Two oleanene glycosides from the aerial parts of Caltha polypetala

Two new oleanene glycosides (1-2) possessing hederagenin as the aglycone were isolated from the methanolic extract of the aerial parts of Caltha polypetala together with four known glycosides. The saccharide portion linked to C-3 of the aglycone is made up of α-L-arabinopyranose, α-L- rhamnopyranose and galactopyranose in the new compounds; while compound 1 possesses linked to C-28 a trisaccharide moiety made up of two β-D- glucopyranose and one α-L-rhamnopyranose unit, in compound 2 the 28-COOH group is free. The structures were elucidated by 1D and 2D NMR experiments including ¹H-¹H (DQF-COSY, 1D-TOCSY, 2D-ROESY) and ¹H-¹³C (HSQC, HMBC) spectroscopy.