Bioactive Compounds from the Stems of Clausena lansium.

In view of the significant neuroprotective effect of Clausena lansium , we continued to separate the n -butanol and the water extracts from the stems of C. lansium in order to find the leading compounds with significant activity. Two new phenolic glycosides, Clausenolside A-B ( 1 - 2 ), one new pair of phenolic enantiomers ( 3a , 3b ), and two new monoterpenoids, clausenapene A-B ( 4 - 5 ), together with twelve known analogues ( 6 - 17 ) were isolated from the stems of C. lansium . Compounds 1 - 17 were obtained from C. lansium for the first time. Compounds 3a , 3b , 4 , 16 , and 17 showed strong or moderate potential neuroprotective effects on inhibited PC12 cell injury induced by okadaic acid, and compound 9 exhibited strong potential hepatoprotective activities. Their structures were elucidated on the basis of spectroscopic analyses, including UV, IR, NMR experiments, and electronic circular dichroism (ECD) spectra.