Analysis of the Influence of Substrate Formulations on the Bioactive Chemical Profile of Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Agaricomycetes) by Conventional and Chemometrics Methods.

Ganoderma lucidum, a mushroom with medicinal properties, can grow on diverse lignocellulosic substrates. Substrate enrichment with additives has been used as a strategy to increase mushroom productivity. In this study, we evaluated the impact of substrate formulation on the bioactive chemical profile of the basidiome. The bioactive chemical profile of basidiomes cultivated on rice agro-residues (RA) or sunflower seed hulls (SSH) enriched with olive oil and/or copper was evaluated using conventional colorimetric methods and FT-MIR spectrometry coupled with chemometrics. The contents of total triterpenoids, ganoderic acids, high-molecular-weight carbohydrates, and phenolic compounds were sensitive to substrate formulation and harvest time. Moreover, cluster analysis and principal component analysis of the mid-IR spectra were able to discriminate between basidiomes cultivated on either RA or SSH substrates, and for SSH substrates between enriched and nonenriched formulas. These results indicate that the bioactive composition of G. lucidum can be influenced by the formulation of the cultivation substrate.

Conditions Affecting Lingzhi or Reishi Medicinal Mushroom Ganoderma lucidum (Agaricomycetes) Basidiome Quality, Morphogenesis, and Biodegradation of Wood By-products in Argentina.

Solid-state fermentation (SSF) with the medicinal higher Basidiomycete Ganoderma lucidum was studied as a strategy to use pine (Pinus radiata D. Don) and poplar (Populus nigra L.) wood chips and sawdust. Fruiting bodies were produced and the value of the biotransformed substrate was assessed. The highest mushroom yield (63 g dry weight per kilogram of dry substrate) was obtained with poplar sawdust and wood chips. Immersion of the bioreactors was a simple watering method that obtained suitable yields. Two morphological types were induced using 2 different incandescent light intensities. High light irradiation induced the highest valued mushroom morphology (as a whole product). Time course study of substrate biodegradation and mycelial growth dynamics indicated that the trophophase lasted 20 days and presented laccase activity of 0.01-0.03 units · g-1. The activity at idiophase was 10 times higher. Aqueous and alkali extracts, as well as carbohydrase enzyme profile activity, revealed differences in the properties of the residual substrate; some related to the substrate source are considered to be of concern for further use of this pretreated biomass. In view of the results obtained, we propose use of SSF of pine and poplar with G. lucidum to profitably recycle softwood by-products from the timber industry.

In Vitro Studies of Secondary Metabolite-Related Responses in Some Species of Genus Grifola (Agaricomycetes) from Argentina.

Grifola gargal Singer and Grifola sordulenta (Mont.) Singer mushrooms are related to Grifola frondosa (Dicks.) Gray, which is well known for its medicinal properties. In vitro studies were performed to find a useful guide for optimizing the environmental parameters through biotransformation of lignocellulosic materials and basidiome development, also considering secondary metabolism-related responses (SMRRs) associated with these processes and the variability among species and strains; this optimization is necessary to make the mushroom's industrial cultivation profitable. Morphological features of mycelial cultures revealed that intraspecific variability was of taxonomic relevance. A low ligninolytic capacity in studied Grifola species was observed when compared with 2 control species: G. frondosa and Ganoderma lucidum. Experiments with nutrient media containing different carbohydrate sources indicated that G. gargal mycelia grew better in xylulose and G. sordulenta, in xylulose or cellulose; in addition, the latter species presented cellobiose dehydrogenase activity. An additional study of SMRRs under different light conditions (aroma, pigmentation, and morphogenic manifestations) showed that white light was better than blue, green, or red-filtered light at inducing advanced SMRRs. The results of SMRR stimulation are proposed as useful guidance for optimizing the environmental parameters for bioprocesses aimed at metabolite production.

Submerged Culture of Grifola gargal and G. sordulenta (Higher Basidiomycetes) from Argentina as a Source of Mycelia with Antioxidant Activity.

Submerged culture is an alternative mycelium source for Grifola gargal and G. sordulenta, two rare edible mushrooms related to Grifola frondosa. This work studies their mycelia as a source of antioxidants. The efficient concentrations of methanolic extracts in both radical scavenging (RS) and reducing power (RP) abilities in G. gargal and in G. sordulenta showed a high antioxidant activity. In the experimental design used, the antioxidant activity mainly depended on the culture conditions rather than on the media composition. Irrespective of the basal culture medium, mycelium methanolic extracts of G. sordulenta obtained from culture in Erlenmeyer flasks showed equivalents to ascorbic acid (EQ(AA)) RS-EQ(AA) and RP-EQ(AA) contents higher than the corresponding values obtained with jar cultures. Under stationary cultivation, G. sordulenta produced approximately 50% higher content in both RS-EQ(AA) and RP-EQ(AA) than the medicinal mushroom G. frondosa. Phenolics correlated with RS-EQ(AA) and RP-EQ(AA) in G. gargal and with RP-EQ(AA) in G. sordulenta; besides, thin-layer chromatography showed these compounds to be at least in part related to the RS capacity. It is concluded that G. gargal and G. sordulenta mycelia are excellent sources of antioxidant metabolites.

Protective effects of new medicinal mushroom, Grifola gargal singer (higher Basidiomycetes), on induced DNA damage in somatic cells of Drosophila melanogaster.

Grifola gargal is an edible mushroom with attributed antioxidant properties. Different sources of G. gargal materials, i.e., fruit bodies and mycelia grown in liquid or solid media, were used to study its potential protective capacity when somatic mutation and recombination is induced in Drosophila melanogaster using DMBA (7-12-dimethyl-benz(α)anthracene) as promutagen. Heterozygote larvae (white/white+) were grown in media with different concentrations of DMBA. Grifola gargal fruit bodies (GgFB) or mycelia from liquid culture (GgLC) or from solid culture (GgWG), i.e., biotransformed wheat kernel flour, were added to the culture media in combined treatments with DMBA. Water, DMBA solvent, or wheat flour (WF) plus DMBA solvent were used as negative controls. Larval mortality increased from 9% to 11% in negative controls to 31% to 36% in DMBA treatments. The addition of GgFB, GgLC, or GgWG materials produced a protective effect on 25 µmol/vial DMBA-induced mortality. Mutations observed in SMART, as light spots per 100 eyes (LS/100 eyes), increased with increasing doses of DMBA; this was also true when considering the mutation incidence expressed as percentage of eyes exhibiting light spots (% eyes with LS). Interestingly, mycelia from GgFB, GgLC, or GgWG, in the presence of 25 µmol/vial DMBA, showed lower values in SMART of both the total LS/100 eyes and the percentage of eyes with LS. Thus, Grifola gargal materials were not only nontoxic, but in combination with 25 µmol/vial DMBA lowered the mortality induced by the promutagen and showed antimutagenic effects. Protective effects of G. gargal against DMBA are discussed in terms of the onset of desmutagenic and/or bioantimutagenic mechanisms of detoxification in the host organism, probably due to some bioactive compounds known to occur in higher mushrooms.