This study attempted to investigate the antioxidant properties of four different species of sand dune plants (Calystegia soldanella, Messerschmidia sibirica, Vitex rotundifolia and Rosa rugosa). In order to validate the antioxidant activity of these plants, we first determined the total amount of flavonoid versus phenolic contents (TFC/TPC) and extracted crude flavonoids for measuring antioxidant activities that were determined by DPPH, ABTS and FRAP assays with radical scavenging effects. We found that highest amounts of TPC were detected in R. rugose with values of 110.20 ㎎/g (leaves) and 65.71 ㎎/g (stems), while the highest amounts of TFC in V. rotundifolia with values of 38.07 ㎎/g (leaves) and 6.55 ㎎/g (stems). We further examined how closely related the amounts of TFC/TPC in antioxidant activities and found that R. rugose has the highest activities of radical scavenging with values of 63.4 ㎍/㎖ and 51.2 ㎍/㎖ determined by DPPH and ABTS assays compared with the value of 21.2 ㎍/㎖ by FRAP assay. It is of note that there is a statistically significant correlation between the resulting antioxidant activities and the total ratio of TFC and TPC, suggesting that the different amounts of TFC/TPC may directly contribute to the various antioxidant activities.

Antioxidant activity, total phenolics level and cytotoxicity of the methanol extracts from the young sprouts of 5 Korean woody salad plants were determined. Methanol extracts of Kalopanax pictus had the highest DPPH radical scavenging activity, with an IC50 value of 23.5mg 100g-1, and followed by Valeriana fauriei(43.1mg 100g-1), and Morus alba(〉100mg 100g-1). Total phenolic content showed the highest amount in methanol extracts from Kalopanax pictus(23.7mg 100g-1), and followed by Valeriana fauriei(22.7mg 100g-1), Aralia elata(16.8mg 100g-1) and Morus alba(14.2mg 100g-1). In a MTT assay, methanol extracts of Aralia elata with IC50 values of 151.0 and 140.7μg mL-1 showed the most potent cytotoxicity on Calu-6 and MCF-7, respectively. On the other hand, methanol extracts of Kalopanax pictus(IC50=96.5μg mL-1) showed the highest activity against HCT-116, and followed by those of Aralia elata(123.3μg mL-1), and Actinidia arguta(162.0μg mL-1). Total phenolic content of the tested plant extracts was correlated with the DPPH radical scavenging activity, suggesting the phenolic compounds may contribute to the antioxidant properties of Korean salad plants.