Greensporones: Resorcylic Acid Lactones from an Aquatic Halenospora sp.

Abstract

Fourteen new resorcylic acid lactones (1–14) were isolated from an organic extract of a culture of a freshwater aquatic fungus Halenospora sp. originating from a stream in North Carolina. The structures were elucidated using a set of spectroscopic and spectrometric techniques. The absolute configuration of one representative member of the compounds (7) was assigned using X-ray crystallography of an analogue that incorporated a heavy atom, whereas for compounds 8–11, a modified Mosher’s ester method was utilized. The relative configurations of compounds 12–14 were determined on the basis of NOE data. Compounds 12–14 were proposed as artifacts produced by intramolecular cycloetherification of the ε-hydroxy-α,β-unsaturated ketone moieties of the parent compounds during the purification processes. The isolated compounds, except for 8 and 12, were tested against the MDA-MB-435 (melanoma) and HT-29 (colon) cancer cell lines. Compound 5 was the most potent, with IC50 values of 2.9 and 7.5 μM, respectively. The compounds were evaluated as TAK1–TAB1 inhibitors but were found to be inactive.

Fungal Identification Using Molecular Tools: A Primer for the Natural Products Research Community

“…The consensus sequence of the ITS region is submitted for a BLAST search using the NCBI GenBank database to obtain species-level information and then utilized in combination with the D1/D2 regions of the LSU for subsequent phylogenetic analyses. 39,172,176 …”

Isolation, semisynthesis, covalent docking and transforming growth factor beta-activated kinase 1 (TAK1)-inhibitory activities of (5Z)-7-oxozeaenol analogues

“…17 Six structurally related analogues of 1 were concomitantly isolated from this fungus (Figure 1, 2–7 ) and 16 compounds from other strains ( 8 and S1–S15; see SI for full listing of structures). 18 Seven additional compounds were also produced by semisynthesis using (5 Z )-7-oxozeaenol as the starting material (Scheme 1). All 30 compounds were analyzed for their inhibitory activity with TAK1.…”

In situ mass spectrometry monitoring of fungal cultures led to the identification of four peptaibols with a rare threonine residue

“…The fungal fermentations were performed using procedures reported previously (Ayers et al, 2012; Ayers et al, 2011; El-Elimat et al, 2014; Figueroa et al, 2012). Briefly, fresh cultures were inoculated in a medium containing 2% soy peptone, 2% dextrose, and 1% yeast extract (YESD media).…”

“…The scale-up fungal culture was extracted using a previously reported procedure (Ayers et al, 2012; Ayers et al, 2011; El-Elimat et al, 2014; Figueroa et al, 2012). Briefly, the culture was extracted by adding 500 ml of MeOH–CHCl 3 (1:1) to a 2.8 l fernbach flask containing 150 g of rice with fungal growth.…”