Bioactive Glycosides from the Twigs of Litsea cubeba

The air-dried twigs of Litsea cubeba, a traditional Chinese medicinal tree, afforded 10 new aromatic glycosides (1-10) and 26 known analogues. Their structures were assigned by extensive 1D and 2D NMR experiments, and the absolute configurations were resolved by chemical methods, electronic circular dichroism, specific rotation, and X-ray crystallographic analysis. Compound 4 is the first example of a naturally occurring homoneolignan glucoside. Compounds 4, 6-8, and the known neolignan glucosides (11, 12, and 14) at respective 10 mu M concentrations were found to reduce acetaminophen-induced HepG2 cell injury with 30.5-46.0% inhibitions. Furthermore, compounds 12 and 15 demonstrated moderate inhibitory activities against HDACl, with IC50 values of 3.6 and 4.6 mu M, respectively.