Anti-inflammatory Endiandric Acid Analogues from the Roots of Beilschmiedia tsangii

Bioassay-guided fractionation of roots of Beilschmiedia tsangii led to the isolation of six new endiandric acid analogues: tsangibeilin A (1), tsangibeilin B (2), endiandramide A (3), endiandric acid K (4), endiandric acid L (5), and endiandramide B (6). Also isolated were two new lignans, beilschminol A (7) and tsangin C (8), and six known compounds. The structures of 18 were determined by spectroscopic techniques. Compounds 3 and 6 exhibited potent iNOS inhibitory activity, with IC50 values of 9.59 and 16.40 μM, respectively.