Chemical Composition, Bioactive Compounds and Antioxidant Activity of Two Wild Edible Mushrooms Armillaria mellea and Macrolepiota procera from Two Countries (Morocco and Portugal)

The present study aimed to investigate the chemical composition, bioactive compounds, and antioxidant activity of two wild edible mushrooms, the honey fungus (Armillaria mellea) and the parasol mushroom (Macrolepiota procera), collected from Northern Morocco (MA) and Portugal (PT). Those species were chosen due to their edibility, nutraceutical, and medicinal properties. Bioactive compounds (ascorbic acid, tannin, total phenolic, total flavonoid, β-carotene, and lycopene) and their antioxidant activity were determined by spectrophotometric methods. Herein, the fruiting body of the samples revealed a significantly higher amount of bioactive compounds, and values varied between the Moroccan and the Portuguese ones. Methanolic extracts shown a strong antioxidant capacity: Using DPPH free radical-scavenging activity radicals (IC50 1.06–1.32 mg/mL); inhibition of β-carotene bleaching radicals (IC50 0.09–0.53 mg/mL); and, reducing power radicals (IC50 0.52–1.11 mg/mL). The mushroom species with the highest antioxidant capacity was A. mellea from MA. Chemical composition was analyzed by GC-MS and LC-MS methodologies. GC-MS analysis showed that the most abundant biomolecules group was sugar compositions in the four samples (62.90%, 48.93%, 59.00%, and 53.71%) and the main components were galactitol 16.74%, petroselinic acid 19.83%, d-galactose 38.43%, and glycerol 24.43% in A. mellea (MA), A. mellea (PT), M. procera (MA), and M. procera (PT), respectively. LC-MS analysis of individual phenolic compounds revealed that vanillic acid (198.40±2.82 µg/g dry weight (dw) and cinnamic acid (155.20 ± 0.97 µg/g dw) were the main compounds detected in A. mellea, while protocatechuic acid (92.52 ± 0.45 and 125.50 ± 0.89 µg/g dw) was predominated in M. procera for MA and PT samples, respectively. In general, the results of this comparative study demonstrate that the geographic and climatic conditions of the collection site can influence biomolecule compounds and antioxidant properties of wild mushrooms. This study contributes to the elaboration of nutritional, nutraceutical, and pharmaceutical databases of the worldwide consumed mushrooms.

In vitro co-culture system for Prunus spp. and Armillaria mellea in phenolic foam rooting matric

Armillaria and Desarmillaria spp. are causal agents of a devastating root-borne disease of peach. Breeding resistant rootstock requires a reliable screening tool. An in vitro co-culture screen designed for almond was modified by replacing agar-gelled medium with a more aerated phenolic foam and combining resistant and susceptible rootstocks (i.e., common garden experiment) and minimizes variation in inoculum pressure or rooting substrate among replicate vessels. Eight Prunus rootstocks tested (peach, plum, peach × plum, and choke cherry) were rooted and had no decline in health. Susceptible peach rootstock, ‘GF 305’, was cultured for 15 wk in phenolic foam in the same vessel with a resistant peach × plum hybrid, ‘MP-29’, inoculated with Armillaria mellea at week 5, that led to more severe shoot symptoms in the former after an additional 8 wk. This method accommodated peach genotypes that were difficult to root in agar medium. The difference during a uniform challenge with the A. mellea fungus recapitulates resistant/susceptible reactions. The phenolic foam-based co-culture method will work on many Prunus spp. of potential use in rootstock breeding.

Nutritivna vrijednost i antioksidacijska aktivnost jestivih samoniklih gljiva Albatrellus pes-caprae i Armillaria mellea

Ovo istraživanje namijenjeno je određivanju prosječnog kemijskog sastava, udjela bioaktivnih spojeva i antioksidacijske aktivnosti jestivih samoniklih gljiva Albarellus per-caprae i Armilaria mellea. Rezultati određivanja kemijskog sastava su pokazali da su gljive bogat izvor bjelančevina i ugljikohidrata te da imaju male količine masti, a dobar su izvor energije. Koncentracije pet bioaktivnih spojeva (askorbinska kiselina, β-karoten, likopen, ukupni fenoli i flavonoidi) određene su ekstrakcijom plodišta gljiva u vrućoj vodi i metanolu. Tri komplementarna kemijska ispitivanja; reducirajuća snaga, uklanjanje slobodnih radikala (DPPH) i sposobnost keliranja iona željeza korišteni su za određivanje antioksidacijskih svojstava ekstrakata. Najveće vrijednosti antioksidacijskog kapaciteta određene su u ekstraktima A. mellea s vrućom vodom (9,01 μM TE/g s.tv. u reducirajućoj snazi, 65% u sposobnosti uklanjanja slobodnih radikala, i 85% u sposobnosti keliranja). Vrijednosti EC50 za tri različita ispitivanja antioksidanta bile su između 1,63 mg/ mL i 6,86 mg/mL. Zbog ovih karakteristika, jestive samonikle gljive A. per-caprae i A. mellea mogu biti dio dobro uravnotežene prehrane i izvor bioaktivnih sastojaka.

Plant Performance and Metabolomic Profile of Loquat in Response to Mycorrhizal Inoculation, Armillaria mellea and Their Interaction

A greenhouse experiment was established with loquat plants to investigate the role of arbuscular mycorrhizal fungi (AMF) in the control of the white root rot fungus Armillaria mellea and to determine the changes produced in the plant metabolome. Plants inoculated with two AMF, Rhizoglomus irregulare and a native AMF isolate from loquat soils, were infected with Armillaria. Although mycorrhization failed to control the Armillaria root infection, the increased growth of infected plants following inoculation with the native mycorrhizal isolate suggests an initial tolerance towards Armillaria. Overall, metabolomics allowed highlighting the molecular basis of the improved plant growth in the presence of Armillaria following AMF colonization. In this regard, a wide and diverse metabolic response was involved in the initial tolerance to the pathogen. The AMF-mediated elicitation altered the hormone balance and modulated the production of reactive oxygen species (mainly via the reduction of chlorophyll intermediates), possibly interfering with the reactive oxygen species (ROS) signaling cascade. A complex modulation of fucose, ADP-glucose and UDP-glucose, as well as the down-accumulation of lipids and fatty acids, were observed in Armillaria-infected plants following AMF colonization. Nonetheless, secondary metabolites directly involved in plant defense, such as DIMBOA and conjugated isoflavone phytoalexins, were also involved in the AMF-mediated plant response to infection.