Osteoarthritis (OA) is the most prevalent articular chronic disease. Although, to date there is no cure for OA. Fucoidans, one of the main therapeutic components of brown algae, have emerged as promising molecules in OA treatment. However, the variability between fucoidans makes difficult the pursuit of the most suitable candidate to target specific pathological processes. By an in vitro experimental approach in chondrocytes and fibroblast-like synoviocytes, we observed that chemical composition of fucoidan, and specifically the phlorotannin content and the ratio sulfate:fucose, seems critically relevant for its biological activity. Nonetheless, other factors like concentration and molecular weight of the fucoidan may influence on its beneficial effects. Additionally, a cell-type dependent response was also detected. Thus, our results shed light on the potential use of fucoidans as natural molecules in the treatment of key pathological processes in the joint that favor the development of rheumatic disorders as OA.

骨关节炎（OA）是最常见的关节慢性疾病。尽管如此，迄今为止还没有治愈 OA 的方法。褐藻糖胶是褐藻的主要治疗成分之一，已成为 OA 治疗中很有前途的分子。然而，岩藻依聚糖之间的差异使得寻找最合适的候选物来针对特定的病理过程变得困难。通过软骨细胞和成纤维样滑膜细胞的体外实验方法，我们观察到岩藻依聚糖的化学成分，特别是根皮单宁含量和硫酸盐：岩藻糖的比例，似乎与其生物活性密切相关。尽管如此，其他因素，如岩藻依聚糖的浓度和分子量，可能会影响其有益效果。此外，还检测到细胞类型依赖性反应。因此，我们的结果揭示了岩藻依聚糖作为天然分子在治疗关节关键病理过程中的潜在用途，这些病理过程有利于风湿性疾病如 OA 的发展。