Bioactive Ascochlorin Analogues from the Marine-Derived Fungus Stilbella fimetaria |
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Authors: | Karolina Subko Sara Kildgaard Francisca Vicente Fernando Reyes Olga Genilloud Thomas O Larsen |
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Institution: | 1.DTU Bioengineering, Technical University of Denmark, Søltofts Plads 221, DK-2800 Kgs. Lyngby, Denmark;2.Department of Biology, Universitetsparken 15, DK-2100 København Ø, Denmark;3.Fundación MEDINA, Avda. del Conocimiento, 34, Armilla, 18016 Granada, Spain; (F.V.); (F.R.); (O.G.) |
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Abstract: | The marine-derived fungus Stilbella fimetaria is a chemically talented fungus producing several classes of bioactive metabolites, including meroterpenoids of the ascochlorin family. The targeted dereplication of fungal extracts by UHPLC-DAD-QTOF-MS revealed the presence of several new along with multiple known ascochlorin analogues (19–22). Their structures and relative configuration were characterized by 1D and 2D NMR. Further targeted dereplication based on a novel 1,4-benzoquinone sesquiterpene derivative, fimetarin A (22), resulted in the identification of three additional fimetarin analogues, fimetarins B–D (23–25), with their tentative structures proposed from detailed MS/HRMS analysis. In total, four new and eight known ascochlorin/fimetarin analogues were tested for their antimicrobial activity, identifying the analogues with a 5-chloroorcylaldehyde moiety to be more active than the benzoquinone analogue. Additionally, the presence of two conjugated double bonds at C-2′/C-3′ and C-4′/C-5′ were found to be essential for the observed antifungal activity, whereas the single, untailored bonds at C-4′/C-5′ and C-8′/C-9′ were suggested to be necessary for the observed antibacterial activity. |
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Keywords: | meroterpenoids ascochlorin bioactivity dereplication MS/HRMS |
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