[Study on communities of endophytic fungi from Pogostemon cablin and their antimicrobial activities].

Seventy-two strains of endophytic fungi were isolated from roots, stems and leaves of Pogostemon cablin and identified as 40 species of 25 genera based on ITS sequences analysis. Among them, Phomopsis, Colletotrichum and Fusarium were dominant genera. Distribution of endophytic fungi in P. cablin showed obvious tissue-specificity, and more strains were isolated from stems with an isolation rate of 78%. The bioassay results indicated that 34 strains of 15 genera displayed antimicrobial activities against at least one of test bacteria or plant pathogenic fungi. The results obtained in this study showed that endophytic fungi in P. cablin were rich in species diversity, and some strains exhibited strong antimicrobial activities, which deserve further research.

Two New Secondary Metabolites from the Endophytic Fungus Endomelanconiopsis endophytica.

Two new secondary metabolites, endomeketals A-B (1-2), a new natural product (3), and a known compound (4) were isolated from the ethyl acetate extract of the endophytic fungus Endomelanconiopsis endophytica A326 derived from Ficus hirta. Their structures were determined on the basis of extensive spectroscopic analysis. All compounds were evaluated for their cytotoxic activities against SF-268, MCF-7, NCI-H460, and HepG-2 tumor cell lines. However, no compound showed cytotoxic activity against these human tumor cell lines.

[Study on cytotoxic secondary metabolites of endophytic fungus Diaporthe longicolla A616 from Pogostemon cablin].

To study active secondary metabolites of endophytic fungus Diaporthe longicolla A616 isolated from Pogostemon cablin. Ten compounds were isolated from fermentation product of the strain 616 by silica gel, reverse phase silica gel, Sephadex-LH20, HPLC and so on. Their structures were identified as 1,3-diamino-1,3-dimethylurea(1),(7R,9R)-7-hydroxy-9-propyl-5-nonen-9-olide(2), Ergosta-5,7,22-trien-3ß-ol(3),(22E,24R)-ergosta-4,6,8(14)-22-tetraen-3-one(4),(22E,24R)-3ß,5α-dihydroxy-6ß-ergosta-7,22-diene(5), citreoisocoumarin(6), glycerol monolinoleate(7), 1-(2-hydroxyethoxy)ethyl(E)-octadec-9-enoate(8), cyclo-(L-Pro-L-Ala)(9), cyclo(L)-Pro-(L)-Val(10), respectively, based on extensive spectroscopic analysis and literature comparisons. Compounds 6-10 were isolated from the genus Diaporthe for the first time. All isolated compounds were evaluated for in vitro cytotoxic activities against SF-268, MCF-7, NCI-H460 and HepG-2 tumor cell lines. Compounds 4 and 5 showed potent growth inhibitory activities against the four cell lines with IC50 values of 5.3, 6.5, 12.2, 6.1µmol•L⁻¹ and 8.2, 5.2, 6.1, 9.4µmol•L⁻¹, respectively.

Guignardones P-S, New Meroterpenoids from the Endophytic Fungus Guignardia mangiferae A348 Derived from the Medicinal Plant Smilax glabra.

Four new meroterpenoids, guignardones P-S (1-4), and three known analogues (5-7) were isolated from the endophytic fungal strain Guignardia mangiferae A348. Their structures were elucidated on the basis of spectroscopic analysis and single crystal X-ray diffraction. All the isolated compounds were evaluated for their inhibitory effects on SF-268, MCF-7, and NCI-H460 human cancer cell lines. Compounds 2 and 4 exhibited weak inhibitions of cell proliferation against MCF-7 cell line.

[Study on secondary metabolites of endophytic fungus Arthrinium sp. A092 from Uvaria microcarpa].

OBJECTIVE: To study the secondary metabolites of the endophytic fungus Arthrinium sp. A092 from Uvaria microcarpa. METHODS: The compounds were isolated and purified by silica gel column chromatography, reverse silica gel column chromatography, Sephadex LH-20 column chromatography, HPLC, preparative TLC and recrystallization. Their structures were identified by extensive analysis of their spectroscopic data. RESULTS: Ten compounds were isolated from the fermentation broth extract of strain A092 and identified as flemingipanic acid(1), ( - )-gynuraone(2),2-(4-methoxy-phenyl)-ethanol(3),2-hexyl-methymaleic anhydride(4), {1-[(12E, 16E)]-12,16-eicosadienoyl]-2-[ (E, E)-7, 10-octadecadienoyl]-3-stearoylglycerol} (5), mycoediketoperazine (6), libertellenone C(7),4-hydroxymethyl-4, 6-octadiene-2, 3-diol (8), dimethyl phthalate (9), and di-(2-ethyl)-hexylphthalate (10). CONCLUSION: Compounds 1,3 - 5 and 8 - 10 are isolated from the genus Arthrinium for the first time.

Cytotoxic cochlioquinone derivatives from the endophytic fungus Bipolaris sorokiniana derived from Pogostemon cablin.

Chemical investigation of the liquid culture of the endophytic fungus Bipolaris sorokiniana A606, which was isolated from the medicinal plant Pogostemon cablin resulted in the isolation of four new cytotoxic compounds, named isocochlioquinones D-E (1-2) and cochlioquinones G-H (3-4), along with five known cochlioquinone analogues (5-9). Their structures were determined on the basis of extensive spectroscopic analysis. Isocochlioquinone D (1) possessed a rare benzothiazin-3-one moiety and cochlioquinone G (3) was the first example of cochlioquinones bearing an indole-4,7-dione fragment. All of the isolates (1-9) were evaluated for their cytotoxic activities against MCF-7, NCI-H460, SF-268 and HepG-2 tumor cell lines by the sulforhodamine B (SRB) assay. Compounds 4 and 6-9, featuring a cochlioquinone core, exhibited potent cytotoxicities in vitro against the four tumor cell lines, and a preliminary structure-activity relationship of these compounds was also discussed.