Degraded Porphyra haitanensis sulfated polysaccharide relieves ovalbumin-induced food allergic response by restoring the balance of T helper cell differentiation.

We previously described that Porphyra haitanensis sulfated polysaccharide (PHSP) maintains the balance of pro-inflammation and immunosuppression. However, it is unclear whether degraded PHSP (DPHSP) still shows the immunomodulatory activity. Here, we degraded PHSP by four different methods alone or combined in pairs, and the results showed that the molecular weight and viscosity of DPHSP were significantly decreased, while the main chemical bonds and functional structure were consistent with those of PHSP. We then investigated the immunomodulatory function of DPHSP in vitro and in vivo. Actually, DPHSP enhances the inhibitory effects on mast cell activation and improves the suppression activity of PHSP on the food anaphylactic response. In an ovalbumin-induced food allergy mouse model, the production of allergic mediators and cytokines (interleukin-4 and 13, and interferon-γ) was inhibited by DPHSP. Meanwhile, DPHSP had a stronger ability to up-regulate the differentiation of regulatory T (Treg) cells and its related cytokines. These results suggested that DPHSP showed a better anti-food allergic ability than PHSP by regulating T helper cell balance and promoting Treg cell differentiation, which indicates that DPHSP is a novel potential nutrient component against food allergy.

Nevadensin relieves food allergic responses and passive cutaneous anaphylaxis in mice through inhibiting the expression of c-Kit receptors.

Nevadensin (NEV), a natural flavonoid compound derived from Lysionotus pauciflorus Maxim, has numerous biological activities. However, few researchers have examined its potential impact on alleviating allergies. In the present study, NEV was found to upregulate rectal temperature, suppress the development of diarrhea, and decrease the levels of serum specific immunoglobulin E, histamine and mouse MC protease-1 in ovalbumin-allergic mice. Moreover, NEV also alleviated passive cutaneous anaphylaxis reactions and inhibited the release of ß-hexosaminidase and histamine in bone marrow-derived mast cells. Furthermore, we provide the first demonstration that NEV decreases the expression of c-Kit and suppresses the proliferation of bone marrow-derived mast cells and accelerates their apoptosis. These findings indicated that L. pauciflorus-derived NEV might have the potential to alleviate food hypersensitivity.

Viridicatol Isolated from Deep-Sea Penicillium Griseofulvum Alleviates Anaphylaxis and Repairs the Intestinal Barrier in Mice by Suppressing Mast Cell Activation.

Viridicatol is a quinoline alkaloid isolated from the deep-sea-derived fungus Penicillium griseofulvum. The structure of viridicatol was unambiguously established by X-ray diffraction analysis. In this study, a mouse model of ovalbumin-induced food allergy and the rat basophil leukemia (RBL)-2H3 cell model were established to explore the anti-allergic properties of viridicatol. On the basis of the mouse model, we found viridicatol to alleviate the allergy symptoms; decrease the levels of specific immunoglobulin E, mast cell protease-1, histamine, and tumor necrosis factor-α; and promote the production of interleukin-10 in the serum. The treatment of viridicatol also downregulated the population of B cells and mast cells (MCs), as well as upregulated the population of regulatory T cells in the spleen. Moreover, viridicatol alleviated intestinal villi injury and inhibited the degranulation of intestinal MCs to promote intestinal barrier repair in mice. Furthermore, the accumulation of Ca2+ in RBL-2H3 cells was significantly suppressed by viridicatol, which could block the activation of MCs. Taken together, these data indicated that deep-sea viridicatol may represent a novel therapeutic for allergic diseases.

Sulfated oligosaccharide of Gracilaria lemaneiformis protect against food allergic response in mice by up-regulating immunosuppression.

Sulfated oligosaccharide of Gracilaria lemaneiformis (GLSO) was prepared from sulfated polysaccharides which possessed antiallergic activity by degradation with high temperature and pressure combined with vitamin C treatment. The present study demonstrated that GLSO could attenuate food anaphylaxis, and inhibit the production of immunoglobulin E, histamine, and related cytokines in both prevention and therapy ovalbumin-induced mice model. Additionally, the gut microbiota analysis revealed that GLSO markedly rescued OVA-induced changes in the Firmicutes to Bacteroidetes ratio. Following flow cytometry, GLSO was found to suppress the subpopulation of T helper 2 and B cells, and significantly up-regulate regulatory T cells (Tregs) differentiation. Furthermore, GLSO-mediated immunosuppression could be verified by co-culturing Tregs sorted from GLSO-treated mice and CD4+ T cells or mast cells. In a word, GLSO attenuated food anaphylaxis through the regulation of gut microbiota and induction of immunosuppression. GLSO had the potential to be used as a nutrient component against food allergy.

Dihydromyricetin inhibited ovalbumin-induced mice allergic responses by suppressing the activation of mast cells.

Dihydromyricetin (DMY) is a natural flavonoid compound derived from Lysionotus pauciflorus Maxim and has been found to possess numerous biological activities. However, there have been few reports regarding its anti-food allergic activity. In this study, we demonstrated that DMY could upregulate the rectal temperature, suppress the development of diarrhea, decrease the levels of serum specific immunoglobulin (Ig)E, histamine, and mouse mast cell protease-1, and promote the production of interleukin-10 in ovalbumin-allergic mice. Moreover, DMY downregulated the population of B cells and mast cells and upregulated the population of regulatory T cells in the spleens of ovalbumin-allergic mice. Furthermore, DMY blocked the high affinity IgE receptor (FcεRI)-IgE interaction, inhibited the release of ß-hexosaminidase and histamine in rat basophilic leukemia-2H3 cells, and alleviated passive cutaneous anaphylaxis reactions. These findings indicated that L. pauciflorus derived DMY might have the potential to alleviate food hypersensitivity or allergic diseases.