Quinoline Functionalized Schiff Base Silver (I) Complexes: Interactions with Biomolecules and In Vitro Cytotoxicity, Antioxidant and Antimicrobial Activities

A series of fifteen silver (I) quinoline complexes - have been synthesized and studied for their biological activities. - were synthesized from the reactions of quinolinyl Schiff base derivatives - (obtained by condensing 2-quinolinecarboxaldehyde with various aniline derivatives) with AgNO, AgClO and AgCFSO. - were characterized by various spectroscopic techniques and the structures of [Ag()]NO, [Ag()]ClO, [Ag()]ClO, [Ag()]CFSO and [Ag()]CFSO were unequivocally determined by single crystal X-ray diffraction analysis. In vitro antimicrobial tests against Gram-positive and Gram-negative bacteria revealed the influence of structure and anion on the complexes' moderate to excellent antibacterial activity. In vitro antioxidant activities of the complexes showed their good radical scavenging activity in ferric reducing antioxidant power (FRAP). Complexes with the fluorine substituent or the thiophene or benzothiazole moieties are more potent with IC between 0.95 and 2.22 mg/mL than the standard used, ascorbic acid (2.68 mg/mL). The compounds showed a strong binding affinity with calf thymus-DNA via an intercalation mode and protein through a static quenching mechanism. Cytotoxicity activity was examined against three carcinoma cell lines (HELA, MDA-MB231, and SHSY5Y). [Ag()]ClO with a benzothiazole moiety and [Ag()]ClO with a methyl substituent had excellent cytotoxicity against HELA cells.