Two new quinones and six additional metabolites with potential anti-inflammatory activities from the roots of Juglans mandshurica

Abstract

Two new quinones, 4-(5-hydroxy-1,4-dioxo-1,4-dihydronaphtha-len-3-ylamino)-butyric acid methyl ester (compound 1) and 1,3-dimethoxycarbonyl-8-hydroxy-9,10-anthraquinone (2), and six known compounds (3–8) were isolated from the roots of Juglans mandshurica Maxim., a member of the Juglandaceae family. The chemical structures of the compounds were elucidated by nuclear magnetic resonance spectroscopy and compared with data from the literature. The isolated compounds were evaluated for their ability to inhibit the production of nitric oxide, tumour necrosis factor-α, and interleukin-6 by the mouse macrophage RAW 264.7 cell line after lipopolysaccharide stimulation in vitro. We found that compounds 1–4 exhibited potent anti-inflammatory effects, as indicated by suppression of lipopolysaccharide-stimulated nitric oxide and cytokine production with 50% inhibitory concentrations between 20.09 μM and 27.63 μM. These results identify two novel quinones from J. mandshurica with potential utility as anti-inflammatory compounds.