Bioactive properties of the medicinal mushroom Leucopaxillus giganteus mycelium obtained in the presence of different nitrogen sources

Abstract

Leucopaxillus mushroom species are used in the chemical industry for extraction of clitocybin antibiotic and particularly the edible mushroom Leucopaxillus giganteus can be found in Northeast Portugal. Nevertheless, the production of its mycelium for pharmacological applications has not been explored. Herein, the mycelium obtained in the presence of four different nitrogen sources was investigated with regard to phenol production and antimicrobial and antioxidant properties. Phenol concentration increased along the growth time as a response to the oxidative stress and therefore free radical production. Although significant differences for mycelium growth between the nitrogen sources had not been observed, (NH 4 ) 2 HPO 4 proved to be the most appropriate to increase bioactive properties, leading to the highest phenol content and lowest EC 50 and MIC values. The antimicrobial capacity was screened against Gram positive and Gram negative bacteria, and fungi. The samples selectively inhibited the growth of Gram positive bacteria, Staphylococcus aureus being the most susceptible one. Gram negative bacteria and fungi were resistant to the extracts. Antioxidant activity was calculated by the reducing power assay, the scavenging effect on DPPH radicals, and hemolysis and lipid peroxidation inhibition. Significantly negative linear regressions were established between phenols/flavonoids contents, which increased along the mycelia growth time and antioxidant activity.

Biological activity of fluidized bed ethanol extracts from several edible mushrooms

“…The results show that species harvested from the wild exhibited higher correlation values with the phenolic component than those obtained by cultivation in a laboratory greenhouse. Previous studies confirmed these differences indicating that the presence of polyphenolic compounds is negatively correlated with the antioxidant activities (36). It has been shown that the principle component is the main contributor to the causal effect (37).…”

Spatial distribution of Beta glucan containing wild mushroom communities in subtropical dry forest, Thailand

“…(Cheung 1998;Manzi and Pizzoferrato 2000;Bobek et al 2001;Mau et al 2001;Mau et al 2002). These papers covered species of the genera Lentinus, Hericium, Grifola, Flammulina, Pleurotus, Tremella, Boletus, Agrocybe and Leucopaxillus which occur in forest areas from the most diverse climates around the world (Gunde-Cimerman 1999; Kues and Liu 2000;Manzi et al 2004;Carbonero et al 2006; Barros et al 2007; Barros et al 2008). Interspecific differences in health beneficial functions of various species of mushrooms were examined by Rosado et al (2002) and Rhee et al (2008).…”

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“…The ability of L. edodes extracts to improve oral health has also been extensively researched, since it showed a strong bactericidal effect upon Streptococcus mutans, which is strongly implicated in dental caries and tooth decay [53,54]. The mycelium of Leucopaxillus giganteus (methanolic extract) presented antimicrobial capacity, inhibiting only gram-positive bacteria and, in decreasing order, Staphylococcus aureus > Bacillus cereus > Bacillus subtilis [55]. The authors stated that the most promising nitrogen source to produce mushrooms with an increased content in bioactive compounds that inhibit gram-positive bacteria growth was (NH 4 ) 2 HPO 4 .…”