New coumarins from a hot water extract of Daphne mezereum bark

This study aimed to investigate the low-molecular weight compounds in a hot water extract of the bark of Daphne mezereum L. (Thymelaceae), a medicinal plant with a longstanding medicinal use in Scandinavia. Among the fourteen isolated compounds, two coumarin glycosides are reported for the first time, and four known compounds were reported in D. mezereum for the first time. Their structures were elucidated by NMR, HRESIMS and methanolysis. The new compounds were identified as 3-(2-(β-d-glucopyranosyloxy)-4-[(7-hydroxy-6-methoxy-2-oxo-2H-chromen-3-yl)oxy]phenyl)propanoic acid (9), and 7-hydroxycoumarin-5,8-di-β-d-glucopyranoside (11). Cytotoxic effects were assessed by the MTT assay, while the anti-inflammatory effects were assessed by measuring the inhibition of NO-release by dendritic cells. The results revealed negligible cytotoxic effect and NO-inhibitory activity of compounds 9 and 11.