Bioactive Iridoid Glycosides from the Whole Plants of Rehmannia chingii

Nine new iridoid glycosides, rehmachingiiosides A-I (1-9), together with 16 known analogues, were isolated from the whole plants of Rehmannia chingii. The structures of compounds 1-9 were elucidated on the basis of spectroscopic data analysis and from chemical evidence. Furthermore, in two vitro assays, compounds 5 and 10 showed an inhibitory effect on LPS-induced NO production with IC50 values of 2.5 and 7.3 mu M, and compounds 4, 6, and 10-12 (when evaluated at 10 mu M) exhibited evidence of hepatoprotective effects against APAP-induced HepG2 cell damage.