• Journal of Marine Bioscience and Biotechnology
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• v.1 no.4
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• pp.252-259
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• 2006

Extracts which were prepared by four different extractions - 80% methanol extracts (ME) at high ($70^{\circ}C$) and a room temperature ($20^{\circ}C$), respectively and aqueous extracts (AE) at both temperatures with the residue after the methanol extracts - of 10 green, 19 brown and 25 red seaweeds collected in Jeju Island coast were examined for their DPPH free radical scavenging activity using a ESR (electron spin resonance) spectroscopy. A variety of the extracts showed positive scavenging effect against DPPH free radical (except the green seaweeds). Among the extracts, the brown seaweed extracts exhibited the highest scavenging activity. Especially, Sargassum spp. of the brown seaweeds have remarkable scavenging activities - both methanolic and aqueous at the both temperatures ($20^{\circ}C$ and $70^{\circ}C$). On the other hand, ME showed better scavenging activity than AE in the red seaweed extracts. These results indicate that autogenous seaweeds in Jeju will be potential natural antioxidants for functional food compounds.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.9
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• pp.1399-1406
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• 2015

The purpose of this study was to investigate the antioxidant activity of Korean traditional soy sauce and its relationship with physicochemical properties. Seventeen samples of soy sauce prepared by using a Korean traditional method were obtained from six provinces of Korea. The most powerful antioxidant activity of soy sauce was ranging from 8.96 to 63.39% for 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, from 0.12 to 2.41 AE mg/mL for ferric reducing antioxidant power (FRAP) value, and from 8.42 to 115.69 TE mg/mL for oxygen radical absorbance capacity (ORAC). Protease activity and total polyphenol contents were highly correlated with antioxidant activities such as DPPH radical scavenging activity and FRAP value (R=0.97). The contents of amino nitrogen were also correlated with DPPH radical scavenging activity (R=0.92), FRAP (R=0.93), and ORAC values (R=0.80). Based on these results, antioxidant activities were highly influenced by protease activity, contents of total polyphenols, and amino nitrogen.

• Food Science and Preservation
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• v.24 no.6
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• pp.879-884
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• 2017

In a continuing screening of selected medicinal plants native to Mongolia, the antioxidant and ${\alpha}$-glucosidase inhibitory activities of methanol extract of Iris bungei were investigated. After extraction with 80% of methanol, the methanol fraction was further extracted with n-hexane, EtOAc and n-BuOH in order to obtain four different solvent-soluble fractions, namely n-hexane-soluble, EtOAc-soluble, n-BuOH-soluble and $H_2O$ residue. The antioxidant properties were evaluated by radical scavenging assay using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radicals. The anti-diabetic efficacy of I. bungei extract was investigated by ${\alpha}$-glucosidase assay. All tested samples showed dose-dependent radical scavenging and ${\alpha}$-glucosidase inhibitory activities. Among the tested extracts, the EtOAc-soluble fractions showed the greatest radical scavenging activity and ${\alpha}$-glucosidase inhibitory properties among other solvent-soluble fractions. This result suggested that there was a significant relationship between the total phenolic content and biological efficacy. Thus, I. bungei extract might be considered as a new potential source of natural antioxidant and as a ${\alpha}$-glucosidase inhibitory source. A more systematic investigation of this biomass sill be performed for further investigation of activity against antioxidative and anti-diabetic effects.

• The Korean Journal of Food And Nutrition
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• v.26 no.4
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• pp.857-864
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• 2013

This study was investigated the effects of heat treatment on polyphenolic compounds and antioxidant activities of yacon. Raw yacon was heated at $100^{\circ}C$ and $121^{\circ}C$ for 15, 30, or 60 min by using an autoclave. The browning intensity, levels of free and bound phenolic and flavonoid compounds, and 1,1-diphenyl-2-picrylhydrazyl(DPPH) and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) radical-scavenging activity of yacon extracts following heat treatment were measured. The browning index, free polyphenolic content, and antioxidant activities in the extracts were significantly increased (p<0.05) with both increased heating temperature and time, while bound polyphenolic levels were decreased. The levels of free phenolic and flavonoid compounds in the yacon extract heated to $121^{\circ}C$ for 60 min were increased by 1.2 and 1.1 folds compared to raw yacon respectively. Moreover, DPPH and ABTS radical-scavenging activities of the yacon heated to $121^{\circ}C$ for 60 min were 1.7 fold and 2.0 fold higher, respectively, than those of raw yacon. A significant (p<0.01) correlation was observed among browning intensity, free and bound phenolic and flavonoid levels, and DPPH and ABTS radical-scavenging activities in heated yacon extract. Thus, heat treatment can be used as a method to enhance the antioxidant compound content in and the antioxidant activity of yacon.

• Food Science and Preservation
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• v.17 no.1
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• pp.131-138
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• 2010

To obtain basic data on the use of lotus as a raw material in functional food, antioxidant and anticancer activities of the leaf and root were investigated. Total flavonoid and total phenolic contents, at 12.84 mg/g and 24.33 mg/g respectively, were higher in white lotus leaf (WLL) than in any other part of the plant. The radical-scavenging activity of different tissues of lotus, measured in the DPPH radical-scavenging assay, increased with higher concentrations of solvent fractions. The butanol fraction of white lotus leaf showed the highest DPPH radical-scavenging activity. The reducing power of fractions increased in a dose-dependent manner. The butanol fraction of WLL had the greatest reducing power, and showed strong antioxidant activity in the linoleic acid system, and high-level inhibition of tyrosinase. Fractions from lotus were also capable of scavenging nitrite, depending on the concentration of the fractions. Butanol fractions of the leaf of white and red lotus scavenged 95.61% and 92.15% of available nitrite, respectively, when used at 1 mg/mL concentrations. Butanol fractions from leaf of white and red lotus exhibited the strongest inhibitory effects on human lung and colon cancer cells.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.296-304
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• 2017

The purpose of this study was to investigate the applicability of the Psidium guajava leaf extract as a whitening functional cosmetic material. We measured DPPH radical scavenging activity, intracellular ROS, cytotoxicity in B16F10 melanoma cells and cytoprotective effect on ultraviolet A, in vitro tyrosinase inhibitory effect and melanin biosynthesis inhibitory effect. The antioxidative effect was confirmed through high DPPH radical scavenging activity and intracellular ROS activity inhibition measurement of the Psidium guajava leaf extract. The survival rate of B16F10 melanoma cells was more than 98% at all concentrations, and the cytoprotective effect from ultraviolet ray A was found to increase in a concentration-dependent manner. In addition, in vitro tyrosinase activity inhibitory effect of 10% and melanin biosynthesis inhibitory effect of 20% were observed. Through less toxicity for B16F10 melanoma cell, high antioxidant activity, inhibition of tyrosinase activity and melanin biosynthesis inhibitory effect, we confirmed the possibility of developing the Psidium guajava leaf extract as a whitening functional cosmetic material with a safe and excellent whitening effect.

• Food Science and Preservation
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• v.11 no.2
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• pp.201-206
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• 2004

The activities of antioxidation and alcohol dehydrogenase in hibitionin methanol extracts of thirty two medical herbs were tested using the method of DPPH activity, nitrite scavenging effect and alcohol dehydrogenase assay in vitro. In DPPH method, Eugenia caryophyllata, Thea sinensis, Paeonia suffruticosa, Alnus japonica showed over 90 % of free radical scavenging activities. The nitrite scavenging ability appeared Zanthoxylum bungeanum, Alnus japonica, Thea sinensis, Hovenia dulcis(cortex) and Illicium verum showed the high value. In connection with in vivo alcohol metabolism, thirteen medicinal herbs were screened for inhibition. As a reasult, we found significant inhibition of ADH by methanolic extracts of Glycyrrhiza uralensis, Pueraria thunbergiana(radix), Alnus japonica. These results indicate that the antioxidative effect was strongly related with alcohol dehydrogenase inhibitor; Thea sinensis and Alnus japonica.

• Journal of agriculture & life science
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• v.44 no.3
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• pp.69-78
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• 2010

To get basic data for the utilization of Pinkpop Borisu fruit and leaf as a raw material in functional food, antioxidative activities were investigated. The radical scavenging activity of various solvent fraction from fruit and leaf against the DPPH and ABTS radicals increased with the increasing amount of various solvent fractions and butanol fraction of leaf showed the highest DPPH radical scavenging activities. Among the various solvent fractions from fruit and leaf of Pinkpop Borisu, butanol fraction of leaf showed the strongest scavenging effect on ABTS radicals. Reducing power and ferric reducing/antioxidant power (FRAP) of the various solvent fractions from fruit and leaf increased with the increasing concentration of fractions and butanol fraction of leaf showed the highest reducing power. The butanol fraction of fruit and leaf showed strong antioxidative activity on linoleic acid system. Total phenolics contents of butanol fraction from fruit and leaf were 106.34 and 252.46 mg/g, respectively. The antioxidative activities of the butanol fraction from fruit and leaf are attributed to phenolic compounds. The present results suggest that butanol fraction of Pinkpop Borisu leaf would have the protective potential from oxidative stress induced by free radicals.

• Food Science and Preservation
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• v.23 no.4
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• pp.585-590
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• 2016

In this study, the antioxidant and tyrosinase inhibitory activities of aqueous ethanolic extract from the immature fruits of Malus pumila cv. Fuji were evaluated. The antioxidant capacities of the extract was investigated employing radical scavenging assays using DPPH and $ABTS^+$ radicals. The skin-whitening effect of M. pumila cv. Fuji extract was tested using mushroom tyrosinase assay. In addition, the total phenolic content was measured by a spectrophotometric analysis. All tested samples showed a dose-dependent radical scavenging and tyrosinase inhibitory activities. Among the tested samples, the ethyl acetate (EtOAc)-soluble portion from the immature fruits of M. pumila cv. Fuji was showed the significant DPPH and $ABTS^+$ radicals scavenging activities. Also, the tyrosinase inhibitory activity of the ethyl acetate (EtOAc)-soluble portion from immature apples was higher than other solvent-soluble portion. These results suggest that unripe fruits of M. pumila cv. Fuji could be considered as a new valuable source of natural antioxidant and skin-whitening agents. Systematic investigation of immature fruits of Malus pumila cv. Fuji will be performed for the further development of its biological properties.

• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.539-546
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• 2016

The aim of this study was to analyze antioxidant activity, total phenolics, and vitamin C content in unripe and ripe jujube cultivar and to investigate correlation between antioxidant and chemical constituents including total phenolics and vitamin C. The antioxidant activity was measured by the DPPH radical scavenging activity, ABTS radical scavenging activity, and reducing power. Although, the weight, diameter and soluble solids of Zyziphus jujuba fruit were increased with the progress of ripening, antioxidant activity and total phenolics were decrease during ripening. The highest free-radical scavenging activity (at 2.5 ㎎/㎖) and reducing power (at 1 ㎎/㎖) in fruit were 81.75% (Bokjo, unripe) and 0.80 (Mudeung, unripe), respectively. The highest total phenolic content in unripe fruit of Mudeung was 62.50 ㎍/g. A linear correlation (r=0.911) was shown between DPPH radical scavenging activity and total phenolic content.