Three new triterpenoid saponins from Aralia echinocaulis

To study the active ingredients in the root bark of Aralia echinocaulis. Three triterpenoid saponins were separated from the 70% ethanol extracts and purified by column chromatography and their structures were determined by spectroscopic analysis. Compound 1 and 3 were evaluated for antioxidant activity by the in vitro DPPH free radical scavenging ability and the protective effect of OH− induced DNA oxidative damage. Compound 1 was a new type of triterpenoid saponin, named as echinocaulisaglycone 3-O-β-D-glucopyranoside (echinocaulisaponin A), and it had good antioxidant activity. Compound 2 was similar to compound 1, named as 1-hydroxyl-echinocaulisaglycone 3-O-β-D-glucopyranoside (echinocaulisaponin B). Compound 3 was also a new type of triterpenoid saponin, named as echinocaulisaglycone II 3-O-α-L-arabinopyranosyl-(1″→4′)-β-D-glucopyranosiduronic acid (echinocaulisaponin C), and its antioxidant activity was weaker than compound 1. In this study, three new compounds were discovered and two of them were carried out in vitro anti-oxidation studies, laying the foundation for further research on the treatment of related diseases (cardiovascular disease, arthritis, age-related macular degeneration, etc.) through anti-oxidation or quenching free radical function.