Evaluation of novel antioxidant triterpenoid saponins from the halophyte Salicornia herbacea

As a part of an ongoing search for novel antioxidants from the salt marsh plants, bioactivity-isolation and structure determination of constituents from Salicornia herbacea were performed. One new triterpenoid saponin ( 4 ), along with three known saponins ( 1 – 3 ), has been isolated from n -BuOH fraction of S. herbacea . On the basis of the spectroscopic methods, the structure of the new saponin 4 was elucidated as 3β-hydroxy-23-oxo-30-noroleana-12, 20(29)-diene-28-oic acid 3- O -β- d -glucuronopyranosyl-28- O -β- d -glucopyranoside. Scavenging effects of saponins 1 - 4 were examined on 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical and peroxynitrite. Particularly, saponin 3 exerted significant antioxidant activity on both authentic peroxynitrite and peroxynitrite generated from morpholinosydnonimine (SIN-1).