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Srinivas S, Senthil Kumar A. Electrical Wiring of Malarial Parasite Intermediate Hematin on a Tailored N-Doped Carbon Nanomaterial Surface and Its Bioelectrocatalytic Hydrogen Peroxide Reduction and Sensing. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:10634-10647. [PMID: 38723623 DOI: 10.1021/acs.langmuir.4c00583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Hematin, an iron-containing porphyrin compound, plays a crucial role in various biological processes, including oxygen transport, storage, and functionality of the malarial parasite. Specifically, hematin-Fe interacts with the nitrogen atom of antimalarial drugs, forming an intermediate step crucial for their function. The electron transfer functionality of hematin in biological systems has been scarcely investigated. In this study, we developed a biomimicking electrical wiring of hematin-Fe with a model N-drug system, represented as {hematin-Fe---N-drug}. We achieved this by immobilizing hematin on a multiwalled carbon nanotube (MWCNT)/N-graphene quantum dot (N-GQD) modified electrode (MWCNT/N-GQD@Hemat). N-GQD serves as a model molecular drug system containing nitrogen atoms to mimic the {hematin-Fe---N-drug} interaction. The prepared bioelectrode exhibited a distinct redox peak at a measured potential (E1/2) of -0.410 V vs Ag/AgCl, accompanied by a surface excess value of 3.54 × 10-9 mol cm-2. This observation contrasts significantly with the weak or electroinactive electrochemical responses documented in literature-based hematin systems. We performed a comprehensive set of physicochemical and electrochemical characterizations on the MWCNT/N-GQD@Hemat system, employing techniques including FESEM, TEM, Raman spectroscopy, IR spectroscopy, and AFM. To evaluate the biomimetic electrode's electroactivity, we investigated the selective-mediated reduction of H2O2 as a model system. As an important aspect of our research, we demonstrated the use of scanning electrochemical microscopy to visualize the in situ electron transfer reaction of the biomimicking electrode. In an independent study, we showed enzyme-less electrocatalytic reduction and selective electrocatalytic sensing of H2O2 with a detection limit of 319 nM. We achieved this using a batch injection analysis-coupled disposable screen-printed electrode system in physiological solution.
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Affiliation(s)
- Sakthivel Srinivas
- Nano and Bioelectrochemistry Research Laboratory, Carbon Dioxide Research and Green Technology Centre, Vellore 632014, India
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632 014, India
| | - Annamalai Senthil Kumar
- Nano and Bioelectrochemistry Research Laboratory, Carbon Dioxide Research and Green Technology Centre, Vellore 632014, India
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore 632 014, India
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Suhail M. The Target Determination and the Mechanism of Action of Chiral-Antimalarial Drugs: A Docking Approach. JOURNAL OF COMPUTATIONAL BIOPHYSICS AND CHEMISTRY 2021. [DOI: 10.1142/s2737416521500290] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Due to an undecided target and the prescription of chiral-aminoquinolines (chloroquine, primaquine and quinacrine) in the racemic form, the mechanism of action as well as the reason of causing side effects become unclear. Based on computationally evaluated literature data, the things determined theoretically were (i) the target of aminoquinolines during antimalarial activity, (ii) the mechanism of action of chiral-aminoquinolines and (iii) biologically active enantiomers of aminoquinolines. For the presented study, the enantiomeric binding affinities of aminoquinolines with all the targets claimed by other scientists were calculated, and then used in interpretation with the help of many investigations done/observed by others. The results were very interesting based on which, a new and acceptable mechanism of action of chiral-aminoquinolines during malaria curing step, is given for the first time. The current docking study not only resolves the questionable point about a definite target of aminoquinolines but also makes the mechanism of action understandable.
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Affiliation(s)
- Mohd. Suhail
- Department of Chemistry, Jamia Millia Islamia (A Central University), Jamia Nagar, New Delhi 110025, India
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Evidence for in vitro and in vivo activity of the antimalarial pyronaridine against Schistosoma. PLoS Negl Trop Dis 2021; 15:e0009511. [PMID: 34166393 PMCID: PMC8263063 DOI: 10.1371/journal.pntd.0009511] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 07/07/2021] [Accepted: 05/27/2021] [Indexed: 11/19/2022] Open
Abstract
Background Schistosomiasis is highly prevalent in Africa. Praziquantel is effective against adult schistosomes but leaves prepatent stages unaffected—which is a limit to patient management and elimination. Given the large-scale use of praziquantel, development of drug resistance by Schistosoma is feared. Antimalarials are promising drugs for alternative treatment strategies of Schistosoma infections. Development of drugs with activity against both malaria and schistosomiasis is particularly appealing as schistosome infections often occur concomitantly with malaria parasites in sub-Saharan Africa. Therefore, antiplasmodial compounds were progressively tested against Schistosoma in vitro, in mice, and in a clinical study. Results Amongst 16 drugs and 1 control tested, pyronaridine, methylene blue and 5 other antimalarials were highly active in vitro against larval stage schistosomula with a 50% inhibitory concentration below 10 μM. Both drugs were lethal to ex vivo adult worms tested at 30 μM with methylene blue also active at 10 μM. Pyronaridine treatment of mice infected with S. mansoni at the prepatent stage reduced worm burden by 82% and cured 7 out of 12 animals, however in mice adult stages remained viable. In contrast, methylene blue inhibited adult worms by 60% but cure was not achieved. In an observational pilot trial in Gabon in children, the antimalarial drug combination pyronaridine-artesunate (Pyramax) reduced S. haematobium egg excretion from 10/10 ml urine to 0/10 ml urine, and 3 out of 4 children were cured. Conclusion Pyronaridine and methylene blue warrant further investigation as candidates for schistosomiasis treatment. Both compounds are approved for human use and evidence for their potential as antischistosomal compounds can be obtained directly from clinical testing. Particularly, pyronaridine-artesunate, already available as an antimalarial drug, calls for further clinical evaluation. Trial registration ClinicalTrials.gov Identifier NCT03201770. Praziquantel is still the only drug in use for the treatment of all Schistosoma spp. and is exclusively active against the adult life cycle stage, since schistosomes in the prepatent period of up to eight weeks are not affected by the drug. Although resistance to praziquantel has not been confirmed and its existence remains controversial, some countries have identified clinical schistosome isolates with reduced sensitivity to praziquantel, after deployment in mass drug administration programs. The need for a new antischistosomal compound is urgent, ideally exhibiting broad activity against all stages of the parasite’s life cycle present in humans. After testing a series of antiplasmodial compounds, the authors found that several compounds also exhibited antischistosomal activity at various life cycle stages of the worms, including pyronaridine and methylene blue, both compounds already approved for human use. A pilot trial with pyronaridine-artesunate done in Gabon showed the first promising results against Schistosoma infections.
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Osman CP, Ismail NH, Widyawaruyanti A, Imran S, Tumewu L, Choo CY, Ideris S. Evaluation of a Series of 9,10-Anthraquinones as Antiplasmodial Agents. LETT DRUG DES DISCOV 2019. [DOI: 10.2174/1570180815666180607085102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background: A phytochemical study on medicinal plants used for the treatment of fever
and malaria in Africa yielded metabolites with potential antiplasmodial activity, many of which are
Anthraquinones (AQ). AQs have similar sub-structure as naphthoquinones and xanthones, which
were previously reported as novel antiplasmodial agents.
</P><P>
Objective: The present study aimed to investigate the structural requirements of 9,10-
anthraquinones with hydroxy, methoxy and methyl substituents to exert strong antiplasmodial activity
and to investigate their possible mode of action.
</P><P>
Methods: Thirty-one AQs were synthesized through Friedel-Crafts reaction and assayed for antiplasmodial
activity in vitro against Plasmodium falciparum (3D7). The selected compounds were
tested for toxicity and probed for their mode of action against β-hematin dimerization through
HRP2 and lipid catalyses. The most active compounds were subjected to a docking study using
AutoDock 4.2.
</P><P>
Results: The active AQs have similar common structural characteristics. However, it is difficult to
establish a structure-activity relationship as certain compounds are active despite the absence of the
structural features exhibited by other active AQs. They have either ortho- or meta-arranged
substituents and one free hydroxyl and/or carbonyl groups. When C-6 is substituted with a methyl
group, the activity of AQs generally increased. 1,3-DihydroxyAQ (15) showed good antiplasmodial
activity with an IC50 value of 1.08 µM, and when C-6 was substituted with a methyl group, 1,3-
dihydroxy-6-methylAQ (24) showed stronger antiplasmodial activity with an IC50 value of 0.02
µM, with better selectivity index. Compounds 15 and 24 showed strong HRP2 activity and mild
toxicity against hepatocyte cells. Molecular docking studies showed that the hydroxyl groups at the
ortho (23) and meta (24) positions are able to form hydrogen bonds with heme, of 3.49 Å and 3.02
Å, respectively.
</P><P>
Conclusion: The activity of 1,3-dihydroxy-6-methylAQ (24) could be due to their inhibition against
the free heme dimerization by inhibiting the HRP2 protein. It was further observed that the
anthraquinone moiety of compound 24 bind in parallel to the heme ring through hydrophobic interactions,
thus preventing crystallization of heme into hemozoin.
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Affiliation(s)
- Che Puteh Osman
- Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
| | - Nor Hadiani Ismail
- Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
| | - Aty Widyawaruyanti
- Department of Pharmacognosy and Phytochemistry, Faculty of Pharmacy, Universitas Airlangga, Surabaya 60286, Indonesia
| | - Syahrul Imran
- Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
| | - Lidya Tumewu
- Department of Pharmacognosy and Phytochemistry, Faculty of Pharmacy, Universitas Airlangga, Surabaya 60286, Indonesia
| | - Chee Yan Choo
- MedChem Herbal Research Group, Faculty of Pharmacy, Universiti Teknologi MARA, 42300 Bandar Puncak Alam, Selangor, Malaysia
| | - Sharinah Ideris
- MedChem Herbal Research Group, Faculty of Pharmacy, Universiti Teknologi MARA, 42300 Bandar Puncak Alam, Selangor, Malaysia
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Osman CP, Ismail NH. Antiplasmodial Anthraquinones from Medicinal Plants: The Chemistry and Possible Mode of Actions. Nat Prod Commun 2018. [DOI: 10.1177/1934578x1801301207] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Malaria killed nearly half a million people in 2015, and 70% of this victims were young children. Malarial chemotherapy makes use of several drugs, each with its own pharmacological limitations, and with parasite resistance being the most challenging. People of low income nations often rely on traditional medicine as a treatment due to limited access to modern healthcare services. Despite uncertainties present in the outcome of traditional medicine, ethnomedicine approach has yielded important lead candidates. The investigation of medicinal plants utilized in the malaria endemic region yielded many antiplasmodial compounds with anthraquinone moiety. This paper describes natural anthraquinones extracted from medicinal plants utilized in traditional medicine for the treatment of malaria. In addition, the insight on structure-activity relationship and their mode of actions are also elaborated.
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Affiliation(s)
- Che Puteh Osman
- Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
- Atta-ur Rahman Institute of Natural Product Discovery, Universiti Teknologi MARA Cawangan Selangor, 42300 Bandar Puncak Alam, Selangor, Malaysia
| | - Nor Hadiani Ismail
- Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
- Atta-ur Rahman Institute of Natural Product Discovery, Universiti Teknologi MARA Cawangan Selangor, 42300 Bandar Puncak Alam, Selangor, Malaysia
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Evaluation of Phytochemistry and Some Biological Activities of Aerial Parts and Seed of Scrophularia Umbrosa Dumort. Jundishapur J Nat Pharm Prod 2017. [DOI: 10.5812/jjnpp.65054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Osman CP, Ismail NH. A REVIEW ON THE CHEMISTRY AND PHARMACOLOGY OF Rennellia elliptica Korth. INDONESIAN JOURNAL OF TROPICAL AND INFECTIOUS DISEASE 2017. [DOI: 10.20473/ijtid.v6i6.6642] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Rennellia elliptica, popularly dubbed as Malaysian Ginseng, is widely used in traditional medicine among the local Jakun community in Endau-Rompin State Park, Pahang, Malaysia. The decoction of the roots is traditionally taken for treatment of body aches, as postpartum tonic, as aphrodisiac and for the treatment of jaundice. In the effort of searching new botanical drugs and drug candidates from tropical rainforest, the team from this laboratory had conducted a sizeable phytochemical and biological screening program of tropical plant at Endau Rompin State Park, Pahang with the help from the indigenous people. R. elliptica showed strong antiplasmodial activity in vitro with the IC50 value of 4.04µg/mL. The comprehensive study on the root extract of R. elliptica in this laboratory yielded seventeen compounds from four different classes, including 2 new pyranoanthraquinones, one new anthraquinone, eleven known anthraquinones, one lactone triterpenoid, one coumarin and one phenolic acid. The chemical profile of the root extract was established using HPLC and the selected marker compounds were used as external standards and quantified using standard calibration curve. Nordamnacanthal 5, damnacanthal 7, 2-formyl-3-hydroxy-9,10-anthraquinone 6, 2-methyl-3-hydroxy-9,10-anthraquinone 11 and 1,2-dimethoxy-6-methyl-9,10-anthraquinone 3 were determined at 3.57, 10.32, 4.47, 12.18 and 4.09 µg/g, respectively. Owing to the toxicity of dichloromethane, the extraction of the desired marker compounds was attempted using accelerated solvent extraction and soxhlet extraction using ethanol and water at different compositions. R. elliptica root extract and the isolated anthraquinones showed potential antiplasmodial activity, and the active compounds were probed for their mode of action. In addition, the dichloromethane root extract of R. elliptica and the selected anthraquinones were screened for anticancer, antioxidant, and α-glucosidase inhibitory activities as well as toxicity study in vitro. The review summarizes the findings on Rennellia elliptica which includes phytochemistry, toxicity and its biological activities. The chemotaxonomic significance of Rennellia elliptica is also discussed
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Characterization of the commercially-available fluorescent chloroquine-BODIPY conjugate, LynxTag-CQGREEN, as a marker for chloroquine resistance and uptake in a 96-well plate assay. PLoS One 2014; 9:e110800. [PMID: 25343249 PMCID: PMC4208776 DOI: 10.1371/journal.pone.0110800] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 09/18/2014] [Indexed: 11/24/2022] Open
Abstract
Chloroquine was a cheap, extremely effective drug against Plasmodium falciparum until resistance arose. One approach to reversing resistance is the inhibition of chloroquine efflux from its site of action, the parasite digestive vacuole. Chloroquine accumulation studies have traditionally relied on radiolabelled chloroquine, which poses several challenges. There is a need for development of a safe and biologically relevant substitute. We report here a commercially-available green fluorescent chloroquine-BODIPY conjugate, LynxTag-CQGREEN, as a proxy for chloroquine accumulation. This compound localized to the digestive vacuole of the parasite as observed under confocal microscopy, and inhibited growth of chloroquine-sensitive strain 3D7 more extensively than in the resistant strains 7G8 and K1. Microplate reader measurements indicated suppression of LynxTag-CQGREEN efflux after pretreatment of parasites with known reversal agents. Microsomes carrying either sensitive- or resistant-type PfCRT were assayed for uptake; resistant-type PfCRT exhibited increased accumulation of LynxTag-CQGREEN, which was suppressed by pretreatment with known chemosensitizers. Eight laboratory strains and twelve clinical isolates were sequenced for PfCRT and Pgh1 haplotypes previously reported to contribute to drug resistance, and pfmdr1 copy number and chloroquine IC50s were determined. These data were compared with LynxTag-CQGREEN uptake/fluorescence by multiple linear regression to identify genetic correlates of uptake. Uptake of the compound correlated with the logIC50 of chloroquine and, more weakly, a mutation in Pgh1, F1226Y.
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Evaluation of in vitro antimalarial activity of different extracts of Artemisia aucheri Boiss. and A. armeniaca Lam. and fractions of the most potent extracts. ScientificWorldJournal 2014; 2014:825370. [PMID: 24558335 PMCID: PMC3914376 DOI: 10.1155/2014/825370] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/24/2013] [Indexed: 11/17/2022] Open
Abstract
Ten extracts with different polarity from two Iranian Artemisia species, A. armeniaca Lam. and A. aucheri Boiss, were screened for their antimalarial properties by in vitro
β-hematin formation assay. Dichloromethane (DCM) extracts of both plants showed significant antimalarial activities with IC50 values of 1.36 ± 0.01 and 1.83 ± 0.03 mg/mL and IC90 values of 2.12 ± 0.04 and 2.62 ± 0.09 mg/mL for A. armeniaca and A. aucheri, respectively. Bioactivity-guided fractionation of DCM extracts of both plants by vacuum liquid chromatography (VLC) over silica gel with solvent mixtures of increasing polarities afforded seven fractions. Two fractions from DCM extract of A. armeniaca and four fractions from DCM extract of A. aucheri showed potent antimalarial activity with reducing IC50 and IC90 values compared to extracts. The most potent fraction belonged to DCM extract of A. armeniaca with IC50 and IC90 values of 0.47 ± 0.006 and 0.71 ± 0.006 mg/mL, respectively.
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Alam A, Goyal M, Iqbal MS, Pal C, Dey S, Bindu S, Maity P, Bandyopadhyay U. Novel antimalarial drug targets: hope for new antimalarial drugs. Expert Rev Clin Pharmacol 2012; 2:469-89. [PMID: 22112223 DOI: 10.1586/ecp.09.28] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Malaria is a major global threat, that results in more than 2 million deaths each year. The treatment of malaria is becoming extremely difficult due to the emergence of drug-resistant parasites, the absence of an effective vaccine, and the spread of insecticide-resistant vectors. Thus, malarial therapy needs new chemotherapeutic approaches leading to the search for new drug targets. Here, we discuss different approaches to identifying novel antimalarial drug targets. We have also given due attention to the existing validated targets with a view to develop novel, rationally designed lead molecules. Some of the important parasite proteins are claimed to be the targets; however, further in vitro or in vivo structure-function studies of such proteins are crucial to validate these proteins as suitable targets. The interactome analysis among apicoplast, mitochondrion and genomic DNA will also be useful in identifying vital pathways or proteins regulating critical pathways for parasite growth and survival, and could be attractive targets. Molecules responsible for parasite invasion to host erythrocytes and ion channels of infected erythrocytes, essential for intra-erythrocyte survival and stage progression of parasites are also becoming attractive targets. This review will discuss and highlight the current understanding regarding the potential antimalarial drug targets, which could be utilized to develop novel antimalarials.
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Affiliation(s)
- Athar Alam
- Division of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Jadavpur, Kolkata-700032, West Bengal, India.
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