Potential antioxidant components and characteristics of fresh Polygonum multiflorum

The leaf, stem and root of fresh Polygonum multiflorum plant were investigated. The contents of bioactive compounds and their antioxidant potential were studied by several radicals scavenging assay, and the antioxidative substances measured. The total phenolic contents were 179.0, 70.3 and 118.0 mg/g, whereas flavonoids contents were 7.3, 8.0 and 37.5 mg/g for water extracts from root (R), stem (S) and leaf (L), respectively. Further HPLC analysis revealed that the leaf and stem of this functional plant contained quercetin at 13,469 and 1,095 mg/kg, respectively. Furthermore, the root and stem contained rich emodin-related compounds that were 6,620 and 1,245 mg/kg, respectively. And different concentrations of emodin-related compounds and quercetin in root, stem and leaf showed different antioxidative ability. We observed that the DPPH scavenging activity, total antioxidant activity (TEAC), reducing power and NO scavenging ability of the three parts of the plant samples and found that the activities were R > L > S except that was S > L > R on superoxide anion scavenging effect. Our results indicated that the radical scavenging abilities of the three sample parts were more potent than that of emodin and quercetin. P. multiflorum contains rich emodin-related compounds and quercetin, indicating that these compounds played important roles in antioxidative effect. We suggested that the antioxidative effect of the fresh P. multiflorum plant correlate-well with emodin-related compounds and quercetin.