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 values ranging from 8.30 to 112.11 μM, better than that of the positive control, acarbose, whose IC value was 1727.07 μM.