Sulfur-containing amides from Entada phaseoloides

To study the chemical constituents of the Entada phaseoloides (L.) Merr., seeds of Entada  phaseoloides were extracted with 70% ethanol at room temperature.  Isolation and purification were performed by silica gel, reversed-phase silica gel column chromatography and semi-preparative HPLC.  Structures of the pure compounds were established on the basis of spectral analysis.  Four sulfur-containing amide compounds were isolated from the n-BuOH-soluble fraction and identified as entadamide A-β-D-glucopyranosyl-(1→3)-β-D-  glucopyranoside (1), entadamide A (2), entadamide A-β-D-glucopyranoside (3) and clinacoside C (4).  Compound 1 is a new compound.  Compound 4 is isolated from the genus Entada for the first time.