Bioactive Ascochlorin Analogues from the Marine-Derived Fungus Stilbella fimetaria
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.
Info
Journal Article, 2021
UN SDG Classification
DK Main Research Area
Science/Technology
