Bipolaricins A-I, Ophiobolin-Type Tetracyclic Sesterterpenes from a Phytopathogenic Bipolaris sp. Fungus

J Nat Prod. 2019 Oct 25;82(10):2897-2906. doi: 10.1021/acs.jnatprod.9b00744. Epub 2019 Oct 1.

Abstract

A preliminary phytochemical investigation on the EtOAc extracts of the fungus Bipolaris sp. TJ403-B1 resulted in the identification of 12 ophiobolin-type phytotoxins (1-12), including nine new ones, termed bipolaricins A-I (1-9). The structures of 1-9 were elucidated via spectroscopic data (including HRESIMS and 1D and 2D NMR) and single-crystal X-ray diffraction (Cu Kα) analyses. All of the isolated compounds were tested in terms of HMG-CoA reductase inhibitory, anti-inflammatory, and cytotoxic activities. Compound 10 showed HMG-CoA reductase inhibitory activity (IC50 = 8.4 ± 0.4 μM), and 2, 3, and 10-12 showed significant inhibitory potency against lipopolysaccharide (LPS)-induced nitric oxide production, with IC50 values in the range of 5.1 ± 0.3 to 20 ± 1 μM. Further experiments showed that 10 could significantly inhibit the production of IL-1β, RANTES, MIP-1β, and TNF-α as well as enhance the release of IL-13 in macrophages through the inhibition of HO-1 induction as well as the NF-κB pathway. These findings provide a scientific rationale for an anti-inflammatory therapeutic and a template for a new HMG-CoA reductase inhibitor to produce a potential anti-hyperlipidemia agent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / chemistry
  • Anti-Inflammatory Agents / isolation & purification*
  • Anti-Inflammatory Agents / pharmacology
  • Ascomycota / metabolism*
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / chemistry
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / isolation & purification*
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / pharmacology
  • Mice
  • NF-kappa B / physiology
  • Nitric Oxide / biosynthesis
  • RAW 264.7 Cells
  • Sesterterpenes / chemistry
  • Sesterterpenes / isolation & purification*
  • Sesterterpenes / pharmacology

Substances

  • Anti-Inflammatory Agents
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • NF-kappa B
  • Sesterterpenes
  • ophiobolins
  • Nitric Oxide