Four new fatty acid derivatives from Diaporthe sp. T24, an endophytic fungus isolated from Ligularia fischer.

The endophytic fungus Diaporthe sp. is known to contain many secondary metabolites, but fatty acid derivatives have rarely been found. In this study, four new fatty acid derivatives (1-4), together with four known compounds (5-8), were isolated from Diaporthe sp., which was obtained from the stem of Ligularia fischeri. The absolute configurations of the new compounds 1-4 were deduced based on spectroscopic technique and J-based coupling constant analysis. Moreover, compound 1 exhibited cytotoxic activities against HCT-8 and MCF-7 cancer cells, and compounds 3 and 4 showed modest selectivity for HCT-8 cells by MTT assay.

Oxalic acid and sclerotial differentiation of Polyporus umbellatus.

The present investigation aimed to uncover the effects of exogenous oxalic acid during the sclerotial formation of Polyporus umbellatus, with an emphasis on determining the content of the endogenic oxalic acid in the fungus. To this end, the oxalic acid content of the vegetative mycelia, sclerotia, culture mediums and sclerotial exudate were measured using High Performance Liquid Chromatography (HPLC). Furthermore, the lipid peroxidation was estimated by detecting thiobarbituric bituric acid reactive substances (TBARS). The results showed that the exogenous oxalic acid caused a delay in sclerotial differentiation (of up to 9 or more days), suppressed the sclerotial biomass and decreased the lipid peroxidation significantly in a concentration-dependent manner. Oxalic acid was found at very low levels in the mycelia and the maltose medium, whereas it was found at high levels in the mycelia and sucrose medium. After sclerotial differentiation, oxalic acid accumulated at high levels in both the sclerotia and the sclerotial exudate. Oxalic acid was therefore found to inhibit P. umbellatus sclerotial formation.