• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.367-371
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• 2013

The half maximal inhibitory concentration ($IC_{50}$) values and trolox equivalent antioxidant capacity (TEAC) values were calculated by a 2,2'-diphenylpicrylhydrazyl (DPPH) assay and a 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid ($ABTS^{+{\cdot}}$) assay, in order to determine the antioxidative activities of the compounds. On the basis of the DPPH assay, quercetin had the strongest antioxidative potential of the flavonoids, followed in order by fisetin, 7,8-dihydroxyflavone, morin and kaempferol. Quercetin, fisetin and 7,8-dihydroxyflavone had higher antioxidant potentials than butyl hydroxyl anisole. Quercetin had the highest TEAC value amongst the flavonoids and isoflavonoids, followed in order by 3-hydroxyflavone, fisetin, 7,8-dihydroxyflavone and morin. Comparatively, isoflavonoids were found to have significantly weaker antioxidative potential than the flavonoids.

• Korean Journal of Plant Resources
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• v.20 no.2
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• pp.185-192
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• 2007

The different parts of 8 edible and medicinal ferns were extracted with 80% ethanol and the bioactive substances and antioxidant activities were investigated. Total polyphenol content was highest in Cyrtomium fortunei rhizome ($57.32mg{\cdot}g^{-1}$) and followed by C. fortunei root, Pyrrosia lingua aerial part and Onoclea sensibilis var. interrupta aerial part. Total flavonoid contents ranged from 1.95 (Onoclea sensibilis var. interrupta rhizome) to $27.51mg{\cdot}g^{-1}$ (O. sensibilis var. interrupta aerial part). Among the samples tested, C. fortunei root and rhizome were found to be most effective in both DPPH and ABTS radical scavenging assay. Except in Selaginella tamariscina underground part and Osmunda japonica aerial part, most of the tested samples showed strong potential (above 87%) in inhibition rate on linoleic acid oxidation.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1573-1575
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• 2009

Bioassay-guided fractionation of the culture broth of Aspergillus sp. FN070449 (KCTC 26428) using a DPPH (2,2-diphenyl-1-picrylhydrazyl) assay led to the isolation of two compounds: reticulone (1) and reticulol (2). Their chemical structures were elucidated on the basis of UV, IR, NMR, and MS spectroscopic analyses. Compound 1 exhibited more potent free radical scavenging activity on $ABTS^{\cdot+}$ (2,2'-azino-bis [3-ethylbenzthiazoline-6-sulphonic acid]) and DPPH radicals than did butylated hydroxyanisole (BHA) and caffeic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.7
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• pp.1053-1062
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• 2011

Reactive oxygen species (ROS), including singlet oxygen (${O_2}^1$), superoxide anion radical ($O_2{\cdot}^-$), hydroxyl radical ($HO{\cdot}$), peroxyl radical ($ROO{\cdot}$), hydrogen peroxide ($H_2O_2$), and hypochlorous (HOCl), are generated as byproducts of normal cellular metabolism. ROS induce damage to many biological molecules, such as lipids, proteins, carbohydrates, and DNA. It is widely believed that some degenerative diseases caused by ROS can be prevented by the high intake of fruits and vegetables due to their antioxidant activities. Recently, research on natural antioxidants has become increasingly active in various fields. Several assays have been developed to measure the total antioxidant capacity of antioxidants in fruits and vegetables in vitro. These assays include those for DPPH radical scavenging activity, SOD-like activity, total polyphenol content, oxygen radical absorbance capacity, reducing power, trolox equivalent antioxidant capacity (ABTS assay), single-cell gel electrophoresis (comet assay), and a cellular antioxidant activity assay. Because different antioxidant compounds may act through different mechanisms in vitro, no single assay can fully evaluate the total antioxidant capacity of foods. Due to the complexity of the composition of foods, it is important to be able to measure antioxidant activity using biologically relevant assays. In this review, recently used assays were selected for extended discussion, including a comparison of the advantages and disadvantages of each assay and their application to fruits and vegetables.

• Journal of Life Science
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• v.28 no.10
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• pp.1163-1169
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• 2018

In order to utilize the residue that is thrown away after an onion harvest, we analyzed the physiological activity and cytotoxicity of fermented and hot water extracts of the residue. The pH of the extracts were all acidic, and organic matter content was 0.75% in the fermented extract and four times more than 0.19% in the hot water extract. The contents of nitrogen, phosphoric acid, calcium, and magnesium components, except for the potassium component among macroelements, were higher in the fermented extract than in the hot water extract. The content of iron and silicon among the micro-elements was also higher in the fermented extract than in the hot water extract. In addition, the content of boron was higher in the hot water extract than in the fermented extract. The total polyphenol contents of the fermented and hot water extracts were $16.2{\pm}3.3mg{\cdot}g^{-1}$ and $14.6{\pm}1.4mg{\cdot}g^{-1}$, respectively, which was $1.6mg{\cdot}g^{-1}$ higher in the fermented extract than in the hot water extract. However, the total flavonoid contents of the fermented and hot water extracts were $0.1{\pm}0.1mg{\cdot}g^{-1}$ and $4.8{\pm}0.7mg{\cdot}g^{-1}$, respectively, which was $4.7mg{\cdot}g^{-1}$ higher in the hot water extract than in the fermented extract. DPPH and ABTS radical scavenging ability for antioxidant activity were higher in the hot water extract than the fermented extract. The cytotoxicity of the extract using MTT assay showed cell viability of 101.6% and 97.9% in the fermented and hot water extracts, respectively. It was confirmed that there was no cytotoxicity in either extract.

• Horticultural Science & Technology
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• v.29 no.4
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• pp.358-365
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• 2011

Lespedeza cuneata G. Don is a plant commonly grown in Asian countries, which has been widely used as an oriental medicinal herb to treat diabetes, diarrhea and various other inflammatory diseases. The phenolics of dry leaves of L. cuneata G. Don were extracted by using 80% (v/v) aqueous methanol in assistance with homogenization and sonification. The phenolic extract and its five different fractions (n-hexane, chloroform, ethyl acetate, n-butanol, and water) were used to evaluate the levels of total phenolics, total flavonoids, and antioxidant capacity as well as the inhibitory effect of tyrosinase activity. Ethyl acetate fraction (1 g) had the highest levels of total phenolics at 240.8 mg gallic acid equivalents (GAE), total flavonoids as 90.4 mg catechin equivalents (CE) as well as antioxidant capacity at 523.4 mg vitamin C equivalents (VCE) on ABTS assay and 329.5 mg VCE on DPPH assay among fractions. One g of water fraction contained total phenolics at 133.1 mg GAE, total flavonoids at 34.5 mg CE, and antioxidant capacity at 333.4 mg VCE for ABTS assay and 313.2 mg VCE for DPPH assay. Inhibition of tyrosinase activity of water fraction at 300 ${\mu}g{\cdot}mL^{-1}$ was at 47.2% and 21.1% for L-tyrosine and L-DOPA as its substrate, respectively. On the other hand, ethyl acetate fraction at 300 ${\mu}g{\cdot}mL^{-1}$ showed tyrosinase inhibition of 10.2% for L-tyrosine and 11.9% for L-DOPA. These results suggested that the phenolics from dry leaves of L. cuneata G. Don may be utilized as a potent source of antioxidants and skin whitening agents.

• Journal of the Korean Wood Science and Technology
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• v.45 no.1
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• pp.96-106
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• 2017

This study aims to identify the chemical compositions and antioxidant activities of essential oil, extracted from the leaves of Neolitsea aciculata (Blume) Koidz by the hydrodistillation method. To the end, the chemical composition of N. aciculata leaf oil was firstly analyzed through GC/MS. The major constituents of essential oil were found to be: cis-ocimene (11.00%), trans-ocimene (9.65%), elemol (9.15%), ${\beta}$-elemene (8.75%), germacrene-D (7.55%), trans-caryophyllene (5.90%), ${\gamma}$-elemene (5.40%) and ${\tau}$-muurolol (4.95%). Then, the antioxidant potential of the essential oil was evaluated by the methods of total polyphenolic content (TPC) assay, DPPH radical scavenging activity, ABTS radical scavenging activity and ferric reducing antioxidant power (FRAP). It was estimated that the total polyphenolic content of the oil was $136.7{\pm}0.13\;mg\;GAE/g$ and the efficient concentration of the oil required to scavenge 50% DPPH radicals ($EC_{50}$ value) was $639.33\;{\mu}g/m{\ell}$. Also, ABTS radical scavenging activity was identified to be concentration dependent, while the FRAP value was $31.21{\pm}0.12\;{\mu}M$ $FeSO_4{\cdot}7H_2O/g$. Such figures, as a result, suggest that the essential oil extracted from the leaves of N. aciculata has its antioxidant activity, which can serve as significant health functional benefits.

• Korean Journal of Plant Resources
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• v.21 no.1
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• pp.52-59
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• 2008

This study was conducted to evaluate the antioxidative potentials of 4 Aster species. Flowers and aerial parts were extracted with 80% ethanol, and antioxidative activities and bioactive substance contents were investigated. Flowers showed higher extraction yield than aerial parts of all 4 species used. Among the samples tested, Flowers of A. scaber were found to be the most effective in both DPPH and ABTS radical scavenging assay. However, $Fe^{2+}$ chelate effect of all samples were lower than EDTA. Four samples(A. scaber flowers, A. sphathulifolius aerial parts, A. koraiensis flowers, A. scaber aerial parts) out of eight showed stronger inhibitory activities against linoleic acid oxidation than BHT at 8 days. Total polyphenol and flavonoid contents of A. scaber flowers(90.46 and $75.36mg{\cdot}g^{-1}$) were the highest, and followed by A. sphathulifolius flowers.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1415-1422
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• 2014

Hot water extraction concentrate was prepared from Alliun hookeri root (AHR) to evaluate its applicability to yogurt. The highest antioxidant activity of hot water concentrates was obtained under extraction conditions of 4 hr at $95^{\circ}C$. Antioxidant activities measured by DPPH radical assay, ABTS radical cation assay, reducing power, and cheating activity were highly correlated with total phenolic (89.51 mg/g) and total flavonoid (52.71 mg/g) contents, with R values of 0.94 and 0.96, respectively. Yogurt was fermented with a commercial lactic acid bacteria mixed strain (Yo-mix$^{TM}$ 305) for 10 hr at $42^{\circ}C$ after addition of 0~10% (w/w) hot water concentrates from AHR to yogurt base. As fermentation proceeded, pH and $^{\circ}Brix$ of yogurt decreased from 6.57~6.60 to 4.34~4.51 and from 8.10~8.90% to 4.60~5.25%, respectively, whereas titrate acidity, viscosity, and viable cell numbers increased from 0.22~0.23% to 1.01~1.10%, from $0mPa{\cdot}s$ to $202.55{\sim}290.50mPa{\cdot}s$, and from 6.40~6.80 log CFU/mL to 8.60~9.20 log CFU/mL, respectively. There was no significant difference in any sensory attribute between the control and 2.5% addition group, suggesting that 2.5% hot water concentrate from AHR could be used to manufacture yogurt.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.128-134
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• 2006

Antioxidant activities of methanol extracts from sarcocarp and seed of Zizyphus jujuba var. inermis Rehder were investigated in vitro. Contents of total polyphenols in methanol extracts from sarcocarp and seed were 98.83, $138.99\;{\mu}g/mg$, respectively. Radical-scavenging activities of methanol extracts were examined using ${\alpha},{\alpha}-diphenyl-{\beta}-picrylhydrazyl$ and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radicals, and hydrogen peroxide assay. Inhibition effects of methanol extracts on peroxidation of linoleic acid were examined by ferric thiocyanate and thiobarbituric acid methods. Both sarcocarp and seed of Zizyphus jujuba var. inermis Rehder showed relatively high antioxidant activities in various systems.