Neoveratrol A-D: Four new arylbenzofurans from Veratrum nigrum

Four new arylbenzofurans, 2-(3′,5′-dimethoxy) phenyl-6-hydroxy-7-methoxy benzofuran (1, Neoveratrol A), 2-(3′-O-β-D-glucosyl-5′-hydroxy) phenyl-4,6-dimethoxy benzofuran (2, Neoveratrol B), 2-(3′,5′-dimethoxy) phenyl-4-O-β-D-glucosyl-6-hyroxy benzofuran (3, Neoveratrol C), 2-(3′,5′-dimethoxy) phenyl-6-hydroxy-7-O-β-D-glucosyl benzofuran (4, Neoveratrol D), together with nine known ones (5-13) were isolated from the dried root and rhizome of a Traditional Mongolian medicinal herb Veratrum nigrum. The structures were elucidated by various spectroscopic methods including UV, IR, NMR and HR-MS. Among these compounds, 1-3, 5, 7-9 and 11-13 showed significant inhibitory effects on lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW264.7 cells at the concentration ranging from 50.0–200.0 μM. Compound 1 exhibited moderate activity against HepG2 and HCT-15. In addition, compound 5 and 6 showed inhibitory activities against human tumor cell lines HepG2, HCT-15, A549, MDA-MB-231 and SH-SY5Y with IC50 range of 40–100 μM.