Antimicrobial compounds from endophytic fungi of goldenseal (Hydrastis canadensis)

摘要

With this study, we explored the potential role of fungal endophytes in the antimicrobial activity of the medicinal plant goldenseal, Hydrastis canadensis L. (Ranunculaceae). A total of 23 fungal cultures were obtained from surface-sterilized samples of H. canadensis roots, leaves and seeds. Eleven secondary metabolites were isolated from these fungal endophytes, five of which had reported antimicrobial activity. Hydrastis canadensis plant material from the same harvest was analyzed for the presence of fungal metabolites using liquid chromatography coupled to high resolving power mass spectrometry. One fungal metabolite, the antimicrobial compound alternariol monomethyl ether, was detected both as a metabolite of the fungal endophyte Alternaria sp. isolated from H. canadensis seeds and as a component of an extract from the H. canadensis seed material. The concentration of this compound (991 ppm in dry seed material) was in a similar range that has previously been reported for metabolites of ecologically important fungal endophytes. The seed extracts themselves, however, possessed no significant antimicrobial activity.