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Rants’o TA, van Greunen DG, van der Westhuizen CJ, Riley DL, Panayides JL, Koekemoer LL, van Zyl RL. The in silico and in vitro analysis of donepezil derivatives for Anopheles acetylcholinesterase inhibition. PLoS One 2022; 17:e0277363. [PMID: 36350894 PMCID: PMC9645637 DOI: 10.1371/journal.pone.0277363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 10/25/2022] [Indexed: 11/11/2022] Open
Abstract
Current studies on Anopheles anticholinesterase insecticides are focusing on identifying agents with high selectivity towards Anopheles over mammalian targets. Acetylcholinesterase (AChE) from electric eel is often used as the bioequivalent enzyme to study ligands designed for activity and inhibition in human. In this study, previously identified derivatives of a potent AChE, donepezil, that have exhibited low activity on electric eel AChE were assessed for potential AChE-based larvicidal effects on four African malaria vectors; An. funestus, An. arabiensis, An. gambiae and An. coluzzii. This led to the identification of four larvicidal agents with a lead molecule, 1-benzyl-N-(thiazol-2-yl) piperidine-4-carboxamide 2 showing selectivity for An. arabiensis as a larvicidal AChE agent. Differential activities of this molecule on An. arabiensis and electric eel AChE targets were studied through molecular modelling. Homology modelling was used to generate a three-dimensional structure of the An. arabiensis AChE for this binding assay. The conformation of this molecule and corresponding interactions with the AChE catalytic site was markedly different between the two targets. Assessment of the differences between the AChE binding sites from electric eel, human and Anopheles revealed that the electric eel and human AChE proteins were very similar. In contrast, Anopheles AChE had a smaller cysteine residue in place of bulky phenylalanine group at the entrance to the catalytic site, and a smaller aspartic acid residue at the base of the active site gorge, in place of the bulky tyrosine residues. Results from this study suggest that this difference affects the ligand orientation and corresponding interactions at the catalytic site. The lead molecule 2 also formed more favourable interactions with An. arabiensis AChE model than other Anopheles AChE targets, possibly explaining the observed selectivity among other assessed Anopheles species. This study suggests that 1-benzyl-N-(thiazol-2-yl) piperidine-4-carboxamide 2 may be a lead compound for designing novel insecticides against Anopheles vectors with reduced toxic potential on humans.
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Affiliation(s)
- Thankhoe A. Rants’o
- Pharmacology Division, Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- WITS Research Institute for Malaria (WRIM), Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- * E-mail:
| | - Divan G. van Greunen
- Department of Chemistry, Natural and Agricultural Sciences, University of Pretoria, Tshwane, South Africa
| | - C. Johan van der Westhuizen
- Department of Chemistry, Natural and Agricultural Sciences, University of Pretoria, Tshwane, South Africa
- Pharmaceutical Technologies, CSIR Future Production: Chemicals, Tshwane, South Africa
| | - Darren L. Riley
- Department of Chemistry, Natural and Agricultural Sciences, University of Pretoria, Tshwane, South Africa
| | - Jenny-Lee Panayides
- Pharmaceutical Technologies, CSIR Future Production: Chemicals, Tshwane, South Africa
| | - Lizette L. Koekemoer
- WITS Research Institute for Malaria (WRIM), Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
| | - Robyn L. van Zyl
- Pharmacology Division, Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- WITS Research Institute for Malaria (WRIM), Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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van der Westhuizen CJ, Stander A, Riley DL, Panayides JL. Discovery of Novel Acetylcholinesterase Inhibitors by Virtual Screening, In Vitro Screening, and Molecular Dynamics Simulations. J Chem Inf Model 2022; 62:1550-1572. [PMID: 35139637 DOI: 10.1021/acs.jcim.1c01443] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alzheimer's disease is the most common neurodegenerative disease and currently poses a significant socioeconomic problem. This study describes the uses of computer-aided drug discovery techniques to identify novel inhibitors of acetylcholinesterase, a target for Alzheimer's disease. High-throughput virtual screening was employed to predict potential inhibitors of acetylcholinesterase. Validation of enrichment was performed with the DUD-E data set, showing that an ensemble of binding pocket conformations is critical when a diverse set of ligands are being screened. A total of 720 compounds were submitted for in vitro screening, which led to 25 hits being identified with IC50 values of less than 50 μM. The majority of these hits belonged to two scaffolds: 1-ethyl-3-methoxy-3-methylpyrrolidine and 1H-pyrrolo[3,2-c]pyridin-6-amine both of which are noted to be promising compounds for further optimization. As various possible binding poses were suggested from molecular docking, molecular dynamics simulations were employed to validate the poses. In the case of the most active compounds identified, a critical, stable water bridge formed deep within the binding pocket was identified potentially explaining in part the lack of activity for subsets of compounds that are not able to form this water bridge.
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Affiliation(s)
- C Johan van der Westhuizen
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Lynnwood Road, Pretoria 0028, South Africa.,Pharmaceutical Technologies, CSIR Future Production: Chemicals, Meiring Naudé Road, Pretoria 0184, South Africa
| | - André Stander
- Department of Physiology, Faculty of Health Science, University of Pretoria, Lynnwood Road, Pretoria 0031, South Africa
| | - Darren L Riley
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Lynnwood Road, Pretoria 0028, South Africa
| | - Jenny-Lee Panayides
- Pharmaceutical Technologies, CSIR Future Production: Chemicals, Meiring Naudé Road, Pretoria 0184, South Africa
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Neyt NC, van der Westhuizen CJ, Panayides JL, Riley DL. Design and testing of an ozonolysis reactor module with on-the-fly ozone degassing under flow conditions. REACT CHEM ENG 2022. [DOI: 10.1039/d1re00554e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Ozonolysis is an attractive, efficient, and green means of introducing oxygen containing functionalities using only oxygen and electricity.
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Affiliation(s)
- Nicole C. Neyt
- Department of Chemistry, Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0028, South Africa
- Pharmaceutical Technologies, Council for Scientific and Industrial Research Future Production: Chemicals, Meiring Naudé Road, Pretoria, South Africa, 0184
| | - C. Johan van der Westhuizen
- Department of Chemistry, Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0028, South Africa
- Pharmaceutical Technologies, Council for Scientific and Industrial Research Future Production: Chemicals, Meiring Naudé Road, Pretoria, South Africa, 0184
| | - Jenny-Lee Panayides
- Pharmaceutical Technologies, Council for Scientific and Industrial Research Future Production: Chemicals, Meiring Naudé Road, Pretoria, South Africa, 0184
| | - Darren L. Riley
- Department of Chemistry, Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0028, South Africa
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Rants'o TA, Johan van der Westhuizen C, van Zyl RL. Optimization of covalent docking for organophosphates interaction with Anopheles acetylcholinesterase. J Mol Graph Model 2021; 110:108054. [PMID: 34688161 DOI: 10.1016/j.jmgm.2021.108054] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 11/29/2022]
Abstract
Organophosphates (OPs) used as potent insecticides for malaria vector control, covalently phosphorylate the catalytic serine residue of Anopheles gambiae AChE (AgAChE) in a reaction that liberates their leaving groups. In the recent 10-year insecticide use assessment, OPs were the most frequently used World Health Organization prequalified insecticides. Molecular modelling programs are best suited to display molecular interactions between ligands and the target proteins. The docking modes that generate ligand poses closer to the binding site show high accuracy in predicting the ligand binding mode. The implicit solvation approach such as molecular mechanics-generalized born surface area (MM-GBSA) is a more reliable method to predict ligand onformations and binding affinities. Apart from covalent docking studies being scarce, current molecular docking programs do not adequately possess the covalent docking reaction algorithm to display the molecular mechanism of OPs at the AgAChE catalytic site. This results into OP docking studies commonly being conducted through noncovalent pannels. The aim of this study was to establish the optimim covalent docking system for OPs through manual customization of Schrödinger's Glide covalent docking reaction algorithm. To achieve this, a newly customized covalent reaction algorithm was assessed on a set of ligands covering aromatic, non-aromatic and hydrophobic OPs and compared to the noncovalent docking results in terms of reliability based on the reported X-ray diffraction molecular interactions and crystal poses. The study established that by virtue of omitting the well-known OP hydrolysis, noncovalent mode suggested molecular interactions that were further from the catalytic triad and could not otherwise occur when the molecule is hydrolyzed as in the customized covalent docking mode. Moreover, the MM-GBSA concurred with the optimized covalent docking in eliminating such inaccurate molecular interactions. Additionally, the covalent docking mode confined the interactions and ligand poses to the catalytic site indicating relatively high accuracy and reliability. This study reports the optimized covalent docking panel that effectively confirmed the molecular mechanisms of OPs, as well as indentifying the corresponding amino acid residues required to stabilize the aromatic, non-aromatic and hydrophobic OPs at the AgAChE catalytic site in line with the reported X-ray diffraction studies. As such, the proposed manual customization of the Schrödinger's Glide covalent docking platform can be used to reliably predict molecular interactions between OPs and AgAChE target.
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Affiliation(s)
- Thankhoe A Rants'o
- Pharmacology Division, Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2193, South Africa; WITS Research Institute for Malaria (WRIM), Faculty of Health Sciences, University of Witwatersrand, Johannesburg, 2193, South Africa.
| | - C Johan van der Westhuizen
- Council for Scientific and Industrial Research (CSIR), Future Production: Chemicals Cluster, Meiring Naude Road, Brummeria, Pretoria, 0001, South Africa
| | - Robyn L van Zyl
- Pharmacology Division, Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2193, South Africa; WITS Research Institute for Malaria (WRIM), Faculty of Health Sciences, University of Witwatersrand, Johannesburg, 2193, South Africa
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Chawuke P, van den Berg N, Fouche G, Maharaj V, Shoko T, Johan van der Westhuizen C, Invernizzi L, Alexandre KB. Lobostemon trigonus (Thunb.) H. Buek, a medicinal plant from South Africa as a potential natural microbicide against HIV-1. J Ethnopharmacol 2021; 277:114222. [PMID: 34033901 DOI: 10.1016/j.jep.2021.114222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/08/2021] [Accepted: 05/18/2021] [Indexed: 05/26/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE There have been different methods proposed to prevent the sexual transmission of HIV-1 and many of them have centered on the use of anti-retrovirals as microbicides. Given that a large section of the African population still relies on herbal medicine, Lobostemon trigonus (L. trigonus), a traditionally used medicinal plant in South Africa to treat HIV-1 was further investigated for its potential as a natural microbicide to prevent the sexual transmission of HIV-1. METHODS The aerial parts of L. trigonus were oven-dried at 80 °C, ground, extracted with boiling water for 30 min and then filtered. The aqueous extract produced was then bioassayed using different HIV-1 inhibition assays. The active components were purified and chemically profiled using ultra-performance liquid chromatography/quadrupole time-of flight mass spectrometry (UPLC-qTOF-MS). The mechanism of HIV-1 inhibition was determined by fusion arrest assay and time of addition assay. Molecular modelling and molecular dynamic simulations, using Schrödinger, were used to better understand the molecule's mechanism of entry inhibition by evaluating their docking affinity and stability against the gp120 of HIV-1. RESULTS The aqueous extract of this plant had a broad spectrum of activity against different subtypes of the virus; neutralizing subtype A, B and C in the TZM-bl cells, with IC50 values ranging from 0.10 to 7.21 μg/mL. The extract was also inhibitory to the virus induced cytopathic effects in CEM-SS cells with an EC50 of 8.9 μg/mL. In addition, it inhibited infection in peripheral blood mononuclear cells (PBMC) and macrophages with IC50 values of 0.97 and 4.4 μg/mL, respectively. In the presence of vaginal and seminal simulants, and in human semen it retained its inhibitory activity albeit with a decrease in efficiency, by about 3-fold. Studies of the mode of action suggested that the extract blocked HIV-1 attachment to target cells. No toxicity was observed when the Lactobacilli strains, L. acidophilus, L. jensenii, and L. crispatus that populate the female genital tract were cultured in the presence of L. trigonus extract. UPLC-qTOF-MS analyses of the purified fraction of the extract, confirmed the presence of six compounds of which four were identified as rosmarinic acid, salvianolic acids B and C and lithospermic acid. The additional molecular dynamic simulations provided further insight into the entry inhibitory characteristics of salvianolic acid B against the HIV-1 gp120, with a stable pose being found within the CD4 binding site. CONCLUSION The data suggests that the inhibitory effect of L. trigonus may be due to the presence of organic acids which are known to possess anti-HIV-1 properties. The molecules salvianolic acids B and C have been identified for the first time in L. trigonus species. Our study also showed that the L. trigonus extract blocked HIV-1 attachment to target cells, and that it has a broad spectrum of activity against different subtypes of the virus; thus, justifying further investigation as a HIV-1 microbicide.
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Affiliation(s)
- Phindiwe Chawuke
- Council for Scientific and Industrial Research, Pretoria, South Africa; University of Pretoria, Department of Chemistry, Pretoria, South Africa.
| | | | - Gerda Fouche
- University of Pretoria, Department of Chemistry, Pretoria, South Africa.
| | - Vinesh Maharaj
- University of Pretoria, Department of Chemistry, Pretoria, South Africa.
| | - Tinotenda Shoko
- University of Pretoria, Department of Chemistry, Pretoria, South Africa.
| | | | - Luke Invernizzi
- University of Pretoria, Department of Chemistry, Pretoria, South Africa.
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van der Westhuizen D, Slabber CA, Fernandes MA, Joubert DF, Kleinhans G, van der Westhuizen CJ, Stander A, Munro OQ, Bezuidenhout DI. A Cytotoxic Bis(1,2,3-triazol-5-ylidene)carbazolide Gold(III) Complex Targets DNA by Partial Intercalation. Chemistry 2021; 27:8295-8307. [PMID: 33822431 PMCID: PMC8251726 DOI: 10.1002/chem.202100598] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Indexed: 12/13/2022]
Abstract
The syntheses of bis(triazolium)carbazole precursors and their corresponding coinage metal (Au, Ag) complexes are reported. For alkylated triazolium salts, di- or tetranuclear complexes with bridging ligands were isolated, while the bis(aryl) analogue afforded a bis(carbene) AuI -CNC pincer complex suitable for oxidation to the redox-stable [AuIII (CNC)Cl]+ cation. Although the ligand salt and the [AuIII (CNC)Cl]+ complex were both notably cytotoxic toward the breast cancer cell line MDA-MB-231, the AuIII complex was somewhat more selective. Electrophoresis, viscometry, UV-vis, CD and LD spectroscopy suggest the cytotoxic [AuIII (CNC)Cl]+ complex behaves as a partial DNA intercalator. In silico screening indicated that the [AuIII (CNC)Cl]+ complex can target DNA three-way junctions with good specificity, several other regular B-DNA forms, and Z-DNA. Multiple hydrophobic π-type interactions involving T and A bases appear to be important for B-form DNA binding, while phosphate O⋅⋅⋅Au interactions evidently underpin Z-DNA binding. The CNC ligand effectively stabilizes the AuIII ion, preventing reduction in the presence of glutathione. Both the redox stability and DNA affinity of the hit compound might be key factors underpinning its cytotoxicity in vitro.
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Affiliation(s)
| | - Cathryn A. Slabber
- Molecular Sciences InstituteSchool of ChemistryUniversity of the Witwatersrand2050JohannesburgSouth Africa
| | - Manuel A. Fernandes
- Molecular Sciences InstituteSchool of ChemistryUniversity of the Witwatersrand2050JohannesburgSouth Africa
| | - Daniël F. Joubert
- Department of PhysiologyUniversity of Pretoria0031PretoriaSouth Africa
| | - George Kleinhans
- Molecular Sciences InstituteSchool of ChemistryUniversity of the Witwatersrand2050JohannesburgSouth Africa
- Chemistry DepartmentUniversity of Pretoria0028PretoriaSouth Africa
| | - C. Johan van der Westhuizen
- Chemistry DepartmentUniversity of Pretoria0028PretoriaSouth Africa
- Future Production: ChemicalsPharmaceutical Technologies Research GroupCouncil for Scientific and Industrial Research (CSIR)0184PretoriaSouth Africa
| | - André Stander
- Department of PhysiologyUniversity of Pretoria0031PretoriaSouth Africa
| | - Orde Q. Munro
- Molecular Sciences InstituteSchool of ChemistryUniversity of the Witwatersrand2050JohannesburgSouth Africa
| | - Daniela I. Bezuidenhout
- Molecular Sciences InstituteSchool of ChemistryUniversity of the Witwatersrand2050JohannesburgSouth Africa
- Laboratory of Inorganic ChemistryEnvironmental and Chemical EngineeringUniversity of Oulu3000OuluFinland
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Westhuizen CJVD, Greunen DGV, Cordier W, Nell M, Steenkamp V, Stander A, Panayides JL, Riley DL. Binding pose analysis of hydroxyethylamine based β-secretase inhibitors and application thereof to the design and synthesis of novel indeno[1,2-b]indole based inhibitors. ARKIVOC 2020. [DOI: 10.24820/ark.5550190.p011.350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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van Greunen DG, Johan van der Westhuizen C, Cordier W, Nell M, Stander A, Steenkamp V, Panayides JL, Riley DL. Novel N-benzylpiperidine carboxamide derivatives as potential cholinesterase inhibitors for the treatment of Alzheimer's disease. Eur J Med Chem 2019; 179:680-693. [PMID: 31280020 DOI: 10.1016/j.ejmech.2019.06.088] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 06/28/2019] [Accepted: 06/28/2019] [Indexed: 12/24/2022]
Abstract
A series of fifteen acetylcholinesterase inhibitors were designed and synthesised based upon the previously identified lead compound 5,6-dimethoxy-1-oxo-2,3-dihydro-1H-inden-2-yl 1-benzylpiperidine-4-carboxylate (5) which showed good inhibitory activity (IC50 0.03 ± 0.07 μM) against acetylcholinesterase. A series of compounds were prepared wherein the ester linker in the original lead compound was exchanged for a more metabolically stable amide linker and the indanone moiety was exchanged for a range of aryl and aromatic heterocycles. The two most active analogues 1-benzyl-N-(5,6-dimethoxy-8H-indeno[1,2-d]thiazol-2-yl)piperidine-4-carboxamide (28) and 1-benzyl-N-(1-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) piperidine-4-carboxamide (20) afforded in vitro IC50 values of 0.41 ± 1.25 and 5.94 ± 1.08 μM, respectively. In silico screening predicts that 20 will be a blood brain-barrier permeant, and molecular dynamic simulations are indicative of a close correlation between the binding of 20 and the Food and Drug Administration-approved cholinesterase inhibitor donepezil (1).
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Affiliation(s)
- Divan G van Greunen
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Lynnwood Road, Pretoria, South Africa
| | - C Johan van der Westhuizen
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Lynnwood Road, Pretoria, South Africa
| | - Werner Cordier
- Department of Pharmacology, Faculty of Health Sciences, University of Pretoria, Bophelo Road, Pretoria, South Africa
| | - Margo Nell
- Department of Pharmacology, Faculty of Health Sciences, University of Pretoria, Bophelo Road, Pretoria, South Africa
| | - Andre Stander
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Lynnwood Road, Pretoria, South Africa
| | - Vanessa Steenkamp
- Department of Pharmacology, Faculty of Health Sciences, University of Pretoria, Bophelo Road, Pretoria, South Africa
| | - Jenny-Lee Panayides
- Pioneering Health Sciences, CSIR Biosciences, Meiring Naudé Road, Pretoria, South Africa.
| | - Darren L Riley
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Lynnwood Road, Pretoria, South Africa.
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