The inflammatory activity of purified-ferulic acid from tetragonia tetragonioides

In this study, an evaluation of the anti-inflammatory effect of ferulic acid isolated from Tetragonia tetragonioides in lipopolysaccharide (LPS) simulated RAW 264.7 cells was made. The chemical structure of the active compound was elucidated by ¹H-NMR, ¹³C-NMR, and FAB-MS, and was confirmed to be ferulic acid. Ferulic acid was purified via open column chromatography with Sephadex LH-20 and MCI gel CHP-20. To test the antiinflammatory effect of ferulic acid, LPS-stimulated RAW 264.7 cells were treated in subsequent experiments with different concentrations of ferulic acid (5, 10, and 25 µg/mL) and the levels of inflammatory cytokines and enzymes were also measured by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. Cell viability was above 95% at acid concentrations ranging from 5-25 µg/mL. The results showed that 30% of the production of nitric oxide and 66% of prostaglandin E2 were inhibited by 25 µg/mL of ferulic acid, it also inhibited the protein expression of both inducible nitric oxide synthase and cyclooxygenase-2 by 70%. Additionally, it inhibited the production of the pro-inflammatory cytokines, tumor necrosis factor-α, interleukin-6, and interleukin- 1β by 40, 75, and 77%, respectively. According to these results, the anti-inflammatory activity of ferulic acid was demonstrated via his implication in the inhibition of the expression and secretion of inflammatory substances in LPS-stimulated RAW 264.7 cells. Therefore, we concluded that ferulic acid can be used as a functional additive having anti-inflammatory activity.