Asprenols A-H, phenolic constituents from the stems of Ilex asprella

Encouraged by the in vivo anti-inflammatory effect of aqueous extract of Ilex asprella stems, a further phytochemical investigation on I. asprella stems oriented by the in vitro NO production inhibition in RAW264.7 cells was conducted, which led to the isolation of eight new phenolic constituents, namely asprenols A-H (1-8), together with 12 known ones (9-20). The structures of the new compounds were established by extensive spectroscopic data analyses of HR-ESI-MS, IR, UV, and 1D and 2D NMR, and the absolute configurations were determined by comparison of experimental and calculated ECD analyses. All isolated were evaluated for the inhibition against NO production in RAW 264.7 cells, and several compounds showed moderate inhibitory effect.