Antioxidant Properties of Selected Boletus Mushrooms

Abstract

Considering the growing interest for mushrooms and the demand search of natural antioxidants sources, the aim of this study was to investigate the antioxidant properties of two edible widely used Boletus species, Boletus edulis, and Boletus auranticus, collected from Istra region in Croatia in late summer 2007. To evaluate the antioxidant properties and content of antioxidant compounds, scavenging capacity on DPPH˙, OH˙, and O 2˙− radicals, reducing power and capacity to inhibit lipid peroxidation has been investigated. It is determined that content of total phenols (41.82± 0.08 mg gallic acid equivalent per gram of dry extract) was higher for B. edulis. Using high performance liquid chromatography/ diode array detector analysis, the main antioxidant compound, variegatic acid, has been detected and quantified. 1,1-Diphenyl-2-picryl-hydrazyl-hydrate assay was used as a preliminary free radical-scavenging evaluation. By this assay, it has been found that B. edulis dry mushroom extract exhibits 50% of inhibition value at the extract concentration of 0.016±0.0003 mg/ml. The extracts were capable of reducing iron(III) and, thus, are capable of donating electrons. Using electron paramagnetic resonance spintrapping and spin-probing techniques, activity against relevant reactive species,˙OH and O 2˙− radical, was analyzed for both mushroom extracts. Both investigated extracts are determined as good inhibitors for˙OH radical reduction, and both exhibited significant capacity for scavenging O 2˙− radical and for that could help to prevent or meliorate oxidative damage. Only B. edulis extract prevents lipid peroxidation. Investigated mushroom extracts could represent easily accessible natural antioxidant resource. AbbreviationsLDL Low density proteins DPPH 1,1-Diphenyl-2-picryl-hydrazyl-hydrate BHA Butylated hydroxyanisole 7-DS 2-(5-Carboxypentyl)-2-undecyl-4, 4-dimethyloxazolidine-3-oxylstearate DEPMPO 5-Diethoxyphosphoryl-5-methyl-1-pyrroline-N-oxide GAE Gallic acid equivalent CE Catechin equivalent RI Relative inhibition LC/MS Liquid chromatography/mass spectrometry HPLC/ DAD High performance liquid chromatography/ diode array detector EPR Electron paramagnetic resonance TP Total phenolic content TF Total flavonoid content UV/VIS Ultraviolet/visible spectroscopy IC 50 50% of inhibition value RSC radical scavenging capacity

The antioxidant properties of polypore mushroom Daedaleopsis confragosa

“…For example at the concentration of 0.2 mg/ml measured absorbance of ascorbic acid was 1.192±0.03, while for D. confragosa was 0.442±0.06. However, the reducing power of the investigated mushroom extract was higher than the previously reported reducing power for mushroom Boletus edulis and Boletus aurantiacus (0.223 and 0.192, respectively) [30] and also for the reported reducing powers of the methanolic extracts of Dictyophora indusiata, Grifola frondosa, Hericium erinaceus and Tricholoma giganteus [31]. This property suggests that D. confragosa extracts may act as free radical chain terminators, transforming reactive free radical species into more stable non-radical products.…”

“…The radical scavenging activity was found to exhibit 50% of the inhibition value (IC 50 value) at the extract concentration of 0.015±0.007 mg/ml for the investigated D. confragosa extract. The calculated IC 50 value was slightly lower than the reported IC 50 value for Boletus edulis (0.016±0.003 mg/ml) and lower than the reported value for Boletus aurantiacus (0.024±0.004 mg/ml) dry extract [30], or methanolic extract of Ganoderma tsugae, known as Ling chic (0.25±0.0016 mg/ml) [34], which indicated a higher antioxidant activity in comparison to the reported values.…”

“…These compounds can play a double role in reducing the rate of oxidation, as they participate in Iron chelation and trapping radicals [28]. The total phenolic content of D. confragosa extract is higher than it was reported for some other mushrooms extracts (39.09±0.17 mg GAE/g for Boletus edulis, 38.53±0.03 mg GAE/g for Boletus aurantiacus, 26.89 mg GAE/g for Armillaria mellea and 24.48 mg GAE/g for Lycoperdon saccatum) [29,30]. It was also higher than the reported content of the methanolic extracts for Grifola frondosa (12.31 mg/g), Hericium erinaceus (12.05 mg/g) and Trichloma giganteum (7.61 mg/g) [31].…”

Evaluation of metal contents and bioactivity of two edible mushrooms Agaricus campestris and Boletus edulis

“…There are several reports on antioxidant activity of B. edulis and A. campestris (Vidović et al, 2010;Kosanić et al, 2012;Woldegiorgis et al, 2014) by using other extraction solvents. In this study, the antioxidant capacity of selected mushrooms was confirmed by methanol extracts.…”

Comprehensive evaluation of the antioxidant activity of six wild edible mushroom species

“…The investigation of mushrooms and their extracts antioxidant activity and the content of antioxidant compounds is very actual scientific subject [2]. The antioxidant activity of some mushrooms extracts were also studied by other researchers.…”