Furoic acid derivatives from the endophytic fungus Coniothyrium sp.

Abstract

The endophytic fungus Coniothyrium sp. was isolated from leaves of Quercus robur. Fermentation of this fungus on solid rice medium yielded two new furoic acid derivatives (1 and 2) and two additional known compounds. The structures of the new compounds were determined by extensive analysis of 1D and 2D nuclear magnetic resonance spectra as well as high-resolution mass spectrometry data. Compound 1, containing three aromatic chromophores attached by rotatable sigma bonds and a chirality center in benzylic position, was found to be a scalemic mixture with an excess of the (S) enantiomer, the absolute configuration of which was elucidated as by the solution timedependent density functional theory-electronic circular dichroism approach. The ωB97X/TZVP PCM/MeCN and SOGGA11-X/TZVP SMD/MeCN methods were used for geometry reoptimization to reproduce the solution conformational ensemble. All isolated compounds were tested for their cytotoxicity but proved to be inactive. K E Y W O R D SConiothyrium sp, electronic circular dichroism, furoic acid derivatives, TDDFT-ECD calculation

Isolation and Biological Characterization of Homoisoflavanoids and the Alkylamide N-p-Coumaroyltyramine from Crinum biflorum Rottb., an Amaryllidaceae Species Collected in Senegal

“…: phantasmidine, an alkaloid found to be a 4:1 scalemic mixture, enriched in the (2a R ,4a S ,9a S ) enantiomer isolated from the poison frog Epipedobates anthonyi [ 56 ]; α-pinene, 1-octen-3-ol linalool found as a scalemic mixture of 34% ( R )-(+) to 66% ( S )-(−), 95% ( R )-(−) to 5% ( S )-(+), 96% ( R )-(−) to 4% ( S )-(+) when isolated from the edible wild mushroom Tricholoma magnivelare [ 57 ]; a furoic acid derivative, containing a chiral center in benzylic position, was found to be a scalemic mixture with an excess of the ( S ) enantiomer, when obtained from the endophytic fungus Coniothyrium sp. was isolated from leaves of Quercus robur [ 58 ]; six pairs of new 6-monosubstituted dihydrobenzophenanthridine alkaloids were separated as scalemic mixtures from the aerial part of Chelidonium majus , a plant belonging to the Papaveraceae family, which is widely used in Chinese folk medicine [ 59 ].…”