The potential of fungal endophytes to alter or contribute to plant chemistry and biology has been the topic of a great deal of recent interest. For plants that are used medicinally, it has been proposed that endophytes might play an important role in biological activity. With this study, we sought to identify antimicrobial fungal endophytes from the medicinal plant goldenseal (Hydrastis canadensis L., Ranunculaceae), a plant used in traditional medicine to treat infection. 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 was then analyzed for the presence of fungal metabolites using liquid chromatography coupled to high resolving power mass spectrometry. The antimicrobial compound alternariol monomethyl ether was detected both as a metabolite of the fungal endophyte Alternaria spp. isolated from H. canadensis seeds, and as a component of an extract from the H. canadensis seed material. Notably, fungi of the Alternaria genus were isolated from three separate accessions of H. canadensis plant material collected in a time period spanning 5 years. The concentration of alternariol monomethyl ether (991 mg/kg in dry seed material) was in a similar range to that previously reported for metabolites of ecologically important fungal endophytes. The seed extracts themselves, however, did not possess antimicrobial activity.

中文翻译：

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植物药金毛（Hydrastis canadensis）的抗菌真菌内生菌。

真菌内生菌改变或促进植物化学和生物学的潜力已成为近期引起人们广泛关注的话题。对于药用的植物，已经提出内生菌可能在生物活性中起重要作用。通过这项研究，我们试图从药用植物金枪鱼（Hydrastis canadensis L.，毛un科）中鉴定出抗菌真菌内生菌，这是一种用于治疗感染的传统药物。从经过表面灭菌的加拿大H. canadensis根，叶和种子样品中获得总共23种真菌培养物。从这些真菌内生菌中分离出11种次级代谢产物，其中5种具有抗菌活性。然后使用液相色谱与高分辨功率质谱联用分析加拿大Hydrastis canadensis植物材料中真菌代谢产物的存在。检测到抗菌化合物交替戊醇单甲醚均作为真菌内生真菌链格孢属的一种代谢产物。从加拿大H.canadensis种子中分离，并作为加拿大H.canadensis种子材料提取物的成分。值得注意的是，在5年的时间里，从三种加拿大H.canadensis植物材料的分离物中分离出了Alternaria属的真菌。交替戊醇单甲醚的浓度（干种子材料中为991 mg / kg）与先前报道的具有重要生态意义的真菌内生菌代谢产物的浓度相似。然而，种子提取物本身不具有抗菌活性。