Browsing by Author "KWAO, SARAH"
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- Synthesis, characterization and biological evaluation of new Zinc(II)-8-hydroxyquinoline derived complexesPublication . KWAO, SARAH; Correia, Isabel Maria Palma Antunes; Cavaco, Maria Isabel RodriguesMetallodrugs like cisplatin and related platinum compounds, widely used for the treatment of cancer patients, have severe side effects and acquired resistance, which are limiting their use. In addition, several cancer conditions are not responsive to available treatments and thus, viable clinical solutions are still lacking. Metal-based drugs have received a great deal of attention in recent years owing to their properties and benefits in biomedical, therapeutic and diagnostic systems. A wider understanding of the anticancer properties of transition metal complexes like Ru, V, Cu, and Zn and their interactions in biological media is very necessary to ensure their effectiveness and safety. In the current work, four Schiff base ligands derived from the condensation of 8-hydroxy-2-quinolinecarbaldehyde and benzohydrazides (H2L1-H2L4), and their corresponding zinc complexes, ZnL1, ZnL2, ZnL3, and ZnL4 were synthesized. All compounds were characterized by elemental analyses, FTIR, UV–Vis and NMR spectroscopies as well as ESI-MS spectrometry. The stability of the complexes was evaluated in DMSO and under physiological conditions (HEPES buffer (10 mM, pH 7.4) containing DMSO). The interaction between Schiff bases and their corresponding Zn(II) complexes with biological molecules, namely bovine serum albumin (BSA) was investigated using UV-Vis and fluorescence spectroscopies at 298 K. Fluorescence quenching of BSA upon interaction with the complexes was also analyzed at 298, 301, 305 and 310 K. Using the Stern-Volmer formalism, the binding constants indicated moderate to strong binding to albumin with values ranging from Kb = 0.63 to 7.81×104 M-1 for the first three complexes. These results reveal good binding propensity with the protein. Additionally, evaluation of thermodynamic parameters revealed that hydrophobic interactions are the main interactive forces involved in the zinc complexes binding to BSA. In vitro cytotoxic activity of the ligands and their complexes was evaluated on prostate carcinoma (LNCaP FGC), acute T-cell leukaemia (Jurkat E6-1), myeloma (MM.1S), and non-cancerous immortalized human HEK-293 cell lines. Strong cytotoxic activities of both ligands and complexes were observed against all three cancer cell lines. In the non-cancer cell line, the ligands exhibited lower IC50 values than their counterpart complexes. However, the metal complexes have solubility issues, making it difficult for their evaluation.Overall, the current ligand system shows high potential for cancer treatment due to the high selectivity towards the studied cancer cells.