Three new triterpenoids from Mallotus macrostachyus

Three new triterpenoids, mallomacrostins A-C (1-3), and 11 known ones (4-14) were obtained from the twigs and leaves of Mallotus macrostachyus. Mallomacrostin A possessed a new trinor-D:B-friedobaccharane skeleton. The structures of the new compounds were elucidated on the basis of extensive spectroscopic techniques including HR-ESIMS and NMR and the structure of 1 was confirmed by single crystal X-ray diffraction analysis. Spectroscopic data of the known compound 4 were provided for the first time. Compounds 2 and 10 exhibited significant anti-inflammatory activity by inhibiting LPS-induced release of nitric oxide with IC50 of 70.0 mu M and 14.0 mu M, respectively.