Secondary metabolites of an endophytic fungus Diaporthe sp. derived from Blumea balsamifera (L.) DC.

Abstract:

[Objective] To obtain effective secondary metabolites from endophyte J1 originated from Blumea balsamifera (L.) DC. [Methods] The endophytic fungus J1 was identified based on ITS gene phylogenies. Various chromatographic methods were used to isolate and purify compounds from the fermentation extract, and their structures were elucidated by NMR spectroscopy and MS analyses. [Results] J1 was determined as Diaporthe sp. by analyses of phylogenetic tree. Seven compounds were afforded from the rice culture of this fungus, and they were identified to be Dicerandrol A (1), Dicerandrol B (2), 4,6-dihydroxy-1H-isoindole1,3(2H)-dione (3), Cytochalasin H (4), Cytochalasin J (5), 4,6-dihydroxy-2,3-dihydro-1H-isoindol-1-one (6), Cerebroside C (7), individually. All of the seven metabolites were isolated from this fungus for the first time, and compound 1 displays potent inhibitory activity towards Bacillus subtilis KCTC 1021, with an MIC value of 0.125 μg/mL. [Conclusion] This study demonstrated that Diaporthe sp. contains many antimicrobial compounds and may serve as a potential microbial-origin antibacterial agent.