Synthesis, structure identification, antioxidant and antimicrobial activities of some novel quinoline derivatives

Abstract

Excellent yields (moreover 87%) were achieved in the single-step synthesis of a number of new quinoline compounds, in an ethanolic medium containing various aromatic substituted benzaldehydes, N-phenylacetamide hydrate, and 5,5-dimethylcyclohexane-1,3-dione. The quinoline derivatives were confirmed by mass spectroscopy and Nuclear Magnetic Resonance Spectroscopy (NMR). Strains of pathogenic bacteria and fungi were employed to assess the antimicrobial properties. Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus and Candida albicans were the fungal strains used in the study, whereas the bacterial strains were Enterobacter cloacae, Staphylococcus haemolyticus, Bacillus cereus, and Staphylococcus aureus. For the bacterial and fungal investigations, respectively, ciprofloxacin and fluconazole were utilized as references, with Dimethyl Sulfoxide (DMSO) serving as the control. Quinoline derivatives 1, 2, 3, and 5 exhibit the highest level of antibacterial activity against all strains of bacteria, whereas quinoline derivatives 4, 5 demonstrate the highest level of inhibitory activity against all strains of fungi. The complexes were subjected to a Nash method inspection using their ability to scavenge hydroxyl (OH·) radicals. Additionally, the superoxide radical was indirectly evaluated using the MET-VitB2-NBT system. Using common vitamin C drugs, the overall antioxidant activity of the quinoline derivatives (1–5) was evaluated in an effort to identify possible antioxidants and therapeutic agents for respiratory conditions such as asbestosis, emphysema, and asthma. The results revealed that the compounds 5 and 3 possess significant antioxidant activity. Quinoline derivatives are a promising possibility for further biomedical research and therapeutic development due to antioxidant characteristics and their synthesis and characterisation.