Skeletocutins A-L: Antibacterial Agents from the Kenyan Wood-Inhabiting Basidiomycete, Skeletocutis sp

  • J Agric Food Chem. 2019 Aug 7;67(31):8468-8475. doi: 10.1021/acs.jafc.9b02598.
Clara Chepkirui  1 ,  Tian Cheng  1 ,  Winnie Chemutai Sum  2 ,  Josphat Clement Matasyoh  3 ,  Cony Decock  4 ,  Dimas F Praditya  5  6  7 ,  Kathrin Wittstein  1 ,  Eike Steinmann  5  6 ,  Marc Stadler  1
Affiliations
  • 1. Department of Microbial Drugs , Helmholtz Centre for Infection Research (HZI), German Centre for Infection Research (DZIF) , Partner Site Hannover/Braunschweig, Inhoffenstrasse 7 , 38124 Braunschweig , Germany.
  • 2. Department of Biochemistry , Egerton University , P.O. BOX 536, 20115 Njoro , Kenya.
  • 3. Department of Chemistry, Faculty of Sciences , Egerton University , P.O. Box 536, 20115 Njoro , Kenya.
  • 4. Mycothéque de l' Universite Catholique de Louvain (BCCM/MUCL) , Place Croix du Sud 3 , B-1348 Louvain-la-Neuve , Belgium.
  • 5. Department of Molecular and Medical Virology , Ruhr-University Bochum , 44801 Bochum , Germany.
  • 6. TWINCORE-Centre for Experimental and Clinical Infection Research (Institute of Experimental Virology) Hanover , Feodor-Lynen-Str. 7-9 , 30625 Hannover , Germany.
  • 7. Research Center for Biotechnology , Indonesian Institute of Science , Jl. Raya Bogor KM 46 , Cibinong 16911 , Indonesia.
PMID: 31310114 DOI: 10.1021/acs.jafc.9b02598
Abstract

Fermentation of the Fungal strain Skeletocutis sp. originating from Mount Elgon Natural Reserve in Kenya, followed by bioassay guided fractionation led to the isolation of 12 previously undescribed metabolites named skeletocutins A-L (1-5 and 7-13) together with the known tyromycin A (6). Their structures were assigned by NMR spectroscopy complemented by HR-ESIMS. Compounds 1-6 and 11-13 exhibited selective activities against Gram-positive bacteria, while compound 10 weakly inhibited the formation of biofilm of Staphylococcus aureus. The isolated metabolites were also evaluated for inhibition of L-leucine Aminopeptidase, since tyromycin A had previously been reported to possess such activities but only showed weak effects. Furthermore, all compounds were tested for Antiviral activity against Hepatitis C virus (HCV), and compound 6 moderately inhibited HCV infectivity with an IC50 of 6.6 μM.

Keywords
basidiomycota; polyporaceae; secondary metabolites; structure elucidation.
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