New Triterpenoid Saponins from the Herb Hylomecon japonica.

: , a plant of the family which is well-known for the alkaloids they produce, is a perennial plant widely distributed in the northeast, central and east regions of China. Although a variety of chemical constituents, including alkaloids, flavonoids, and megastigmoids, have been isolated from , the investigation of saponins in has not been reported until now. : Various separation techniques, including polyporous resin column chromatography, silica gel column chromatography and hemi-preparative HPLC were applied to the isolation of triterpenoid saponins, and chemical methods such as acid hydrolysis and spectroscopic methods including HRESIMS and NMR were applied to their structure elucidation, and the XTT reduction method was used to assay cytotoxicity. : Two new triterpenoid saponins, named hylomeconoside A () and B () which were identified as 3--β-d-galactopyranosyl-(1→2)-β-d-glucuronopyranosyl-gypsogenin-28--β-d-xylopyranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→2)-β-d-quinovopyranoside () and 3--β-d-galactopyranosyl-(1→2)-β-d-glucuronopyranosyl-gypsogenin-28--β-d-xylopyranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside (), and two known triterpenoid saponins identified as dubioside C () and lucyoside P () on the basis of spectroscopic and chemical evidence, were isolated from Compound exhibited moderate cytotoxicity on MGC-803 and HL-60 cells, with IC values of 43.8 and 32.4 μg·mL, respectively. Compounds and are new saponins, and is considered to be one of the antitumor principles in this plant. This is the first time that triterpenoid saponins have been isolated from plants of the family.