Diversity of Pleurotus spp. (Agaricomycetes) and Their Metabolites of Nutraceutical and Therapeutic Importance.

Pleurotus spp. have been gaining popularity as a source for the creation of functional foods, nutraceuticals and novel pharmaceuticals. Despite Pleurotus is a specious genus including 208 legitimate species, only a few of them such as P. ostreatus are commercially accessible. The genetic and metabolic diversity of Pleurotus both at specific and subspecific level is therefore of main concern for many researchers. In addition to the conventional morphological approach, molecular and biochemical markers have been greatly contributing to investigate these issues. In this study, samples from six Pleurotus species (P. eryngii is represented by three varieties) were molecularly identified and the phylogeny was inferred to assess the relationships between the various taxa. Strains in pure culture obtained from 6 out of 7 species were cultivated as mycelium in vitro to investigate the metabolites by untargeted LC-MS/MS-based metabolomics. The results pointed out species-specific metabolite patterns and highlighted a clear difference between the P. eryngii group and P. ostreatus, although the latter appears more versatile depending on the strain. This is the first study pointing out and comparing different metabolite patterns in Italian samples of Pleurotus species, including P. eryngii varieties.

Fomitopsis officinalis: Spatial (Pileus and Hymenophore) Metabolomic Variations Affect Functional Components and Biological Activities.

Fomitopsis officinalis is a holartic polyporous mushroom that forms large fruiting bodies on old standing trees, fallen logs, or stumps. F. officinalis is a medicinal mushroom species that is most commonly used in traditional European medicine. In this study, we explore the spatial metabolic differences in F. officinalis' mushroom parts, i.e., the cap (median and apical parts) and the hymenium. Additionally, chromatographic analysis was conducted in order to unravel the composition of specialized metabolites in the hydroalcoholic mushroom extracts. The potential antifungal and bacterial effects of extracts were tested against pathogen strains of Gram+ and Gram- bacteria, and yeast, dermatophytic, and fungal-pool species. Extracts from the apical part were the richest in terms of phenolic compounds; consistent with this finding, the extracts were also the most effective antiradical and antimicrobial agents with MIC values < 100 µg/mL for most of the tested bacterial and dermatophytic species. According to these findings, F. officinalis extracts are valuable sources of primary and secondary metabolites, thus suggesting potential applications in the formulation of food supplements with biological properties in terms of antioxidant and antimicrobial activities.

Lipidomic profiling of Pleurotus ostreatus by LC/MS Q-TOF analysis.

In this paper, for the first time a lipidomic analysis on Pleurotus ostreatus species was performed by liquid chromatography quadrupole time-of-flight mass spectrometry (LC/MS Q-TOF). Twenty-seven lipid classes, including polar and non-polar lipid classes, were detected. Free fatty acids (FA) were the predominant fraction (>57%), followed by fatty acid ester of hydroxyl fatty acid and ceramide. C18 chain length and two double bonds were the main structural characteristics for FA. Phosphatydilcholine, phosphatydiletanolamine, and glycerophosphates showed high percentages of polyunsaturated fatty acids. Unconventional fatty acids, such as odd and oxygenated chains, were detected. The highest odd/even ratio was found in hexosylceramides and sphingomyelin, while oxygenated chains were mainly represented in ceramides. As a preliminary approach, the results of lipid molecular species, subjected to principal component analysis and discriminant analysis, were able to differentiate P. ostreatus samples on the base of grown substrate. The results of the comprehensive analysis of P. ostreatus lipids are useful to evaluate the lipid nutritional value and could facilitate exploitation of P. ostreatus consumption.

Biochemical and immunological characterization of pollen-derived beta-galactosidase reveals a new cross-reactive class of allergens among Mediterranean trees.

BACKGROUND: The most potent allergens in the Spermatophytae family exhibit significant homology with enzymes. Some of these are though to be involved in pectin metabolism, recognition of compatible stigma and delivery of sperm cells to the ovule. OBJECTIVE: To test if glycohydrolase activities from some Mediterranean tree pollens could act as allergens in sensitized hosts. METHODS: Freshly collected Cupressus and Olea pollens were investigated for their glycohydrolase activities by means of synthetic fluorogenic substrates and isoenzymes characterized by DEAE-cellulose ion-exchange chromatography. Binding of specific IgE was investigated by immunoblotting in 30 tree-sensitive subjects, as well as in 20 atopic non-tree-sensitive and 15 healthy controls. The enzymes were also adopted to stimulate proliferation of allergen-specific T cell clones. Finally, they were tested in vivo in a cutaneous immediate wheal and flare reaction. RESULTS: beta-Galactosidase (beta-GAL) is present with different isoenzymatic patterns on both pollen extracts, could be recognized by circulating IgE, as well as immunoprecipitated by sera from allergic subjects. The enzyme could stimulate the proliferation of T cells from allergic subjects, and favor the emergence of CD4+ T cell clones with specific in vitro reactivity to beta-GAL. Finally, the enzyme induced in vivo a cutaneous wheal and flare reaction in clinically sensitive subjects. CONCLUSIONS: Despite different isoenzymatic patterns, Olea-derived beta-GAL cross-reacted with that from cypress pollen, suggesting that these enzymatic glycoproteins may represent major native allergens among these Mediterranean trees.