## 4 Discussion
### Evaluation of the Anti-Inflammatory Properties of Fucus vesicusus Extract  
Among the various bioactive components, _Fucus vesicususus_ is especially known for its fucoidan content, a molecule recognized for its anti-inflammatory power [79]. The present study, which focused on the overall extract of _Fucus vesicusus_, highlights the anti-inflammatory properties of this brown seaweed. Specifically, it can downregulate pro-inflammatory mediators such as TNF-\(\alpha\), IL-1\(\beta\), and IL-6. These cytokines play pivotal roles in orchestrating the inflammatory response. They are not only crucial in the initiation and propagation of inflammation but also in the resolution phase. Their roles are diverse, ranging from modulating immune cell activity to influencing systemic responses, such as fever and the production of acute-phase proteins [80; 81; 82]. As our study revealed the anti-inflammatory capacity of _Fucus vesicolusus_, likely due to its fucoidan content, various studies have highlighted the anti-inflammatory properties of fucoidan from different algae in murine RAW 264.7 macrophage cell lines. For example, [PERSON] et al. [83] reported that fucoidan from _Fucus vesicolusus_ (50 and 100 \(\mathrm{\SIUnitSymbolMicro\SIUnitSymbolMicro\SIUnitSymbolMicro}\)/mL) diminishes the secretion of TNF-\(\alpha\) and IL-1\(\beta\) in RAW 264.7 macrophages, highlighting its potential to suppress the early stages of the inflammation. In line with this and with the present study, other researchers have disclosed a down-regulation in the levels of TNF-\(\alpha\), IL-1\(\beta\), and IL-6 in comparison to nontreated LPS-stimulated RAW 264.7 cells once macrophages are treated with fucoidan derived from different algae species, such as _Chnoospora minima_, _Ecklonia cava_, _Sargassum horneri_, and _Laminaria japonica_[79; 84; 85]. It is important to emphasize that the response to fucoidan is often concentration-dependent and influenced by the structural characteristics of the polysaccharide, such as sulfation degree, molecular weight, and algal source. These factors can modulate receptor binding and cellular uptake mechanisms in macrophages, thereby altering the downstream signaling pathways involved in cytokine expression [57]. If the downregulation of interleukin IL-1\(\beta\) and IL-6 occurs for all concentrations tested, the downregulatory effect of TNF-\(\alpha\) was observed only in the lowest concentration tested. This outcome might initially appear counterintuitive, as higher concentrations are typically expected to exert stronger effects. However, TNF-\(\alpha\) is a cytokine primarily involved in the early stages of inflammation, initiating a cascade that leads to the expression of other cytokines such as IL-1\(\beta\) and IL-6 [86; 87]. Thus, at lower concentrations, fucoidan may effectively inhibit this initial response. Moreover, increased concentration could paradoxically activate stress response pathways or lead to receptor desensitization, thereby attenuating the inhibitory effect. Additionally, this study considered the expression of pro-inflammatory cytokines and the pro-inflammatory enzyme nitric oxide synthase 2 (iNOS). The results showed that, regardless of the concentration of the algal extract used, it undergoes upregulation. This seems to be in contradiction with other studies found in the literature. [PERSON] et al. found dose-dependent inhibition of NO production (IC50 27.82 \(\mathrm{\SIUnitSymbolMicro\SIUnitSymbolMicro}\)/mL), iNOS, and COX-2 expression in LPS-induced RAW 264.7 macrophages treated with fucoidan fractions derived from _Chnoospora minima_[88]. Similarly, [PERSON] and colleagues reported decreased NO production, iNOS, and COX-2 expression in LPS-stimulated RAW 264.7 macrophage cells following fucoidan application [79].