• Archives of Pharmacal Research
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• v.21 no.1
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• pp.41-45
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• 1998

Hypericin, a photosensitizing plant pigment, was found to be a potent inducer of differentiation of human myeloid leukemia U-937 cells. At a concentration of $0.2{\mu}M$, hypericin exhibited 50% growth inhibition. An effect on cell differentiation by hypericin was assessed by its ability to induce phagocytosis of latex particles, and to reduce nitroblue tetrazolium (NBT). Approximately 51% of $0.2{\mu}M$ hypericin-treated cells were stained with NBT and 63% showed phagocytic activity. In order to establish whether hypericin induces differentiation of U-937 cells to macrophage or granulocyte, esterase activities and cell sizes were measured. When U-937 cells were treated with $0.2{\mu}M$ and $0.15{\mu}M$ of hypericin, the .alpha.-naphthyl acetate esterase activity was increased by 38.4% and 48.1%, respectively, but naphthol AS-D chloroacetate esterase activity was not influenced. The size of hypericin-treated cells in terms of cell mass was larger than that observed in untreated cells as determined by flow cytometry. Protein kinase C (PKC) inhibitor, NA-382, decreased the NBT reducing activity of hypericin, whereas a cAMP-dependent protein kinase A (PKA) inhibitor, H-89, did not show any influence on the differentiations. These results indicate that hypericin triggers differentiation toward monocyte/macrophage lineage by PKC stimulation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.4
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• pp.160-165
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• 2015

Lead-free piezoelectric materials have been actively studied to substitute for conventional PZT based solid solution, $Pb(Zr_xTi_{1-x}O_3)$, which occurs unavoidable PbO during the sintering process. Among them, Bismuth Sodium Titanate, $Na_{0.5}Bi_{0.5}TiO_3$ (abbreviated as NBT) based solid solution is attracted for the one of excellent candidates which shows the strong ferroelectricity, Curie temperature (Tc), remnant polarization (Pr) and coercive field (Ec). Especially, the solid solution of rhombohedral phase NBT with tetragonal perovskite phase has a rhombohedral - tetragonal morphotropic phase boundary. Modified NBT with tetragonal perovskite at the region of MPB can be applied for high frequency ultrasonic application because of not only its low permittivity, high electrocoupling factor and high mechanical strength, but also effective piezoelectric activity by poling. In this study, solid state ceramic processing of NBT and modified NBT, $(Na_{0.5}Bi_{0.5})_{0.93}Ba_{0.7}TiO_3$ (abbreviated as NBT-7BT), at the region of MPB using 7 % $BaTiO_3$ as a tetragonal perovskite was introduced and the structure between NBT and NBT-7BT were analyzed using rietveld refinement. Also, the ferroelectric and piezoelectric properties of NBT-7BT such as permittivity, piezoelectric constant, polarization hysteresis and strain hysteresis loop were compared with those of pure NBT.

• 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.

• 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.

• Journal of Ginseng Research
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• v.11 no.1
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• pp.24-31
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• 1987

We studied a assay method on the measurement of superoxide dismutase (SOD Superoxide : superoxide oxidoreductase, EC. 1. 15. 1. 1) activity with photoreduced flavin and nitroblue tetrazolium (NBT) as superoxide (${O_2}^{-}$) source and detector, respectively. The $\Delta$E (1000 ng SOD$.$$min.)^{-1}$ of photoreduced flavin-NBT system was 0.08, whereas that of xanthine-xanthine-cytochrome system used broadly in experiments was 0.014. Therefore, the new method was regarded more simple and utilizable than xanthine-xanthine cytochrome system method. In the present paper, we also carried out to investigate the SOD activity and isozyme pattern for the parpose of study of leaf-burning disease in ginseng (Panax ginseng C.A. Meyer) leaves.

• 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.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.4
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• pp.283-289
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• 2000

Natriuretic peptides comprise a family of three structurally related peptides; atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP). The present study was performed to investigate the effect of ANP on the proliferation and activity of ROS17/2.8 and HOS cells which are well-characterized osteoblastic cell lines. ANP dose-dependently decreased the number of ROS17/2.8 and HOS cells after 48-hour treatment. ANP generally increased the alkaline phosphatase activity of ROS17/2.8 and HOS cells after 48 hr treatment, regardless of the fact that basal activity of alkaline phosphatase was much lower in HOS cells compared to that of ROS17/1.8 cells. ANP increased the NBT reduction by ROS17/2.8 and HOS cells. ANP showed the variable but no significant effect on the nitric oxide production by ROS17/2.8 and HOS cells. ROS17/2.8 and HOS cells produced and secreted gelatinase into culture medium, and this enzyme was thought to be the gelatinase A type with the molecular weight determination. The gelatinase activity produced by ROS17/2.8 cells was increased by the treatment of ANP. However, the enzyme activity was not affected by ANP treatment in the HOS cell culture. In summary, ANP decreased the proliferation and increased the alkaline phosphatase activity and NBT reduction of osteoblasts. These results indicate that ANP is one of the important regulators of bone metabolism.

• 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.

• Biomolecules & Therapeutics
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• v.17 no.4
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• pp.412-417
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• 2009

In the course of screening for antioxidant compounds by measuring the radical scavenging effect on DPPH (1,1-diphenyl- 2-picrylhydrazyl), a total extract of the twigs of Vitex rotundifolia (Verbenaceae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of three iridoid compounds, 10-O-vanilloylaucubin (1), 10-O-p-hydroxybenzoylaucubin (2) and aucubin (3), two C-glycoside flavones, vitexin (4) and orientin (5), and a quinic acid derivative, 3,4-di-O-caffeoylquinic acid (6). Their structures were elucidated by spectroscopic studies. Among them, compounds 5 and 6 showed the significant antioxidative effects on DPPH free radical scavenging test. In riboflavin-NBT-light and xanthine-NBT-xanthine oxidase systems, compounds 5 and 6 exhibited the formation of the blue formazan in a dose-dependent manner. Compounds 5 and 6 showed better superoxide quenching activities than vitamin C.

• Proceedings of the Korean Nutrition Society Conference
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• 1995.05c
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• pp.39-40
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• 1995