Terpenoids and bisbibenzyls from Chinese liverworts Conocephalumconicum and Dumortierahirsuta

Abstract

Four new monoterpene esters, 2α,5β-dihydroxybornane-2-cinnamate (1), 2α,5β-dihydroxybornane-5-acetyl-2-cinnamate (2), 2α,5β-dihydroxybornane-2-p-hydroxycinnamate (3) and 2α,5β-dihydroxy-bornane-2-cis-p-hydroxycinnamate (4), together with a known compound 3,4-dimethoxystyrene (5) were isolated from Chinese liverwort Conocephalum conicum and six known compounds, 5,7-dihydroxycalamenene (6), 7-hydroxycalamenene (7), lunularin (8), riccardin C (9), marchantin C (10) and riccardin D (11) were isolated from Dumortiera hirsuta. Their structures were elucidated by extensive spectral analysis and chemical correlations. Compounds 1 and 8 showed moderate cytotoxicity against human HepG2 cells with IC₅₀ 4.5 μg/ml and 7.4 μg/ml, respectively, while compound 8 also showed antimicrobacterial activity against Pseudomonas aeruginosa with minimum inhibitory concentration at 64 μg/ml.

Keywords:

• Liverwort
• Conocephalum conicum
• Dumortiera hirsuta
• Monoterpenoid
• Sesquiterpenoid
• Bisbibenzyls

Acknowledgements

The research is funded by the National Natural Science Foundation of China (No. 30271537) and Teaching Foundation from China Educational Administration. The authors thank Dr Guangzhong Tu, Beijing Institute of Microchemistry, for recording the NMR spectra, Yanhui Gao, School of Pharmaceutical Sciences of this University, for recording the mass spectra, and Professor Ruiliang Zhu, HuaDong Normal University, for identification of the plant material.