Inhibitory effect of Pleurotus eryngii extracts on the activities of allergic mediators in antigen-stimulated mast cells

Experimental Models in Unraveling the Biological Mechanisms of Mushroom-Derived Bioactives against Aging- and Lifestyle-Related Diseases: A Review

Mushrooms have garnered considerable interest among researchers due to their immense nutritional and therapeutic properties. The presence of biologically active primary and secondary metabolites, which includes several micronutrients, including vitamins, essential minerals, and other dietary fibers, makes them an excellent functional food. Moreover, the dietary inclusion of mushrooms has been reported to reduce the incidence of aging- and lifestyle-related diseases, such as cancer, obesity, and stroke, as well as to provide overall health benefits by promoting immunomodulation, antioxidant activity, and enhancement of gut microbial flora. The multifunctional activities of several mushroom extracts have been evaluated by both in vitro and in vivo studies using cell lines along with invertebrate and vertebrate model systems to address human diseases and disorders at functional and molecular levels. Although each model has its own strengths as well as lacunas, various studies have generated a plethora of data regarding the regulating players that are modulated in order to provide various protective activities; hence, this review intends to compile and provide an overview of the plausible mechanism of action of mushroom-derived bioactives, which will be helpful in future medicinal explorations.

Antioxidant and Immunostimulatory Activities of Fermented Sour Soybean Milk Added With Polypeptides From Pleurotus eryngii

The improved quality of sour soybean milk by adding polypeptide from Pleurotus eryngii was investigated in this study, and the immunomodulatory effect of sour soybean milk fermented with polypeptides from P. eryngii was also evaluated in immunosuppressed mice induced by cyclophosphamide. Results showed the physicochemical property of sour soybean milk fermented with small-molecular-weight polypeptide (<3 kDa) were superior to the others including the decrease of pH, and increase of acidity, water-holding capacity and lactic acid bacteria count. The animal experiment demonstrated that sour soybean milk with polypeptide could effectively reverse the decreasing trend of thymus/spleen index and hematological parameters, enhance murine immune functions including serum hemolysin and splenic lymphocyte proliferation, and inhibit oxidative stress. In addition, sour soybean milk fermented with polypeptide could increase the diversity of intestinal flora, and increase the abundances of Firmicutes, Bacteroides, and Lactobacillus. Taken together, it could provide a theoretical basis for developing an immunomodulatory agent or functional food additives with antioxidant activity.

Docosahexaenoyl ethanolamide mitigates IgE-mediated allergic reactions by inhibiting mast cell degranulation and regulating allergy-related immune cells

Docosahexaenoic acid (DHA) is a long-chain polyunsaturated fatty acid mainly found in fish oil. Although several studies have suggested that it can alleviate allergy symptoms, its mechanism of action remains to be elucidated. In the present study, we found that docosahexaenoyl ethanolamide (DHEA), a metabolite of DHA produced in the human body, exerts the anti-allergic activity in vitro and in vivo. DHEA suppressed degranulation of rat basophilic leukemia RBL-2H3 cells and bone marrow-derived mast cells in a dose-dependent manner without cytotoxicity. This occurred due to a decrease in Ca²⁺ influx, which is critical for mast cell degranulation. DHEA also suppressed IgE-mediated passive cutaneous anaphylaxis reaction in mice. In addition, DHEA was demonstrated to lessen an allergic symptom in a mouse model of pollinosis and to alter the production of IgE and cytokines secreted by splenocytes collected from the pollinosis mice. Taken together, this study indicates that DHEA is a promising anti-allergic agent as it inhibits mast cell degranulation and modulates other immune cells.

Mast cell stabilizing effect of a geranyl acetophenone in dengue virus infection using in vitro model of DENV3-induced RBL-2H3 cells

Mast cells (MCs), a type of immune effector cell, have recently become recognized for their ability to cause vascular leakage during dengue virus (DENV) infection. Although MC stabilizers have been reported to attenuate DENV induced infection in animal studies, there are limited in vitro studies on the use of MC stabilizers against DENV induced MC degranulation. 2,4,6-trihydroxy-3-geranyl acetophenone (tHGA) has been reported to be a potential MC stabilizer by inhibiting IgE-mediated MC activation in both cellular and animal models. The present study aims to establish an in vitro model of DENV3-induced RBL-2H3 cells using ketotifen fumarate as a control drug, as well as to determine the effect of tHGA on the release of MC mediators upon DENV infection. Our results demonstrated that the optimal multiplicities of infection (MOI) were 0.4 × 10^-2 and 0.8 × 10^-2 focus forming units (FFU)/cell. Ketotifen fumarate was proven to attenuate DENV3-induced RBL-2H3 cells degranulation in this in vitro model. In contrast, tHGA was unable to attenuate the release of both β-hexosaminidase and tumor necrosis factor (TNF)-α. Nonetheless, our study has successfully established an in vitro model of DENV3-induced RBL-2H3 cells, which might be useful for the screening of potential MC stabilizers for anti-dengue therapies.

Ergostane-Type Sterols from King Trumpet Mushroom (Pleurotus eryngii) and Their Inhibitory Effects on Aromatase

Two new ergostane-type sterols; (22E)-5α,6α-epoxyergosta-8,14,22-triene-3β,7β-diol (1) and 5α,6α-epoxyergost-8(14)-ene-3β,7α-diol (2) were isolated from the fruiting bodies of king trumpet mushroom (Pleurotus eryngii), along with eight known compounds (3-10). All isolated compounds were evaluated for their inhibitory effects on aromatase. Among them, 4 and 6 exhibited comparable aromatase inhibitory activities to aminoglutethimide.

LAT is essential for the mast cell stabilising effect of tHGA in IgE-mediated mast cell activation

Mast cells play a central role in the pathogenesis of allergic reaction. Activation of mast cells by antigens is strictly dependent on the influx of extracellular calcium that involves a complex interaction between signalling molecules located within the cells. We have previously reported that tHGA, an active compound originally isolated from a local shrub known as Melicope ptelefolia, prevented IgE-mediated mast cell activation and passive systemic anaphylaxis by suppressing the release of interleukin-4 (IL-4) and tumour necrosis factor (TNF)-α from activated rat basophilic leukaemia (RBL)-2H3 cells. However, the mechanism of action (MOA) as well as the molecular target underlying the mast cell stabilising effect of tHGA has not been previously investigated. In this study, DNP-IgE-sensitised RBL-2H3 cells were pre-treated with tHGA before challenged with DNP-BSA. To dissect the MOA of tHGA in IgE-mediated mast cell activation, the effect of tHGA on the transcription of IL-4 and TNF-α mRNA was determined using Real Time-Polymerase Chain Reaction (qPCR) followed by Calcium Influx Assay to confirm the involvement of calcium in the activation of mast cells. The protein lysates were analysed by using Western Blot to determine the effect of tHGA on various important signalling molecules in the LAT-PLCγ-MAPK and PI3K-NFκB pathways. In order to identify the molecular target of tHGA in IgE-mediated mast cell activation, the LAT and LAT2 genes in RBL-2H3 cells were knocked-down by using RNA interference to establish a LAT/LAT2 competition model. The results showed that tHGA inhibited the transcription of IL-4 and TNF-α as a result of the suppression of calcium influx in activated RBL-2H3 cells. The results from Western Blot revealed that tHGA primarily inhibited the LAT-PLCγ-MAPK pathway with partial inhibition on the PI3K-p65 pathway without affecting Syk. The results from RNAi further demonstrated that tHGA failed to inhibit the release of mediators associated with mast cell degranulation under the LAT/LAT2 competition model in the absence of LAT. Collectively, this study concluded that the molecular target of tHGA could be LAT and may provide a basis for the development of a mast cell stabiliser which targets LAT.

Effects of Nigella sativa seeds and certain species of fungi extracts on number and activation of dural mast cells in rats

In this study, we aimed to investigate the effects of Nigella sativa seeds and certain species of fungi extracts on the number and degranulation states of dural mast cells in rats. Rats were fed ad libitum with normal tap water or tap water with extract of N. sativa seed, Ramaria condensata, Lactarius salmonicolor, Lactarius piperatus, and Tricholoma terreum for 3 days. Mast cells in dura mater were counted and evaluated in terms of granulation and degranulation states. Compound 48/80, a mast cell degranulating agent, and T. terreum significantly increased the percent of degranulated mast cells in dura mater, respectively (p < 0.01 and p < 0.05). Moreover, T. terreum causes a significant increase in the total number of mast cells (p < 0.05). N. sativa significantly inhibited mast cell degranulation induced by both the compound 48/80 and T. terreum (p < 0.05), and significantly decreased the mast cell numbers increased by T. terreum (p < 0.05). Our results suggested that T. terreum following ingestion can contribute to headaches like migraine via dural mast cell degranulation and N. sativa may be able to exert analgesic and anti-inflammatory effects by stabilizing dural mast cells. However, investigation is needed to determine the ingredients of N. sativa that may be responsible for these beneficial effects.

Anti-allergic activity of 2,4,6-trihydroxy-3-geranylacetophenone (tHGA) via attenuation of IgE-mediated mast cell activation and inhibition of passive systemic anaphylaxis

tHGA, a geranyl acetophenone compound originally isolated from a local shrub called Melicope ptelefolia, has been previously reported to prevent ovalbumin-induced allergic airway inflammation in a murine model of allergic asthma by targeting cysteinyl leukotriene synthesis. Mast cells are immune effector cells involved in the pathogenesis of allergic diseases including asthma by releasing cysteinyl leukotrienes. The anti-asthmatic properties of tHGA could be attributed to its inhibitory effect on mast cell degranulation. As mast cell degranulation is an important event in allergic responses, this study aimed to investigate the anti-allergic effects of tHGA in cellular and animal models of IgE-mediated mast cell degranulation. For in vitro model of IgE-mediated mast cell degranulation, DNP-IgE-sensitized RBL-2H3 cells were pre-treated with tHGA before challenged with DNP-BSA to induce degranulation. For IgE-mediated passive systemic anaphylaxis, Sprague Dawley rats were sensitized by intraperitoneal injection of DNP-IgE before challenged with DNP-BSA. Both in vitro and in vivo models showed that tHGA significantly inhibited the release of preformed mediators (β-hexosaminidase and histamine) as well as de novo mediators (interleukin-4, tumour necrosis factor-α, prostaglandin D₂ and leukotriene C₄). Pre-treatment of tHGA also prevented IgE-challenged RBL-2H3 cells and peritoneal mast cells from undergoing morphological changes associated with mast cell degranulation. These findings indicate that tHGA possesses potent anti-allergic activity via attenuation of IgE-mediated mast cell degranulation and inhibition of IgE-mediated passive systemic anaphylaxis. Thus, tHGA may have the potential to be developed as a mast cell stabilizer for the treatment of allergic diseases in the future.

Antioxidant, antitumor and immunostimulatory activities of the polypeptide from Pleurotus eryngii mycelium

The objective of this study was to investigate the antioxidant, antitumor and immunological activities of the polypeptide from Pleurotus eryngii mycelium (PEMP). The ability of the polypeptide to stimulate Ana-1 macrophages to englobe neutral red, secrete NO, H₂O₂, TNF-α, and IL-6, increase TLR2 and TLR4 expression levels and Ana-1 cell survival rate were investigated to study its immunocompetence. Its antitumor activities were studied by examining the survival of cervical, breast, and stomach cancer cells. The antioxidant activities of the polypeptide were studied by examining its reducing power and its ability to scavenge DPPH, O₂^-, and OH radicals. The results showed that the PEMP was a good antioxidant with antitumor and immunostimulatory activities that was concentration dependent. At concentrations from 0.05 to 2mg/mL, it inhibited the proliferation of cancer cells, but promoted the proliferation of macrophages, TNF-α and IL-6 secretion, TLR2 and TLR4 expression and increased macrophage phagocytic ability through NO and H₂O₂ release. From 0.2 to 1mg/mL, the polypeptide had strong reducing power to clear free radical of DPPH, O₂^-, OH^-, with a concentration-response relationship. Based on these results, PEMP has potential applications in functional foods as a natural anti-aging and anti-virus agent with antioxidant and immunostimulatory activities.

Factors affecting mushroom Pleurotus spp

Pleurotus genus is one of most extensively studied white-rot fungi due to its exceptional ligninolytic properties. It is an edible mushroom and it also has several biological effects, as it contains important bioactive molecules. In basidiomycete fungi, lignocellulolytic enzymes are affected by many typical fermentation factors, such as medium composition, ratio of carbon to nitrogen, pH, temperature, air composition, etc. The survival and multiplication of mushrooms is related to a number of factors, which may act separately or have interactive effects among them. Out that understanding challenges in handling Pleurotus species mushroom requires a fundamental understanding of their physical, chemical, biological and enzymatic properties. This review presents a practical checklist of available intrinsic and extrinsic factors, providing useful synthetic information that may help different users. An in-depth understanding of the technical features is needed for an appropriate and efficient production of Pleurotus spp.

Six new ergostane-type steroids from king trumpet mushroom (Pleurotus eryngii) and their inhibitory effects on nitric oxide production

Six new ergostane-type steroids; (22E)-3β,5α,6α,11-tetrahydroxy-9(11)-seco-ergosta-7,22-dien-9-one (1), (22E)-8,14-epoxyergosta-6,22-diene-3β,5α,9α-triol (2), (22E)-4α,5α-epoxyergosta-7,22-diene-3β,6β-diol (3), (22E)-3β,4β,5α-trihydroxyergosta-7,22-dien-6-one (4), (22E)-ergosta-7,22-diene-3β,5β,6α-triol (5), and (22E)-6β-methoxyergosta-7,22-diene-3β,5α-diol 3-O-β-d-glucopyranoside (6) were isolated from the fruiting bodies of king trumpet mushroom (Pleurotus eryngii), along with fourteen known compounds (7-20). All isolated compounds were evaluated for their inhibitory effects on macrophage activation using a nitric oxide production inhibition assay.

Antiproliferative and immunostimulatory activity of a protein from Pleurotus eryngii

BACKGROUND

Currently, the use of mushrooms as functional foods, nutraceuticals or phytopharmaceuticals source has risen. In contrast, the possible cellular cytotoxicity and immunostimulatory activity of Pleurotus eryngii (DC. ex Fr.) Quel protein (PEQP) is unknown. Here we report extraction, anti-tumorigenic and immunostimulatory activity of PEQP in vitro.

RESULTS

PEQP was extracted from the dried fruiting bodies of P. eryngii, purified and characterised. Its in vitro antiproliferative activity was then evaluated in human non-small cell lung cancer A549 (NSCLC), stomach adenocarcinoma BGC-823, hepatocellular carcinoma HepG2 and gastric carcinoma HGC-27 cell lines using conventional cancer drugs (paclitaxel, doxorubicin and mitomycin C) as positive controls. The protein fractions (PEQP 1, 2, 3 and 4) obtained inhibited tumour cell proliferation dose-dependently with fraction PEQP 2 having significant (P < 0.05) toxicity in all tumour cells. PEQP had no significant toxicity on normal liver Chang cells but their proliferation was significantly inhibited by mitomycin C. Moreover, PEQP stimulated the proliferation, lysosomal enzyme activity, pinocytosis, nitric oxide and hydrogen peroxide production of RAW 264.7 cell lines dose-dependently.

CONCLUSION

Based on these results, P. eryngii protein has a potential application in functional foods as a natural anti-tumour agent with immunostimulatory activity.

Pleurotus eryngii Ameliorates Lipopolysaccharide-Induced Lung Inflammation in Mice

Pleurotus eryngii (P. eryngii) is consumed as a fresh cultivated mushroom worldwide and demonstrated to have multiple beneficial effects. We investigated the anti-inflammatory effect of P. eryngii in mice with acute lung injury (ALI). Intranasal instillation of lipopolysaccharide (LPS) (10 μg/site/mouse) induced marked lung inflammation (increase in the number of inflammatory cells, protein leakage, and production of nitric oxide in bronchoalveolar lavage fluid) as well as histopathological damage in the lung, 6 h after treatment. Mice administered heat-treated P. eryngii (0.3–1 g/kg, p.o. (HTPE)) 1 h before LPS challenge showed decreased pulmonary inflammation and ameliorated histopathological damage. These results suggest that HTPE has anti-inflammatory effects against ALI. Thus, P. eryngii itself may also have anti-inflammatory effects and could be a beneficial food for the prevention of ALI induced by bacterial infection.