Food allergies affect an estimated 3%–4% of the global population, yet no definitive cure is currently available. Existing strategies generally aim either to reduce food allergenicity through processing or to regulate immune responses using bioactive compounds. Fucoidans—sulfated polysaccharides found mainly in brown algae—have attracted attention because of their safety and anti-inflammatory, immunomodulatory, and anti-allergic properties. However, their biological activity varies considerably with molecular composition, degree of sulfation, monosaccharide profile, and purification method. Most earlier studies have focused on crude fucoidan extracts, leaving the relationship between individual structural characteristics and anti-allergic effects insufficiently understood.
A study (DOI: 10.48130/fia-0026-0005) published in Food Innovation and Advances on 09 March 2026 by Ziye Zhang's team, Ocean University of China, reports that salt-gradient purification produced a sulfate- and rhamnose-rich fraction with enhanced hyaluronidase inhibition and dose-dependent suppression of inflammatory and allergic responses in macrophages and mast cells.
The researchers first extracted crude fucoidan from ground L. japonica through lipid removal, hot-water extraction, ethanol precipitation, deproteinization, dialysis, and freeze-drying. They then separated the material using DEAE-52 cellulose chromatography with 0.5 and 1.0 mol/L sodium chloride, producing the fractions LJF-1 and LJF-2, respectively. Chemical assays, monosaccharide analysis, Fourier-transform infrared spectroscopy, particle-size measurements, and zeta-potential analysis were used to characterize the fractions. Compared with crude LJF, LJF-2 contained substantially more carbohydrate, uronic acid, and sulfate groups, reaching 62.29%, 17.20%, and 35.07%, respectively. It also contained nine monosaccharides and was especially enriched in rhamnose, which accounted for 21.42% of its monosaccharide composition. Infrared spectra confirmed that purification preserved characteristic sulfate groups and β-glycosidic linkages, while LJF-2’s zeta potential of −44.83 mV indicated strong colloidal stability. Hyaluronidase assays showed that LJF-2 had the greatest inhibitory activity, supporting an association between its high sulfate and rhamnose contents and its anti-allergic potential. The researchers therefore selected LJF-2 for cellular testing. In lipopolysaccharide-stimulated RAW264.7 macrophages, LJF-2 reduced nitric oxide and reactive oxygen species and dose-dependently lowered the expression of the inflammatory mediators TNF-α, IL-6, and IL-1β. At 100 μg/mL, their relative expression levels fell to 0.64, 0.55, and 0.68, respectively. In activated RBL-2H3 mast cells, LJF-2 reduced β-hexosaminidase activity, a marker of degranulation, and lowered histamine from 19.24 to 10.13 ng/mL at the highest tested concentration. It also suppressed reactive oxygen species and calcium influx. Further gene-expression analysis showed that LJF-2 downregulated STIM1 and TRPC1, two proteins associated with calcium entry into mast cells, suggesting that it limits degranulation and mediator release partly by regulating calcium-signaling pathways. No significant cytotoxicity was detected at concentrations ranging from 25 to 400 μg/mL.
Together, the findings demonstrate that the anti-allergic performance of L. japonica fucoidan depends strongly on its physicochemical and structural composition, which can be selectively modified through sodium-chloride-gradient purification. The sulfate- and rhamnose-rich LJF-2 fraction simultaneously moderated macrophage inflammation and stabilized mast cells, highlighting its potential as a natural functional ingredient. However, because the evidence was obtained from enzyme assays and cultured cells, further animal studies, mechanistic investigations, and clinical validation will be needed before therapeutic or dietary applications can be established.
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References
DOI
10.48130/fia-0026-0005
Original Source URL
https://doi.org/10.48130/fia-0026-0005
Funding information
The work was financially supported by National Natural Science Foundation of China (32572710).
About Food Innovation and Advances
Food is essential to life and relevant to human health. The rapidly increasing global population presents a major challenge to supply abundant, safe, and healthy food into the future. The open access journal Food Innovation and Advances (e-ISSN 2836-774X), published by Maximum Academic Press in association with China Agricultural University, Zhejiang University and Shenyang Agricultural University, publishes high-quality research results related to innovations and advances in food science and technology. The journal will strive to contribute to food sustainability in the present and future.