Phenolics level, total flavonoid content, and antioxidant were determined from the methanol extracts of the eight medicinal plants using roots. Total phenolics were found as the highest levels in the methanol extracts of Arctium lappa, and followed by Youngia sonchifolia and Cirsium japonicum. Total amount of the each phenol compounds were detected in C. japonicum extracts (319.2 mg kg-1) as the greatest component, and followed by A. lappa (96.3 mg kg-1) and Y. sonchifolia (22.9 mg kg-1). Total flavonoid content showed the highest amount in methanol extracts from A. lappa (68.1 mg 100 g-1) and followed by Y. sonchifolia (11.2 mg 100 g-1) Lycoris radiate extracts (87.2%) had the highest nitrite scavenging activity and followed by A. lappa (81.5%) and Y. sonchifolia (77.5%). Methanol extracts of A. lappa at 25 mg 100 g-1 exhibited the highest DPPH radical scavenging activity by 90.8%, even though less activity than synthetic antioxidants Vitamin C or butylated hydroxytoluene (BHT). Level of polyphenols was highly correlated with anti oxidative activity (r2 = 0.85). The results suggest that several medicinal plants selected had the potent biological activities, and that their activities were differential depending on plant species.

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.

A series of aqueous or methanol extracts from four different Korean salad plants were assayed to determine their allelopathy and antioxidant activity. The extracts applied on filter paper in a Petri-dish bioassay significantly inhibited root growth of against alfalfa (Medicago sativa) seedlings. Leaf extracts from 40 g dry tissue L-1 of Aster yomena was most phytotoxic to alfalfa root growth, and followed by that of Cirsium japonicum, Taraxacum officinale, and Ixeris dentate. Methanol extracts of plants dose-dependently increased DPPH free radical scavenging activity in vitro. Antioxidant activity of methanol extracts from the same plant species was investigated, and the result showed high DPPH free radical scavenging activity in Cirsium japonicum, Aster yomena, and Ixeris dentate, however, in Taraxacum officinale was least activity. By means of HPLC analysis, chlorogenic acid, p-coumaric acid, and total phenolics with 7.68, 17.47 and 18.64 mg, 100g-1, respectively, showed the highest amounts in methanol extracts from Cirsium japonicum leaves. These results suggest that Compositae salad plants contain water-soluble substances with allelopathic potential as well as antioxidant activity.