All experiments were performed with 70% ethanol extract, ethyl acetate fraction and aglycone fraction of the G. affine extract. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity (FSC50) of ethyl acetate fraction (6.15 μg/mL) of the G. affine was higher than that of (+)-α-tocopherol (8.89 μg/mL), which is known as a reference control. Reactive oxygen species (ROS) scavenging activities (OSC50) of the 70% ethanol extract (1.60 μg/mL), ethyl acetate fraction (0.075 μg/mL) and aglycone fraction (2.28 μg/mL) of extract of G. affine on ROS generated in Fe 3+ -EDTA/H2O2 system using the luminol-dependent chemiluminescence assay were much higher than that of L-ascorbic acid (6.88 μg/mL). The cellular protective effects of 70% ethanol extract (τ50 = 52.0 min) and aglycone fraction of the extract (τ50 = 60.6 min) on the 1 O2-induced cellular damage of human erythrocytes were exhibited the higher protective effect than (+)-α-tocopherol (τ50 = 38.0 min), known as a lipophilic antioxidant. TLC and HPLC were used to analyse active components in the aglycone fraction of the extract. Results showed that luteolin 1) † 주 저자

In this study, three dicaffeoylquinic acids (DCQAs) isolated from Gnaphalium affine D. DON. extracts were structurally identified and evaluated for their antioxidant activities, cellular protective effects, and tyrosinase inhibitory activities. The ethyl acetate fraction of G. affine was chromatographed, which yielded 3 DCQA derivatives of 1-3 : 3,5-dicaffoylquinic acid (3,5-DCQA, 1), 4,5-dicaffeoylquinic acid (4,5-DCQA, 2), 1,5-dicaffoylquinic acid (1,5-DCQA, 3). The structure of each compounds was determined using 1 H NMR and MS analyses. Compounds of 1-3 showed strong free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activities (FSC50 = 3.70, 5.80, and 5.50 µM, respectively) compared to those of a commonly used lipophilic antioxidant, (+)-α-tocopherol (21.90 µM). Cellular protective effects of 1-3 compounds on the 1 O2 sensitized photohemolysis of human erythrocytes were similar to (+)-α-tocopherol. 1-3 compounds also exhibited higher tyrosinase inhibitory effects (IC50 = 0.15, 0.16, and 0.13 mM) compared to arbutin (0.33 mM), known as a skin-whitening agent. These results indicate that three DCQA derivatives may be applied as an antioxidant and a skin whitening agent in food or cosmetic industries.