Fucoidan isolated from Padina commersonii inhibit LPS-induced inflammation in macrophages blocking TLR/NF-κB signal pathway

Brown seaweeds are well-known source of bioactive compounds, which are producing a variety of secondary metabolites with promising bioactive properties. Traditionally, seaweeds used as ingredients in medicine for many centuries in Asian countries. However, the protective mechanisms of many metabolites found in seaweeds are remains to be determined. Thus, applications of seaweeds are limited because of poor understanding of their structural features and mechanisms responsible for their bioactive properties. In the present study, anti-inflammatory properties of fucoidan isolated from the brown seaweed Padina commersonii (PCF) was evaluated against LPS-activated RAW 264.7 macrophages. PCF was characterized using NMR, FT-IR, and HPAE-PAD spectrum (for mono sugar composition). It was observed that PCF is rich in fucose and sulfate as well as a similar structure to the commercial fucoidan. Western blots and RT-qPCR analysis were used to determine the protective effects of PCF after LPS challenge using RAW 264.7 macrophages. According to the results, PCF significantly down-regulated LPS-activated mRNA and protein expression levels of TLR2, TLR4, and MyD88 which are known inducers/activators of NF-κB transcriptional factors. The results, obtained from this study demonstrated PCF has a potential to inhibit LPS-induced inflammatory responses via blocking TLR/MyD88/ NF-κB signal transduction.