Diarylheptanoids and Flavonoids from Viscum Album Inhibit LPS-stimulated Production of Pro-inflammatory Cytokines in Bone Marrow-derived Dendritic Cells

Three new diarylheptanoids, (3S,5R)-3-hydroxy-5-methoxy-1,7-bis(4-hydroxyphenyl)-6E-heptene (1), (3S,5S)-3-hydroxy-5-methoxy-1,7-bis(4-hydroxyphenyl)-6E-heptene (2), and (3S)-3-hydroxy-1,7-bis(4-hydroxyphenyl)-6E-hepten-5-one (3), four new flavonoid glycosides, 3,7,3'-tri-O-methylquercetin-4'-O-β-d-apiofuranosyl-(1→2)-O-β-d-glucopyranoside (4), 7,3'-di-O-methylquercetin-4'-O-β-d-glucopyranosyl-3-O-[6‴-(3-hydroxy-3-methylglutaroyl)]-α-d-glucopyranoside (5), 7,3'-di-O-methylquercetin-4'-O-β-d-glucopyranosyl-3-O-[(6'''''→5'''')-O-1'''''-(sinap-4-yl)-β-d-glucopyranosyl-6‴-(3-hydroxy-3-methylglutaroyl)]-α-d-glucopyranoside (6), and (2S)-5-hydroxy-7,3'-dimethoxyflavanone-4'-O-β-d-apiofuranosyl-(1→5)-O-β-d-apiofuranosyl-(1→2)-O-β-d-glucopyranoside (9), and 17 known compounds were isolated from the leaves and twigs of Viscum album. Compounds 1, 4, and 19 significantly inhibited LPS-stimulated production of TNF-α, IL-6, and IL-12p40 with IC50 values ranging from 0.09 ± 0.01 to 8.96 ± 0.45 μM. (+)-Medioresinol (13) showed inhibitory effects on LPS-stimulated production of IL-12p40 with an IC50 value of 2.00 ± 0.15 μM.