Frontiers in Microbiology (May 2020)

Novel Antimicrobial Compounds as Ophiobolin-Type Sesterterpenes and Pimarane-Type Diterpene From Bipolaris Species TJ403-B1

  • Ling Shen,
  • Mengting Liu,
  • Yan He,
  • Weaam Hasan Al Anbari,
  • Huaqiang Li,
  • Shuang Lin,
  • Chenwei Chai,
  • Jianping Wang,
  • Zhengxi Hu,
  • Yonghui Zhang

DOI
https://doi.org/10.3389/fmicb.2020.00856
Journal volume & issue
Vol. 11

Abstract

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Six previously undescribed ophiobolin-type sesterterpenes, namely, bipolatoxins A–F (1–6); and one previously undescribed pimarane-type diterpene, namely, 1β-hydroxy momilactone A (7); together with three known compounds, namely, 25-hydroxyophiobolin I (8), ophiobolin I (9), and ophiobolin A lactone (10); were isolated and identified from the endophytic fungus Bipolaris species TJ403-B1. Their structures with absolute configurations were elucidated on the basis of extensive spectroscopic analyses (including 1D and 2D nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectroscopy data), single-crystal X-ray diffraction analyses, and comparison of experimental circular dichroism data. All compounds (except for 5) were evaluated for antimicrobial potential, which indicated that bipolatoxin D (4) showed significant inhibitory activity against Enterococcus faecalis with a minimum inhibitory concentration (MIC) value of 8 μg/mL, and ophiobolin A lactone (10) showed significant inhibitory activity against Acinetobacter baumannii and E. faecalis with MIC values of 8 and 8 μg/mL, respectively.

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