New lignan glycosides from Justicia procumbens

Abstract

Four new lignan glycosides (1–4), named procumbenosides I, K, L, and M, together with cleistanthin B (5) reported for the first time in the genus Justicia, and 5 other known arylnaphthalene lignan glycosides (6–10) were isolated from the whole plant of Justicia procumbens. The structures of the new compounds were elucidated by extensive one-dimensional (1D) and two-dimensional (2D) NMR experiments and mass spectrometry. Procumbenoside M (4) was a rare sesquilignan glycoside never previously reported in the species of Justicia. The paper also provided insight into the conformational equilibria existing in the lignan glycosides of the plant.

Keywords:

• Justicia procumbens
• Acanthaceae
• lignan glycosides
• sesquilignan glycoside
• conformational equilibria

Acknowledgements

The authors are really grateful to Mrs Yan Xue and Mrs Mei-feng Xu of the National Center of Biomedical Analysis for the measurements of the HRESIMS and NMR spectra.