Two new flavonol glycosides from Epimedium koreanum Nakai

Two new flavonol glycosides, named icarisid B (1) and icarisid C (2), along with seven known flavonol glycosides were isolated from the bioassay-directed fractions of the aqueous extract of Epimedium koreanum Nakai. The structures of the two new compounds were established on the basis of chemical and spectroscopic methods (ESI-MS, 1D, and 2D NMR) as 5-hydroxyl-4'-methoxy-8-(-hydroxyl-,-dimethyl)-propyl-3-O--l-rhamnopyranosyl-flavonol-7-O--d-glucopyranoside (1) and 5-hydroxyl-4'-methoxy-8-(-methoxy-,-dimethyl)-propyl-3-O--d-glucopyranosyl(13)--l-rhamnopyranosyl-flavonol-7-O--d-glucopyranoside (2), respectively. All the nine compounds were tested for their effects on proliferation and alkaline phosphatase (ALP) activity using UMR106 cells. As a result, five compounds showed stimulating effects on both the proliferation and ALP activity, which suggested that they might be used as potential leading compounds to cure osteoporosis.