Comprehensive determination of nine polyphenols in Polygoni Avicularis Herba with a new HPLC–DAD method and their correlation with the antioxidant activities

Abstract

A simple high performance liquid chromatography (HPLC) method was established for identification and quantification of nine polyphenols (gallic acid, chlorogenic acid, caffeic acid, myricetrin, hyperoside, luteoloside, quercitrin-3-rhamnoside, quercetin and kaempferol) in Polygoni Avicularis Herba. The analysis was performed on a Pinnacle II C18 column (250 × 4.6 mm, 5.0 µm) with a gradient elution of an aqueous mobile phase (containing 0.3% acetic acid) modified by acetonitrile. Diode-array detector (DAD) was used to detect the analytes at four wavelengths (270, 326, 355, and 370 nm). The established method was validated with good linearity, precision, accuracy and reproducibility to determine the polyphenols in Polygoni Avicularis Herba. The applicability of this analytical method was confirmed by successful analysis of the herb samples. The results indicated that the contents of these polyphenols varied with different locations of the samples. The anti-oxidation activities of Polygoni Avicularis Herba were further evaluated based on DPPH, ABTS and superoxide anion free radical scavenging assay. The herb exhibited obvious radical scavenging capacity, and gallic acid, chlorogenic acid, myricetrin and hyperoside played important roles in this activity.