Anti-inflammatory isocoumarins from the bark of Fraxinus chinensis subsp. rhynchophylla

Abstract

A new isocoumarin (1) named fraxicoumarin was isolated from the bark of Fraxinus chinensis subsp. rhynchophylla along with three known compounds (2–4). The structure of the new compound was established by extensive spectroscopic studies and chemical evidence. The anti-inflammatory effects of the isolated compounds (1–4) on lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells were evaluated in vitro. Of the compounds tested, compounds 1 and 3 inhibited LPS-induced nitric oxide (NO) production in RAW 264.7 cells. Consistent with these findings, they also suppressed LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein level in RAW 264.7 cells.

Graphical Abstract

Keywords:

• Fraxinus chinensis subsp. rhynchophylla
• isocoumarins
• anti-inflammation
• nitric oxide
• inducible nitric oxide synthase
• cyclooxygenase-2

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by a grant (KSN1812080) from the Korea Institute of Oriental Medicine.