Flavonoid glycosides from seeds of Hippophae rhamnoides subsp. Sinensis with α-glucosidase inhibition activity

Hippophae rhamnoides subsp. Sinensis is a famous traditional medicinal plant in Tibet and Mongolia of China. Three novel flavonoid glycosides and ten known analogues were obtained from the seeds of H. rhamnoides . The structures of new compounds were elucidated by spectroscopics, chemical methods as well as literature data. In vitro assay, compounds 5–9 , kaempferol and 70% ethanolic elution fraction showed prominent α -glucosidase inhibitory activities with IC 50 values ranging from 8.30 to 112.11 μM, better than that of the positive control, acarbose , whose IC 50 value was 1727.07 μM.