Inhibition of Lipopolysaccharide-Induced Nitric Oxide Production by Antofine and Its Analogues in RAW 264.7 Macrophage Cells

Based on the anti-inflammatory activity of phenanthroindolizidine alkaloids, the inhibitory effect of antofine and its analogues on lipopolysaccharide (LPS)-induced nitric oxide (NO) production was examined, and structure-activity relationships are discussed. Antofine and several analogues suppressed NO production in LPS-stimulated RAW 264.7 cells. The MeO group at C(2), and the bulkiness of the substituents; at C(3) and C(6) in the phenanthrene ring might be critical for this effect. Besides, regulation of iNOS expression might be involved in the inhibitory effect of antofine on LPS-induced NO production in macrophage cells.