Americanin, a bioactive dibenzylbutyrolactone lignan, from the seeds of Centaurea americana

The reversed-phase preparative HPLC analysis of the methanol (MeOH) extract of the seeds of Centaurea americana afforded a dibenzylbutyrolactone lignan, 3″-O-caffeoyl arctiin (named americanin), together with five known lignans, arctiin, arctigenin, matairesinol, matairesinoside and lappaol A, and two known phytoecdysteroids, 20-hydroxyecdysone and makisterone A. The antioxidant properties and toxicity of the extracts and the isolated compounds were determined by the DPPH and the brine shrimp lethality assays, respectively.