• Journal of the East Asian Society of Dietary Life
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• v.12 no.1
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• pp.23-31
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• 2002

The antioxidative activity was measured on the substances of water and ethanol soluble extract from Astragalus membranaceus Bunge, Chrysanthemum morifolium Ramat, Lycium chinensis Miller, Glycyrrhiza uralensis Fischer, Angelica gigas Nakai, Zizyphus jojoba Miller, Paeonia lactiflora Pallas, Cnidium officinale Makino by four different in vitro experimental models of DPPH (a,a'-diphenyl-$\beta$-picrylhydrazyl) method, superoxide dismutase like activity, thiocyanate method, and TBARS (thiobarbituric acid reactive substances) method. The Lycium chinensis Miller contained the highest amount of polyphenolic compounds. The electron donating ability of water extract from Glycyrrhiza uralensis Fischer and ethanol extract from Chrysanthemum were higher than those of the others. The superoxide dismutase-like activity of water extract from Astragalus membranaceus Bunge was the highest among those of all the others. The water extract from Zizyphus jujuba Miller showed the highest antioxidative activity determined by TBARS method. Compared to the control, the inducing period associated with the oxidation degree was delayed up to 8 days in both the water extract from Chrysanthemum, Lycium chinensis Miller, Glycyrrhiza uralensis Fischer, and Paeonia lactiflora Pallas and the in ethanol extract from Chrysanthemum and Glycyrrhiz uralensis Fischer. These results support that water and ethanol extracts from 8 kinds of medicinal herbs contain antioxidative compounds.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.261-266
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• 2015

To quantitatively evaluate the total phenolics, total flavonoids, and antioxidant capacity in the leaves, bulbs, and roots of fresh Allium hookeri, they were extracted using various solvents including water, aqueous methanol (20, 40, 60, and 80%; v/v), and absolute methanol. The leaves had the highest levels of total phenolics (240.4-276.6 mg gallic acid equivalents/100 g) and total flavonoids (9.7-34.1 mg catechin equivalents/100 g). The highest antioxidant capacities of 78.7- 103.4 mg vitamin C equivalents (VCE)/100 g, 24.4-59.0 mg VCE/100 g, and 1,798.8-2,169.7 mg VCE/100 g in the leaves were also observed using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and oxygen radical absorbance capacity (ORAC) assays, respectively. The total phenolics had a higher linear correlation with antioxidant capacity than the total flavonoids. In general, 60% (v/v) aqueous methanol extract had higher levels of total phenolics and flavonoids, and higher antioxidant capacity than any other solvents used. This study suggested that A. hookeri might be a good source of phenolics and antioxidants.

• Journal of Life Science
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• v.13 no.2
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• pp.168-174
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• 2003

The chemical compositions and antioxidant activity of green tea extracts in medilite-extraction water were compared to that of distilled water(DW). Antioxidant activity was fetermined by the formation of thiobarbituric acid reactive substances (TBARS) in rat liver homogenates and microsomes and the scavenging activity of free radicals by DPPH ($\alpha$, $\alpha$'-diphenyl-$\beta$-picrylhydrazyl). The order of total polyphenolic compounds and extracted yield by extracts was medilite 325 mesh-extraction water, medilite 600 mesh-extraction water and distilled water(DW). The ranges of scavenging activity of green tea extracts in DPPH method were 60.95% - 64.51%. The inhibition ratios of TBARS formation in the rat liver homogenates and microsomal fractions were significantly lower with green tea extracts by DW-extraction than with both medilite 325 mesh and 600 mesh-extraction water. The concentration of iron ion of water containing medilite 325 mesh and green tea extracts and of water containing medilite 600 mesh and green tea extracts were significantly higher compared to DW. Therefore, this result suggested that enhanced concentration of iron ion in green tea extracts by medilite-extraction water containing high iron ion content was associated with enhanced peroxidation of the rat liver microsomal fractions. These results showed that total polyphenolic compounds, the % of yield and mineral compounds of green tea extracts were increased using medilite 325 mesh and 600 mesh-extraction water.

• Korean Journal of Food Science and Technology
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• v.23 no.3
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• pp.256-261
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• 1991

To isolate new antioxidants from twelve edible seaweeds, mixed methanol and chloroform extract of marine algae was fractionated into several subfractions and their antioxidant activities were measured by using AOM and 1, 1-diphenyl-2-picrylhydrazyl (DPPH). Especially the aqueous-methanol soluble fractions of brown and red algae showed a considerable antioxidant effect. Their antioxidant activities were stronger than synthetic antioxidants such as BHA, BHT, under the same concentration. Further fractionation of the aqueous-methanol soluble fractions using silica gel column chromatography yielded five subfractions. Among them methanol fraction exhibited high DPPH quenching activities. Also, it was confirmed to be benzene-derivative substances of two compounds by UV, HPLC, GC/MS analysis. Its each molecular weight was about 181, 238. These results suggested the existence of two effective natural antioxidant compounds in three edible marine algae.

• Korean Journal of Food Science and Technology
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• v.54 no.3
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• pp.280-287
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• 2022

The loquat (Eriobotrya japonica) is a fruit tree belonging to the Rosaceae family. Loquat fruit extracts from three cultivars (Tanaka, Mogi, and Jinwang) were prepared using absolute methanol and homogenization and ultrasound sonication procedures. We measured the total phenolic and flavonoid content of the fruit extracts and their antioxidant capacities. In addition, we evaluated tyrosinase activity and anti-melanogenic effects in B16F1 melanoma cells. The fruit extract from cv. Tanaka had the highest total phenolic content and showed the highest antioxidant capacity in the ABTS assay. The loquat fruit extract from cv. Jinwang had the highest total flavonoid content and showed the highest antioxidant capacity in the DPPH assay. Loquat fruit extracts from the Tanaka and Jinwang cultivars effectively inhibited mushroom tyrosinase activity. The loquat fruit extracts reduced intracellular oxidative stress in B16F1 melanoma cells. Treating B16F1 melanoma cells with loquat fruit extract from cv. Tanaka at a concentration of 125 ㎍/mL effectively inhibited melanin synthesis. However, treating the B16F1 melanoma cells with loquat fruit extracts from the Jinwang and Mogi cultivars did not. These results suggest that loquat fruit extracts from the Tanaka cultivar may serve as potential sources of antioxidants and act as a skin-whitening agent.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.29-34
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• 2015

N,N'-Diferuloyl-putrescine (DFP) present in plants such as Sophora japonica has been reported to have skin depigmentative and antioxidative activities. In this study, DFP, usually presents in nature a very little amount and its derivative (DFP-D) were synthesized in a large quantity for the use as functional cosmetical materials. The antioxidative activities of synthesized DFP and DFP-D were evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, chemiluminescence assay, and cell protective effect induced by $^1O_2$, stress. DFP and DFP-D showed DPPH radical scavenging activities ($FSC_{50}$) at $61.25{\pm}2.25{\mu}M$ and $12.92{\pm}0.72{\mu}M$, respectively. ROS (reactive oxygen species) scavenging activities ($OSC_{50}$) in the $Fe^{3+}-EDTA/H_2O_2$ system of DFP and DFP-D were 2 times ($1.84{\pm}0.12{\mu}M$) and 13 times ($0.174{\pm}0.01{\mu}M$), respectively higher than that of L-ascorbic acid. $^1O_2$, one of ROS playing a key role in the skin photo-aging, induces cellular membrane damages. DFP-D ($50{\mu}M$) showed good cell protective effects (${\tau}_{50}=80.2min$) about 2 times more than that of (+)-${\alpha}$-tocopherol (${\tau}_{50}=43.6min$). These results suggest that the great antioxidative activities of DFP and DFP-D could be applied to cosmetic industries as functional cosmetic materials.