Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis.

From a fresh root of Trema guineensis (Ulmaceae), endophytic fungi were isolated, among which a taxon belonging to the new species Diaporthe cameroonensis. This strain was fermented in shake flask batch cultures and the broth was extracted with ethyl acetate. From the crude extract, a hemiketal polyketide 1, and an acetylated alternariol 2 were isolated, along with fifteen known secondary metabolites. Their structures were established by extensive NMR spectroscopy and mass spectrometry analyses, as well as by comparison with literature data of their analogs.

Unreported cytochalasins from an acid-mediated transformation of cytochalasin J isolated from Diaporthe cf. ueckeri.

Chemical investigation of an endophytic fungus herein identified as Diaporthe cf. ueckeri yielded four known compounds, named cytochalasins H and J and dicerandrols A and B. Reports of acid sensitivity within the cytochalasan family inspired an attempt of acid-mediated conversion of cytochalasins H and J, resulting in the acquisition of five polycyclic cytochalasins featuring 5/6/5/8-fused tetracyclic and 5/6/6/7/5-fused pentacyclic skeletons. Two of the obtained polycyclic cytochalasins constituted unprecedented analogues, for which the trivial names cytochalasins J4 and J5 were proposed, whereas the others were identified as the known phomopchalasin A, phomopchalasin D and 21-acetoxycytochalasin J3. The structures of the compounds were determined by extensive spectral analysis, namely HR-ESIMS, ESIMS and 1D/2D NMR. The stereochemistry of cytochalasins J4 and J5 was proposed using their ROESY data, biosynthetic and mechanistic considerations and by comparison of their ECD spectra with those of related congeners. All compounds except for cytochalasins H and J were tested for antimicrobial and cytotoxic activity. Cytochalasins J4 and J5 showed neither antimicrobial nor cytotoxic activity in the tested concentrations, with only weak antiproliferative activity observable against KB3.1 cells. The actin disruptive properties of all cytochalasins obtained in this study and of the previously reported cytochalasins RKS-1778 and phomopchalasin N were examined, and monitored by fluorescence microscopy using human osteo-sarcoma (U2-OS) cells. Compared to their precursor molecules (cytochalasins H and J), phomopchalasins A and D, 21-acetoxycytochalasin J3, cytochalasins J4 and J5 revealed a strongly reduced activity on the F-actin network, highlighting that the macrocyclic ring is crucial for bioactivity.

Mimonoside D: a new triterpenoid saponin from Mimosa diplotricha Sauvalle (Fabaceae).

A new triterpenoid saponin (Mimonoside D: 3-O-α-L-arabinopyranosyl-3ß-hydroxyolean-12-en-28-oic acid 28-O-ß-D-xylopyranosyl-(1→2)-ß-D- glucopyranoside ester (1)) was isolated from the aerial parts of Mimosa diplotricha Sauvalle together with nine known compounds: 7,4'-dihydroxyflavone (2), kaempferol (3), lupeol (4), betulinic acid (5), ß-sitosterol (6), ß-sitosterol-3-O-ß-D-glucopyranoside (7), lutein (8), 5,2'-dihydroxy-7,4',5'-trimethoxyflavone (9) and vitexin (10). Their structures were elucidated on the basis of spectroscopic (1 D and 2 D nuclear magnetic resonance) and high-resolution mass spectrometric data as well as by comparison of their spectral data with those of related compounds. Compounds 2, 7 and 8 had already been isolated from M. diplotricha, while compounds 3, 4, 5 and 6 have been isolated from other Mimosa species. Compound 2 moderately inhibited Proteus mirabilis (MIC = 32 µg/mL), weakly inhibited Pseudomonas aeruginosa (MIC = 64 µg/mL) and very weakly inhibited Staphylococcus aureus (MIC = 128 µg/mL) and Enterococus faecalis (MIC = 128 µg/mL).

Ten decadal advances in fungal biology leading towards human well-being.

Fungi are an understudied resource possessing huge potential for developing products that can greatly improve human well-being. In the current paper, we highlight some important discoveries and developments in applied mycology and interdisciplinary Life Science research. These examples concern recently introduced drugs for the treatment of infections and neurological diseases; application of -OMICS techniques and genetic tools in medical mycology and the regulation of mycotoxin production; as well as some highlights of mushroom cultivaton in Asia. Examples for new diagnostic tools in medical mycology and the exploitation of new candidates for therapeutic drugs, are also given. In addition, two entries illustrating the latest developments in the use of fungi for biodegradation and fungal biomaterial production are provided. Some other areas where there have been and/or will be significant developments are also included. It is our hope that this paper will help realise the importance of fungi as a potential industrial resource and see the next two decades bring forward many new fungal and fungus-derived products.

Terpenoids and Meroterpenoids from Cultures of Two Grass-Associated Species of Amylosporus (Basidiomycota).

An investigation of the chemical components of the fermentation extract of two cultures of Amylosporus cf. graminicola and Amylosporus cf. campbelii from Cuba and Zimbabwe, respectively, led to the isolation of seven previously undescribed secondary metabolites for which we proposed the trivial names amylosporanes A-G (1-7) along with the known compounds orsellinic acid (11), colletorin D acid (12), colletorin B (13), colletochlorin B (14), and the ß-lactam cyclo-(S-Pro-R-Leu) (15). Three additional compounds (8-10) previously unknown from a fungal source were also characterized for the first time, and two of them were assigned the trivial names amylosporanes H-I (8-9) while the other was identified as cannabigerorcinic acid (10). The structures of the isolated compounds were determined based on their high-resolution electrospray ionization mass spectrometry (HR-ESIMS) spectra and an extensive analysis of their 1D and 2D NMR spectroscopic data. Based on literature searches, we hypothesized that a majority of the isolated metabolites have orsellinic acid (11) as a biosynthetic precursor following a combined route of mevalonate-associated and orsellinic acid-associated pathways. Colletochlorin B (14), the only compound possessing chlorine in its structure, exhibited significant activity against Bacillus subtilis (minimum inhibitory concentration, 2 µg/mL), stronger than that of oxytetracycline, and significant cytotoxicity against A431 cells with an IC50 value of 4.6 µM.