Amenyunnaosides A–C, Three New Neolignans Isolated from Amentotaxus yunnanensis and Their Anti‐inflammatory Activities

Abstract

Phytochemical study on the leaves of Amentotaxus yunnanensis led to the isolation of seventeen phenolic compounds including sixteen neolignans and lignans, and one flavone glycoside. Three among the isolates were previously unreported neolignans and named as amenyunnaosides A–C, respectively. Their structures were elucidated by extensive analyses of HR‐ESI‐MS, 1D and 2D NMR, and ECD spectra. The isolated neolignans potentially inhibited NO production in LPS‐activated RAW264.7 cells with their IC50 values ranging from 11.05 to 44.07 μM, compared to that of the positive control compound, dexamethasone, IC50 value of 16.93 μM. Additionally, amenyunnaoside A dose‐dependently reduced production of IL‐6 and COX‐2 but did not effect to that of TNF‐α at concentrations of 0.8, 4, and 20 μM.