38.    Anti-Inflammatory effect of Smilax campestris rhizomes aqueous extract: Inhibition           of NF-κB nuclear translocation, pro-inflammatory cytokines, MMP-9 and                           superoxide anion levels in THP-1 human macrophages

Macrophages play a crucial role in inflammatory responses. Activated macrophages produce several mediators of inflammation that regulate the immune response. Extracts of S. campestris have been used in folk medicine in the treatment of several inflammatory diseases, however the cellular and molecular mechanisms involved in the effects observed are still unknown. In this study, we aimed to study anti-inflammatory effect of S. campestris aqueous extract in THP-1 PMAdifferentiated macrophages. The latter cells were incubated with different concentrations of S. campestris aqueous extract (10, 100, 1000 and 10000 ng of tannic acid/mL extract) and then activated or not with lipopolysaccharide (LPS, 1 μg/mL). The pro- inflammatory cytokine levels (ELISA), cell cytotoxicity (LDH release), metalloprotease activity (zymography), superoxide anion and glutathione levels (flow cytometry) and NF-κB/ I-κB expression (WB) were assayed. A p value <0.05 was considered significant. We demonstrate that the aqueous extract of S. campestris significantly decreases the production of the pro-inflammatory cytokines interleukin 1 beta (IL-1β), interleukin 6 (IL-6), interleukin 8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1), and the activity of the metalloproteinase MMP- 9, in LPS-activated THP-1 macrophages. Moreover, the S. campestris aqueous extract inhibited NF-κB nuclear translocation. Futhermore, the extract of S. campestris decreased the production of superoxide anion in THP-1 macrophages,
without altering the levels of reduced glutathione. These results suggest that the aqueous extract of S. campestris exerts its anti-inflammatory effects in human macrophages by inhibiting NF-κB nuclear translocation with a consequent down regulation in the production of several proinflammatory mediators such as proinflammatory cytokines and matrix metalloproteinases, along with a reduction of oxidative stress mediators, superoxide anion. Our findings contribute to the understanding of some anti-inflammatory mechanisms responsible of the beneficial effects described to S. campestris. These results are relevant to expand our knowledge about novel therapeutic alternatives employing natural products. It could allow inferring its potential usefulness to mitigate tissue damage in several inflammatory diseases. Keywords: Smilax campestris extract, NF-κB pathway, cytokines, MMP, superoxide anion, THP-1 macrophages