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

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.