Studies On Chemical Constituents Of Euonymus Glabra Roxb. As Potential Dopa Decarboxylase Inhibitors

Euonymus glabra Roxb., belonged to Euonymus genus, Celastraceae family, is mainly distributed in Xishuangbanna in Yunnan province at the elevation of900-1800meters. And it was recorded in list of plants in Xishuangbanna that the twigs and leaves of this species are poisonous. So far, no phytochemical or biological research has been reported about this species.Previous investigations showed that plants from genus Euonymus exhibited high diversity of both secondary metabolites and biological activities. For further seeking bioactive natural products from this genus, phytochemical investigations of E. glabr were carried out.EtOH extract of stems and twigs of E. glabra were isolated and purified using chromatographic methods (column chromatography of silica gel, MCI gel, Sephadex LH-20and preparative HPLC) to yield35compounds. Their structures were elucidated by spectroscopic methods (ESI-MS,1H NMR,13C NMR, DEPT and2D NMR, etc.). Among the35compounds, two were new phenylpropanes, eight were new dimer phenylpropanes and three were new flavanes. And fifteen compounds were isolated from genus Euonymus for the first time, and all compounds were isolated from this plant for the first time.Isolated phenylpropanes and dimer phenylpropanes were evaluated for inhibitory activity against dopa decarboxylase using DDC assay. EG-10and EG-11exhibited moderate activity with IC50values of20μM and12μM. Structure-activity relationship (SAR) research indicated that dimer phenylpropanes possessed stronger inhibitory effect than phenylpropanes and dimer phenylpropanes with three carbonyl groups showed stronger activity than dimer phenylpropanes with two carbonyl groups.