Iridoid glycosides link with phenylpropanoids from Rehmannia glutinosa

Abstract

Two new iridoid glycosides link with phenylpropanoids, rehmanniosides G (1) and H (2) along with 11 known compounds, 6-O-(E)-caffeoylajugol (3), 6-O-(E)-feruloylajugol (4), verbasoside (5), jionoside C (6), acteoside (7), leucosceptoside A (8), brachynoside (9), jionoside B1 (10), jionoside A1 (11), isoacteoside (12) and isomartynoside (13) were isolated from the roots of Rehmannia glutinosa (Gaertn.) DC. Their chemical structures were elucidated on the basis of extensive spectroscopic methods, including 1D, 2D NMR and mass spectra. Compounds 7 − 11 showed significant inhibitory α-glucosidase with IC₅₀ values ranging from 261.4 to 408.7 μM (acarbose, IC₅₀ of 204.2 ± 19.9 μM).

Keywords:

• Rehmannia glutinosa
• rehmannioside G
• rehmannioside H
• α-glucosidase activity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research is funded by the Vietnam Ministry of Education and Training under grant number B2020-MDA-09.