A new cis-p-coumaroyl flavonol glycoside from the inner barks of Sophora japonica L.

Tree barks could be a rich source of novel bioactive compounds, which are not well explored. In this work, the chemical constituent investigation of extractives from the inner barks of Sophora japonica L. (Leguminosae) led to the isolation of a new cis-p-coumaroyl flavonol glycoside, which was elucidated as kaempferol 3-O-(4"-cis-p-coumaroyl)-alpha-rhamnopyranoside (IV). The structure of the new compound was established mainly based on extensive spectroscopic techniques. In addition, among the four known phenolics purified in this study, including three flavonol glycosides [rutin (I), kaempferol-3-O-(6"-galloyl)-beta-glucopyranoside (II), and quercitrin (V)], as well as a phenolic acid [trans-ferulic acid (III)], compounds II and III have never been reported in S. japonica previously.