoquinones containing a CF3 on a phenyl amine ring inhibited T. brucei proliferation in the nanomolar range, and naphthopterocarpanquinones stood out for their activity on a range of Leishmania species. Some of these compounds showed a promising selectivity index (SI) (30 to 1900), supporting further analysis in animal models. Indeed, high toxicity to the host and inactivation by blood components are crucial obstacles to be overcome to use naphthoquinones and/or their derivatives for chemotherapy. Multidisciplinary initiatives embracing medicinal chemistry, bioinformatics, biochemistry, and molecular and cellular biology need to be encouraged to allow the optimization of these compounds. Large scale automated tests are pivotal for the efficiency of the screening step, and subsequent evaluation of both the mechanism of action in vitro and pharmacokinetics in vivo are essential for the development of a novel, specific and safe derivative, minimizing adverse effects.



Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 458
Author(s):  
Emmanuel Broni ◽  
Samuel K. Kwofie ◽  
Seth O. Asiedu ◽  
Whelton A. Miller ◽  
Michael D. Wilson

The huge burden of leishmaniasis caused by the trypanosomatid protozoan parasite Leishmania is well known. This illness was included in the list of neglected tropical diseases targeted for elimination by the World Health Organization. However, the increasing evidence of resistance to existing antimonial drugs has made the eradication of the disease difficult to achieve, thus warranting the search for new drug targets. We report here studies that used computational methods to identify inhibitors of receptors from natural products. The cell division cycle-2-related kinase 12 (CRK12) receptor is a plausible drug target against Leishmania donovani. This study modelled the 3D molecular structure of the L. donovani CRK12 (LdCRK12) and screened for small molecules with potential inhibitory activity from African flora. An integrated library of 7722 African natural product-derived compounds and known inhibitors were screened against the LdCRK12 using AutoDock Vina after performing energy minimization with GROMACS 2018. Four natural products, namely sesamin (NANPDB1649), methyl ellagic acid (NANPDB1406), stylopine (NANPDB2581), and sennecicannabine (NANPDB6446) were found to be potential LdCRK12 inhibitory molecules. The molecular docking studies revealed two compounds NANPDB1406 and NANPDB2581 with binding affinities of −9.5 and −9.2 kcal/mol, respectively, against LdCRK12 which were higher than those of the known inhibitors and drugs, including GSK3186899, amphotericin B, miltefosine, and paromomycin. All the four compounds were predicted to have inhibitory constant (Ki) values ranging from 0.108 to 0.587 μM. NANPDB2581, NANPDB1649 and NANPDB1406 were also predicted as antileishmanial with Pa and Pi values of 0.415 and 0.043, 0.391 and 0.052, and 0.351 and 0.071, respectively. Molecular dynamics simulations coupled with molecular mechanics Poisson–Boltzmann surface area (MM/PBSA) computations reinforced their good binding mechanisms. Most compounds were observed to bind in the ATP binding pocket of the kinase domain. Lys488 was predicted as a key residue critical for ligand binding in the ATP binding pocket of the LdCRK12. The molecules were pharmacologically profiled as druglike with inconsequential toxicity. The identified molecules have scaffolds that could form the backbone for fragment-based drug design of novel leishmanicides but warrant further studies to evaluate their therapeutic potential.



Author(s):  
Kuldeepsingh A. Kalariya ◽  
Ram Prasnna Meena ◽  
Lipi Poojara ◽  
Deepa Shahi ◽  
Sandip Patel

Abstract Background Squalene synthase (SQS) is a rate-limiting enzyme necessary to produce pentacyclic triterpenes in plants. It is an important enzyme producing squalene molecules required to run steroidal and triterpenoid biosynthesis pathways working in competitive inhibition mode. Reports are available on information pertaining to SQS gene in several plants, but detailed information on SQS gene in Gymnema sylvestre R. Br. is not available. G. sylvestre is a priceless rare vine of central eco-region known for its medicinally important triterpenoids. Our work aims to characterize the GS-SQS gene in this high-value medicinal plant. Results Coding DNA sequences (CDS) with 1245 bp length representing GS-SQS gene predicted from transcriptome data in G. sylvestre was used for further characterization. The SWISS protein structure modeled for the GS-SQS amino acid sequence data had MolProbity Score of 1.44 and the Clash Score 3.86. The quality estimates and statistical score of Ramachandran plots analysis indicated that the homology model was reliable. For full-length amplification of the gene, primers designed from flanking regions of CDS encoding GS-SQS were used to get amplification against genomic DNA as template which resulted in approximately 6.2-kb sized single-band product. The sequencing of this product through NGS was carried out generating 2.32 Gb data and 3347 number of scaffolds with N50 value of 457 bp. These scaffolds were compared to identify similarity with other SQS genes as well as the GS-SQSs of the transcriptome. Scaffold_3347 representing the GS-SQS gene harbored two introns of 101 and 164 bp size. Both these intronic regions were validated by primers designed from adjoining outside regions of the introns on the scaffold representing GS-SQS gene. The amplification took place when the template was genomic DNA and failed when the template was cDNA confirmed the presence of two introns in GS-SQS gene in Gymnema sylvestre R. Br. Conclusion This study shows GS-SQS gene was very closely related to Coffea arabica and Gardenia jasminoides and this gene harbored two introns of 101 and 164 bp size.





Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4204
Author(s):  
George E. Magoulas ◽  
Pantelis Afroudakis ◽  
Kalliopi Georgikopoulou ◽  
Marina Roussaki ◽  
Chiara Borsari ◽  
...  

A library of seventeen novel ether phospholipid analogues, containing 5-membered heterocyclic rings (1,2,3-triazolyl, isoxazolyl, 1,3,4-oxadiazolyl and 1,2,4-oxadiazolyl) in the lipid portion were designed and synthesized aiming to identify optimised miltefosine analogues. The compounds were evaluated for their in vitro antiparasitic activity against Leishmania infantum and Leishmania donovani intracellular amastigotes, against Trypanosoma brucei brucei and against different developmental stages of Trypanosoma cruzi. The nature of the substituents of the heterocyclic ring (tail) and the oligomethylene spacer between the head group and the heterocyclic ring was found to affect the activity and toxicity of these compounds leading to a significantly improved understanding of their structure–activity relationships. The early ADMET profile of the new derivatives did not reveal major liabilities for the potent compounds. The 1,2,3-triazole derivative 27 substituted by a decyl tail, an undecyl spacer and a choline head group exhibited broad spectrum antiparasitic activity. It possessed low micromolar activity against the intracellular amastigotes of two L. infantum strains and T. cruzi Y strain epimastigotes, intracellular amastigotes and trypomastigotes, while its cytotoxicity concentration (CC50) against THP-1 macrophages ranged between 50 and 100 μM. Altogether, our work paves the way for the development of improved ether phospholipid derivatives to control neglected tropical diseases.



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