Antiproliferative and antibacterial activity of extracts of Ganoderma strains grown in vitro.

In this bioprospecting study the biological activities of extracts of the in vitro culture of Ganoderma Mexican strains were evaluated. The extracts were tested by the Sulforhodamine B staining method for antiproliferative activity and the plate microdilution method for antibacterial activity. Extracts that proved bioactive in these two activities, the antioxidant activity (Galvinoxyl, ABTS, and DPPH) and total phenolic contents (Folin-Ciocalteu) were additionally determined, as well as acute toxicity (Artemia franciscana). In the antiproliferative activity Ganoderma curtisii strain (GH-16-015) obtained a remarkable value of GI50 ≤ 50 µg/mL against tumor lines: A549, HBL-100, HeLa, and T-47D. G. curtisii strains (GH-16-012 and GH-16-015) showed MIC values = 500 µg/mL against Staphylococcus aureus. G. curtisii strain (GH-16-012) almost reduced by 50% the radical Galvinoxyl. Finally, G. curtisii strain (GH-16-023) presented the lowest level of toxicity with a LC50 of 490.881 µg/mL against A. franciscana. These results support the potential medicinal effects of Mexican strains of G. curtisii.

Biological Activities of Different Strains of the Genus Ganoderma spp. (Agaricomycetes) from Mexico.

Antiproliferative, antioxidant, and antibacterial activities were determined for 14 extracts obtained with a mixture of chloroform-methanol (1:1) from the mycelial cultures of 14 wild strains of the genus Ganoderma collected in the central-south part of Veracruz Province, Mexico. Identification of the strains collected was confirmed based on rDNA internal transcribed spacer phylogenetic analysis. The strains G. tuberculosum (GVL-04 and GVL-21), G. tornatum (GVL-05), and G. weberianum (GVL-17 and GVL-26) manifested activity in at least one of the six cancer cell lines tested (HBL-100 and T-47D [breast], HeLa [cervix], A-549 and SW1573 [lung], and WiDr [colon]), with a minimum concentration necessary to cause 50% growth inhibition of cancer cells (GI50) < 50 µg/mL-1. The strains G. tuberculosum (GVL-21) and G. martinicense (GVL-35) had the best antioxidant activity, with values of 62.5 ± 3.9 and 40 ± 2.0 µM Trolox equivalents/mg according to the 1,1-diphenyl-2-picrihydrazyl assay. In addition, nine extracts demonstrated antibacterial activity against Clavibacter michiganensis in a concentration range of 31.5 to 1000 µg/mL. Although these results were expected due to the bioactive potential of Ganoderma species, the antibacterial activity against C. michiganensis causing tomato canker is highlighted.

Analysis of Intraspecies Genetic Variability among Collections of Medicinal Red Belt Conk Mushroom, Fomitopsis pinicola (Agaricomycetes).

Intraspecies genetic variability of the medicinal dikaryotic polypore mushroom Fomitopsis pinicola was analyzed by using variable internal transcribed space (ITS) region of the ribosomal DNA gene cluster and the somatic compatibility test. The results revealed very low ITS sequence polymorphism among strains of F. pinicola from geographically distant origins (Russia, Finland, and France). Because of its conserved structure, the ITS region of the ribosomal DNA cluster can be proposed as a reliable molecular code for identifying and taxonomically verifying F. pinicola sensu stricto species. Four types of somatic incompatibility interactions were found in the Moscow population; 29 dikaryotic isolates revealed 27 somatically incompatible groups with an overall diversity index (HVC) of 0.782. Moderate antagonistic (somatically incompatible) interactions were predominant, with a frequency (p) of 0.56; strong antagonism with the heavily pigmented interaction zone was estimated as p = 0.35. These findings regarding the genetic diversity of natural F. pinicola isolates will assist further research and development of novel strains useful in food, medicine, and industrial applications.

Antiproliferative Activity and Cytotoxicity of Some Medicinal Wood-Destroying Mushrooms from Russia.

We analyzed the antiproliferative activity of 6 medicinal wood-destroying mushrooms (Fomes fomentarius, Fomitopsis pinicola, Trametes versicolor, Trichaptum biforme, Inonotus obliquus, and Coniophora puteana) that are common in deciduous and mixed coniferous forests in Central Russia. Morphological identification of strains collected from the wild was confirmed based on ribosomal DNA internal transcribed spacer phylogenetic analysis. We observed cytotoxic and cell growth-inhibitory effects of hot water extracts from mycelial biomass of 5 species-T. versicolor, C. puteana, F. fomentarius, F. pinicola, and I. obliquus-on leukemia cell lines (Jukart, K562, and THP-1); the effective extract concentrations were mostly less than 50 µg · mL-1. However, we observed no antiproliferative activity of dry biomass from methanol-chloroform (1:1) extracts of C. puteana and F. fomentarius. A chemosensitivity assay showed that the most effective polypore mushroom extract was the methanol extract of T. versicolor (strain It-1), which inhibited the growth of 6 various solid tumors (A-549 and SWi573 [lung], HBL-100 and T-47D [breast], HeLa [cervix], and WiDr [colon]) at concentrations below 45 µg · mL-1, with a concentration as low as 0.7-3.6 µg · mL-1 causing 50% reduction in the proliferation of cancer cells in lung and cervix tumors. Methanol extracts of F. pinicola and I. obliquus were less effective, with proliferation-inhibiting capacities at concentrations below 70 and 200 µg · mL-1, respectively. Thus, T. versicolor is a prospective candidate in the search for and production of new antiproliferative chemical compounds.

Genetic resources and mycelial characteristics of several medicinal polypore mushrooms (Polyporales, Basidiomycetes).

Mycelial characteristics of dikaryotic collections of 6 medicinal polypore mushrooms (Fomes fomentarius, Fomitopsis pinicola, Ganoderma adspersum, G. applanatum, G. lucidum, and G. resinaceum) with different geographical origins (Armenia, China, France, Iran, Italy, and Russia) were screened. A total of 42 polypore collections were molecularly identified by sequencing the internal transcribed spacer region of the ribosomal RNA genes' cluster, and a phylogenetic tree was constructed. Morphological characteristics of 37 cultures were observed on agar media (malt extract agar, potato dextrose agar) at different temperatures (25, 30, 35, and 38°C) at a pH of 6.0. Colony morphology, pigmentation of mycelium and agar, mycelial growth rate, in vitro teleomorph formation, and other macromorphological characteristics were thoroughly described and illustrated. Micromorphological features of mycelia, such as different hyphal structures, clamp cells, presence and type of asexual sporulation, chlamydospores, and others were observed. The taxonomic significance of the mycelial characteristics revealed was estimated. The obtained results will assist further biotechnological cultivation of medicinal polypore mushrooms to develop novel health care biotechnological products.