A Rare Secoiridoid Dimer Derivative from Ligustri lucidi fructus

A secoiridoid glucoside dimer derivative, named as 4', 5'-(2'-hydroxy ligustrosidic acid) dimer (1), together with two known secoiridoids were isolated from the aqueous extract of Ligustri lucidi fructus. Structures of these compounds were elucidated by analysis of spectroscopic data including 1D-, 2D-NMR and HR-ESI-MS, and the reported literature data comparison. This is the first report on iridoid dimer derivative isolation from the genus Ligustrum. Their antioxidant activities were evaluated by using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Compound 1 exhibited moderate antioxidant activity.