Triterpenoid saponins from the roots of Clematis chinensis Osbeck

A new triterpenoid saponin named clematichinenoside AR2, along with the six known compounds, was isolated and characterized from Clematis chinensis Osbeck (Ranunculaceae), a commonly used traditional Chinese medicine with anti-inflammatory and anti-rheumatoid activities. The structure of the new saponin was elucidated as 3-O--[(O--l-rhamnopyranosyl-(16)-O--d-glucopyranosyl-(14)-O--d-glucopyranosyl-(14)-O--d-ribopyranosyl-(13)-O--l-rhamnopyranosyl-(12)--l-arabinopyranosyl)oxy]olean-12-en-21-hydroxy-28-oic acid-O--l-rhamnopyranosyl-(14)-O--d-glucopyranosyl-(16)--d-glucopyranosyl ester (1) by spectral analysis and chemical methods. The effects of two major saponins (clematichinenosides AR and AR2) on the secretion of TNF- in murine peritoneal macrophages induced by lipopolysaccharides were further investigated. The result indicated that a majority of triterpenoid saponins of this herb may be useful in the exploration of lead compounds for the treatment of some autoimmune diseases.