Eckol from Ecklonia cava Suppresses Immunoglobulin E-mediated Mast Cell Activation and Passive Cutaneous Anaphylaxis in Mice

Fucosterol isolated from Sargassum horneri attenuates allergic responses in immunoglobulin E/bovine serum albumin-stimulated mast cells and passive cutaneous anaphylaxis in mice

Allergic diseases have become a serious problem worldwide and occur when the immune system overreacts to stimuli. Sargassum horneri is an edible marine brown alga with pharmacological relevance in treating various allergy-related conditions. Therefore, this study aimed to investigate the effect of fucosterol (FST) isolated from S. horneri on immunoglobulin E(IgE)/bovine serum albumin (BSA)-stimulated allergic reactions in mouse bone marrow-derived cultured mast cells (BMCMCs) and passive cutaneous anaphylaxis (PCA) in BALB/c mice. The in silico analysis results revealed the binding site modulatory potential of FST on the IgE and IgE-FcεRI complex. The findings of the study revealed that FST significantly suppressed the degranulation of IgE/BSA-stimulated BMCMCs by inhibiting the release of β-hexosaminidase and histamine in a dose-dependent manner. In addition, FST effectively decreased the expression of FcεRI on the surface of BMCMCs and its IgE binding. FST dose-dependently downregulated the expression of allergy-related cytokines (interleukin (IL)-4, -5, -6, -13, tumor necrosis factor (TNF)-α, and a chemokine (thymus and activation-regulated chemokine (TARC)) by suppressing the activation of nuclear factor-κB (NF-κB) and Syk-LAT-ERK-Gab2 signaling in IgE/BSA-stimulated BMCMCs. As per the histological analysis results of the in vivo studies with IgE-mediated PCA in BALB/c mice, FST treatment effectively attenuated the PCA reactions. These findings suggest that FST has an immunopharmacological potential as a naturally available bioactive compound for treating allergic reactions.

Leaves and pseudostems extract of Curcuma longa attenuates immunoglobulin E/bovine serum albumin-stimulated bone marrow-derived cultured mast cell activation and passive cutaneous anaphylaxis in BALB/c mice

ETHNOPHARMACOLOGICAL RELEVANCE

Curcuma longa, known as turmeric, is an herbaceous perennial plant belonging to the genus Curcuma. It is dispersed throughout tropical and subtropical regions worldwide. Since ancient times, turmeric has been used as an ethnomedicinal plant in the Ayurvedic system, particularly in Asian countries. Rhizomes of turmeric possess several pharmacological properties that give high value as a medicinal remedy for treating a range of conditions, including inflammation, pain, allergies, and digestive issues. Moreover, turmeric leaves and pseudostems also contain a variety of health-enhancing secondary metabolites, such as curcumin, flavonoids, and other phenolic compounds, which exhibit anti-inflammatory, antitumor, antibacterial, and antioxidant properties.

AIM OF THE STUDY

Allergic diseases are a group of immune-mediated disorders mainly caused by an immunoglobulin E (IgE)-dependent immunological response to an innocuous allergen. Therefore, this study aimed to investigate the effect of leaves and pseudostems extract of turmeric (TLSWE-8510) on IgE/bovine serum albumin (BSA)-stimulated allergic responses in mouse bone marrow-derived cultured mast cells (BMCMCs) and passive cutaneous anaphylaxis (PCA) in BALB/c mice.

MATERIALS AND METHODS

The effect of TLSWE-8510 on mast cell degranulation has been evaluated by investigating the release of β-hexosaminidase and histamine in IgE/BSA-stimulated BMCMCs. Additionally, anti-allergic properties of TLSWE-8510 on IgE/BSA-stimulated BMCMCs were investigated using suppression of nuclear factor-kappa B (NF-κB), and spleen tyrosine kinase (Syk)-linker for T-cell activation (LAT)-extracellular-signal-regulated kinase (ERK)-GRB2 associated binding protein 2 (Gab2) signaling pathway and downregulation of allergy-related cytokines and chemokines expression. Furthermore, in vivo, studies were conducted using IgE-mediated PCA in BALB/c mice.

RESULTS

TLSWE-8510 treatment significantly inhibited the degranulation of IgE/BSA-stimulated BMCMCs by inhibiting the release of β-hexosaminidase and histamine dose-dependently. Additionally, TLSWE-8510 reduced the expression of high-affinity IgE receptors (Fc epsilon receptor I-FcεRI) on the surface of BMCMCs and the binding of IgE to FcεRI. Besides, the expression of cytokines and chemokines is triggered by IgE/BSA stimulation via activating the allergy-related signaling pathways. TLSWE-8510 dose-dependently downregulated the mRNA expression and the production of allergy-related cytokines (interleukin (IL)-1β, IL-3, IL-4, IL-5, IL-6, IL-13, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ), and chemokines (thymus and activation-regulated chemokine (TARC), and regulated upon activation, normal T cell expressed and secreted (RANTES)) by regulating the phosphorylation of downstream signaling molecules, NF-κB, and Syk, LAT, ERK and Gab2 in IgE/BSA-stimulated BMCMCs. Moreover, PCA reaction in IgE/BSA-stimulated BALB/c mice ears was effectively decreased by TLSWE-8510 treatment in a dose-dependent manner.

CONCLUSIONS

These results collectively demonstrated that TLSWE-8510 suppressed mast cell degranulation by inhibiting the release of chemical mediators related to allergies. TLSWE-8510 downregulated the allergy-related cytokines and chemokines expression and phosphorylation of downstream signaling molecules in IgE/BSA-stimulated BMCMCs. Furthermore, in vivo studies with IgE-mediated PCA reaction in the BALB/c mice ears were attenuated by TLSWE-8510 treatment. These findings revealed that TLSWE-8510 has the potential as a therapeutic agent for the treatment of allergic diseases.

Protective Effect and Mechanisms of Eckol on Chronic Ulcerative Colitis Induced by Dextran Sulfate Sodium in Mice

The use of functional foods and their bioactive components is receiving increasing attention as a complementary and alternative therapy for chronic ulcerative colitis (UC). This study explored the protective effect and mechanisms of Eckol, a seaweed-derived bioactive phlorotannin, on the dextran sodium sulfate (DSS)-induced chronic UC in mice. Eckol (0.5-1.0 mg/kg) reduced DSS-enhanced disease activity indexes, and alleviated the shortening of colon length and colonic tissue damage in chronic UC mice. The contents of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 were significantly decreased, and the level of anti-inflammatory IL-10 was enhanced in the serum and colonic tissues collected from Eckol-treated mice compared with the DSS controls. Eckol administration significantly reduced the number of apoptotic cells and the expression of cleaved Caspase-3, and increased the B-cell lymphoma-2 (Bcl-2)/B-cell lymphoma-2- associated X (Bax) ratio in DSS-challenged colons. There were more cluster of differentiation (CD)11c⁺ dendritic cells and CD8⁺ T cells, and less CD4⁺ T cells infiltrated to inflamed colonic tissues in the Eckol-treated groups. Expression of colonic Toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB) p65, phosphorylated-signal transducer and activator of transcription (pSTAT)3 was significantly down-regulated by Eckol compared with the DSS-challenged group. In conclusion, our data suggest that Eckol appeared to be a potential functional food ingredient for protection against chronic UC. The anti-colitis mechanisms of Eckol might be attributed to the down-regulation of the TLR4/NF-κB/STAT3 pathway, inhibition of inflammation and apoptosis, as well as its immunoregulatory activity.

Phytotoxicity and cytotoxicity attributes of immobilized Bacillus cereus treated and untreated textile effluents on Vigna mungo seeds and Artemia franciscana larvae

The physicochemical attributes of textile effluents collected from secondary treatment stage was investigated in this study and also assess the biosorption potential of membrane immobilized Bacillus cereus and free form of Bacillus cereus on textile effluent through bioreactor model study to find a sustainable solution to manage the textile effluent as vital need. Furthermore, the phytotoxicity and cytotoxicity nature of treated and untreated textile effluents on Vigna mungo and Artemia franciscana larvae under laboratory conditions as a novel approach. The textile effluent physicochemical parameter analysis results showed that the properties such as colour (Hazen unit), pH, turbidity, As, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Cd, Cl, Cr, Cu, Hg, Ni, Pb, SO₄^2-, and Zn were beyond the acceptable limits. Bacillus cereus immobilized on a polyethylene membrane eliminated greater amounts of dye (25.0 ± 1.3, 56.5 ± 1.8, 57.18 ± 1.5, and 54.34 ± 1.7 Hazen unit from An1, Ae2, Ve3, and So4 respectively) and pollutants (As: 0.9-2.0, Cd: 6-8, Cr: 300-450, Cu: 5-7, Hg: 0.1-0.7, Ni: 8-14, Pb: 4-5, and Zn: 4-8 mg L^-1) from textile effluent in a week of biosorption investigation using a bioreactor model (batch type) compared to a free form of B. cereus on textile effluent. The phytotoxicity and cytotoxicity study results revealed that the membrane immobilized B. cereus treated textile effluent exposure showed reduced phytotoxicity and minimal cytotoxicity (including mortality) percentage compared with free form B. cereus treated and untreated textile effluents. These entire results conclude that the membrane immobilized B. cereus may considerably minimize/detoxify the harmful pollutants from the textile effluents. A large scale level biosorption approach need to be performed to validate the maximum pollutants removing potential of this membrane immobilized bacteria species and optimal conditions for effective remediation.

Structures and Anti-Allergic Activities of Natural Products from Marine Organisms

In recent years, allergic diseases have occurred frequently, affecting more than 20% of the global population. The current first-line treatment of anti-allergic drugs mainly includes topical corticosteroids, as well as adjuvant treatment of antihistamine drugs, which have adverse side effects and drug resistance after long-term use. Therefore, it is essential to find alternative anti-allergic agents from natural products. High pressure, low temperature, and low/lack of light lead to highly functionalized and diverse functional natural products in the marine environment. This review summarizes the information on anti-allergic secondary metabolites with a variety of chemical structures such as polyphenols, alkaloids, terpenoids, steroids, and peptides, obtained mainly from fungi, bacteria, macroalgae, sponges, mollusks, and fish. Molecular docking simulation is applied by MOE to further reveal the potential mechanism for some representative marine anti-allergic natural products to target the H1 receptor. This review may not only provide insight into information about the structures and anti-allergic activities of natural products from marine organisms but also provides a valuable reference for marine natural products with immunomodulatory activities.

The Immunomodulating Effect of Phlorotannins from a Brown Alga, Eisenia nipponica, on Mice Stimulated with Ovalbumin through T Cell Regulation

The immunomodulating effect of phlorotannin was investigated in mice stimulated by ovalbumin. When analyzing the main components of phlorotannin concentrate (PTC) from Eisenia nipponica, seven phlorotannins [eckol, 6,6'-bieckol, 6,8'-bieckol, 8,8'-bieckol, dieckol, phlorofucofuroeckol (PFF)-A, and PFF-B] were detected. These phlorotannins accounted for approximately 80% of PTC. Oral administration of PTC to mice daily for 21 days reduced serum immunoglobulin E (IgE) and total IgG1 levels attributable to Th2 cells. The production of splenic cytokines [interleukin (IL)-10 and transforming growth factor-β1] and Treg cell-mediated expression of forkhead box protein P3 mRNA were significantly increased whereas the production of inflammatory cytokines (interferon-γ, IL-4, IL-5, and IL-17) by Th1, Th2, and Th17 cells was markedly suppressed. IL-21 production and basic leucine zipper ATF-like transcription factor mRNA expression attributable to follicular helper T (Tfh) cells were also suppressed. Flow cytometric analyses demonstrated increased number of Treg cells despite a decrease in the total T cell population. An increase in total B cells was also observed by the flow cytometric analyses in addition to increases in IL-10 production, which activates B cells. In contrast, the significantly suppressed production of inflammatory cytokines and moderate increase in Treg cell subpopulation indicated a direct impact of PTC on inflammatory lymphocytes (Th1, Th2, Th17, and Tfh). Thus, PTC may exert antiallergic effects by immunomodulation of T cells and inactivation of inflammatory lymphocyte.

Three phlorotannins from Sargassum carpophyllum are effective against the secretion of allergic mediators from antigen-stimulated rat basophilic leukemia cells

Sargassum carpophyllum (Sargassaceae) is a brown seaweed that contains phlorotannins, which are phloroglucinol polymers with reported anti-inflammatory activities. The phlorotannins 2-[2-(3,5-dihydroxyphenoxy)-3,5-dihydroxyphenoxy]-1,3,5-benzenetriol (1), 2,2'-[[2-(3,5-dihydroxyphenoxy)-5-hydroxy-1,3-phenylene]bis(oxy)]bis(1,3,5-benzenetriol) (2), and 2-[2-[4-[2-(3,5-dihydroxyphenoxy)-3,5-dihydroxyphenoxy]-3,5-dihydroxyphenoxy]-3,5-dihydroxyphenoxy]-1,3,5-benzenetriol (3) were isolated from S. carpophyllum. Here, we evaluated the anti-allergic activities of these compounds and comprehensively explored their effects on intracellular protein levels. Immunoglobulin E-sensitized rat basophilic leukemia cells pretreated with any of these three compounds exhibited reduced β-hexosaminidase, prostaglandin D2, and tumor necrosis factor-α secretion compared with dinitrophenyl-human serum albumin (DNP-HSA)-stimulated cells. Reduction of β-hexosaminidase release was dose-dependent but the half-maximal inhibitory concentrations of the compounds were similar (36-51 μM). Proteomics analysis revealed that the three compounds up-regulated 25 proteins and down-regulated 33 proteins compared with DNP-HSA stimulation alone, and slightly suppressed proteasome 5 expression linked to the regulation of IκB. These results demonstrate that these phlorotannins are potentially useful for preventing immediate hypersensitivity. S. carpophyllum may be a functional food.

Plant-Derived Molecule 4-Methylumbelliferone Suppresses FcεRI-Mediated Mast Cell Activation and Allergic Inflammation

Mast cells (MCs) are an important treatment target for high-affinity IgE Fc receptor (FcεRI)-mediated allergic diseases. The plant-derived molecule 4-methylumbelliferone (4-MU) has beneficial effects in animal models of inflammation and autoimmunity diseases. The aim of this study was to examine 4-MU effects on MC activation and probe the underlying molecular mechanism(s). We sensitized rat basophilic leukemia cells (RBLs) and mouse bone marrow-derived mast cells (BMMCs) with anti-dinitrophenol (DNP) immunoglobulin (Ig)E antibodies, stimulated them with exposure to DNP-human serum albumin (HSA), and then treated stimulated cells with 4-MU. Signaling-protein expression was determined by immunoblotting. In vivo allergic responses were examined in IgE-mediated passive cutaneous anaphylaxis (PCA) and ovalbumin (OVA)-induced active systemic anaphylaxis (ASA) mouse models. 4-MU inhibited β-hexosaminidase activity and histamine release dose-dependently in FcεRI-activated RBLs and BMMCs. Additionally, 4-MU reduced cytomorphological elongation and F-actin reorganization while down-regulating IgE/Ag-induced phosphorylation of SYK, NF-κB p65, ERK1/2, p38, and JNK. Moreover, 4-MU attenuated the PCA allergic reaction (i.e., less ear thickening and dye extravasation). Similarly, we found that 4-MU decreased body temperature, serum histamine, and IL4 secretion in OVA-challenged ASA model mice. In conclusion, 4-MU had a suppressing effect on MC activation both in vitro and in vivo and thus may represent a new strategy for treating IgE-mediated allergic conditions.

Anti-Allergic Effect of 3,4-Dihydroxybenzaldehyde Isolated from Polysiphonia morrowii in IgE/BSA-Stimulated Mast Cells and a Passive Cutaneous Anaphylaxis Mouse Model

In this study, we investigated the anti-allergic effects of 3,4-dihydroxybenzaldehyde (DHB) isolated from the marine red alga, Polysiphonia morrowii, in mouse bone-marrow-derived cultured mast cells (BMCMCs) and passive cutaneous anaphylaxis (PCA) in anti-dinitrophenyl (DNP) immunoglobulin E (IgE)-sensitized mice. DHB inhibited IgE/bovine serum albumin (BSA)-induced BMCMCs degranulation by reducing the release of β-hexosaminidase without inducing cytotoxicity. Further, DHB dose-dependently decreased the IgE binding and high-affinity IgE receptor (FcεRI) expression and FcεRI-IgE binding on the surface of BMCMCs. Moreover, DHB suppressed the secretion and/or the expression of the allergic cytokines, interleukin (IL)-4, IL-5, IL-6, IL-13, and tumor necrosis factor (TNF)-α, and the chemokine, thymus activation-regulated chemokine (TARC), by regulating the phosphorylation of IκBα and the translocation of cytoplasmic NF-κB into the nucleus. Furthermore, DHB attenuated the passive cutaneous anaphylactic (PCA) reaction reducing the exuded Evans blue amount in the mouse ear stimulated by IgE/BSA. These results suggest that DHB is a potential therapeutic candidate for the prevention and treatment of type I allergic disorders.

The Anti-Allergic and Anti-Inflammatory Effects of Phlorotannins from the Edible Brown Algae, Ecklonia sp. and Eisenia sp

Because the number of people suffering from allergies has significantly increased, improved ways of treating these conditions by medical, pharmaceutical, and dietary means are required. Large numbers of studies on allergy have been conducted, and many anti-allergic compounds have been found. Phenolic compounds from terrestrial plants, including catechins and flavonoids, possess anti-allergic properties. Although polyphenols are present in some brown algae, their anti-allergic activities were not studied in detail before the 1990s. The focus was on the algal polyphenols, collectively called phlorotannins (eg., eckol, 6,6′-bieckol, 8,8′-bieckol, dieckol, and phlorofucofuroeckol-A), and research was conducted to clarify their anti-allergic activities. This review summarizes the anti-allergic effects of phlorotannins isolated from the brown alga, Eisenia nipponica, and related reports by other research groups.

Brown Seaweed Food Supplementation: Effects on Allergy and Inflammation and Its Consequences

Multiple health benefits have been ascribed to brown seaweeds that are used traditionally as dietary component mostly in Asia. This systematic review summarizes information on the impact of brown seaweeds or components on inflammation, and inflammation-related pathologies, such as allergies, diabetes mellitus and obesity. We focus on oral supplementation thus intending the use of brown seaweeds as food additives. Despite the great diversity of experimental systems in which distinct species and compounds were tested for their effects on inflammation and immunity, a remarkably homogeneous picture arises. The predominant effects of consumption of brown seaweeds or compounds can be classified into three categories: (1) inhibition of reactive oxygen species, known to be important drivers of inflammation; (2) regulation, i.e., in most cases inhibition of proinflammatory NF-κB signaling; (3) modulation of adaptive immune responses, in particular by interfering with T-helper cell polarization. Over the last decades, several inflammation-related diseases have increased substantially. These include allergies and autoimmune diseases as well as morbidities associated with lifestyle and aging. In this light, further development of brown seaweeds and seaweed compounds as functional foods and nutriceuticals might contribute to combat these challenges.

Inhibitory effect of paeoniflorin on IgE-dependent and IgE-independent mast cell degranulation in vitro and vivo

The incidence of allergic diseases has increased to such a point that they have become common and have reached epidemic levels. However, their pathogenesis is not fully understood. Paeoniae Radix Rubra is a traditional Chinese medicine that is also used as a dietary supplement. Its main active ingredient is paeoniflorin. Paeoniflorin has good anti-inflammatory, immunomodulation, and antitumor effects. It is utilized in the treatment of various diseases in clinical settings. However, its effects on type I allergies and pseudoallergic reactions have not been comprehensively studied. In this study, we aimed to use DNP-IgE/DNP-BSA and C48/80 to simulate type I allergies and pseudoallergic reactions to evaluate the therapeutic effects of paeoniflorin to these diseases and identify its molecular mechanisms in cell degranulation both in vivo and in vitro. Results showed that paeoniflorin inhibited the degranulation of RBL-2H3 cells induced by these two stimuli (IgE-dependent and IgE-independent stimuli) in a dose-dependent manner. Moreover, qPCR and western blot analyses indicated that paeoniflorin may regulate the IgE/FcεR I, MRGPRB3, and downstream signal transduction pathways to exert its therapeutic effects on type I allergies and pseudoallergic reactions. In addition, DNP-IgE/DNP-BSA and compound 48/80 were used to induce the establishment of a passive cutaneous anaphylaxis mouse model. Paeoniflorin was found to suppress the extravasation of Evans Blue and tissue edema in the ears, back skin, and paws of the mice. This result further confirmed that paeoniflorin has a notable therapeutic effect on type I allergies and pseudoallergic reactions. Therefore, paeoniflorin could potentially be used as a drug for the treatment of type I allergies and pseudoallergic reactions. This study provides new insights into expanding the treatment range of paeoniflorin and its pharmacological mechanism.

Polyphenols from Brown Seaweeds (Ochrophyta, Phaeophyceae): Phlorotannins in the Pursuit of Natural Alternatives to Tackle Neurodegeneration

Globally, the burden of neurodegenerative disorders continues to rise, and their multifactorial etiology has been regarded as among the most challenging medical issues. Bioprospecting for seaweed-derived multimodal acting products has earned increasing attention in the fight against neurodegenerative conditions. Phlorotannins (phloroglucinol-based polyphenols exclusively produced by brown seaweeds) are amongst the most promising nature-sourced compounds in terms of functionality, and though research on their neuroprotective properties is still in its infancy, phlorotannins have been found to modulate intricate events within the neuronal network. This review comprehensively covers the available literature on the neuroprotective potential of both isolated phlorotannins and phlorotannin-rich extracts/fractions, highlighting the main key findings and pointing to some potential directions for neuro research ramp-up processes on these marine-derived products.

Sargassum horneri as a Functional Food Ameliorated IgE/BSA-Induced Mast Cell Activation and Passive Cutaneous Anaphylaxis in Mice

Sargassum horneri (S. horneri), an edible brown alga, has been proposed as a functional food with an improvement effect on abnormal skin immune responses. The present study investigates the anti-allergic effect of an ethanol extract from S. horneri (SHE) on immunoglobulin E (IgE)/bovine serum albumin (BSA)-mediated activation in bone marrow-derived cultured-mast cells (BMCMCs) and passive cutaneous anaphylaxis (PCA) reaction in mice. SHE markedly and dose-dependently suppressed the degranulation of BMCMCs by reducing the β-hexosaminidase and histamine release without cytotoxicity. In addition, SHE significantly decreased the FcεRI expression on the surface of BMCMCs and its IgE binding. Moreover, SHE reduced the mRNA expression and the production of allergic cytokines; interleukin (IL)-1β, IL-4, IL-5, IL-6, IL-10, IL-13; interferon (IFN)-γ and/or tumor necrosis factor (TNF)-α; and a chemokine, thymus and activation-regulated chemokine (TARC), by suppressing the activation of Src-family kinases and nuclear factor (NF)-κB signaling. In further study, the application of SHE reduced the PCA reaction in an IgE/BSA-induced type I allergic mice model. Taken together, we suggest that SHE has an anti-allergic effect in type I allergic responses.