Structural Analysis of a Polysaccharide Isolated from the Alkali Extract of an Edible Mushroom, Pleurotus sajor-caju, Cultivar Black Japan

A heteropolysaccharide (PS-I) and an insoluble glucan (PS-II) were isolated from the alkaline extract of an edible mushroom Pleurotus sajor-caju, cultivar Black Japan. The polysaccharide (PS-I) was found to consist of D-glucose and D-galactose in a molar ratio of 3:1. Based on total acid hydrolysis, methylation analysis, and NMR experiments (1H, 13C, DQF-COSY, TOCSY, NOESY, ROESY, HMQC, and HMBC), the structure of the repeating unit of the polysaccharide was established.

Antiviral, Cytotoxic, and Antioxidant Activities of Three Edible Agaricomycetes Mushrooms: Pleurotus columbinus, Pleurotus sajor-caju, and Agaricus bisporus

In this study, we investigated aqueous extracts of three edible mushrooms: Agaricus bisporus (white button mushroom), Pleurotus columbinus (oyster mushroom), and Pleurotus sajor-caju (grey oyster mushroom). The extracts were biochemically characterized for total carbohydrate, phenolic, flavonoid, vitamin, and protein contents besides amino acid analysis. Triple TOF proteome analysis showed 30.1% similarity between proteomes of the two Pleurotus spp. All three extracts showed promising antiviral activities. While Pleurotus columbinus extract showed potent activity against adenovirus (Ad7, selectivity index (SI) = 4.2), Agaricus bisporus showed strong activity against herpes simplex II (HSV-2; SI = 3.7). The extracts showed low cytotoxicity against normal human peripheral blood mononuclear cells (PBMCs) and moderate cytotoxicity against prostate (PC3, DU-145); colorectal (Colo-205); cecum carcinoma (LS-513); liver carcinoma (HepG2); cervical cancer (HeLa); breast adenocarcinoma (MDA-MB-231 and MCF-7) as well as leukemia (CCRF-CEM); acute monocytic leukemia (THP1); acute promyelocytic leukemia (NB4); and lymphoma (U937) cell lines. Antioxidant activity was evaluated using 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging, 2,2′-Azinobis-(3-Ethylbenzthiazolin-6-Sulfonic Acid) ABTS radical cation scavenging, and oxygen radical absorbance capacity (ORAC) assays. The three extracts showed potential antioxidant activities with the maximum activity recorded for Pleurotus columbinus (IC50 µg/mL) = 35.13 ± 3.27 for DPPH, 13.97 ± 4.91 for ABTS, and 29.42 ± 3.21 for ORAC assays.

Pro-Health and Anti-Cancer Activity of Fungal Fractions Isolated from Milk-Supplemented Cultures of Lentinus (Pleurotus) Sajor-caju

The present study aimed to demonstrate Lentinus (formerly Pleurotus) sajor-caju (PSC) as a good source of pro-health substances. It has also shown that supplementation of its culture medium with cow milk may further improve its beneficial properties. Intracellular fractions from fungi grown on a medium supplemented with cow milk were analyzed using various biochemical methods for determination of the nutrient composition. Furthermore, anti-cancer properties of selected extracts were investigated on colorectal cancer cell lines (HT-29, LS 180, and SW948) in vitro. Biochemical analysis showed enrichment in health-enhancing compounds, such as proteins or polysaccharides (about 3.5- and 4.5-fold increase in concentration of proteins and carbohydratesin extracts of mycelia cultured on whole milk (PSC2-I), respectively), with a decrease in the level of free radicals (10-fold decrease in extract grown on milk and medium mixture (1:1) (PSC3-II)), which was related to increased catalase and superoxide dismutase activity (7.5-fold increase in catalase activity and 5-fold in SOD activity in PSC3-II compared to the control). Moreover, the viability of the cancer cells was diminished (to 60.0 ± 6.8% and 40.0 ± 8.6% of the control, on HT-29 and SW948 cells, respectively), along with pro-apoptotic (to 18.8 ± 11.8 and 14.7 ± 8.0% towards LS 180 and SW948 cells, respectively) and NO-secreting effects (about 2-fold increase) of the extracts. This study suggests that PSC has multiple nutritional and anti-cancer properties and can be used as a source of healthy biomolecules in modern medicine or functional foods.

Effect of extraction conditions (temperature, pH and time) by cellulase on chemical properties of dried oyster mushroom (Pleurotus sajor-caju) extract

Oyster mushroom (Pleurotus sajor-caju) is known to be highly nutritious food. However, the understanding of its quality and food products produced from it are still very limited. With the desire to increase the value of oyster mushroom and to create an intermediate product with high nutrients content for further processing, a cellulase enzyme-assisted extract of dried oyster mushroom was investigated. The effects of extraction conditions in terms of temperature (40, 45, 50, 55oC), pH (4.5, 5.0, 5.5, 6.0) and extraction time (4, 6, 8, 10 hrs) on nutrients and bioactive compounds of extract were studied. The results showed that the highest extraction efficiency was obtained at 50oC, pH 5.5 and 8 hrs of hydrolysis. The Brix of the extract was 2.53. In 100 g dry matter of extract, the content of saccharose, reducing sugar, total protein, amino acids, lysine, β-glucan, total phenolic and total flavonoid was 15.13 g, 19.41 g, 43.65 g, 7.96 g, 0.82 g, 10.63 mg, 62.60 mg TAE, 5.54 mg QE, respectively. The highest antioxidant capacity of the extract determined by Ferric reducing antioxidant power (FRAP assay) was 165.50 mM Fe2+/100 g dry matter and that measured by scavenging 2,2 -diphenyl-1-picrylhydrazyl (DPPH) radicals was 69.32%.