Introduction
Reactive oxygen species (ROS) are generated during mitochondrial oxidative metabolism and during a cellular response to xenobiotics, cytokines, and bacterial invasion (Ray et al., 2012). Low levels of ROS are beneficial to cells, but when they reach high levels, they cause serious harm, for example, damage to nucleic acids, oxidization of proteins, and lipid peroxidation (Sánchez, 2017; Mhamdi and Van Breusegem, 2018). Endogenous antioxidants serve to reduce the effect of ROS, but a deficiency of endogenous antioxidants in organisms can lead to severe disorders such as cardiovascular diseases, diabetes, cancer, Alzheimer’s disease, Parkinson’s disease, and neural complications (Wei et al., 2008; Bal et al., 2017). In addition, because ROS can damage DNA, proteins, and other macromolecules, the changes accumulate over time and can cause aging of the organism (Sánchez, 2017). Hence, the presence of antioxidants in the diet plays an important role in preventing various diseases. Presently, natural products with medicinal properties (e.g., biologically active compounds from Allium calocephalum Wendelbo, galantamine from the plant family Amaryllidaceae, psychotrine from Cephaelis acuminata H. Karst., the alkaloid capsaicin from the genus Capsicum, and many others) are receiving increasing interest, as some synthetic drugs have been reported to have carcinogenic properties (Mohammed et al., 2019; Alrasheid et al., 2021). Therefore, the search for effective and nontoxic natural products is increasing, and it has been proven that antioxidants are present in all biological systems (Lee et al., 2004; Donglu et al., 2016). In addition to being a nutritious food, mushrooms have high medicinal properties as they contain important bioactive compounds. Mushrooms are rich in proteins (19–35% of dry weight), carbohydrates (50–65% of dry weight), fat (2–6% of dry weight), vitamins (thiamin, riboflavin, niacin, biotin, and ascorbic acid), and minerals (Ca, K, Mg, Na, P, Cu, Fe, Mn, Cd, Pb, and Se) (Rathore et al., 2017; Copetti, 2019; Vetter, 2019). Various mushrooms play an important role in the treatment of various diseases, including viral, bacterial, and fungal infections (Chang and Buswell, 1996; Khatua et al., 2013; Muszyńska et al., 2018). The mushroom kingdom contains many compounds with antioxidant properties, which include ergothioneine (a compound occurring in relatively few organisms) and glutathione (an insufficiently explored compound) (Kalaras et al., 2017; Quintero-Cabello et al., 2021).
Among the mushroom species, Hohenbuehelia sp. is currently of particular interest as it shows promising radioprotective (Li et al., 2015), antioxidant, and antimicrobial activities (Bala et al., 2011; Li et al., 2017). H. myxotricha is a rare representative of Hohenbuehelia species (Angeli and Scandurra, 2012). H. myxotricha is a fungus from Basidiomycota division, Agaricomycetes class, Agaricales order, and Pleurotaceae family. It was first described by French physician and mycologist Joseph-Henri Léveillé in the 19th century, and its current name was given by German-born mycologist Rolf Singer in 1951. There are very limited studies on this fungus, and its extracellular enzymatic activity, alternative substrates for the cultivation of its mycelia, and antibacterial activity of mycelia and culture liquid have been investigated only in the past few years (Krupodorova et al., 2014; Krupodorova and Barshteyn, 2015; Krupodorova et al., 2016). H. myxotricha was reported as a species that produces extracellular enzymes (Krupodorova et al., 2014); in their study, the authors reported for the first time the production of amylase, lipase, and urease by H. myxotricha. High biological efficiency of H. myxotricha mycelia cultivation on a soybean cake was also established (Krupodorova and Barshteyn, 2015). The antibacterial activities of H. myxotricha were observed against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus (Krupodorova et al., 2016).
The present study aimed to evaluate the total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), and antimicrobial activities of H. myxotricha (Lév.) Singer mycelia cultivated in different liquid media.
Materials and methods
Fungal strain
H. myxotricha (synonyms: Acanthocystis myxotricha, Agaricus myxotrichus, Calathinus myxotrichus, Dendrosarcus myxotrichus, and Pleurotus myxotrichus) strain 1599 was kindly provided by the Mushroom Culture Collection (IBK) of the M.G. Kholodny Institute of Botany of the National Academy of Sciences of Ukraine (Bisko et al., 2020). Stock cultures were maintained on beer wort agar slants at 4°C.
Culture media and growth conditions
H. myxotricha was grown in Petri dishes (90 mm diameter) on glucose peptone yeast (GPY) agar medium pH 6.0 with the following composition (g/l): 25.0 glucose, 3.0 yeast extract, 2.0 peptone, 1.0 K2HPO4, 1.0 KH2PO4, 0.25 MgSO4 ∙ 7H2O, and 20.0 agar. The GPY liquid culture medium without agar and Sabouraud dextrose broth (HiMedia, India) pH 5.6 with the following composition (g/l): 20.0 dextrose and 10.0 peptone, were sterilized by autoclaving for 15 min at 121°C. Flasks (250 ml) with 100 ml liquid culture medium were inoculated with three mycelial plugs of 8 mm diameter cut from the Petri dishes by using a sterile borer at the stage of actively growing mycelia. Mycelia were grown under static conditions (without agitation and in dark) in flasks for 14 days at 26°C. The mycelium was then separated from the medium by filtration through a Whatman filter paper No. 4 (Whatman plc, UK) and washed with distilled water. The mycelium was dried at 60°C (Snol-58/350, UMEGA, Republic of Lithuania) until it reached a constant weight.
Extract preparation
Five grams of samples were taken from each of the mycelia samples obtained from liquid GPY or SDB medium and pulverized. The samples were then extracted with 30 ml of ethanol (EtOH) with a heated magnetic stirrer for approximately 24 h. Subsequently, the obtained extracts were sieved through a filter paper and concentrated at 40°C in a rotary evaporator (Heidolph Laborota 4000 Rotary Evaporator) until the solvent was completely evaporated.
Antimicrobial activity tests
Antimicrobial activity tests of EtOH extracts of mycelia samples were performed using the agar dilution method as recommended by the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The minimum inhibitory concentrations (MIC) were determined in the tests. MIC values are the lowest extract concentrations that inhibit the growth of microorganisms (CLSI 2012; EUCAST 2014; EUCAST 2015). Staphylococcus aureus ATCC 29213, methicillin-resistant S. aureus (MRSA) ATCC 43300, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Acinetobacter baumannii ATCC 19606 were used as bacterial strains and precultured in Muller Hinton Broth. Candida albicans ATCC 10231, C. glabrata ATCC 90030, and Issatchenkia orientalis (formerly C. krusei ) ATCC 34135 were used as fungal strains and precultured in RPMI 1640 broth medium. The turbidity of the test bacterial and fungal suspensions was adjusted according to McFarland 0.5 scale to obtain a standard inoculum. The extracts were adjusted with distilled water to the concentrations of 12.5–800 μg/ml. The solvent (as control) used for the extraction was also tested for antimicrobial activity. Fluzole (Fluconazole; Nobel Ilac Sanayii Ve Ticaret A.S., Turkey), Ampholip (Amphotericin B; Bharat Serums and Vaccines, India), Amikacin (Provet Veterinary Products, Turkey), Alfasid (Ampicillin; Avis Ilac A.S., Turkey), and Flaprox (Ciprofloxacin; World Medicine Ilac San. Ve Tic. A.S., Turkey) were used as reference drugs (Bauer et al., 1966; Hindler et al., 1992; Matuschek et al., 2014).
TAS and TOS determination
TAS and TOS of the mycelial samples were determined using Rel Assay TAS kits (Erel, 2004) according to the manufacturer’s protocol. Trolox was used as a standard in antioxidant tests. Hydrogen peroxide was used as a standard in oxidant tests. OSI (arbitrary unit: AU) was determined according to the following formula (Erel, 2005):
Result and discussion
Antimicrobial activity of H. myxotricha mycelial extract
Microbial infections have been quite harmful for human health from past to present. Antibiotics are drugs used in the treatment of diseases caused by many different microorganisms (Tanhaeian et al., 2020). Presently, the effectiveness of the use of synthetic antibiotics is gradually decreasing due to the emergence and spread of multidrug-resistant bacteria (Fair and Tor, 2014; Dunai et al., 2019). In addition, the use of synthetic antibiotics may have side effects such as allergic reaction, vomiting, nausea, diarrhea, bloating, indigestion, abdominal pain, and fungal infections (Anderson, 2019). The discovery of new antimicrobial products has therefore become necessary, as microorganisms are increasingly acquire resistance to antibiotics (Klaus et al., 2020). The establishment of the presence of antibacterial activity in a poorly studied fungus H. myxotricha shows the potential of this species. Growing the fungus under controlled conditions allows, to a certain extent, to regulate the biosynthesis of its metabolites. In particular, the optimization of the culture medium can enhance secondary metabolite production. A previous study on the antimicrobial activity of different extracts of Lentinus tigrinus demonstrated that ethanolic extracts generally exhibited higher levels of activity against test microorganisms than other extracts (Sevindik, 2018a). It was also found that an ethanolic extract of Stereum hirsutum had higher antimicrobial and antioxidant activity than its methanolic extract (Sevindik et al., 2021a). Ethanol is a very suitable solvent for the extraction of polar and some nonpolar metabolites. It is also a preferred solvent because it is nontoxic to human and animal cells, unlike methanol. In the present study, the antimicrobial activities of ethanolic extracts of H. myxotricha mycelia produced in different culture media were determined. The obtained findings are shown in Table 1. A negative control of the solvent (ethanol) was also tested to ensure that any activity on the microorganisms is not caused by the solvent. The solvent did not show any inhibitory activity against the tested pathogenic bacteria and fungi. The effect of the influence of commercial antibiotics was also determined. The antimicrobial activity of the ethanolic extract of H. myxotricha mycelia was significantly lower than that of commercial antibiotics. This was, however, an expected result because the crude extract was analyzed, while the tested antibiotics contain purified isolated substances.
Table 1
Minimum inhibitory concentration (μg/ml) values of H. myxotricha mycelial extract and commercial drugs
The MIC values of mycelia samples of H. myxotricha varied from 25 to 200 μg/ml depending to the tested pathogens. Our results indicate that the mycelial extract of H. myxotricha contained effective antimicrobial compounds with a broad spectrum of activity against the tested pathogens, both gram-positive and gram-negative [(gram-positive: S. aureus (MIC 50 μg/ml), MRSA (MIC 50 μg/ml), E. faecalis (MIC 100 μg/ml); gram-negative: E. coli (MIC 100–200 μg/ml), P. aeruginosa (MIC 200 μg/ml), A. baumannii (MIC 100 μg/ml)] and fungus: C. albicans (MIC 25–50 μg/ml), C. glabrata (MIC 25 μg/ml), I. orientalis (MIC 25–50 μg/ml). To the best of our knowledge, the present study is the first report to demonstrate the antimicrobial effect of H. myxotricha against E. faecalis, P. aeruginosa, A. baumannii, and C. glabrata. The gram-negative bacteria A. baumannii, E. coli, and P. aeruginosa with an MIC value between 100 and 200 μg/ml were less sensitive than the gram-positive bacteria S. aureus and MRSA with an MIC value of 50 μg/ml (Table 1). This tendency can be explained by the structural intricacy of gram-negative bacteria as their cell walls are less permeable (Walsh, 2003). The antifungal activity of the ethanolic extract of H. myxotricha mycelia (MIC value ranging from 25 to 50 μg/ml) was stronger than its antibacterial activity (MIC value ranging from 50 to 200 μg/ml). This tendency was also observed for extracts in a similar experiment with the same pathogens (S. aureus, MRSA, E. faecalis, E. coli, P. aeruginosa, A. baumannii, C. albicans, C. glabrata, and C. krusei ) for the extracts of Cerrena unicolor fruiting bodies (Sevindik, 2018b). In the present study, the cultivation medium had no effect on the antibacterial activity of the extract, except for E. coli ; however, the extract of H. myxotricha mycelia grown in SDB medium (MIC 25 μg/ml for C. albicans, C. glabrata, and I. orientalis) showed more effective antifungal activity than the extract of the strain grown in GPY medium (MIC 50 μg/ml for C. albicans and I. orientalis, and MIC 25 μg/ml for C. glabrata ). Thus, it was observed that the antimicrobial activities of the same mushroom strain cultivated in different culture media can change depending on the medium used. This observation is in line with other studies that reported on the effect of carbohydrate composition of the cultivation medium for manifestation of the antimicrobial activity of Pleurotus ostreatus (Barakat and Sadik, 2014), Cantharellus cibarius (Popova, 2015), Lentinula edodes, and Fomitopsis betulina (Krupodorova et al., 2019). It should be noted that the tested mycelial extract inhibited the growth of S. aureus and MRSA at the same MIC value of 50 μg/ml. Many studies on the significant antimicrobial potential of the extracts of mushrooms (Basidiomycetes, Ascomycetes) have been appropriately summarized in different reviews (Alves et al., 2012; Ranadive et al., 2013; Sharma et al., 2014; Shen et al., 2017; Rosenberger et al., 2018; Román et al., 2020). In previous studies, by using the disc diffusion method, the mycelia of H. myxotricha obtained after growth in GPY medium was shown to exert some effect against Bacillus subtilis ATCC 6633 (zone of inhibition (ZOI): 13.3 ± 0.7 mm) and after growth in amaranth flour medium against Escherichia coli 06, (ZOI: 10.0 ± 0.0 mm), Staphylococcus aureus 209 (ZOI: 15.0 ± 1.0 mm), and B. subtilis (ZOI: 19.0 ± 1.0 mm) (Krupodorova et al., 2016). The antibacterial activity against S. aureus and E. coli has also been noted for water extract (75–100% inhibition) and ethanolic extract (25–100% inhibition) of fruiting bodies of Hohenbuehelia sp. (Bala et al., 2011). Some activity (hazy/very hazy inhibition zone) against S. aureus was recorded for the methanolic extracts of Hohenbuehelia mastrucata (Fr.) Singer culture liquids (Suay et al. 2000). It is important to note that the effective concentrations of H. myxotricha mycelial extract against all the tested pathogens were lower than those of L. tigrinus (Sevindik, 2018a), Ganoderma lucidum (Bal, 2019), and Lactifluus rugatus (Sevindik, 2020) mushrooms. Previous studies have shown that the different extracts of L. tigrinus caprophores were effective against S. aureus (MIC values: 200 μg/ml for ethanol extract, 200 μg/ml for methanol extract, and 800 μg/ml for dichloromethane extract), MRSA (MIC values: 200 μg/ml for ethanol extract, 400 μg/ml for methanol extract, and 800 μg/ml for dichloromethane extract), E. faecalis (MIC values: 200 μg/ml for ethanol extract, 200 μg/ml for methanol extract, and 800 μg/ml for dichloromethane extract), E. coli and P. aeruginosa (MIC value: 880 μg/ml for ethanol extract), C. albicans (MIC values: 400 μg/ml for ethanol extract, 800 μg/ml for methanol extract, and 800 μg/ml for dichloromethane extract), C. glabrata (MIC values: 100 μg/ml for ethanol extract, 200 μg/ml for methanol extract, and 400 μg/ml for dichloromethane extract), and C. krusei (MIC values: 200 μg/ml for ethanol extract, 200 μg/ml for methanol extract, and 400 μg/ml for dichloromethane extract) (Sevindik, 2018a). The methanolic extract of G. lucidum fruiting bodies also possessed antimicrobial activity against S. aureus and MRSA (both MIC 200 μg/ml), C. albicans and C. krusei (both MIC 50 μg/ml), and C. glabrata (MIC 100 μg/ml) (Bal, 2019). The extracts of L. rugatus fruiting bodies exhibited activities against S. aureus and MRSA (MIC values: 100 μg/ml for methanol extract and 200 μg/ml for dichloromethane extract), E. faecalis (MIC values: 100 μg/ml for methanol extract and 400 μg/ml for dichloromethane extract), E. coli (MIC values: 200 μg/ml methanol extract, 400 μg/ml for dichloromethane extract), P. aeruginosa and A. baumannii (MIC values: 50 μg/ml for methanol extract and 200 μg/ml for dichloromethane extract), and C. albicans, C. glabrata, and C. krusei (MIC value: 1000 μg/ml for methanol and dichloromethane extracts) (Sevindik, 2020). The results of our studies clearly showed that the ethanolic extract of H. myxotricha mycelia contains potential antimicrobial compounds.
Antioxidant and oxidant status of the mycelial extract of H. myxotricha
Mushrooms are known to be an important source of antioxidants (Lu et al., 2018; Nkadimeng et al., 2020; Sevindik et al., 2020). In our present study, the TAS, TOS, and OSI values of mycelia samples of H. myxotricha grown in SDB and GPY media were determined. The obtained values are given in Table 2.
Table 2
Total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) values of H. myxotricha mycelial extract
| Media | TAS [mmol/l] | TOS [μmol/l] | OSI |
|---|---|---|---|
| Mycelial extract, grown on SDB | 5.416 ± 0.150 | 1.320 ± 0.156 | 0.024 ± 0.003 |
| Mycelial extract, grown on GPY | 4.549 ± 0.136 | 2.623 ± 0.157 | 0.058 ± 0.004 |
To the best of our knowledge, the TAS, TOS, and OSI values of mycelial extracts of H. myxotricha have been determined for the first time. The effect of the nutritional media on the antioxidant and oxidant status of H. myxotricha was assessed, and it was found that the mycelium produced in SDB medium had a higher TAS value of 5.416 ± 0.150 mmol/l. The ethanolic extract of the mycelium grown in GPY medium also showed higher TOS (2.623 ± 0.157 μmol/l) and OSI (0.058 ± 0.004) values. Differences in the antioxidant activity of the cultivated fungus Pleurotus citrinopileatus, depending on the content of the substrate used for growth, was also reported previously (Gürgen et al., 2020). The technique used in this work for assessing the antioxidant and oxidative potential has been successfully tested for fruiting bodies of different species of Basidiomycetes belonging to various ecological and systematic groups (Akgül et al., 2016; Sevindik et al., 2016; Akgül et al., 2017; Bal et al., 2017, 2019a; Sevindik, 2018a; Sevindik et al., 2018a,b,c; Sevindik, 2019, 2019a; Bal, 2019; Gürgen et al., 2020; Krupodorova and Sevindik, 2020; Mushtaq et al., 2020; Sevindik, 2020; Sevindik et al., 2020, 2020b). It was found that the TAS values of the mycelia extracts of H. myxotricha grown in SDB (TAS 5.416 mmol/l) and GPY (TAS 4.549 mmol/l) media were higher than those of wild-type Macrolepiota procera (2.805 mmol/l) (Akgül et al., 2016), Ompholatus olearius (2.827 mmol/l) (Sevindik et al., 2016), Auricularia auricula (1.010 mmol/l), Trametes versicolor (0.820 mmol/l) (Akgül et al., 2017), Daedalea quercina (0.312 mmol/l), Inonotus hispidus (2.922 mmol/l), Fomes fomentarius (3.270 mmol/l), Fuscoporia torulosa (4.033 mmol/l), Trametes gibbosa (0.590 mmol/l), Trichaptum biforme (0.802 mmol/l) (Bal et al., 2017), Gyrodon lividus (2.077 mmol/l) (Bal 2018), L. tigrinus (1.748 mmol/l) (Sevindik, 2018a), Cyclocybe cylindracea (4.325 mmol/l) (Sevindik et al., 2018a), Laetiporus sulphureus (1.748 mmol/l) (Sevindik et al., 2018c), Cerioporus varius (2.312 mmol/l) (Sevindik, 2019), Pholiota limonella (2.378 and 2.263 mmol/l) (Sevindik et al., 2018b), Lepista nuda (3.102 mmol/l) (Bal et al., 2019a), Infundibulicybe geotropa (1.854 mmol/l) (Sevindik et al., 2020), Octaviania asterosperma (3.410 mmol/l) (Sevindik et al., 2020b), L. rugatus (3.237 mmol/l) (Sevindik, 2020), Suillus granulatus (3.143 mmol/l) (Mushtaq et al., 2020), Ramaria stricta (4.223 mmol/l) (Krupodorova and Sevindik, 2020), and Pleurotus citrinopileatus cultivated on different substrates (2.428–3.125 mmol/l) (Gürgen et al., 2020), but lower than that of Cerrena unicolor (6.706 mmol/l) (Sevindik, 2018b). The TAS value of 5.416 mmol/l for the mycelial extracts of H. myxotricha grown in SDB medium was quite close to that of Cantharellus cibarius (5.268 mmol/l) (Sevindik, 2019a) and G. lucidum (5.509 mmol/l) (Bal, 2019). On the basis of these results, it can concluded that for H. myxotricha, SDB medium is more appropriate than GPY medium for producing metabolites with antioxidant properties. The effect of carbohydrate sources on the antioxidant activity of basidiomycetes has also been documented (Barros et al., 2008; Barakat and Sadik, 2014; Zhang et al., 2015; Bai et al., 2020). The comparison of our results with the data from other similar studies proved that H. myxotricha contained significant antioxidant compounds. The TAS value is an indicator of the total antioxidant compounds produced by the mushroom (Gürgen et al., 2020). The differences among the TAS values for the abovementioned fungus species may be attributed to the potential of these species to produce different antioxidant compounds and the differences in the environments in which they grow. It was also found that the ethanolic extract of H. myxotricha mycelia grown in SDB and GPY media had significantly lower TOS (1.320 μmol/l) and OSI (0.024) values than those for previously studied fungi species such as M. procera (TOS: 6.596 and 10.349 μmol/l, OSI: 0.235 and 0.367) (Akgül et al., 2016), O. olearius (TOS: 14.210 μmol/l, OSI: 0.503) (Sevindik et al., 2017), A. auricula (TOS: 23.910 μmol/l, OSI: 2.367), T. versicolor (TOS: 17.760 μmol/l, OSI: 2.166) (Akgül et al., 2017), D. quercina (TOS: 6.868 μmol/l, OSI: 2.201), I. hispidus (TOS: 6.534 μmol/l, OSI: 0.224), F. fomentarius (TOS: 2.601 μmol/l, OSI: 0.080), F. torulosa (TOS: 2.969 μmol/l, OSI: 0.074), T. gibbosa (TOS: 3.522 μmol/l, OSI: 0.597), T. biforme (TOS: 4.356 μmol/l, OSI: 0.543) (Bal et al., 2017), C. unicolor (TOS: 19.308 μmol/l, OSI: 0.288) (Sevindik, 2018b), G. lividus (TOS: 13.465 μmol/l, OSI: 0.651) (Bal, 2018), L. tigrinus (TOS: 19.294 μmol/l, OSI: 1.106) (Sevindik, 2018a), C. cylindracea (TOS: 21.109 μmol/l, OSI: 0.488) (Sevindik et al., 2018a), P. limonella (TOS: 4.742 and 33.022 μmol/l, OSI: 0.199 and 1.459) (Sevindik et al., 2018b), L. sulphureus (TOS: 19.294 μmol/l, OSI: 1.106) (Sevindik et al., 2018c), C. varius (TOS: 14.358 μmol/l, OSI: 0.627) (Sevindik, 2019), C. cibarius (TOS: 6.380 μmol/l, OSI: 0.121) (Sevindik, 2019a), G. lucidum (TOS: 10.177 μmol/l, OSI: 0.185) (Bal, 2019), L. nuda (TOS: 36.920 μmol/l, OSI: 1.190) (Bal et al., 2019a), I. geotropa (TOS: 30.385 μmol/l, OSI: 1.639) (Sevindik et al., 2020), O. asterosperma (TOS: 7.548 μmol/l, OSI: 0.221) (Sevindik et al., 2021b), L. rugatus (TOS: 8.178 μmol/l, OSI: 0.254) (Sevindik, 2020), R. stricta (TOS: 8.201 μmol/l, OSI: 0.194) (Krupodorova and Sevindik, 2020), and S. granulatus (TOS: 18.933 μmol/l, OSI: 0.603) (Mushtaq et al., 2020). The TOS value is an indicator of the total oxidant compounds produced in the fungus, and it shows how much the endogenous oxidants in the fungus are suppressed by the endogenous antioxidants (Gürgen et al., 2020). The mycelia of H. myxotricha used in our study were grown in two different culture media. The analysis revealed that the TOS values of the ethanolic extract of H. myxotricha mycelia changed depending on the culture media used. The TOS value was two times lower in mycelia obtained in SDB medium (1.320 μmol/l) than that of mycelia grown in GPY medium (2.623 μmol/l). The study samples were also found to have very low TOS values (1.320 and 2.623 μmol/l) as compared to the above-mentioned mushroom species, which were collected from their natural environment. This difference might be due to the lesser environmental impact on H. myxotricha metabolite composition in the culture environment as compared to the natural habitat. In addition, the low level of oxidant compounds produced in the mushroom and the excess of endogenous antioxidants led to a stronger antioxidant defense system (Sharifi-Rad et al., 2020). Therefore, the OSI value was low. The obtained results showed that H. myxotricha has a significant antioxidant potential.
Conclusions
Presently, the antioxidant and antimicrobial properties of fungi are important research topics. The results of the present study show that H. myxotricha exhibits significant antioxidant and antimicrobial activities. The antioxidant, oxidant, and antimicrobial potentials of the ethanolic extract of H. myxotricha mycelia varied depending on the culture medium used. GPY medium stimulated the synthesis of a high amount of antibacterial compounds against E. coli. However, the antioxidant and antifungal properties of the ethanolic extract of H. myxotricha mycelia were better after growth in SDB medium. Thus, our results confirm the importance of finding an optimal cultivated medium that provides the best manifestation of antimicrobial and antioxidant activities. Further research is needed to isolate and identify the active compounds responsible for the antioxidant and antimicrobial activities that can provide new sources in pharmacological drug designs.
