Triterpenoid saponins from Stauntonia chinensis

Abstract

A new triterpenoid saponin, named stauntoside A (1) along with four known saponins (2,3,4,5) was isolated from Stauntonia chinensis DC., (Lardizabalaceae). Their structures were elucidated by spectroscopic analysis and chemical methods as 3-O-α-l-arabinopyranosyl-30-norhederagenin -28-O-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (1), 3-O-α-l-arabinopyranosyl-30- norhederagenin-28-O-α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (2), 3-O-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl-30-norhederagenin-28-O-α-l- rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (3), 3-O-α-l- arabinopyranosyl-hederagenin-28-O-α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d- glucopyranosyl ester (4), 3-O-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl-hederagenin -28-O-α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (5). The ¹H and ¹³C NMR data for Glycoside L-G1 or Sinofoside A are paradox in the reported before. Thus, the structure elucidation of saponin 2, known as Glycoside L-G1 or Sinofoside A, was discussed and the unambiguous assignments were given.

Keywords:

• Stauntonia chinensis
• Lardizabalaceae
• Stauntoside A
• Triterpenoid saponins

Acknowledgements

We appreciate the kind help of LifeTech Pharmaceuticals Ltd, Guangzhou for collecting the plant material and Traditional Chinese Medicine Department, Shenzhen Institute of Drug Control for identifying the plant material. Thanks are also extended to Professor Yang Ye, Shanghai Institute of Materia Medica of Chinese Academy of Science for HR-ESI-Q-TOP-MS experiments and to Sanlin Jin for partial NMR experiments and to Dr Bin Chen, Dr Yi Dai and Qunhui Luo for IR and optical rotation experiments.