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 guided 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 and the structure of 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. 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).