Anticomplement activity of cycloartane glycosides from the rhizome of Cimicifuga foetida.

A tetranor-cycloartane glycoside and two 9,19-cycloartane glycosides were isolated from the EtOAc-soluble fraction of the rhizome of Cimicifuga foetida. The structures of the compounds were determined to be cimilactone A (1), 25-O-acetylcimigenol 3-O-beta-d-xylopyranoside (2) and cimigenol 3-O-alpha-l-arabinopyranoside (3), respectively, using spectroscopic analysis. The three compounds were examined for their anticomplement activity against the classical pathway of the complement system. Compound 1 showed significant anticomplement activity with an IC(50) value of 28.6 microm, whereas compounds 2 and 3 were inactive.