Three new flavonoid glycosides from the herbaceous stems of Ephedra intermedia

Phytochemical investigation of the n-butanol extracts of the herbaceous stems of Epheda intermedia led to the isolation of eight flavonoids that included three new flavonoid glycosides (1-3) and five previously reported analogues (4-8). Their structures have been identified on the basis of various spectral data. Besides, all the flavonoids were tested in vitro for their ability to inhibit α-glucosidase under the positive control of acarbose, and the results indicated that none of them exhibited significant inhibitory effect on α-glucosidase at 100 μM.