Nitric oxide production inhibitory activity of clerodane diterpenes from Monoon membranifolium

Abstract

A new clerodane diterpene, 2β-methoxyhardwickiic acid (1), and four known compounds (2–5) were isolated from the twigs of Monoon membranifolium. The structure of the new compound was determined by extensive spectroscopic methods and ESITOFMS data. The absolute configuration of 1 was established by a comparison of its ECD spectrum and specific rotation with those of related previously reported compounds. All compounds were evaluated for their nitric oxide (NO) production inhibitory activities in RAW264.7 macrophage cells. Compounds 3 and 5 inhibited NO production with IC₅₀ values of 16.1 and 28.9 μM, respectively, which were better than that of standard compound, indomethacin (IC₅₀ = 32.2 μM).

Graphical Abstract

Keywords:

• Monoon membranifolium
• Annonaceae
• clerodane diterpene
• nitric oxide production inhibitory activity

Acknowledgments

We thank Mae Fah Luang University, Chiang Mai University, and the University of Wollongong for laboratory facilities.

Disclosure statement

The authors declare no conflicts of interest.

Additional information

Funding

Thailand Science Research and Innovation supported this work through the Direct Basic Research Grant (DBG6280007). Thailand Research Fund is also acknowledged for financial support through the Royal Golden Jubilee PhD program (PHD/0098/2560) and the Advanced Research Scholar (BRG5980012).