Two New Ionone Glycosides from the Roots of Rehmannia Glutinosa Libosch

Two new ionone glycosides, named frehmaglutoside G (1) and frehmaglutoside H (2), together with six known compounds, rehmapicroside (3), sec-hydroxyaeginetic acid (4), dihydroxy-β-ionone (5), trihydroxy-β-ionone (6), rehmaionoside A (7) and rehmaionoside C (8), were isolated from the 95% EtOH extract of the dried roots of Rehmannia glutinosa Libosch. Their structures were determined on the basis of extensive spectroscopic analyses, including HR-ESI-MS, UV, IR, 1D and 2D NMR ((1)H-(1)H COSY, HSQC, HMBC and NOESY) methods. The absolute configurations were confirmed via the circular dichroism spectra.