• Food Science and Preservation
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• v.9 no.2
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• pp.253-259
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• 2002

The antioxidative and free radical scavenging activity of water extracts of dandelion were investigated. Antioxidative and radical scavenging activity were assessed by means of different tests; inhibition of peroxidation on linoleic acid model system, scavenging DPPH radical, scavenging of hydroxyl radical by chemiluminescence assay, scavenging of superoxide anion radical by EPR spectroscopy and scavenging of hydrogen peroxide. The leaf extract showed strong antioxidant activity in linoleic acid system. The antioxidant activity of water extracts of dandelion increased with increasing concentrations of extracts. The scavenging activity of the dandelion extracts, on inhibition of the DPPH radical, was related to the reaction time. Hydroxyl radical were generated by lenten reaction and dandelion extract was found to scavenge OH˙in a concentration-dependent manner. The water extract of leaf had effective scavenging activities on hydrogen peroxide and superoxide anion radical. From the these data, it is evident that water extract of dandelion leaf is an effective scavenger for OH˙, O$_2$¨, DPPH˙, hydrogen peroxide. And, the antioxidative effect observed is believed to be partly due to this radical scavenger activity.

• Journal of Marine Bioscience and Biotechnology
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• v.1 no.3
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• pp.170-177
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• 2006

As a rapid and quick bioactive compound evaluation technique, in this study we utilized a automatic system of High Throughput Screening (HTS) to investigate DPPH radical scavenging efficacy of seaweeds, collected from Jeju Island in Korea. In this study, 6 species of green seaweeds, 18 species of brown seaweeds and 22 species of red seaweeds extracted with methanol at $20^{\circ}C$ and $70^{\circ}C$ were subjected to HTS. Of the green seaweeds tested, Enteromorpha compressa (20G6) of the green seaweeds showed DPPH radical scavenging activity of over 60%. On the other hand, the other green seaweeds showed poor DPPH radical scavenging activities (lees than 40%) at 1 mg/ml. Sargassum siliquastrum (20B17, 70B17), Dictyota dichotoma (70B1), Sargassum coreanum (70B16) and Ecklonia cava (70B26) among the brown seaweeds showed significantly high DPPH radical scavenging activity with 96%, 97%, 92%, 92%, 87%. Polysiphonia japonica (20R24), Schizymenia dubyi (20R17), Gelidium amansii (20R18) and Acrosorium flabellatum (20R23) among the red seaweeds showed remarkable DPPH radical scavenging activity of over 90%.

• Korean Journal of Plant Resources
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• v.26 no.5
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• pp.548-556
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• 2013

The objective of this study was to determine the effect of antioxidant enzyme activity and radical scavenging activities of cucumber grown greenhouse. The analytic method of antioxidant activities were measured by estimating DPPH free radical scavenging, nitrite scavenging ability activity and ABTS radical scavenging ability. The DPPH free radical scavenging activity of Jangjukcheongjang was the highest in most of the growth stage. The Nitrite scavenging ability at pH 1.2 was more than 40% in all cultivars and growth stages. The ABTS radical scavenging ability of Jangjukcheongjang and Nulpureuncheongjang showed relatively little higher than Janghyeongnakhap and Sinjoeunbaekdadagi. The SOD activity showed higher activity than 95% in all cultivars and growth stages. The activity of CAT was highest in the Nulpureuncheongjang of 2 (12~16cm) growth stage, and the APX activity of Nulpureuncheongjang and Janghyeongnakhap showed a relatively high activity. The POX activity showed distinctly different trends depending on the growth stage, and that is, the activity at harvest stage was significantly reduced. These results suggest that the cucumber had the potent biological activities, and that in the future, the availability of cucumber will be increase in the field of high-value cosmetic and food products.

• Korean Journal of Plant Resources
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• v.26 no.4
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• pp.426-432
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• 2013

The results of the content of total polyphenol and flavonoid, DPPH (1-1-diphenyl-2-picryl-hydrazyl) radical scavenging activity, ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)] radical scavenging activity, nitrite scavenging activity and SOD-like activity of methanol extracts from immature cotton boll are follows. The contents of total polyphenol and flavonoid compound were higher in small size cotton boll, and DPPH and ABTS radical scavenging activity also showed a relatively high activity in the small size. These results indicate that there is a correlation between phenol content and DPPH radical scavenging, ABTS radical scavenging. The test concentrations of immature cotton boll extract for measuring DPPH and ABTS radical scavenging activities were set as 1.25, 2.5, 5, 10 and 20 mg/ml. Immature cotton boll has high radical scavenging activity at the concentration of 1.25~20 mg/ml and the result showed a tendency to increase in a concentration-dependent. The nitrite scavenging activity showed high activity in the pH 1.2, and the result in the pH 4.2 showed progressively less active, and in the pH 6.0 near neutral was confirmed that does not affect the nitrite scavenging. In addition, SOD-like activity showed somewhat lower activity compared with ascorbic acid, but tended to be higher when compared with the results of the other natural substances. Through this experiment, we confirmed that immature cotton boll was excellent antioxidant activity. Therefore, it is demonstrated that the cotton suggest the possibility of development of new material for cosmetic product or functional food in the future, and is expected to make a greater usability.

• 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 Applied Science and Technology
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• v.34 no.4
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• pp.1025-1035
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• 2017

In this study, the hot water extract from Mulberry (Morus alba) Leaves fermented with Hericium erinaceum mycelium (MA-HE) was assessed for antioxidant activity. Radical scavenging activity of MA-HE evaluated using 2,2-diphenyl-1-picrylhydrazyl(DPPH) radical and 2,2'-azino-bis(3-ethyl-benzothiazoline-6-sulfonic acid)(ABTS) radical. MA-HE showed 63% DPPH radical scavenging activity at $500{\mu}g/mL$ and 98.27% ABTS radical scavenging activity at $250{\mu}g/mL$. MA-HE was shown to significantly inhibited DNA strand breakage induced by free radical. MA-HE also inhibited free radical-mediated human serum albumin modification. MA-HE effectively inhibited $H_2O_2$ induced cell death and significantly increased of the 8% cell survival at $100{\mu}g/mL$. MA-HE decreased intracellular reactive oxygen species (ROS) levels in $H_2O_2$-treated cells. The results suggested that MA-HE can contribute to antioxidant and protected cells from oxidative stress-induced cell injury.

• The Korean Journal of Pesticide Science
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• v.7 no.2
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• pp.92-99
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• 2003

A 96-well plate was applied to determine the DPPH free radical scavenging activity using 107 plant-specific enzyme inhibitors and 100 unknown plant-originated extracts. The final optimum volume was $250{\mu}L$ containing $100{\mu}M$ DPPH ethanolic solution at pH 7.8. In this condition, the radical scavenging activities were significantly increased by two known antioxidants consisting of ascorbate and a-tocopherol in a concentration-dependent manner. Among the 107 inhibitors, ampicillin and gallic acid showed 90.2% and 92.6% antioxidant activity at $100{\mu}M$, respectively, and these results were consisted with previous findings. In the tested 100 natural materials at $50{\mu}g/mL$, antioxidant activity of AT-407 resulted in the highest of 90.1%, and 10 extracts including AT-388 and AT-443 showed over 70%. Our results suggest that the use of 96-well plate for determining DPPH free radical scavenging activity would be a suitable method to select antioxidant-like substances of both synthetic compounds and natural products.

• Korean Journal of Medicinal Crop Science
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• v.11 no.1
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• pp.1-4
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• 2003

Two antioxidative compounds in Chrysanthemum boreale were isolated by a bioassay using a 2, 2-diphenyl-1-picrydrazyl(DPPH) free radical. They were identified as apigenin, linarin(acacetin-7-O-rutinoside) on the basis of $^1H\;and\;^{13}C-NMR$ and MS data. The DPPH radical scavenging activity$(RC_{50}:\;13.3{\mu}g)$ of apigenin was similar to that of ${\alpha}-tocopherol\;(12.1{\mu}g)$ and L-ascorbic acid$(13.1{\mu}g)$

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.648-654
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• 2004

Physiological functionality of browned oak mushroom was evaluated with focusing its electron-donating ability to DPPH radicals, scavenging ability to superoxide radicals and hydroxyl radicals, and inhibitory activity on lipid peroxidation. The results showed that overall antioxidative activities of browned oak mushroom were superior to those of raw oak mushroom with marketable quality, implying possible involvement of resultant browning reaction products in an increment of antioxidativity. The increased radical-scavenging ability was suggested to mainly be exerted by direct quenching of both superoxide and hydroxyl radicals, not by inhibition of xanthine oxidase activity and $Fe^{2+}$ chelation, respectively. Collectively, these results indicate a possible use of unmarketable browned mushroom as a material for manufacturing various processed functional foods.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.733-736
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• 2010

제주조릿대 잎 열수 추출 진액을 첨가한 식초음료를 개발하기 위해 항산화 활성을 관찰하였다. 항산화활성은 DPPH radical 소거활성, Hydroxyl radical 소거 활성 실험을 진행하였다. Base 식초를 선택하기 위한 쌀 식초와 사과식초의 DPPH 라디칼 소거활성에서는 식초 원액에 비해 제주조릿대를 첨가하였을 때 쌀 식초는 최대 68.07%증가하는 것을 확인 할 수 있었고, 사과식초의 경우 78.74% 증가하는 것을 확인할 수 있었다. 맛, 향, 단가, 항산화활성을 통하여 사과식초를 Base식초로 선택하였으며, Base식초와 제주조릿대 진액의 혼합비를 결정하기 위하여 배합율에 따른 항산화활성 연구에서는, DPPH 라디칼 소거활성의 경우 제주조릿대의 비율이 높아짐에 따라 DPPH 라디칼 소거능 역시 증가하는 것을 확인 할 수 있었다. Hydroxyl 라디칼 소거활성의 경우, 제주조릿대 진액의 비율을 증가시킬 수록 활성이 조금씩 떨어졌으나, 대조군인 석류와 블루베리 식초에 비해서는 10%이상 높은 소거활성이 있는 것을 확인할 수 있었다.