Five Tetramic Acid Derivatives Isolated from the Iranian Fungus Colpoma quercinum CCTU A372

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 β-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.

Two New Triterpenes from Basidiomata of the Medicinal and Edible Mushroom, Laetiporus sulphureus

In the search for novel anti-infectives from natural sources, fungi, in particular basidiomycetes, have proven to still harbor so much potential in terms of secondary metabolites diversity. There have been numerous reports on isolating numerous secondary metabolites from genus Laetiporus. This study reports on two new triterpenoids, laetiporins C and D, and four known triterpenes from the fruiting body of L. sulphureus. The structures of the isolated compounds were elucidated based on their 1D and 2D nuclear magnetic resonance (NMR) spectroscopic data in combination with high-resolution electrospray mass spectrometric (HR-ESIMS) data. Laetiporin C exhibited weak antifungal activity against Mucor hiemalis. Furthermore, the compounds showed weak antiproliferative activity against the mouse fibroblast L929 and human cancer cell lines, including KB-3-1, A431, MCF-7, PC-3 and A549.