Bioactive phenolic compounds from the leaves and twigs of Euonymus alatus

Euonymus alatus (Thunb.) Sieb. (Celastraceae) is commonly known as winged euonymus in Korea and has been widely used in traditional medicine to regulate blood circulation, relieve pain, eliminate stagnant blood and treat dysmenorrhea. In addition, this tree has been clinically used to treat type 2 diabetes for many years as a folk medicine in China. The young leaves of this tree are edible as kitchen herbs, and the cork cambium on the twigs has been traditionally used to treat cancer. Recent pharmacological studies revealed the potential of E. alatus as an antitumor agent using a variety of in vitro and in vivo models, which is also confirmed by our group. In our screening test, the MeOH extract from the leaves and twigs of E. alatus exhibited significant cytotoxicity using a SRB bioassay. The purification of the MeOH extract using repeated column chromatography furnished five new phenolic compounds (1–5), together with seven known ones (6–12). The structures of the new compounds were elucidated by analysis 1D and 2D NMR data. The absolute configurations of 1–5 were determined by a modified Mosher's method. We are studying the antitumor activity of isolates (1-12).