Synthesis, molecular modeling and anti-inflammatory activity of new benzo[a]pyrano[2,3-c]phenazine compounds

Abstract

A convenient microwave-assisted three-component synthetic approach was developed for the synthesis of new benzo[a]pyrano[2,3-c]phenazine derivatives starting from benzo[a]phenazin-5-ol, benzaldehyde derivatives, and enaminone derivatives. Sixteen new derivatives were successfully synthesized and identified by spectroscopic data analysis. To analyse the potent anti-inflammatory activity of these new derivatives, the Griess assay and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were used to assess their effects on NO production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and their cytotoxicity on the cell line, respectively. The in vitro tests showed that all products displayed highly potent NO production inhibitory activity with IC₅₀ values in the range of 0.98–25.43 µM. In addition, treatment of LPS-stimulated cells with the most potent compounds partially reduced the levels of proinflammatory cytokines IL-1β and IL-6 in a dose-dependent manner. Molecular docking studies further supported their interaction with inflammation-related targets, suggesting that the benzo[a]pyrano[2,3-c]phenazine scaffold represents a promising basis for the further development of anti-inflammatory agents.