Diterpenoids and Their Glycosides from the Stems of with Beta-Cell Protective Activity.

Seven previously undescribed diterpenoids, tinocrisposides A-D (-) and borapetic acids A (), B (), and C (), together with 16 known compounds, were isolated from the stem of (Menispermaceae). The structures of the new isolates were elucidated by spectroscopic and chemical methods. The β-cell protective effect of the tested compounds was examined on insulin-secreting BRIN-BD11 cells under dexamethasone treatment. Diterpene glycosides , -, and presented a substantial protective effect on BRIN-BD11 cells treated with dexamethasone in a dose-dependent manner. Compounds and with two sugar moieties exhibited clear protective effects on β-cells.