The sesquiterpenes with the COVID-19 M^pro inhibitory activity from the Carpesium abrotanoides L.

Abstract

The extract of the whole plant of Carpesium abrotanoides L. yielded four new sesquiterpenes including a novel skeleton (claroguaiane A, 1), two guaianolides (claroguaianes B–C, 2–3), and one eudesmanolide (claroeudesmane A, 4), together with three known sesquiterpenoids (5–7). The structures of the new compounds were elucidated by spectroscopic analysis especially 1D and 2D NMR spectroscopy and HRESIMS data. Additionally, all the isolated compounds were preliminarily evaluated for the inhibitive activity of COVID-19 M^pro. As a result, compound 5 showed moderate activity with an IC₅₀ value of 36.81 μM and compound 6 exhibited a potent inhibitory effect with an IC₅₀ value of 16.58 µM, while other compounds were devoid of noticeable activity (IC₅₀ > 50 μM).

Graphical Abstract

Keywords:

• Sesquiterpenes
• Carpesium abrotanoides L.
• structure elucidation
• COVID-19 M^pro
• inhibitory activity

Acknowledgements

We sincerely thank the ‘Cultivation project of Dongguan Institute of Guangzhou University of Chinese Medicine’.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.