## 4 Discussion
This study is limited by the absence of histological evidence demonstrating the rescue of tight junctions by TA and LC through modulation of the AhR pathway. Therefore, further investigations are needed to explore this aspect thoroughly. Another limitation of our study is the absence of a clear synergistic effect observed when administering the TA + LC combination, as compared to the TA alone group. Despite demonstrating excellent anti-inflammatory effects in in vitro experiments with fermented TA and LC, our initial hypothesis of a synergistic effect in animal experiments did not manifest fully. Only spleen size, Lipocalin 2, and TNF-\(\alpha\) showed significant reductions when taken simultaneously. Moreover, tight junction-related genes like _Muc2_, _Zo1_, _Occludin_, etc., exhibited a significant increase following the combination of TA and LC compared to the tannin-only treatment, while other outcomes were similar to those observed with tannin intake alone. The difference in transitioning from in vitro to in vivo conditions can be attributed to two reasons: the methodology of compound delivery and the absorption and metabolism of the compounds in the digestive tract. Oral administration of Lactobacillus spp. and seaweed extracts may result in significant losses through the digestive tract due to variations in temperatures and pH values, potentially affecting the optimal delivery of bioactive compounds [73]. Additionally, differences in intestinal metabolism and the absorption capacity of metabolites may significantly contribute to the complexity of translating in vitro findings to in vivo settings [74]. In discussing the clinical relevance of the findings, it is crucial to consider the potential impact on the main symptoms of UC, which include inflammation, altered tight junction structure, and gut dysbiosis, and how these symptoms were mitigated by TA and LC administration. Phlorotannins have been demonstrated to possess anti-inflammatory properties, modulate the composition of the gut microbiota, and enhance intestinal barrier function [9; 75]. Additionally, our results suggest that the combination of TA and LC may synergistically improve tight junctions. While individual studies have shown the efficacy of phlorotannins and LC in vivo and in clinical trials [70; 76; 77], the efficacy and safety of the combined administration in IBD has not been investigated. Based on our findings and the known properties of TA and LC, they could potentially serve as adjunctive therapies for human IBD. Further research is needed to assess the optimal administration and dosage regimens, as well as to ensure safety and efficacy in human subjects. In future research endeavors, our focus will be on refining the extraction method to enhance the extraction efficiency of phlorotannins. Following this optimization, we aim to conduct more mechanistic studies to thoroughly understand the AhR pathways through which TA and LC modulate intestinal health and inflammation. Additionally, we plan to investigate the dose-response relationship by evaluating the effects of different doses of TA and LC to assess their efficacy and safety. These efforts will be instrumental in facilitating the translation of our findings into clinical applications, ultimately advancing the potential therapeutic utility of TA and LC in managing inflammatory bowel diseases.