[Show abstract][Hide abstract] ABSTRACT: Rhodiola spp. are rare and endangered alpine plants widely used as medicines and food additives by many civilizations since ancient times. Their main effective ingredients (such as salidroside and p-tyrosol) are praised to exhibit pharmacologic effects on high-altitude sickness and possess anti-aging and other adaptogenic capacities based on their antioxidant properties. In this study, 347 endophytic fungi were isolated from R. crenulata, R. angusta, and R. sachalinensis, and the molecular diversity and antioxidant activities of these fungi were investigated for the first time. These fungi were categorized into 180 morphotypes based on cultural characteristics, and their rRNA gene ITS sequences were analyzed by BLAST search in the GenBank database. Except for 12 unidentified fungi (6.67%), all others were affiliated to at least 57 genera in 20 orders of four phyla, namely, Ascomycota (88.89%), Basidiomycota (2.78%), Zygomycota (1.11%), and Glomeromycota (0.56%), which exhibited high abundance and diversity. Antioxidant assay showed that the DPPH radical-scavenging rates of 114 isolates (63.33%) were >50%, and those of five isolates (Rct45, Rct63, Rct64, Rac76, and Rsc57) were >90%. The EC50 values of five antioxidant assays suggested significant potential of these fungi on scavenging DPPH•, O2-•, and OH• radicals, as well as scavenging nitrite and chelating Fe2+, which showed preference and selection between endophytic fungi and their hosts. Further research also provided the first evidence that Rac12 could produce salidrosides and p-tyrosol. Results suggested that versatile endophytic fungi associated with Rhodiola known as antioxidants could be exploited as potential sources of novel antioxidant products.
[Show abstract][Hide abstract] ABSTRACT: Dragon's blood is a rare and precious traditional medicine used by different cultures since ancient times. However, studies on enhancing the rapid accumulation of dragon's blood in Dracaena cambodiana and determining its formation mechanism are unavailable. In this study, the activities of two fungi, namely, BJDC01 and BJDC05, and their effect on promoting the accumulation of five main compositions of dragon's blood in D. cambodiana were investigated for the first time. Results of field tests conducted for ten months indicated that the contents of Loureirin D, 4,4'-dihydroxy-2'-dimethoxychalcone, Loureirin A and Loureirin B in two fungal-inoculated materials were 1.67 to 2.85 times greater than those of natural samples, and thus were significantly higher than those of the control groups. The content of 4,4'-dihydroxy-2'6'- dimethoxydihydrochalcone in each fungal-inoculated sample was close to that of the natural sample, and was more than twice of each of the control group. By combining the results of morphological characterizations, both BJDC01 and BJDC05 can stimulate the accumulation of the compositions of dragon's blood. This stimulation may be considered as a defense response of D. cambodiana tree against the invasion of foreign fungi. Thus, this study provides a potential way of producing dragon's blood via the inoculation of two fungal elicitors.
[Show abstract][Hide abstract] ABSTRACT: Microbial transformation of ursolic acid (UA, 3β-hydroxy-urs-12-en-28 -oic acid, 1) by filamentous fungus Syncephalastrum racemosum CGMCC 3.2500 was conducted. Five metabolites 3β, 7β, 21β-trihydroxy-urs-12-en-28-oic acid (2); 3β, 21β-dihydroxy-urs-11-en-28-oic acid-13-lactone (3); 1β, 3β, 21β -trihydroxy-urs-12-en-28-oic acid (4); 3β, 7β, 21β-trihydroxy-urs-1-en-28-oic acid-13-lactone (5); 21-oxo-1β, 3β-dihydroxy-urs-12-en-28-oic acid (6) were afforded. Elucidation of the structures of these metabolites was primarily based on 1D and 2D-NMR and HR-MS data. Metabolite 2 was a new compound. In addition, the anti-HCV activity of compounds 1-6 was evaluated.
[Show abstract][Hide abstract] ABSTRACT: Holcoglossum is one of the smaller genera of Orchidaceae, mainly distributed in southwest China. Some members of this genus as well as H. rupestre and H. flavescens are endemic and rare Chinese orchids. As far as we know, little work has been done concerning the relationships between the Holcoglossum plants and endophytic microorganisms. In this study, 46 culturable fungal endophytes were isolated and identified from roots of nine Holcoglossum plants collected from Yunnan, Guangxi, and Hainan provinces of China based on molecular techniques. The results showed that all strains belonged to four classes, i.e., Sordariomycetes (41.30%), Dothideomycetes (36.96%), Agaricomycetes (17.39%), Leotiomycetes (4.35%). Thirty-six strains were identified at the genus level, including Alternaria, Cladosporium, Clonostachys, Colletotrichum, Cosmospora, Cryptosporiopsis, Cylindrocarpon, Didymella, Epulorhiza (Anamorphic Tulasnella), Fusarium, Myrmecridium, Leptosphaeria, Paraconiothyrium, Phomopsis, Pyrenochaeta, and Stephanonectria. Fusarium and Epulorhiza (Anamorphic Tulasnella) were the dominant fungal endophytes. Some orchids mycorrhizal fungi as well as Tulasnella calospora and Epulorhiza sp. were found in roots. This is the first report concerning endophytic fungi from Holcoglossum plants (Orchidaceae), suggesting that endophytic fungi in Holcoglossum plants are very abundant.
No preview · Article · Nov 2011 · Current Microbiology
[Show abstract][Hide abstract] ABSTRACT: Endophytic fungi were used not only for their producing bioactive products but also for their ability to transform natural compounds. An endophytic fungus, isolated from medicinal plant Huperzia serrata, was identified as Umbelopsis isabellina based on the internal transcribed spacer of ribosomal DNA (rDNA-ITS) region. It was used to transform ursolic acid (1), a pentacyclic triterpene. Incubation of ursolic acid with U. isabellina afforded three products, 3β-hydroxy-urs-11-en-28,13-lactone (2), 3β,7β-dihydroxy-urs-11-en-28,13-lactone (3), 1β,3β-dihydroxy-urs-11-en-28,13-lactone (4). Although product 2 was a known compound, it was first obtained by microbial transformation. Products 3 and 4 were new compounds. The structural elucidation of the three compounds was achieved mainly by the 1D- and 2D-NMR, MS, IR data. The endophytic fungus U. isabellina can hydroxyate the C12-C13 double bond at position 13 of ursolic acid 1 and form a five-member lactone effectively. In the meantime, this fungus can also introduce the hydroxyl group at C-1 or C-7 of ursolic acid 1.
No preview · Article · Sep 2011 · Chemical & pharmaceutical bulletin
[Show abstract][Hide abstract] ABSTRACT: Endophytic fungi from Dragon's blood specimens of different locations of China were characterized taxonomically and investigated concerning their antimicrobial and antitumor activity against six pathogenic microbes and five tumor cells. A total of 49 endophytic fungi were obtained from Dragon's blood materials of Dracaena spp., 18 taxa were represented by 43 (87.8%) isolates and only six (12.2%) isolates were unknown. Twenty (40.8%) of the isolates displayed antimicrobial activity against at least one pathogenic microorganism. Three isolates YNDC07, BJDC06 and BJDC09 displayed significant antimicrobial activities against Staphylococcus aureus, Cryptococcus neoformans and Aspergillus fumigates, respectively. The results of antitumor activity by the MTT assay revealed that 26.5%, 69.4%, 48.9%, 6.1% and 42.9% of isolate fermentation broths displayed growth inhibition on HepG2 cells, SKVO3 cells, MCF7 cells, HL-60 cells and 293-T cells, respectively. HNDC09 and HNDC10 showed very strong antitumor activity against MCF7 and 293-T, respectively. The results showed that endophytic fungi in Dragon's blood samples were valuable in screening antitumor and antimicrobial bioactivity agents.
No preview · Article · Aug 2011 · Phytotherapy Research
[Show abstract][Hide abstract] ABSTRACT: The structural modification of ursolic acid by an endophytic fungus Pestalotiopsis microspora, isolated from medicinal plant Huperzia serrata was reported for the first time. The structure diversity was very important for the SAR study of ursolic acid and its derivatives. Incubation of ursolic acid 1 with P. microspora afforded four metabolites: 3-oxo-15α, 30-dihydroxy-urs-12-en-28-oic acid (2), 3β, 15α-dihydroxy-urs-12-en-28-oic acid (3), 3β, 15α, 30- trihydroxy-urs-12-en-28-oic acid (4) and 3,4-seco-ursan-4,30-dihydroxy-12-en-3,28-dioic acid (5). All products were new compounds and their structures elucidation was mainly based on the spectroscopic data.
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to isolate and characterize endophytic fungi from the stem tissue which can produce fragrant ingredients in Aquilaria sinensis (also called agarwood) to determine their antitumor and antimicrobial activities. Twenty-eight fungal endophytes were isolated from agarwood by strict sterile sample preparation and were classified into 14 genera and 4 taxonomic classes (Sordariomycetes, Dothideomycetes, Saccharomycetes, and Zygomycetes) based on molecular identification. Of the 28 isolates, 13 (46.4%) showed antimicrobial activity against at least one of the test strains by the agar well diffusion method, and 23 isolates (82.1%) displayed antitumor activity against at least one of five cancer cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The diameters of inhibition zones of YNAS07, YNAS14, HNAS04, HNAS05, HNAS08, and HNAS11 were equal to or higher than 14.0 mm against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, B. subtilis, Aspergillus fumigatus, and B. subtilis, respectively. The inhibition rates of YNAS06, YNAS08, and HNAS06 were not less than 60% to 293-T, 293-T, and SKVO3 cells, respectively. These results suggest that the endophytic fungi associated with agarwood will provide us with not only useful micro-ecological information, but also potential antimicrobial and antitumor agents.
Full-text · Article · May 2011 · Journal of Zhejiang University SCIENCE B
[Show abstract][Hide abstract] ABSTRACT: Endophytic fungi are rich in orchids and have great impacts on their host plants. 53 endophytes (30 isolates from Dendrobium devonianum and 23 endophytic fungi from D. thyrsiflorum) were isolated, respectively, from roots and stems of Dendrobium species. All the fungi were identified by way of morphological and/or molecular biological methods. 30 endophytic fungi in D. devonianum were categorized into 11 taxa and 23 fungal endophytes in D. thyrsiflorum were grouped into 11 genera, respectively. Fusarium was the dominant species of the two Dendrobium species in common. Antimicrobial activity of ethanol extract of fermentation broth of these fungi was explored using agar diffusion test. 10 endophytic fungi in D. devonianum and 11 in D. thyrsiflorum exhibited antimicrobial activity against at least one pathogenic bacterium or fungus among 6 pathogenic microbes (Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus). Out of the fungal endophytes isolated from D. devonianum and D. thyrsiflorum, Phoma displayed strong inhibitory activity (inhibition zones in diameter >20 mm) against pathogens. Epicoccum nigrum from D. thyrsiflorum exhibited antibacterial activity even stronger than ampicillin sodium. Fusarium isolated from the two Dendrobium species was effective against the pathogenic bacterial as well as fungal pathogens. The study reinforced the assumption that endophytic fungi isolated from different Dendrobium species could be of potential antibacterial or antifungal resource.
Full-text · Article · Dec 2010 · Current Microbiology
[Show abstract][Hide abstract] ABSTRACT: Endophytic fungi are rich in species diversity and may play an important role in the fitness of their host plants. This study investigated the diversity and antimicrobial potential of endophytic fungi obtained from Saussurea involucrata KAR. et KIR. A total of 49 endophytic fungi were isolated from S. involucrata and identified using morphological and molecular techniques. Extracts of fermentation broth from the 49 fungi were tested for antimicrobial activity against pathogenic microorganisms using the agar diffusion method. Forty-eight out of the 49 endophytic fungi were identified and grouped into 14 taxa. Cylindrocarpon sp. was the dominant species isolated from S. involucrata, followed by Phoma sp. and Fusarium sp. Among the 49 endophytic fungi, 9 root isolates having darkly pigmented, septate hyphae were identified as dark septate endophytic (DSE) fungus, and 12 fungi inhibited at least one test microorganism. Moreover, 5 strains showed a broader spectrum of antimicrobial activity and 4 strains displayed strong inhibition (+++) against pathogenic fungi. The results indicate that endophytic fungi isolated from S. involucrata are diverse in species and a potential source of antimicrobial agents.