Sugar easters and xanthones from the roots of Polygala tenuifolia Willd. and their cytoprotective activity

Six new sugar esters (1-6), named tenuifolisides F-G (1-2) and tenuifolioses W-Z (3-6), together with 16 known compounds (7-22) were isolated from the roots of Polygala tenuifolia. The chemical structures of the new compounds were elucidated by 1D, 2D NMR and HRESIMS techniques together with chemical methods. All the compounds were evaluated for the cytoprotective activity against hydrogen peroxide (H₂O₂)-induced oxidative stress in human keratinocyte HaCaT cells. Compounds 4, 5, 13, 20 and 22 showed strong cytoprotective effect.