## 4 Discussion  
The PPF extract, which contains high levels of caffe and \(p\)-coumaric acids, induced an increase in IL-10 and IL-6, without modulating TNF-\(\alpha\) secretion by the macrophages, giving effects similar to those produced by caffe acid and by PSDE at low concentrations (1-25 \(\mathrm{\SIUnitSymbolMicro g}\)/mL). In some studies, propolisids extracts also affected both IL-6 and IL-10, but in an opposite direction, decreasing the concentrations of both cytokines, also without affecting TNF-\(\alpha\)[20; 41], while caffe acid caused an increase in IL-6 and IL-10 at lower concentrations (5 and 10 \(\mathrm{\SIUnitSymbolMicro g}\)/mL) and a decrease in these cytokines at higher concentrations (50 and 100 \(\mathrm{\SIUnitSymbolMicro g}\)/mL) [31]. IL-6 is an important pro-inflammatory cytokine that contributes to an organism's defense when tissue injury is detected by the immune system. Increases in the levels of this cytokine are a consequence of an immune system response to aggression [8; 11; 12]. However, persistent secretion of IL-6 by macrophages can contribute to the maintenance of an inflammatory process and eventually to chronic inflammatory disease [13]. On the other hand, IL-10 plays a role in suppressing exacerbated local inflammation, thus helping avoid chronic inflammation [14]. The simultaneous increase in IL-6 and IL-10 secretion by macrophages may be part of an organism's defense process. In this response, IL-6 participates in the stimulation of an inflammatory defense mechanism, and IL-10 prevents an exacerbated inflammatory process, resulting in a controlled inflammatory mechanism of defense [66]. In other studies, propolisids decreased the levels of IL-6 and TNF-\(\alpha\), promoting an anti-inflammatory effect through other mediators, such as NF-kB and IL-1\(\beta\)[63; 64; 65]. A possible explanation for these differences among studies could be the parameters of the protocols used, such as timing of LPS stimulation and whether the treatment with propolisids was included before or after the inflammatory stimulus. In an in vivo model, various other immunological cells and stimuli could be interacting, affecting macrophage response. Other parameters that could affect the response include propolisids extract composition and concentration. The PSDE formulation presented the same immunomododulating profile as PPF and caffeic acid, when used at low concentrations. However, at the highest concentration of PSDE (300 \(\mathrm{\SIUnitSymbolMicro g}\)/mL), there was an increase in the TNF-\(\alpha\) levels and a decrease in IL-10. This effect was similar to that observed for artepillin C, its main component, under the same conditions. The increase in TNF-\(\alpha\) secretion by macrophages may be interpreted as an inflammatory effect participating in the progression to autoimmune and inflammatory chronic diseases [67]; however, this pattern is also essential for the control of infection in organisms through oxidative activation [68]. Thus, this effect may be considered an antimicrobial defense mechanism. Concerning this aspect, future investigations with PSDE and artepillin C in other models may contribute to more comprehensive conclusions. On the other hand, in another study using a macrophage model, artepillin C did not affect IL-6 or IL-10 secretion, but it decreased TNF-\(\alpha\) levels [69]. The authors incubated the cells with artepillin C for 24 h before stimulation with LPS and IFN-\(\gamma\)[69]. Additionally, in this other investigation, the macrophages used were RAW264.7, an immortalized macrophage type, in which some signaling pathways can be altered due to the immortalization process. Of note is the fact that our results are based on a model of primary and non-immortalized cells, which guarantees greater proximity of the results with those found in an in vivo model. These comparisons show that differences between methods can result in different profiles of effects, such as the lack of effect of \(p\)-coumaric acid on the secretion of cytokines that we found.