Three new C₂₁-steroidal glycosides from the roots of Cynanchum inamoenum

Abstract

Three new C₂₁-steroidal glycosides presenting an unusual 13,14:14,15-disecopregnane-type skeleton, named inamosides A–C (1–3), together with two known C₂₁-steroidal glycosides, were isolated from the MeOH extract of the roots of Cynanchum inamoeum (Maxim.) Loes (Asclepiadaceae). The aglycone of compounds 1, 2, and 3 has a 2β-hydroxyl, which has not yet been reported in the literature. The structure and relative configuration of the aglycone of compounds 1, 2, and 3 were established by X-ray crystallographic analysis.

Keywords:

• Cynanchum inamoenum (Maxim.) Loes
• Asclepiadaceae
• Inamosides A, B, C
• 2-Epi-glaucogenin A

Acknowledgements

Financial support was provided by grants from the State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany. We are grateful to Professor Chen Jijun for supplying the deoxy sugars in the State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, and Professor Wang Jianhua of the Laboratory of Medicinal Plants, Agronomy College, Shandong Agriculture University for his kind help.