Colletotrichalactones A-Ca, unusual 5/6/10-fused tricyclic polyketides produced by an endophytic fungus, Colletotrichum sp. JS-0361

Sunghee Bang, Ha Eun Kwon, Ji Yun Baek, Dae Sik Jang, Soonok Kim, Sang Jip Nam, Dongho Lee, Ki Sung Kang, Sang Hee Shim

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6 Citations (Scopus)


Three unusual polyketides with a 5/6/10-fused ring system, named colletotrichalactones A-Ca (1-3a), were isolated from cultures of the endophytic fungus, Colletotrichum sp. JS-0361, which was isolated from a leaf of Morus alba. Their structures, including their absolute stereochemistries, were completely established using extensive spectroscopic methods together with a chemical reaction utilizing competing enantioselective acylation coupled with LC/MS. Compounds possessing this ring skeleton were previously reported in three studies. Our rigorous chemical investigation revealed the complete configuration of this skeleton, which agreed with the results for glabramycin B with this ring skeleton established by computational chemistry and enantioselective synthesis in previous reports. 1 and 2 had unstable aldehyde groups that were easily converted to acetal groups in the presence of solvents. Meanwhile, compound 3a, with terminal acetal functionality, was deduced to be an artefact originating from compound 3 with a terminal aldehyde group. Compounds 1 and 3a displayed moderate-to-potent cytotoxic activities against MCF7 cells with IC50s of 35.06 and 25.20 µM, respectively.

Original languageEnglish
Article number104449
JournalBioorganic Chemistry
Publication statusPublished - 2020 Dec

Bibliographical note

Funding Information:
This research was supported by the National Research Foundation of Korea ( NRF-2019R1A4A1020626 and NRF-2018R1A2B6001733 ).

Publisher Copyright:
© 2020 Elsevier Inc.


  • 5/6/10-Fused ring system
  • Colletotrichum sp.
  • Cytotoxicity
  • Polyketides

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Drug Discovery
  • Organic Chemistry


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