## 4 Discussion
In this past research, though the production IL-6 and TNF-\(\alpha\) in LPS treated macrophages were not affected by 10 \(\upmu\)g/mL R-PE, the production of IL-1\(\upmu\)s was lowered, suggesting an anti-inflammation effect. In addition, another past study showed that the phycobiliproteins of _Palmaria palmata_, as 100 \(\upmu\)g/mL phycobilin, inhibited the production of IL-6 and TNF-\(\alpha\)[50]. The possibility of not using the optimal concentration of R-PE in this assay may have constrained the results; therefore, the potential anti-inflammatory effects of R-PE extracted from _C. formosaum_ might be discovered using higher concentrations of R-PE, or through assays on other pro-inflammatory cytokines. binding to IgE to deal with invading pathogens or allergens in downstream allergic reaction signaling pathways. An increase in the concentration of intracellular calcium cations (Ca2+) has also been reported to possibly lead to the degranulation of mast cells [51]. A calcium ionophore, A23187, can carry extracellular Ca2+ across the plasma membrane into mast cells, thereby initiating degranulation [52]. Therefore, the suppression of degranulation via target extracts or compounds facilitates the alleviation of allergic reactions. As histamine is easily degraded by histamine N-methyltransferaseas as well as other related enzymes after being secreted into the extracellular fluid, the detection of \(\beta\)-hexosaminidase becomes the primary route to evaluate mast cell degranulation levels [53]. Phycobiliproteins are known to have anti-allergic effects. R-PC was reported to have an inhibitory effect on IgE induced mast cell degranulation [54], while PE and phycoerythrobilin (PEB) extracted from _Porphyna yezoensis_ has been reported to decrease the release of \(\beta\)-hexosaminidase induced by A23187, possibly via the chelation of extracellular Ca2+, which then leads to the suppression of Ca2+ influx into cells [29]. Similarly, data within this study revealed that R-PE purified from C. _formosanum_ may inhibit the release of \(\beta\)-hexosaminidase induced by A23187 in a dose-dependent manner (Figure 5), indicating that R-PE purified from C. _formosanum_ is an effective macromolecule with anti-allergy properties when used in suitable concentrations. On the other hand, the inhibitory effect of PEB seems to be stronger than that of PE [29]. Thus, digesting R-PE to obtain R-phycoerythrobilin would be a way to enhance the inhibitory effect on mast cell degranulation. Although the bioactive substances obtained from algae are generally safer compared to synthetic compounds, assessments on their safety upon application is still necessary [21]. In the current study, compared with that of the control group, the R-PE-treated samples did not exhibit a difference regarding cell viability; therefore, this compound is recognized as a non-irritant according to the OECD 493 testing guideline [37]. The results in this study indicate that R-PE does not cause skin irritation when used on the tissue surface in the trial dose; therefore, its safety for application on human skin in the tested doses is guaranteed. Collagen is the most abundant protein in the human body, and it supports the maintenance of tissue structure and elasticity [55]. Skin ages when reactive oxygen species (ROS) trigger the downstream mitogen-activated protein kinase (MAPK) signal transduction pathways, resulting in the induction of metalloproteinase (MMP) expression [19]. MMPs degrade collagen, elastic fiber, and other extracellular compounds, causing wrinkles and aging. To prevent the loss of collagen, efforts have been focused on the search for novel marine-sourced bioactive compounds with properties related to skin-care applications. As such, red algae extracts have become one of the major subjects of interest for study [56; 57].