In our search for quorum-sensing (QS) disrupting molecules, 75 fungal isolates were recovered from reef organisms (endophytes), saline lakes and mangrove rhizosphere. Their QS inhibitory activity was evaluated in Chromobacterium violaceum CVO26. Four strains of endophytic fungi stood out for their potent activity at concentrations from 500 to 50 μg mL⁻¹. The molecular characterization, based on the internal transcribed spacer (ITS) region sequences (ITS1, 5.8S and ITS2) between the rRNA of 18S and 28S, identified these strains as belonging to four genera: Sarocladium (LAEE06), Fusarium (LAEE13), Epicoccum (LAEE14), and Khuskia (LAEE21). Interestingly, three came from coral species and two of them came from the same organism, the coral Diploria strigosa. Metabolic profiles obtained by Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS) suggest that a combination of fungal secondary metabolites and fatty acids could be the responsible for the observed activities. The LC-HRMS analysis also revealed the presence of potentially new secondary metabolites. This is, to the best of our knowledge, the first report of QS inhibition by marine endophytic fungi.

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.

Context: It is well known that marine fungi are an excellent source of biologically active secondary metabolites, and by 2011, it was reported that over 400 bioactive metabolites were derived from marine fungi. Objective: This study establishes the basis for future research on antiproliferative compounds of marine endophytes inhabited in the Veracruz Reef System. Materials and methods: Isolation of the 34 fungal strains was carried out by microbiological method from samples of sponges, corals, and other biological material from the Veracruz Reef System. The fungal biomass and broth were separated and extracted with a mixture of solvents MeOH:CHCl₃. Characterization and molecular identification of the fungal strains were performed through microbiological methods and the analysis of the ITS-rDNA regions. Antiproliferative activity was tested at a dose of 250 μg/mL on human solid tumor cell lines HBL-100, HeLa, SW1573, T-47D, and WiDr by the SRB assay after 48 h-exposure to the fungal extracts. Results: The extracts from five isolates showed an antiproliferative effect against one or more of the tested cell lines (percentage growth < 50%). The mycelial extract from the isolate LAEE 03 manifested the highest activity against the five cell lines (% PG of 17 HBL-100, 19 HeLa, 23 SW1573, -6 T-47D, and 10 WiDr) and the strain was identified as Curvularia trifolii (Kauffman) Boedijn (Pleosporaceae). Discussion and conclusion: The results obtained indicate that the extract from a marine derived C. trifolii has the antiproliferative effect, thus suggesting that this organism is a good candidate for further analysis of its metabolites.