Anti-inflammatory flavonoids from root bark of Broussonetia papyrifera in LPS-stimulated RAW264.7 cells

Abstract

Broussonetia papyrifera has been used as a diuretic, tonic and suppressor of edema. Bioactivity-guided fractionation and metabolite investigation of root bark extracts of this plant resulted in the isolation and identification of six 1,3-diphenylpropanes (1, 2, 8, 10, 17, 20), flavanone (3), two chalcones (4, 5), five flavans (6, 11, 14–16), dihydroflavonol (7) and five flavonols (9, 12, 13, 18, 19), including five new compounds (5, 7, 8, 19, 20) that inhibit NO production in LPS-induced RAW264.7 cells. The structures of compounds 1–20 were elucidated on the basis of spectroscopic data (1D and 2D NMR, MS, MS/MS, and HRMS). In particular, compounds 3, 5, 7, 12, and 20 exhibited significant inhibitory effects on the NO, iNOS, and pro-inflammatory cytokine (TNF-α and IL-6) production. Therefore, this study suggests that the flavonoid-rich products of B. papyrifera, including the new compounds, could be valuable candidates for the development of pharmaceuticals or functional foods in the prevention and treatment of anti-inflammatory disease.