Unraveling the physicochemical, structural, and anti-allergic properties of Laminaria japonica fucoidan: a structure-function perspective

Abstract

Laminaria japonica fucoidan (LJF) is a composite macromolecule with anti-allergic ability. This study investigated the effects of NaCl elution on the physicochemical, structural properties, and anti-allergic ability of LJF, to provide a theoretical basis for the in-depth insights into LJF. The LJF eluted fractions (LJF-1 and LJF-2) using different NaCl concentrations were primarily composed of carbohydrates that are rich in fucose, sulfate radical, uronic acid, and rhamnose, monosaccharide compositions and Fourier transform infrared spectroscopy confirmed the presence of multiple functional components (e.g., sulfate radical and β-glycosidic bonds) in LJF-1 and LJF-2 varied significantly under elution with different NaCl concentrations. As to the hyaluronidase inhibition rate, LJF-2 performed the most potent hyaluronidase inhibition ability, which was particularly attributed to its high sulfate radical and rhamnose contents, LJF-2 was selected for further anti-allergic ability investigation. As for the anti-allergic ability, LJF-2 could mostly decline NO and ROS levels in RAW 264.7 macrophages, and inhibited the release of pro-inflammatory mediators from lipopolysaccharides (LPS)-stimulated macrophages, and inhibited the release of β-hexosaminidase, histamine, Ca²⁺, and ROS from RBL-2H3 mast cells, reduced the degranulation degree and histamine release by downregulating STIM1 and PRTC genes that are associated with the calcium influx signaling pathway. Therefore, LJF-2 performed the strongest anti-allergic ability, which depended on the physicochemical and structural properties that were significantly influenced by elution using different NaCl concentrations.

Keywords

Laminaria japonica fucoidan / Anti-allergy / NaCl-eluted fractions / Structure-function relationship / Hyaluronidase inhibition / Mast cell

Authors contributions

The authors confirm their contributions to the paper as follows: data curation: Wu X, Wang W, She Y, Yang J, Huang X, Li Z; investigation, formal analysis, writing—original draft: Wu X, Wang W, She Y, Yang J, Huang X, Li Z, Zhang Z; writing—review and editing: Li Z, Lin H, Xiao H, Zhang Z; visualization, supervision, funding acquisition, validation, project administration, conceptualization: Zhang Z. All authors reviewed the results and approved the final version of the manuscript.

Data availability

All data generated or analyzed during this study are included in this published article and its supplementary information files. Additional data are available from the corresponding author upon reasonable request.

Acknowledgements

The work was financially supported by National Natural Science Foundation of China (32572710). The authors acknowledge the assistance of Analysis and Testing Center, College of Food Science and Engineering, Ocean University of China.

Conflict of interest

The authors declare that they have no conflict of interest.

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