A new ent-clerodane diterpenoid from Crassocephalum bauchiense Huch. (Asteraceae)

Abstract

A phytochemical investigation of the whole plant of Crassocephalum bauchiense Huch. resulted in the isolation of a new clerodane diterpenoid, ent-2β,18,19-trihydroxycleroda-3,13-dien-16,15-olide (1), together with two known flavonoids 3′,5-dihydroxy-4′,5′,6,7,8-pentamethoxyflavone (2) and 4′,5-dihydroxy-3′,5′,6,7,8-pentamethoxyflavone (3). The compounds were tested against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum. Compound 2 showed weak activity (IC₅₀ = 10.1 g/mL) whilst compounds 1 and 3 were inactive. The structures of the compounds were elucidated by using detailed spectral analyses, especially ¹H and ¹³C NMR, ¹H–¹H COSY, NOESY, HMBC and HR-ESI-MS.

Keywords::

• Crassocephalum bauchiense
• Asteraceae
• clerodane diterpenoid
• flavonoids
• antiplasmodial activity

Acknowledgements

The authors are grateful to Ms. J. Widart, Laboratory of Mass Spectrometry, Giga Center, University of Liège, for the recording of the mass spectrum.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Authors acknowledge the financial support of Aires Sud (Appuis Intégrés pour le Renforcement des Equipes Scientifiques du Sud), Ministère Fran¸ais des Affaires Etrangères et Européennes, France [grant number 7082], the Fund for Scientific Research-FNRS [grant number T.0190.13] and a research fellowship to ATT at the Department of Pharmacognosy, University of Liège, Belgium.