Optimization of extracellular glucan production from Pleurotus eryngii and its impact on angiogenesis

Optimization and reactor-scale production of plant growth regulators by Pleurotus eryngii

The aims of the this study are to select the best cultivation type for plant growth regulator (PGR) production, to optimize PGR production with statistical experimental design, and to calculate bioprocess parameters and yield factors during PGR production by P. eryngii in flask and reactor scales. Submerged fermentation was the best cultivation type with 4438.67 ± 37.14, 436.95 ± 27.31, and 54.32 ± 3.21 mg/L of GA3, ABA, and IAA production values, respectively. The Plackett-Burman and Box-Behnken designs were used to determine effective culture parameters and interactive effects of the selected culture parameters on PGR production by Pleurotus eryngii under submerged fermentation. The statistical model is valid for predicting PGR production by P. eryngii. After these studies, maximum PGR production (7926.17 ± 334.09, 634.92 ± 12.15, and 55.41 ± 4.38 mg/L for GA3, ABA, and IAA, respectively) was reached on the 18th day of fermentation under optimized conditions. The optimum formula was 50 g/L fructose, 3 g/L NaNO3, and 1.5 g/L KH2PO4, 1 mg/L thiamine, incubation temperature 25 °C, initial medium pH 7.0, and an agitation speed of 150 rpm. The kinetics of PGR production was investigated in batch cultivation under 3-L stirred tank reactor conditions. Concentrations of GA3, ABA, and IAA of 10,545.00 ± 527.25, 872.32 ± 21.81, and 60.48 ± 3.48 mg/L were obtained at the reactor scale which were 4.1, 3.4, and 2.3 times higher than the initial screening values. The specific growth rate (µ), the volumetric (rp) and specific (Qp) PGR production rates, 486.11 mg/L/day and 107.43 mg/g biomass/day for GA3, confirmed the successful transfer of optimized conditions to the reactor scale. In the presented study, PGR production of P. eryngii is reported for the first time.

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.

Purification, identification and functional characterization of an immunomodulatory protein from Pleurotus eryngii

Pleurotus eryngii contains bioactive compounds that can activate the immune system. Here we report the identification, purification, and functional characterization of the bioactive P. eryngii protein (PEP) 1b. PEP 1b was discovered to be a 21.9 kDa protein with the ability to induce the M1-polarization of the macrophage cell line RAW 264.7 cells. Biochemical measurements showed that PEP 1b stimulated nitric oxide (NO), IL-1β, IL-6 and TNF-α production and regulated inducible NO synthase. Phosphorylation and inhibitor studies revealed that PEP 1b promoted the translocation of NF-kB from the cytosol to the nucleus allowing the induction of target gene expression and NO production. The phosphorylation of JNK and ERK1/2 was found to be necessary for NO production. Each phosphorylation pathway was found to require a Toll-like receptor (TLR) 4 as a prerequisite for PEP 1b-induced NO production. This study suggests that PEP 1b is an immunomodulatory protein that can boost cellular immune responses through the activation of the TLR4-NF-κB and MAPK signaling pathways.

Identification and characterization of bioactive phenolic constituents, anti-proliferative, and anti-angiogenic activity of stem extracts of Basella alba and rubra

Basella is an important green leafy vegetable species of Chenopodiaceae family and is known for its medicinal properties. Hydroxy-benzoic acids, hydroxy-cinnamic acids and flavones groups were identified and characterized from the aqueous stem extracts of B. alba and B. rubra species. Higher values of phenolics as well as antioxidant activity were noted from B. alba species extracts. The evaluation of the cytoxicity of these extracts on A431 (epidermoid carcinoma), Hep G2 (hepatocellular carcinoma) and MG 63 (osteosarcoma) cells indicated anti-proliferative activity against all the cell lines. B. alba extract showed higher anti-proliferative activity (37.95-84.86%). Chick embryo chorioallantoic membrane (CAM) assay revealed inhibition of neo-vessels formation. Significant suppression was found with extracts of B. alba at 7 mg/ml compared to that of B. rubra. This is the first study to report the anti-angiogenic activity of Basella species. These studies indicate that Basella sps can be used as a source of natural antioxidants and can be of high significance in pharmaceutical and nutraceutical industries.

Exopolysaccharide from Ganoderma applanatum as a promising bioactive compound with cytostatic and antibacterial properties

A new exopolysaccharide preparation isolated from stationary cultures of the white rot fungus Ganoderma applanatum (GpEPS) was tested in terms of its bioactive properties including its cytotoxic and immunostimulatory effect. The results indicate that the tested GpEPS (at concentrations above 22.85 µg/mL and 228.5 µg/mL) may exhibit selective activity against tumor cells (cell lines SiHa) and stimulate production of TNF-α THP-1-derived macrophages at the level of 752.17 pg/mL. The GpEPS showed antibacterial properties against Staphyloccoccus aureus and a toxic effect against Vibrio fischeri cells (82.8% cell damage). High cholesterol-binding capacity and triglycerides-binding capacity (57.9% and 41.6% after 24 h of incubation with the tested substances, resp.) were also detected for the investigated samples of GpEPS.