Antimicrobial fungal endophytes from the botanical medicine goldenseal (Hydrastis canadensis). (September 2016)

• Record Type: Journal Article
• Authors: Egan, Joseph M.; Kaur, Amninder; Raja, Huzefa A.; Kellogg, Joshua J.; Oberlies, Nicholas H.; Cech, Nadja B.
• Is Part Of: Phytochemistry letters. Volume 17(2016:Sep.)
• Page Start: 219
• Page End: 225
• Publication Date: 2016-09
• Subjects: Hydrastis canadensis -- Endophytes -- Secondary metabolites -- Fungi -- Alternariol monomethyl ether; Botanical chemistry -- Periodicals; Chimie végétale -- Périodiques; 572.205
• DOI: 10.1016/j.phytol.2016.07.031
• Languages: English
• ISSNs: 1874-3900

Abstract

Graphical abstract: Highlights: ⿢ A total of 23 fungal isolates were obtained from surface-sterilized samples of Hydrastis canadensis . ⿢ The fungus Alternaria sp. was isolated from 3 H. canadensis accessions spanning 5 years. ⿢ Alternariol monomethyl ether was identified in an extract H. canadensis seeds. ⿢ This metabolite was present at concentrations too low to contribute to antimicrobial activity. ⿢ Alternariol monomethyl ether may, however, be ecologically important. Abstract: 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.