Synthesis, Molecular Docking Analysis, and Evaluation of Antibacterial and Antioxidant Properties of Stilbenes and Pinacol of Quinolines

Abstract

Emergence of antimicrobial resistance to standard commercial drugs has become a critical public health concern worldwide. Hence, novel antimicrobials with improved biological activities are urgently needed. In this regard, a series of quinoline-stilbene derivatives were synthesized from substituted quinoline and benzyltriphenylphosphonium chloride using Wittig reaction. Furthermore, a novel pinacol of quinoline was synthesized by pinacolinazation of 2-methoxyquinoline-3-carbaldehyde which was achieved by aluminum powder-potassium hydroxide reagent combination at ambient temperature in methanol. The structures of the synthesized compounds were established based on their spectral data. The antibacterial activities of the synthesized compounds were evaluated in vitro by the paper disc diffusion method against two Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two Gram-negative bacteria (Escherichia coli and Salmonella typhimurium). The best activity was displayed by compound 19 against E. coli with an inhibition zone of 16.0 ± 0.82 mm and 14.67 ± 0.94 mm at 500 and 250 μg/mL, respectively. This is close to ciprofloxacin which is used as a positive control. The results of in silico molecular docking evaluation of the compounds against E. coli DNA gyraseB were in good agreement with the in vitro antibacterial analysis. Compounds 19 (−6.9 kcal/mol) and 24 (−7.1 kcal/mol) showed the maximum binding affinity close to ciprofloxacin (−7.3 kcal/mol) used as positive control. Therefore, the antibacterial activity displayed by these compounds is encouraging for further investigation to improve the activities of quinoline-stilbenes by incorporating various bioisosteric groups in one or more positions of the phenyl nuclei for their potential pharmacological use. Findings of the DPPH radical scavenging assay indicated that some of the quinolone stilbenes and pinacol possess moderate antioxidant properties compared to ascorbic acid used as a natural antioxidant.

Novel Zinc(II) and Copper(II) Complexes of 2-((2-Hydroxyethyl)amino)quinoline-3-carbaldehyde for Antibacterial and Antioxidant Activities: A Combined Experimental, DFT, and Docking Studies

“…Once the reaction was completed, the resulting product was cooled down to room temperature and then put into 200 mL of ice-cold water, and then the precipitate was filtered and washed with 100 mL of ice-cold water. 5 , 6 …”

“… 2 − 4 In this aspect, quinoline is among the most important nitrogen-containing heterocyclic molecules being used for the synthesis of biologically active molecules. 5 , 6 It plays a vital role in biochemical processes as a pharmaceutical agent with its skeleton being often used for the design of many synthetic compounds having diverse pharmacological properties. 5 − 9 Quinoline derivatives are also being used for antiprotozoal, antifungal, 9 anticancer, 8 antiviral, 7 antioxidant, and antibacterial 5 , 6 , 9 activities.…”

“… 11 , 21 , 30 − 32 These observations aroused our interest in the synthesis of new transition-metal compounds from a single ligand that possesses antimicrobial and antioxidant activities. 5 , 6 In relation to this, we recently investigated and reported the coordinating ability of quinoline derivative ligand complexed with Zn(II), Cu(II), Co(II), Ni(II), and V(IV) metal ions and evaluated their biological activities. 13 This work introduces new Zn(II) and Cu(II) metal complexes with new quinoline derivative ligand 2-((2-hydroxyethyl)amino)quinoline-3-carbaldehyde.…”

“…Microbial drug resistance has become a serious medical problem, causing morbidity and mortality, which has attracted the attention of different researchers working on the discovery of antimicrobial drugs . Therefore, there are reports of extensive drug discovery studies being carried out elsewhere to develop new therapeutic approaches and effective drugs with a wide range of antimicrobial activities toward biological targets. − In this aspect, quinoline is among the most important nitrogen-containing heterocyclic molecules being used for the synthesis of biologically active molecules. , It plays a vital role in biochemical processes as a pharmaceutical agent with its skeleton being often used for the design of many synthetic compounds having diverse pharmacological properties. − Quinoline derivatives are also being used for antiprotozoal, antifungal, anticancer, antiviral, antioxidant, and antibacterial ,, activities.…”

Synthesis, in silico molecular docking analysis, pharmacokinetic properties and evaluation of antibacterial and antioxidant activities of fluoroquinolines

“…At the same time, several 2-chloroquinoline-3-carbaldehyde derivatives were synthesized wherein their biological activities were determined. But, none of them showed strong biological activities to be patented for antimicrobial agents [ 16 , 17 ]. Therefore, anticipating the same trend in quinoline-3-carbaldehyde derivatives with fluoroquinolone, several novel fluoroquinoline derivatives were synthesized and their in vitro antibacterial and antioxidant activities were evaluated.…”