Bioactive constituents of oleanane-type triterpene saponins from the roots of Glycyrrhiza glabra

Abstract

Three new oleanane-type triterpene saponins, namely licorice-saponin M3 (1), licorice-saponin N4 (2), and licorice-saponin O4 (3), an artificial product (4), as well as five known triterpene glucuronides (5–9), were isolated from the roots of Glycyrrhiza glabra L. Their structures were established using 1D and 2D NMR spectroscopy, mass spectrometry, and by comparison with spectroscopic data reported in the literature. The inhibitory effects of the selected compounds on neuraminidase were evaluated, and the preliminary structure–activity relationship was also predicted.

Keywords::

• Glycyrrhiza glabra
• Leguminosae
• licorice saponin
• triterpene glucuronides
• neuraminidase inhibitory activity

Acknowledgments

The authors appreciate financial support from National Natural Science Foundation of China (Program No. 81202881), a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions and Natural Science Fund Project of Jiangsu Province, China (Program No. BK2011814). The authors also thank Dr Qi-Nan Wu (Nanjing University of Chinese Medicine, Nanjing, China) for identification of G. glabra L. and Shanghai Institute of Organic Chemistry (Chinese Academy of Sciences, Shanghai, China) for measuring the NMR spectra.

Notes

^1. Juan-Hua Wei and Dr Yun-Feng Zheng contributed equally to this work.