Antifungal effects of metabolites from Arthrinium sp. 2-65 and identification of main active ingredients.

BACKGROUND: Using microbes and their metabolites as material to develop new biological fungicides is still vital for pesticide development. Our preliminary study found that the endophytic fungi Arthrinium sp. 2-65 of Thymus mongolicus (Ronniger) Ronniger showed a certain inhibitory effect on pathogenic fungi. RESULTS: In this study, the antifungal activity of Arthrinium sp. 2-65 was evaluated. The ethyl acetate extract of Arthrinium sp. 2-65 exhibited significant inhibitory activity against pathogenic fungi, especially Botrytis cinerea. The main compounds of Arthrinium sp. 2-65 metabolites were isolated and purified, and the two compounds were identified by infrared spectroscopy (IR), high-performance liquid chromatography (HPLC), 1H nuclear magnetic resonance (NMR), 13C NMR, and high-resolution mass spectrometry (HRMS) as 2-hexyl-3-methylmaleic anhydride (A) and 2-carboxymethyl-3-n-hexylmaleic acid anhydride (B). CONCLUSIONS: The main compounds (A and B) isolated and characterised from the fermentation broth of Arthrinium sp. 2-65 showed satisfactory inhibitory effects against pathogenic fungi, especially B. cinerea. These compounds could be used as potential molecules for the development of novel pesticides to control grey mould.