Method: different concentrations of ethanolic extract of Brazilian red propolis (EEBRP) were added to RAW 264.7 macrophages after activation with LPS, and NO production and cell viability determined. Production of TNF-α, IL1β, TGF-β, IL-4, IL-6, IL-10, IL-12, GM-CSF, IFN-Ɣ and expression of genes related to cytokines production and nitric oxide , PI3K-AKT and signal transduction pathway were evaluated by ELISA and RT-qPCR, respectively. Differences were determined by one-way ANOVA followed by Tukey-Kramer
Result: EEBRP inhibited NO production by 69% without affecting cell viability at the concentration of 50 µg/ml when compared with control cells (treated with vehicle) (p<0.05). Levels of IL-12, GM-CSF, IFN-Ɣ, IL-1β, IL-4, IL-10 and TGF-β in cell supernatant were reduced and of TNF- α and IL-6 increased with the addition of EEBRP (p<0.05). EEBRP induced alteration in expression of 57 genes. Genes involved in Toll-like response; oxide nitric sintetase production (all types), Nf-KB and MAPK signaling pathways such as Tirap, Pdk1, Pak1, Nfkb1, Mtcp1, Gsk3b, Fos, Elk1, Il1β, Il1f9 were negatively regulated by EEBRP(fold-change rate > 5; p<0.05)
Conclusion: EEBRP presents antiinflammatory properties by altering signaling pathways leading to reduction in production of pro-inflammatory factors.