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Makanyane DM, Maikoo S, Van Heerden FR, Rhyman L, Ramasami P, Mabuza LP, Ngubane P, Khathi A, Mambanda A, Booysen IN. Bovine serum albumin uptake and polypeptide disaggregation studies of hypoglycemic ruthenium(II) uracil Schiff-base complexes. J Inorg Biochem 2024; 255:112541. [PMID: 38554578 DOI: 10.1016/j.jinorgbio.2024.112541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 02/13/2024] [Accepted: 03/22/2024] [Indexed: 04/01/2024]
Abstract
Our prior studies have illustrated that the uracil ruthenium(II) diimino complex, [Ru(H3ucp)Cl(PPh3)] (1) (H4ucp = 2,6-bis-((6-amino-1,3-dimethyluracilimino)methylene)pyridine) displayed high hypoglycemic effects in diet-induced diabetic rats. To rationalize the anti-diabetic effects of 1, three new derivatives have been prepared, cis-[Ru(bpy)2(urdp)]Cl2 (2) (urdp = 2,6-bis-((uracilimino)methylene)pyridine), trans-[RuCl2(PPh3)(urdp)] (3), and cis-[Ru(bpy)2(H4ucp)](PF6)2 (4). Various physicochemical techniques were utilized to characterize the structures of the novel ruthenium compounds. Prior to biomolecular interactions or in vitro studies, the stabilities of 1-4 were monitored in anhydrous DMSO, aqueous phosphate buffer containing 2% DMSO, and dichloromethane (DCM) via UV-Vis spectrophotometry. Time-dependent stability studies showed ligand exchange between DMSO nucleophiles and chloride co-ligands of 1 and 3, which was suppressed in the presence of an excess amount of chloride ions. In addition, the metal complexes 1 and 3 are stable in both DCM and an aqueous phosphate buffer containing 2% DMSO. In the case of compounds 2 and 4 with no chloride co-ligands within their coordination spheres, high stability in aqueous phosphate buffer containing 2% DMSO was observed. Fluorescence emission titrations of the individual ruthenium compounds with bovine serum albumin (BSA) showed that the metal compounds interact non-discriminately within the protein's hydrophobic cavities as moderate to strong binders. The metal complexes were capable of disintegrating mature amylin amyloid fibrils. In vivo glucose metabolism studies in liver (Chang) cell lines confirmed enhanced glucose metabolism as evidenced by the increased glucose utilization and glycogen synthesis in liver cell lines in the presence of complexes 2-4.
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Affiliation(s)
- Daniel M Makanyane
- School of Chemistry and Physics, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Sanam Maikoo
- School of Chemistry and Physics, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Fanie R Van Heerden
- School of Chemistry and Physics, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Lydia Rhyman
- Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit 80837, Mauritius; Centre of Natural Product, Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa
| | - Ponnadurai Ramasami
- Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit 80837, Mauritius; Centre of Natural Product, Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa
| | - Lindokuhle P Mabuza
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa.
| | - Phikelelani Ngubane
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Andile Khathi
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Allen Mambanda
- School of Chemistry and Physics, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Irvin N Booysen
- School of Chemistry and Physics, University of KwaZulu-Natal, Pietermaritzburg, South Africa.
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2
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Maikoo S, Xulu B, Mambanda A, Mkhwanazi N, Davison C, de la Mare J, Booysen IN. Biomolecular Interactions of Cytotoxic Ruthenium Compounds with Thiosemicarbazone or Benzothiazole Schiff Base Chelates. ChemMedChem 2022; 17:e202200444. [PMID: 36041073 PMCID: PMC9826503 DOI: 10.1002/cmdc.202200444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 08/30/2022] [Indexed: 01/11/2023]
Abstract
Herein we illustrate the formation and characterization of new paramagnetic ruthenium compounds, trans-P-[RuCl(PPh3 )2 (pmt)]Cl (1) (Hpmt=1-((pyridin-2-yl)methylene)thiosemicarbazide), trans-P-[RuCl(PPh3 )2 (tmc)]Cl (2) (Htmc=1-((thiophen-2-yl)methylene)thiosemicarbazide) and a diamagnetic ruthenium complex, cis-Cl, trans-P-[RuCl2 (PPh3 )2 (btm)] (3) (btm=2-((5-hydroxypentylimino)methyl)benzothiazole). Agarose gel electrophoresis experiments of the metal compounds illustrated dose-dependent binding to gDNA by 1-3, while methylene blue competition assays suggested that 1 and 2 are also DNA intercalators. Assessment of the effects of the compounds on topoisomerase function indicated that 1-3 are capable of inhibiting topoisomerase I activity in terms of the ability to nick supercoiled plasmid DNA. The cytotoxic activities of the metal complexes were determined against a range of cancer cell lines versus a non-tumorigenic control cell line, and the complexes were, in general, more cytotoxic towards the cancer cells, displaying IC50 values in the low micromolar range. Time-dependent stability studies showed that in the presence of strong nucleophilic species (such as DMSO), the chloride co-ligands of 1-3 are rapidly substituted by the former as proven by the suppression of the substitution reactions in the presence of an excess amount of chloride ions. The metal complexes are significantly stable in both DCM and an aqueous phosphate buffer containing 2 % DMSO.
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Affiliation(s)
- Sanam Maikoo
- School of Chemistry and PhysicsUniversity of KwaZulu-NatalPietermaritzburgSouth Africa
| | - Bheki Xulu
- School of Chemistry and PhysicsUniversity of KwaZulu-NatalPietermaritzburgSouth Africa
| | - Allen Mambanda
- School of Chemistry and PhysicsUniversity of KwaZulu-NatalPietermaritzburgSouth Africa
| | - Ntando Mkhwanazi
- Centre for Chemico and Biomedicinal ResearchDepartment of Biochemistry and MicrobiologyFaculty of ScienceRhodes UniversityPO Box 94Grahamstown6140South Africa
| | - Candace Davison
- Centre for Chemico and Biomedicinal ResearchDepartment of Biochemistry and MicrobiologyFaculty of ScienceRhodes UniversityPO Box 94Grahamstown6140South Africa
| | - Jo‐Anne de la Mare
- Centre for Chemico and Biomedicinal ResearchDepartment of Biochemistry and MicrobiologyFaculty of ScienceRhodes UniversityPO Box 94Grahamstown6140South Africa
| | - Irvin Noel Booysen
- School of Chemistry and PhysicsUniversity of KwaZulu-NatalPietermaritzburgSouth Africa
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Taghizadeh Shool M, Amiri Rudbari H, Gil-Antón T, Cuevas-Vicario JV, García B, Busto N, Moini N, Blacque O. The effect of halogenation of salicylaldehyde on the antiproliferative activities of {Δ/Λ-[Ru(bpy) 2(X,Y-sal)]BF 4} complexes. Dalton Trans 2022; 51:7658-7672. [PMID: 35510940 DOI: 10.1039/d2dt00401a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ru(II) polypyridyl complexes are widely used in biological fields, due to their physico-chemical and photophysical properties. In this paper, a series of new chiral Ru(II) polypyridyl complexes (1-5) with the general formula {Δ/Λ-[Ru(bpy)2(X,Y-sal)]BF4} (bpy = 2,2'-bipyridyl; X,Y-sal = 5-bromosalicylaldehyde (1), 3,5-dibromosalicylaldehyde (2), 5-chlorosalicylaldehyde (3), 3,5-dichlorosalicylaldehyde (4) and 3-bromo-5-chlorosalicylaldehy (5)) were synthesized and characterized by elemental analysis, FT-IR, and 1H/13C NMR spectroscopy. Also, the structures of complexes 1 and 5 were determined by X-ray crystallography; these results showed that the central Ru atom adopts a distorted octahedral coordination sphere with two bpy and one halogen-substituted salicylaldehyde. DFT and TD-DFT calculations have been performed to explain the excited states of these complexes. The singlet states with higher oscillator strength are correlated with the absorption signals and are mainly described as 1MLCT from the ruthenium centre to the bpy ligands. The lowest triplet states (T1) are described as 3MLCT from the ruthenium center to the salicylaldehyde ligand. The theoretical results are in good agreement with the observed unstructured band at around 520 nm for complexes 2, 4 and 5. Biological studies on human cancer cells revealed that dihalogenated ligands endow the Ru(II) complexes with enhanced cytotoxicity compared to monohalogenated ligands. In addition, as far as the type of halogen is concerned, bromine is the halogen that provides the highest cytotoxicity to the synthesized complexes. All complexes induce cell cycle arrest in G0/G1 and apoptosis, but only complexes bearing Br are able to provoke an increase in intracellular ROS levels and mitochondrial dysfunction.
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Affiliation(s)
| | - Hadi Amiri Rudbari
- Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Iran.
| | - Tania Gil-Antón
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain.
| | - José V Cuevas-Vicario
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain.
| | - Begoña García
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain.
| | - Natalia Busto
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain. .,Departamento de Ciencias de la Salud, Facultad de Ciencias de la Salud, Universidad de Burgos, Hospital Militar, Paseo de los Comendadores, s/n, 09001 Burgos, Spain
| | - Nakisa Moini
- Department of Chemistry, Faculty of Physics and Chemistry Alzahra University, P.O. Box 1993891176, Vanak Tehran, Iran
| | - Olivier Blacque
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
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Maikoo S, Booysen IN, Xulu B, Rhyman L, Ramasami P. Stabilization of the ruthenium (II) and -(III) centres by chelating N-donor ligands: Synthesis, characterization, biomolecular affinities and computational studies. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130986] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Photocytotoxic Activity of Ruthenium(II) Complexes with Phenanthroline-Hydrazone Ligands. Molecules 2021; 26:molecules26072084. [PMID: 33917290 PMCID: PMC8038675 DOI: 10.3390/molecules26072084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/29/2021] [Accepted: 03/29/2021] [Indexed: 02/06/2023] Open
Abstract
This paper reports on the synthesis and characterization of two new polypyridyl-hydrazone Schiff bases, (E)-N′-(6-oxo-1,10-phenanthrolin-5(6H)-ylidene)thiophene-2-carbohydrazide (L1) and (E)-N′-(6-oxo-1,10-phenanthrolin-5(6H)-ylidene)furan-2-carbohydrazide (L2), and their two Ru(II) complexes of the general formula [RuCl(DMSO)(phen)(Ln)](PF6). Considering that hydrazides are a structural part of severa l drugs and metal complexes containing phenanthroline derivatives are known to interact with DNA and to exhibit antitumor activity, more potent anticancer agents can be obtained by covalently linking the thiophene acid hydrazide or the furoic acid hydrazide to a 1,10-phenanthroline moiety. These ligands and the Ru(II) complexes were characterized by elemental analyses, electronic, vibrational, 1H NMR, and ESI-MS spectroscopies. Ru is bound to two different N-heterocyclic ligands. One chloride and one S-bonded DMSO in cis-configuration to each other complete the octahedral coordination sphere around the metal ion. The ligands are very effective in inhibiting cellular growth in a chronic myelogenous leukemia cell line, K562. Both complexes are able to interact with DNA and present moderate cytotoxic activity, but 5 min of UV-light exposure increases cytotoxicity by three times.
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