Simultaneous quantification and peroxynitrite-scavenging activities of flavonoids in Polygonum aviculare L. herb.

The plant Polygonum aviculare L. (Polygonaceae) is an annual herbaceous plant which is known to be beneficial for treating gastroduodenal ulcer, hypertension, diarrhea, hemorrhage, and hemorrhoids. Ten phenolic compounds, including nine flavonoids (myricetin, quercetin, kaempferol, myricitrin, desmanthin-1, isoquercitrin, quercitrin, avicularin, juglanin), and gallic acid were used for simultaneous HPLC quantification and peroxynitrite-scavenging assay. Simultaneous quantification of these substances were performed on five extracts (EtOH-, MeOH-, 70% MeOH-, 30% MeOH-, and H2O extracts) as well as on the three fractions (Et2O-, EtOAc-, and BuOH fractions), under the condition of a Capcell Pak C18 column (5μm, 250mm×4.6mm i.d.) and a gradient elution of 0.05% trifluoroacetic acid (TFA) and MeOHCH3CN (60:40). Of the three fractions, the EtOAc fraction displayed the highest content of flavonoids (sum, 208.9mg/g) with the strongest peroxynitrite-scavenging activity (IC50, 2.68μg/mL). The activities of the eight compounds (myricitrin, isoquercitrin, avicularin, quercitrin, myricetin, desmanthin-1, quercetin, and kaempferol) were comparable to that of the positive control (l-penicillamine; IC50: 1.03μg/mL). These results suggest that folkloric medicinal uses of P. aviculare are mainly attributed to flavonoids, such as particularly highly contained myricetin, myricitrin, and desmanthin-1.