Synthesis and biological activity of a styrylquinolinium derivative

The application of styrylium dyes as organic nonlinear optical materials in several photonics fields has been studied for many years. Recently, the biological activity of styrylium dyes has also been examined, namely their antibacterial effects. Therefore, our primary objective was to synthesize a styrylium compound with an antibacterial effect. Knoevenagel condensation was used to obtain a new styrylquinolinium derivative. To verify its structure, spectroscopic methods such as IR, NMR (¹H, ¹³C, COSY, HSQC, and HMBC), HRMS spectra, and X-ray studies were employed.

The compound's antibacterial and anti-inflammatory properties were also evaluated. It was found that the stytylium derivative had excellent antibacterial action against fungi, three Gram-negative strains, and five Gram-positive strains. The compound's most noticeable effects were against Pseudomonas aeruginosa and Escherichia coli. In addition, ex vivo immunohistochemistry was used to assess the compound's anti-inflammatory properties. The substance showed promising immunomodulatory and antimicrobial properties. It can be regarded as a regulated modification of the immune response, particularly in situations requiring local immunological activation, because of its capacity to both stimulate IL-1β and moderately decrease NOS3.

Furthermore, the biological activity was verified using molecular docking modeling. The compound's successful binding to the bacterial protein's active site was demonstrated by docking simulation, which corroborated the compound's antibacterial activity as reported in experiments.