Chemical constituents from the ascomycetous fungus Tuber indicum

Chemical constitutes from Tuber indicum with immunosuppressive activity uncovered by transcriptome analysis

Three previously undescribed compounds including a polyketide (1) and two lactams (2 and 3) were obtained from Tuber indicum. The structures of new findings were elucidated by HRESIMS, NMR as well as NMR and ECD calculations. Transcriptome analysis through RNA-seq revealed that compound 2 exhibits immunosuppressive activity. Lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages were employed as a model to explore the effect of these compounds in immunosuppressive activity. The results showed that 2 could reduce the generation of inflammatory mediators including nitric oxide (NO), reactive oxygen species (ROS), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS). Western blotting analysis demonstrated that 2 could suppressed the PI3K pathway by decreasing the levels of p-PI3K and p-Akt, while increasing the levels of p-PTEN. The anti-inflammatory activity of 2 was further confirmed using a zebrafish in vivo model.

Chemical Constituents from the Fruit Body of Chlorophyllum Molybdites

A new glycoxyuracil and 15 known compounds were isolated from the fruit body of Chlorophyllum molybdites. The structures were determined from their NMR and MS data and by comparison with literature data. Compounds 2–5, 10–11, 13, and 15–16 were isolated from the genus Chlorophyllum for the first time. Compounds (1–9) did not show cytotoxicity against two human cancer cell lines, A549 and Panc-28 (GI50 > 50 μM).

Metabolites from Aspergillus fumigatus, an endophytic fungus associated with Melia azedarach, and their antifungal, antifeedant, and toxic activities

Thirty-nine fungal metabolites 1-39, including two new alkaloids, 12β-hydroxy-13α-methoxyverruculogen TR-2 (6) and 3-hydroxyfumiquinazoline A (16), were isolated from the fermentation broth of Aspergillus fumigatus LN-4, an endophytic fungus isolated from the stem bark of Melia azedarach. Their structures were elucidated on the basis of detailed spectroscopic analysis (mass spectrometry and one- and two-dimensional NMR experiments) and by comparison of their NMR data with those reported in the literature. These isolated compounds were evaluated for in vitro antifungal activities against some phytopathogenic fungi, toxicity against brine shrimps, and antifeedant activities against armyworm larvae (Mythimna separata Walker). Among them, sixteen compounds showed potent antifungal activities against phytopathogenic fungi (Botrytis cinerea, Alternaria solani, Alternaria alternata, Colletotrichum gloeosporioides, Fusarium solani, Fusarium oxysporum f. sp. niveum, Fusarium oxysporum f. sp. vasinfectum, and Gibberella saubinettii), and four of them, 12β-hydroxy-13α-methoxyverruculogen TR-2 (6), fumitremorgin B (7), verruculogen (8), and helvolic acid (39), exhibited antifungal activities with MIC values of 6.25-50 μg/mL, which were comparable to the two positive controls carbendazim and hymexazol. In addition, of eighteen that exerted moderate lethality toward brine shrimps, compounds 7 and 8 both showed significant toxicities with median lethal concentration (LC(50)) values of 13.6 and 15.8 μg/mL, respectively. Furthermore, among nine metabolites that were found to possess antifeedant activity against armyworm larvae, compounds 7 and 8 gave the best activity with antifeedant indexes (AFI) of 50.0% and 55.0%, respectively. Structure-activity relationships of the metabolites were also discussed.

Cytotoxic Metabolites Produced by Alternaria No.28, an Endophytic Fungus Isolated from Ginkgo biloba

From the medicinal plant Ginkgo biloba the fungal endophyte Alternaria no.28 was isolated. Extract of the fungus grown in liquid culture media exhibited marked cytotoxic activity when tested in vitro against brine shrimp (Artemia salina). Eight compounds were isolated from the extract of cultures of this endophytic fungus and were elucidated as alterperylenol (1), altertoxin I (2), alternariol (3), alternariol monomethyl ether (4), tenuazonic acid (5) and its derivative (6), together with ergosterol and ergosta-4, 6, 8, 22-tetraen-3-one by means of spectroscopic analysis. Among them, both 5 and 6 showed significant cytotoxic effects in the brine shrimp bioassy, with mortality rates of 73.6% and 68.9%, respectively, at a concentration of 10 μg.mL−1, and they were first isolated from endophytic fungi.