Biološki potencijal i analiza metabolita jestivih i lekovitih gljiva iz rodova Agrocybe, Laetiporus, Pleurotus i Polyporus sa teritorije Srbije
Biological potential and metabolite analysis of edible and medicinal fungi from genera Agrocybe, Laetiporus, Pleurotus i Polyporus from the territory of Serbia
Doctoral thesis (Published version)
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Macromycetes are fungi from subdivisions Ascomycotina and Basidiomycotina that are large enough to be seen with naked eye and to be picked by hand. In this thesis, selected species from the genera: Agrocybe, Laetiporus, Pleurotus and Polyporus were harvested in Serbia and chemically characterized. Their nutrients profile and selected metabolites as well as their biological potential was evaluated. Quantification of macronutrients (carbohydrates, proteins, fat and ash), selected sugars, tocopherols, fatty, phenolic and organic acids was determined by means of HPLC coupled with various detectors, depending on the type of desired compound. Regarding the evaluation of biological potential, detailed assesments of antioxidant, antimicrobial, anti-quorum sensing and cytotoxic activities were performed. A lectin was extracted from the fruiting body of Laetiporus sulphureus 1 as a compound of interest, and was evaluated for its antibacterial activity. Results of the macronutrient profile suggest that macromycetes are a rich source of carbohydrates and proteins, with low fat content which makes them excellent candidates for food. Sugar analysis revealed the presence of: rhamnose, fructose, mannitol, glucose and trehalose which was the most abundant sugar with 16,50 g/100 g dry weight in Pleurotus ostreatus K and 32,60 g/100 g dry weight in P. ostreatus S. Four isoforms of tocopherols (α-, β-, γ- and δ- tocopherol) were quantified in samples, while the fatty acid analysis revealed the presence of 27 fatty acids with linoleic acid as the most abundant polyunsatturated fatty acid in sample Agrocybe aegerita 1 (78,40%). Amongst simple organic acids, the following were detected in the samples: oxalic, quinic, malic, citric and fumaric acid. Phenolic group containing organic acids analysis indicated the presence of: protocatechuic, p-hydroxybenzoic, p-coumaric and cinnamic acid. Isolation and characterization of lectin from the L. sulphureus 1 basidiocarp revealed that lectin is a multimer with pI value of ~ 4,6. Results of antioxidant activity which was evaluated using four protocols (reducing power, DPPH· scavenging activity, β-caroten/linoleic acid and TBARS test) indicate that selected macromycetes are potent antioxidant agents that showed ability to neutralize free radicals, inhibit lipid peroxidation and reducing power (EC50/EC0.5 is in range of 0,25 – 23,78 mg/mL). Ethanolic and methanolic extracts of mushroom fruiting bodies revealed potent antimicrobial potential against the tested pathogenic microorganisms (compared to the aqueous extracts), while lectin didn't show antibacterial activity at the tested concentrations, which supports the claim that natural sourced substances achieve their full biological potential thanks to the additive and synergistic interactions of all the present compounds. Methanolic extracts of the selected macromycetes were tested at subinhibitory level for their ability to interfere with bacterial cell-cell communication using Pseudomonas aeruginosa PAO1 as a model system. Obtained results suggest that mushroom extract very efficiently reduced the diameter of bacterial colony, structures that enable its dispersion, as well as the synthesis of pigment pyocyanin – its virulent factor. The best antibiofilm effect was observed for the methanolic extract of Polyporus squamosus (88,30%). Moderate cytotoxic potential was exclusive for polysaccharide extract of L. sulphureus 1 against the following carcinogenic cell lines: HeLa, NCI-H460 and MCF-7. In addition, results of the preliminary hepatotoxicity analysis indicate the extracts are non-toxic for the porcine primary cells in tested concentrations, providing the opportunity for safe human consumption of these mushrooms. All the obtained results indicate that the selected macromycetes have potential as functional foods thanks to the production of biologically active compounds which have beneficial health effects and in addition, given their ability to eradicate pathogenic microorganisms, mushrooms are important in the formulation of new available antimicrobial agents. Macromycetes are a true example of tradition and novelty unity and they have significant potential in maintaining and improving health, longevity and quality of life. Their current status and future prospects open up new avenues for improving their status from functional foods to proper medicinal products. Since the tested mushrooms have been successfully cultivated, something like this may actually happen in near future.
Keywords:Edible macromycetes; Nutrients; Selected metabolites; Biological activity; Lectins
Source:University of Belgrade, Faculty of Biology, 2018, 1-153
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