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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] [What about the content of this article? (0)] [Affiliation(s)] [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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