The excreted polysaccharide of Pleurotus eryngii inhibits the foam-cell formation via down-regulation of CD36

The effect of in vitro digestion on the interaction between polysaccharides derived from Pleurotus eryngii and intestinal mucus

Pleurotus eryngii polysaccharides (PEPs) have been proven to display multiple activities through digestive system action, from which the digestion products should first interact with intestinal mucus (MUC), followed by the function of intestinal cells. Hence, possible interacting characterizations between MUC and in vitro simulated digestion products of P. eryngii polysaccharides (DPEPs) and PEP were carried out in the present study. Results showed that both PEP and DPEP could significantly interact with MUC. Moreover, digestion can modify the interaction between polysaccharides and MUC; the degree of interaction also changes with time incrementing. Viscosity could be decreased after digesting. According to the zeta potential and stability analysis result, the digestive behavior could be regular and stable between polysaccharides and MUC interactions. Following fluorescence and infrared spectra, the structure of polysaccharides and mucin might be changed by digestion between polysaccharides and MUC. The study indicates that the interaction formed between DPEP and MUC might indirectly impact the exercise and immune activities of polysaccharides and influence the transportation of other nutrients. Overall, our results, the absorption and transport pathways of PEP, can be initially revealed and may provide a novel research viewpoint on the active mechanism of PEP in the intestinal tract.

Is the suppression of CD36 a promising way for atherosclerosis therapy?

Atherosclerosis is the main underlying pathology of many cardiovascular diseases and is marked by plaque formation in the artery wall. It has posed a serious threat to the health of people all over the world. CD36 acts as a significant regulator of lipid homeostasis, which is closely associated with the onset and progression of atherosclerosis and may be a new therapeutic target. The abnormal overexpression of CD36 facilitates lipid accumulation, foam cell formation, inflammation, endothelial apoptosis, and thrombosis. Numerous natural products and lipid-lowering agents are found to target the suppression of CD36 or inhibit the upregulation of CD36 to prevent and treat atherosclerosis. Here, the structure, expression regulation and function of CD36 in atherosclerosis and its related pharmacological therapies are reviewed. This review highlights the importance of drugs targeting CD36 suppression in the treatment and prevention of atherosclerosis, in order to develop new therapeutic strategies and potential anti-atherosclerotic drugs both preclinically and clinically.

Isolation, purification, and structural elucidation of Stropharia rugosoannulata polysaccharides with hypolipidemic effect

Stropharia rugosoannulata is a widely grown edible mushroom with a high nutritional value. S. rugosoannulata polysaccharides is one of the most important bioactive components of S. rugosoannulata and has a wide range of activities. A S. rugosoannulata polysaccharides, named SRF-3, was derived from the S. rugosoannulata extraction by freeze-thaw combine with hot water extraction method, then prepareed with DEAE-cellulose column and Sephacryl S-200 HR gel column, and its hypolipidemic activity was determined. The structural characteristics of SRF-3 were analyzed by infrared spectral scanning (FT-IR), ultra-high performance liquid chromatography (UHPLC), acid hydrolysis, methylation analysis, nuclear magnetic resonance (NMR), and Gas Chromatography-Mass Spectrometer (GC-MS). SRF-3 is composed of mannose, galactose, methyl galactose and fructose with ratios of 16, 12, 58 and 12, respectively. In addition, the average relative molecular mass of SRF-3 is approximately 24 kDa. The main chain of SRF-3 is mainly composed of repeating α-D-1,6-Galp and α-D-1,6-Me-Galp units, with branches in the O-2 position of Gal. The structure is presumed to be a mannogalactan, with a small amount of t-β-D-Manp present as a side chain. Hypolipidemic activity assay showed that SRF-3 had good antioxidant and hypolipidemic effects in vitro, suggesting that SRF-3 have potential application in reducing liver fat accumulation.

A Review of Development and Utilization for Edible Fungal Polysaccharides: Extraction, Chemical Characteristics, and Bioactivities

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Because of their distinctive flavor and exceptional nutritional and medicinal value, they have been a frequent visitor to people’s dining tables and have become a hot star in the healthcare, pharmaceutical, and cosmetics industries. Edible fungal polysaccharides (EFPs) are an essential nutrient for edible fungi to exert bioactivity. They have attracted much attention because of their antioxidant, immunomodulatory, antitumor, hypoglycemic, and hypolipidemic bioactivities. As a result, EFPs have demonstrated outstanding potential over the past few decades in various disciplines, including molecular biology, immunology, biotechnology, and pharmaceutical chemistry. However, the complexity of EFPs and the significant impact of mushroom variety and extraction techniques on their bioactivities prevents a complete investigation of their biological features. Therefore, the authors of this paper thoroughly reviewed the comparison of different extraction methods of EFPs and their advantages and disadvantages. In addition, the molecular weight, monosaccharide composition, and glycosidic bond type and backbone structure of EFPs are described in detail. Moreover, the in vitro and in vivo bioactivities of EFPs extracted by different methods and their potential regulatory mechanisms are summarized. These provide a valuable reference for improving the extraction process of EFPs and their production and development in the pharmaceutical field.

β-1,6-Glucan From Pleurotus eryngii Modulates the Immunity and Gut Microbiota

Polysaccharides from Pleurotus eryngii exhibit a variety of biological activities. Here, we obtained a homogeneous branched β-1,6-glucan (APEP-A-b) from the fruiting bodies of P. eryngii and investigated its effect on immunity and gut microbiota. Our results showed that APEP-A-b significantly increases splenic lymphocyte proliferation, NK cell activity and phagocytic capacity of peritoneal cavity phagocytes. Furthermore, we found that the proportion of CD4⁺ and CD8⁺ T cells in lamina propria are significantly increased upon APEP-A-b treatment. Additionally, APEP-A-b supplementation demonstrated pronounced changes in microbiota reflected in promotion of relative abundances of species in the Lachnospiraceae and Rikenellaceae families. Consistently, APEP-A-b significantly increased the concentration of acetic and butyric acid in cecum contents. Overall, our results suggest that β-1,6-glucan from P. eryngii might enhance immunity by modulating microbiota. These results are important for the processing and product development of P. eryngii derived polysaccharides.

Fermentation Supernatants of Pleurotus eryngii Mushroom Ameliorate Intestinal Epithelial Barrier Dysfunction in Lipopolysaccharide-Induced Caco-2 Cells via Upregulation of Tight Junctions

In recent years, modulation of gut microbiota through prebiotics has garnered interest as a potential to ameliorate intestinal barrier dysfunction. The aim of the study was to examine the in vitro effect of fermentation supernatants (FSs) from rich in β-glucan Pleurotus eryngii mushrooms on the expression levels of tight junctions (TJs) genes in Caco-2 cells stimulated by bacterial lipopolysaccharides (LPS). Mushrooms were fermented using fecal inocula in an in vitro batch culture model. Caco-2 cells were subjected to LPS and FS treatment under three different conditions: pre-incubation with FS, co- and post-incubation. Reverse transcription PCR was applied to measure the expression levels of zonulin-1, occludin and claudin-1 genes. FSs from P. eryngii mushrooms led to a significant upregulation of the TJs gene expression in pre-incubation state, indicating potential preventive action. Down-regulation of all TJs gene expression levels was observed when the cells were challenged with LPS. The FS negative control (gut microbiota of each donor with no carbohydrate source) exhibited a significant upregulation of TJs expression levels compared to the cells that were challenged with LPS, for all three conditions. Overall, our data highlighted the positive and potential protective effects of P. eryngii mushrooms in upregulation of TJs’ genes.

Structures and anti-atherosclerotic effects of 1,6-α-glucans from Fructus Corni

In this study, two homogeneous polysaccharides (PFC-1 and PFC-2) having anti-atherosclerotic activity were isolated from Fructus Corni. PFC-1 and PFC-2 were 1,6-α-glucans with the molecular weight of 4.4 kDa and 82.0 kDa, respectively. In the in vitro experiments, PFC-1 and PFC-2 showed significant inhibitory effects on the cholesterol accumulation in RAW264.7 macrophages induced by oxidized low-density lipoproteins (ox-LDL), and the inhibitory rate of PFC-2 was 81.62%. Apolipoprotein E-deficient (ApoE^-/-) mice fed high-fat diet (HFD) were used to evaluate the anti-atherosclerotic effects of PFC-2 in vivo. The aortic root lipid area decreased by 55.01% in the PFC-2-administered group as compared to the model group. PFC-2 decreased the levels of serum low-density lipoprotein cholesterol, total cholesterol, triglycerides, and malondialdehyde, increased the superoxide dismutase activity, and reduced the contents of lipid and macrophages in the aortic sinus plaque in ApoE^-/- mice fed with HFD. Furthermore, PFC-2 markedly inhibited the expression of type A1 scavenger receptor (SR-A1) and cluster of differentiation 36 (CD36) in ox-LDL-treated macrophages. Taken together, 1,6-α-glucans from Fructus Corni showed significant anti-atherogenic effect, and the mechanism is related to enhanced antioxidant activity of the ApoE^-/- mice and down-regulated the expression of SR-A1 and CD36 proteins in macrophages.

Exopolysaccharides from Basidiomycota: Formation, isolation and techno-functional properties

This Mini Review gives an overview of and respective references for the production and properties of exopolysaccharides from Basidiomycota in submerged cultivation. Media and conditions that are usually applied in laboratory culture are summarized, and the lack of studies related to up-scaling is addressed. Procedures for isolation and purification of the exopolysaccharides from the fermentation media are reviewed, and challenges related to exopolysaccharide quantification are discussed. Finally, the techno-functional properties of the respective exopolysaccharides, and potential applications in foods are addressed.

Three bisabolane-type sesquiterpenes from edible mushroom Pleurotus eryngii

Three bisabolane-type sesquiterpenes (1-3) were isolated from the fruiting bodies of king trumpet mushrooms (Pleurotus eryngii), together with a known compound (4). All isolated compounds were evaluated for their inhibitory effects on nitric oxide (NO) production. Among these, 2 exhibited a moderate inhibitory effect on NO production with an IC₅₀ of 90.9 μM.

Lipid-Lowering Effect of the Pleurotus eryngii (King Oyster Mushroom) Polysaccharide from Solid-State Fermentation on Both Macrophage-Derived Foam Cells and Zebrafish Models

Hyperlipidemia is a key risk factor in inducing fatty liver, hypertension, atherosclerosis and cerebrovascular diseases. Previous studies have verified that polysaccharides from fruiting bodies (PEPE) of Pleurotus eryngii (king oyster mushroom) are capable of decreasing the lipid content. In this study, the P. eryngii polysaccharide is obtained by solid-state fermentation (PESF) using lignocellulosic wastes, corn-cobs and wheat bran. The high-performance liquid chromatography (HPLC) assays indicate that PESF has a similar composition to that of PEPE. Meanwhile, PESF has no detectable toxicity and is able to significantly inhibit foam-cell formation in murine macrophage cells (RAW264.7) induced by oxidized low-density lipoprotein. Further verification indicates that PESF has lipid-lowering effects during the lipid absorption phase in a zebrafish hyperlipidemia model. Our findings suggest that the P. eryngii polysaccharide from solid-state fermentation (PESF) can be used as a valuable lipid-lowering food additive or raw materials for producing lipid-lowering drugs.

In vitro and in vivo inhibitory effects of a Pleurotus eryngii protein on colon cancer cells

The inhibitory effects of a protein isolated from Pleurotus eryngii were demonstrated in both cell culture and mouse allograft tumor models.