• Korean Journal of Plant Resources
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• v.26 no.3
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• pp.347-354
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• 2013

Apple and pear are popular fruits consumed in Korea and are common fruit in daily diet. In order to compare the antioxidant activity of the apple and pear peels, total polyphenol contents, total flavonoid contents, $ABTS^+$ free radical scavenging activity, and DPPH free radical scavenging activity were measured from hot water, ethanol, and methanol extracts of the two fruit peels. The total polyphenol and flavonoid contents were highest in 95% methanol extracts of the apple peelsand 70% ethanol extract of the pear peels, respectively. Total polyphenol contents of the pear peels were higher than that of apple peels, and total flavonoid contents of the apple peels were higher than that of pear peels. The apple and pear peels had the highest $ABTS^{+{\cdot}}$ and DPPH free radical scavenging activity in 95% methanol extracts and 70% ethanol extracts, respectively. $ABTS^{+{\cdot}}$ and DPPH free radical scavenging activity of pear peels was higher than that of apple peels, and the DPPH free radical scavenging activity of apple and pear peels were detected in hot water, 95% methanol, and 70% ethanol extracts, respectively. Ascorbic acid, a synthetic antioxidant used as positive control, had significantly higher scavenging activity than the apple and pear peels. In conclusion, the apple and pear peelshave great potential as natural antioxidants. Therefore, above results should be considered to provide the possibility for the development of high functional antioxidants.

• Advances in Traditional Medicine
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• v.8 no.1
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• pp.32-38
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• 2008

Galgeuntang water extract exhibited a strong free radical scavenging activity and reducing power determination. However, a gradual increase in the free radical scavenging activity and reducing power determination was obtained with increasing concentrations. The highest radical scavenging activity was shown by the water extract from Galgeuntang (116.93 ${\mu}g$/mL) and the water extract from Cinnamonum cassia Presl. (95.01 ${\mu}g$/mL). These results of phenolic and flavonoid contents of the extracts indicated that the strong radical scavenging activity of the Cinnamonum cassia Presl. extract might be in part due to the phenolic compounds. The correlation coefficient between TPC and DPPH ($r^2$ = 0.9312), TFC and DPPH ($r^2$ = 0.9677), showed positive correlation among total phenolic/flavonoid contents and antioxidant activity. These results suggest that Galgeuntang has a potential antioxidant activity.

• 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.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 Korean Society of Forest Science
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• v.102 no.4
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• pp.566-570
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• 2013

Vaccinium oldhamii Miq. is a Korean native tree, which is deciduous and shrub tree with broad leaf. To develop superior cultivars for edible or medicinal purposes, we evaluated total phenolic content and antioxidant activity. Total phenolic content was measured by folin-denis method and antioxidant activity was measured by DPPH free radical scavenging activity (DPPH method) and reducing power (potassium ferricyanide method). Total phenolic content, DPPH free radical scavenging activity (at 400 ppm) and reducing power (at 700 ppm) were 15.8~19.9 mg/g, 69.1~91.4% and 0.56~0.96, respectively. A linear correlation was shown between DPPH-radical scavenging activity and reducing power (r=0969).

• Preventive Nutrition and Food Science
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• v.4 no.2
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• pp.92-96
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• 1999

The effects of aqueous extracts from Korean commercial teas on excessive free radicals were examined utilizing spin trapping, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical and lipid peroxidation. A potent scavenging effect of green tea and oriental senna tea was dound using sipin trapping. The most effective teasagainst the DPPH radical was green tea, followed inorder by pine leak tea, Chinese gutta percha tea and orietnal senna tea. Similar to the effects of DPPH radical , green tea, pine leaf tea, Chinese gutta percha tea and oriential senna tea had an inhibitory effect on lipid peroxidation. These findings predict that Korean tea is a promising material for scavenging free radicals, and for curing diseases related to free-radical reactions.

• Herbal Formula Science
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• v.13 no.2
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• pp.93-100
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• 2005

In order to find the new hepatoprotective agents preliminary screening of twelve prescriptions which have been used for the treatment of hepatic disease in Oriental traditional medicine has been carried out. Both DPPH free radical scavenging and hepatoprotective effect on tacrine-induced cytotoxicity in Hep G2 cells are performed. Osumokkya-tang which is one of the prescription belongs to interior-warming properties showed the DPPH free radical scavenging effect as well as hepatoprotective activity significantly. It is also suggested that its hepatoprotective effect is derived from Chaenomelis Fructus.

• Journal of the Korean Dietetic Association
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• v.25 no.2
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• pp.105-114
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• 2019

This study examined the quality characteristics of brown rice Sulgidduk containing acorn powder and the optimal mixing rate (0%, 5%, 10%, and 15%). The moisture contents of brown rice Sulgidduk increased with increasing amount of acorn powder. The DPPH free radical scavenging activities (16.15%~28.06%) and ABTS free radical scavenging activities (22.98%~42.81%) of the brown rice Sulgidduk increased with increasing acorn powder content. The L value of the Hunter's color value decreased with increasing amount of acorn powder. The hardness and chewiness of brown rice Sulgidduk increased with increasing amount of acorn powder. The brown rice Sulgidduk containing 10% acorn powder showed the highest score with regard to the sensory characteristics. These results suggest that the most desirable amount of acorn powder is 10% and the addition of acorn powder could contribute positively toward the quality characteristics of brown rice Sulgidduk.

• 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 Food Science and Technology
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• v.51 no.2
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• pp.133-140
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• 2019

Antioxidant activities of Ulmus davidiana root and bark extracts were evaluated by various antioxidant tests, including DPPH radical-scavenging, nitric oxide-scavenging, superoxide anion radical-scavenging, and ABTS radical-scavenging assays, and superoxide dismutase (SOD)-like activity and reducing power analysis, along with the determination of total phenolic and flavonoid contents. Both the extracts showed strong antioxidant activities by these testing methods. Ulmus davidiana root extract possessed strong reducing power and nitric oxide-scavenging activity, and high scavenging activities against free radicals including the superoxide anion, and the ABTS and DPPH radicals, but a weaker scavenging activity of SOD. In contrast, the Ulmus davidiana bark extract exhibited a strong SOD-like activity, but all the other activities were weak. It was observed that the total phenolic and flavonoid contents of the Ulmus davidiana root extract were higher than those of the Ulmus davidiana bark extract.