• Korean Journal of Pharmacognosy
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• v.28 no.4
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• pp.225-232
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• 1997

300 extracts derived from 100 plants were tested for their potential to induce HL-60 cell differentiation using NBT assay and NSE/SE staining methods. Morphological changes from suspended to adherent state of the cells were also observed by microscopic examination. In result, 55 extracts induced cell differentiation into monocyte/macrophage lineage in the NBT and the NSE assay.

• Applied Biological Chemistry
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• v.36 no.5
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• pp.364-369
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• 1993

Triton X-100 enhances to a marked extent the analytical sensitivity of the nitrobluetetrazolium (NBT) reduction method for the assay of superoxide$(O^-_{\.{^.2}})$ production. In the present work, it was attempted to elucidate the physicochemical nature of this Triton X-100 effect, focusing on not only the surfactant-caused stabilization of the water-insoluble formazan colloid but also the kinetic competition between the $NBT-O^-_{\.{^.2}}$ reaction and the autodisproportionation of concommitantly occuring in aqueous media. The measurements of formazan and $H_2O_2$ formed in a number of reaction systems, as prepared by vortex-mixing potassium superoxide dissolved in an aprotic solvent with aqueous solutions of NBT, revealed that Triton X-100 exerts its effect both through preventing formazan colloid from aggregation and thereby increasing the formazan absorbance and through suppressing the autodisproportionation reaction of $O^-_{\.{^.2}}$. It also turned out that the relative shares of the colloid stabilization effect and the kinetic effect in the contribution to the sensitivity amplification of the NBT method are dependent upon the reaction conditions, particulary the molar concentration ratio of NBT to $O^-_{\.{^.2}}$ in the reaction systems.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.1-7
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• 2022

Riboflavin (Rb), in the presence of methionine (Met) under light, generates superoxide radicals that can reduce nitro blue tetrazolium (NBT) to its corresponding formazan. The Rb-Met/NBT system has been used to measure the superoxide dismutase (SOD)-like activities of various antioxidants. However, the reaction mechanisms have not been clearly defined, and the assay conditions are not consistent. In this study, the effects of different photosensitizers and amino acids on NBT reduction in different solvents were investigated. NBT reduction in the Rb-Met/NBT system was more pronounced in phosphate-buffered saline, compared to distilled water or Tris (pH 7.5); histidine (His) instead of Met also led to considerable Rb-induced NBT reduction. Among the photosensitizers, methylene blue with His caused potent NBT reduction in Tris. Rb-induced NBT reduction combined with Met or His was quantitatively inhibited by SOD or gallic acid, but did not affect MB-induced reduction sensitively.

• Archives of Pharmacal Research
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• v.27 no.2
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• pp.173-176
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• 2004

Three phenolic compounds, rosmarinic acid (1), methyl rosmarinate (2), ethyl rosmarinate (3), and two flavonoids, luteolin (4), luteolin-7-O-$\beta$-D-glucuronide methyl ester (5) were isolated from the aerial part of Lycopus lucidus (Labiatae). Their structures were determined by chemical and spectral analysis. Compounds 1-5 exhibited potent antioxidative activity on the NBT superoxide scavenging assay. The $IC_{50}$ values for compounds 1-5 were 2.59, 1.42, 0.78, 2.83, and 3.05 $\mu\textrm{g}$/mL respectively. In addition, five compounds were isolated from this plant for the first time.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.126-134
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• 2007

This study reviewed the application of an extract from Kalopanax pictus stem bark and root bark as natural antioxidants. To investigate the effect on cell toxic level against transformed mouse fibroblast L929 in formula added with various extracts from Kalopanax pictus stem bark and root bark, this experiment was carried out by in vitro cytotoxicity method. Using DCFA-DA method, oxidative stress in cell was measured with other antioxidant activity methods including DPPH assay and NBT assay. Active oxygen inhibition rate for root bark insoluble hot water extracts showed the highest with 57.9% for 15 min treatment. In DPPH and NBT test, antioxidant activities of methanol extract from stem bark and insoluble hot water extract from stem bark were 96% (at 0.1%) and 95% (at 0.5%), respectively.

• YAKHAK HOEJI
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• v.51 no.6
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• pp.500-507
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• 2007

To investigate the possibility of development as a whitening agent using bamboo extracts (Phyllostachys nigra var. henonis), we measured DPPH assay, NBT/XO assay, intracellular ROS scavenging assay, tyrosinase assay and MSH-induced melanin production in B-16 cells. Bamboo extracts had dose-dependently anti-oxidant activity in DPPH, NBT/XO and intracellular ROS assay. Bamboo extracts appear to inhibit xanthine oxidase directly. Bamboo extracts inhibited not only purified tyrosinase activity but also inhibited tyrosinase activity and melanin production in B16 melanoma cells stimulated by $1{\mu}M\;{\alpha}$-MSH. Anti-oxidant activity and cytotoxicity of ethyl acetate fraction was more potent than those of water fraction, whereas whitening effect of water fraction was stronger than ethyl acetate fraction. Therefore, these results suggest that water fraction of bamboo extracts may be useful for the development as whitening agents reducing cytotoxicity.

• YAKHAK HOEJI
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• v.56 no.6
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• pp.395-400
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• 2012

To investigate the possibility of development as a whitening agent using arctigenin, we measured DPPH assay, NBT/XO assay, intracellular ROS scavenging assay, tyrosinase assay and MSH-induced melanin production in B16 melanoma cells. Arctigenin dose-dependently had anti-oxidant activity in DPPH, NBT/XO and intracellular ROS assay. Although arctigenin did not inhibit purified tyrosinase activity, it dose-dependently inhibited tyrosinase activity and melanin production in B16 melanoma cells stimulated by $1{\mu}M$ ${\alpha}$-MSH. In particular, arctigenin at a concentration $100{\mu}M$ inhibited ${\alpha}$-MSH-stimulated tyrosinase activity and melanin production by $50.9{\pm}2.9%$ and $69.0{\pm}6.5%$ respectively. And typical tyrosinase inhibitor, arbutin, inhibited $57.7{\pm}2.9%$ and $65.1{\pm}5.0%$ respectively. Such an similar inhibitory effect of arctigenin and arbutin in B16 melanoma cells may be due to the inhibition of MSH signal pathway rather than the direct inhibition of tyrosinase. Therefore, these results suggest that arctigenin may be useful for the development as whitening agents.

• Natural Product Sciences
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• v.26 no.4
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• pp.334-339
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• 2020

A new compound, 3��-acetoxylanosta-7,9(11),24-triene-26-al (3), and seven known compounds (1 - 2 and 4 - 8) were isolated from Ganoderma tropicum (Jung.) Bres. collected in Tay Nguyen, Vietnam. The structures of these compounds were determined by one- and two-dimensional nuclear magnetic resonance spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and high-resolution ESI-MS, and by comparison with literature data. All of the isolated compounds were tested for nitroblue tetrazolium (NBT) reduction activity in Saccharomyces cerevisiae-stimulated RAW 246.7 cells. Among them, compounds 2 - 4 and 6 - 8 enhanced the NBT reduction in a dose-dependent manner.

• Archives of Pharmacal Research
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• v.26 no.6
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• pp.453-457
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• 2003

Four flavonoids (1-4), a phenylethyl glycoside (5), and a phenylpropanoid glycoside (6) were isolated from the flowers of Buddleia officinalis (Loganiaceae). Their structures were determined by chemical and spectral analysis. Among the isolated compounds, luteolin (1) and acteoside (6) exhibited the most potent antioxidative activity on the NBT superoxide scavenging assay. In addition, compounds 1-6 revealed weak antifungal activity, and no hemolytic activity.

• Archives of Pharmacal Research
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• v.25 no.4
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• pp.433-437
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• 2002

A new phenolic amide, dihydro-N-caffeoyltyramine (1) was isolated from the root bark of Lycium chinense Miller, along with known compounds, trans-N-caffeoyltyramine (2), cis-N-caffeoyltyramine (3), and lyoniresinol $3{\alpha}-Ο-{\beta}-D-glucopyranoside$ (4). Their structures were determined by spectroscopic analysis. A NBT superoxide scavenging assay revealed that three phenolic amides showed potent antioxidative activity.