Wild Mushrooms as a Source of Bioactive Compounds and Their Antioxidant Properties-Preliminary Studies

Abstract

The aim of this study was to preliminarily determine the content of bioactive components in the fruiting bodies of four previously unstudied mushroom species: Aleuria aurantia, Phallus hadriani, Phanus conchatus, Geastrum pectinatum, their antioxidant activity and the content of polyphenols, minerals and heavy metals.

Methods: Determination of active compounds by gas chromatography-mass spectrometry was carried out in addition to thermogravimetric determinations, quantitative determination of total polyphenols by spectrophotometry using Folin-Ciocalteu reagent, determination of antioxidant activity using 2,2-diphenyl-1-picryl hydrazyl radical (DPPH) and 2,2'-azino-di-[3-ethylbentiazoline sulphonated] (ATBS). In addition, spectrometric analysis of selected minerals and heavy metals was performed by inductively coupled plasma optical emission spectroscopy (ICP-OES).

Results: The mushrooms analysed varied in terms of their bioactive constituents. They contained components with varying effects on human health, including fatty acids, oleamide, 1,2-dipalmitoylglycerol, (2-phenyl-1,3-dioxolan-4-yl)-methyl ester of oleic acid, deoxyspergualin, 2-methylenocholestan-3-ol, hexadecanoamide, isoallochan, 2,6-diaminopurine, and adenine. All contained polyphenols and varying amounts of minerals (calcium, magnesium, iron, zinc, potassium, phosphorus, sodium, copper, silicon and manganese) and exhibited antioxidant properties of varying potency. No exceedances of the permissible concentration of lead and cadmium were observed in any of them.

Conclusions: All of the mushrooms studied can provide material for the extraction of various bioactive compounds with physiological effects. In addition, the presence of polyphenols and minerals, as well as antioxidant properties and the absence of exceeding the permissible concentration of heavy metals, indicate that these species could be interesting material in the design of foods with health-promoting properties, nutraceuticals or dietary supplements. However, the use of the fruiting bodies of these mushrooms requires mandatory toxicological and clinical studies.

Keywords: antioxidant properties; bioactive ingredients; heavy metals; polyphenols; wild mushrooms.

Figure 1

Photographs of the fungal species analysed: (a) Aleuria aurantia, (b) Panus conchatus, (c) Phallus hadriani, (d) Geastrum pectinatum (photographs and collection Marcin Szymański).

Figure 2

Thermogravimetric analysis of PH sample, created with NETZSCH proteus software by Marcin Szymański. The solid line denotes the TG curve (TG is a function: G = f(T), where: T—temperature)—the change in mass of the sample as it is heated or cooled, the dashed line denotes the DTG curve (DTG is the derivative of dG/dt = F(T); where: T = β∙t (β—heating rate of the sample; t—time)—the change in decomposition rate of the substance with increasing temperature. As a result of the TG analysis, a curve is obtained on which the y-axis is located the change in mass of the sample (decreasing downwards), and on the x-axis is time or temperature. On the TG curve, it is possible to observe the steps associated with the loss or gain of mass of the sample during heating or cooling. In parallel, a differential thermogravimetric (DTG) analysis is performed. The first derivative of the thermogravimetric curve against time (t) or temperature (T) is then obtained. The DTG curve represents the change in decomposition rate of a substance with an increase or decrease in temperature. In contrast, the total mass loss of the sample is equal to the area of the peak on this curve.

Figure 3

Identification of active compounds in extracts from (a) Geastrum pectinatum: Ethyl iso allocholate, hexadecanoamide, oleic acid, oleamide, 2-methylenocholestan-3-ol, 2-hexadecanol, SYH—(18,19-secoyohimban-19-oic acid, and 16,17,20,21-tetradehydro-16-(hydroxymethyl)-, methyl ester, (15ß,16E)-), (b) Aleuria aurantia: D-mannose, dihydroactinolide, palmitic acid, linoleic acid, oleic acid, 2-methylenocholestan-3-ol, 9 (11)-dehydroergosterol tosylate, (c) Panus conchatus: decanoic acid, palmitic acid, ethyl palmitate, GDA—gibbane-1,10-dicarboxylic acid, 2,3-epoxy- 4a,7-dihydroxy-1-methyl-8-methylene-, 1,4a-lactone, 10-methyl ester, (1a,2ß,3ß,4aa,4ba,10ß)-), linoleic acid, X1—not identified, 1,2-dipalmitoylglycerol, EEO—3-ethyl-5-(2-ethylbutyl)—Octadecane, oleamide, A—17′-acetoxy-3′ß-methyl- (5′ß) Spiro (1,3-dithion)-2,2′-(androstan-3′-ol), 7-methyl-Z-tetradecen-1-ol acetate, 2-hexadecanol, B—1,3,5,7-tetramethyl-2,4-Diselena-6,8-dioxatricyclo[3. 3.1.1(3,7)]decane (d) Phallus hadriani; caproic acid, octadecane, 6-methyl-, ester-1,3,5(10)-trien-17ß-ol, 3-octyl-oxirane-octanoic acid, dasycarpidan-1-methanol acetate, oleamide, deoxyspergualine, oleic acid, X1, X2—not identified, A—(Engl. 8,14-Seco-3,19-epoxyandrostane-8,14-dione, 17-acetoxy-3ß-methoxy-4,4-dimethyl-), B—(2-phenyl-1,3-dioxolan-4-yl)-methyl ester of oleic acid), pseduosarsasapogenin-5,20-diene.