Simultaneous analysis and peroxynitrite-scavenging activity of galloylated flavonoid glycosides and ellagic acid in Euphorbia supina

The herbs of Euphorbia supina (Euphorbiaceae) have been used to treat hemorrhage, chronic bronchitis, hepatitis, jaundice, diarrhea, gastritis, and hemorrhoids as a medicinal herb. This work is aimed to qualitatively and quantitatively analyze the polyphenols with peroxynitrite-scavenging activities. The eight compounds: gallic acid, methyl gallate, avicularin, astragalin, juglanin, isoquercitrin 6aEuro(3)-gallate, astragalin 6aEuro(3)-gallate, and ellagic acid, were isolated from E. supina and used for HPLC analysis and peroxynitrite (ONOO-)-scavenging assay. Simultaneous analysis of the eight compounds was performed on MeOH extract and its fractions. The contents in MeOH extract and peroxynitrite-scavenging activities of the dimer of gallic acid, ellagic acid (15.64 mg/g; IC50 0.89 mu M), and two galloylated flavonoid glycosides, astragalin 6aEuro(3)-gallate (13.72 mg/g; IC50 1.43 mu M) and isoquercitrin 6aEuro(3)-gallate (16.99 mg/g; IC50 1.75 mu M), were high, compared to other compounds. The legendary uses of E. supina could be attributed to the high content of polyphenols, particularly ellagic acid, isoquercitrin 6aEuro(3)-gallate, and astragalin 6aEuro(3)-gallate as active principles.