• Korean Journal of Food Science and Technology
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• v.22 no.6
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• pp.625-631
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• 1990

This study was carried out to investigate the antimutagenic effects of five kinds of apple enzymatic browning reaction products(AEBRP) on mitomycin C (MMC), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 4-nitroquinoline-1-oxide(4NQO), benzo(${alpha}$)pyrene(B(${alpha}$)P) and 3-amino-1,4-dimethyl-5H-pyri-do [4,3-b]indol (Trp-P-1). In spore rec-assay using B. subtilis Hl7($rec^+$) and M45($rec^-$), homocatechol-AEBRP and hydroquinone-AEBRP showed strong antimutagenic effects on MMC and MNNG as the concentration of AEBRP increased. In the Ames test using S. typhimurium TA98 and TA100, hydroxyhydroquinone-AEBRP and pyrogallol-AEBRP showed strong antimutagenic effects on Trp-p-1 and B(${alpha}$)p in TA98 and TA100 in the presence of S-9 mix. Most of AEBRPs suppressed about 50% to 80% the mutagenesis in S. typhimurium TA98 induced by MNNG, however, AEBRPs except hydroxyhydroquinone-AEBRP showed antimutagenic effects of about 94% in TA100. Antimutagenic effects of the five kinds of AEBRPs on 4-NQO were more or less weak, in particular homocatechol-AEBRP exhibited the inhibitory effect of about 48% in TA98, and homocatechol-AEBRP and hydroquinone-AEBRP showed inhibitory effects of about 46% to 58% in TA 100.

• Korean Journal of Weed Science
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• v.12 no.2
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• pp.173-182
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• 1992

Regardless of the test species, germination was adversely affected by the different concentrations of the acidic and neutral fractions of sunflower root exudates while the basic and aqueous fractions had no effect on germination. In both test species, root lengths were inhibited slightly more than shoot lengths. Significant reduction in fresh weights of the test species was observed when the test species were treated with the acidic and neutral fractions but not with the basic and aqueous fractions. Six compounds, hydroquinone, ${\beta}$-resorcyclic acid, vanillic acid, caffeic acid, salicylic acid, and quercetin, were characterized from the acidic fraction. Seven compounds, hydroquinone, gentisic acid, ${\beta}$-resorcyclic acid, vanillic acid, caffeic acid, ferulic acid, and quercetin, were elucidated from the neutral fraction.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.127-129
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• 2004

• Bulletin of the Korean Chemical Society
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• v.17 no.6
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• pp.550-552
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• 1996

• Journal of the Society of Cosmetic Scientists of Korea
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• v.45 no.4
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• pp.399-408
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• 2019

Arbutin, which is used as a whitening ingredient, can produce hydroquinone, known as causing skin disease and carcinogen. Preservatives are essential to prevent microbial contamination during long-term storage and use of cosmetics, but safety issues such as toxicity and skin irritation are being raised. This study was conducted to determine hydroquinone and 21 preservatives levels in 40 arbutin-containing whitening functional cosmetics sold on-line and off-line. Result showed that 9 products contained hydroquinone. The concentrations in 7 products were ranged from 0.3 to 0.9 ppm, which were within the maximum allowed amount established by the Ministry of Food and Drug Safety. However, 2 products were 8.4 and 50.5 ppm and exceeded the allowed amount. Preservatives were detected 20 products. Detected items and ranges were phenoxy ethanol 0.1 ~ 0.7% (N = 15), Methyl paraben 0.19 ~ 0.21% (N = 2), Chlorphenesin 0.13% (N = 1), chlorhexidine 0.006% (N = 1), Propyl paraben 0.06% (N = 1), which were within maximum allowed amount established by the Ministry of Food and Drug Safety. Also, in cases of functional cosmetics the phrase "functional cosmetics" should be expressed on the primary or secondary package of cosmetics by cosmetics act. However, 1 product did not state the phrase as functional cosmetics. This study suggest that preservatives were safely managed. However, hydroquinone in hydroquinone-detected products could be produced by the decomposition of arbutin. Thus, further studies on the decomposition of arbutin are required to improve the quality control of the cosmetics.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.421-425
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• 2013

The effect of pretreatment on indium-tin oxide (ITO) electrodes has been rarely studied, although that on metal and carbon electrodes has been enormously done. The electrochemical and surface properties of ITO electrodes are investigated after 6 different pretreatments. The electrochemical behaviors for oxygen reduction, $Ru(NH_3){_6}^{3+}$ reduction, $Fe(CN){_6}^{3-}$ reduction, and p-hydroquinone oxidation are compared, and the surface roughness, hydrophilicity, and surface chemical composition are also compared. Oxygen reduction, $Fe(CN){_6}^{3-}$ reduction, and p-hydroquinone oxidation are highly affected by the type of the pretreatment, whereas $Ru(NH_3){_6}^{3+}$ reduction is almost independent of it. Interestingly, oxygen reduction is significantly suppressed by the treatment in an HCl solution. The changes in surface roughness and composition are not high after each pretreatment, but the change in contact angle is substantial in some pretreatments.

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.167.2-167.2
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• 2001

• Journal of the Microelectronics and Packaging Society
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• v.24 no.3
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• pp.57-62
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• 2017

In the process for preparing Ag-coated Cu flakes by electroless silver plating using hydroquinone reducing agent, Ag coating qualities were compared by changing various process parameters such as type of pretreatment solution, plating temperature, pH of plating solution, type and injection rate of plating solution, and pulp density. Effective pretreatment solution for removing the oxide layer on a Cu flake was preferentially suggested. The conditions of low plating temperature, pH value of 4.34, slow injection rate of Ag plating solution, elimination of deionized water in the Ag plating solution, and high pulp density significantly suppressed the formation of separated tiny Ag particles, and thus the surface coverage of Ag coating on Cu flakes was enhanced.

• Biomedical Science Letters
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• v.16 no.3
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• pp.179-185
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• 2010

Benzene is known as a ubiquitous air pollutant and has a carcinogenic influence on the human body. Benzene is also metabolized to other volatile organic compounds (VOCs) in the body such as phenol and hydroquinone (HQ). The metabolites are accumulated and further oxidized by myeloperoxidase in bone marrow. They act as toxic agents and cause a variety of diseases, including cancer, atopic dermatitis and asthma. In this study, we examined the effects of benzene and its metabolites on proliferation, differentiation and chemotaxis of EoL-1 cells, the human eosinophilic leukemia cell line. These chemicals had no effect on the proliferation of EoL-1 cells. Benzene decreased the differentiation of EoL-1 cells induced by butyric acid. HQ was induced the cell death during butyric acid-induced EoL-1 cell differentiation. In a chemotaxis experiment, benzene, phenol and HQ enhanced the cell migration induced by Lkn-1 but not by MCP-1, eotaxin, MIP-$1{\alpha}$ and RANTES. These findings provide the effect of VOCs on the regulation of eosinophil-involved immune response.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.3
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• pp.199-204
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• 2016

The objective of this study was to determine the effect of nitrification inhibitor dicyandiamide (DCD) and urease inhibitor hydroquinone (HQ) on ammonia ($NH_3$) and nitrous oxide ($N_2O$) emission from pig slurry applied to Timothy (Phleum pretense L.) sward. The daily emission of ammonia ($NH_3$) and nitrous oxide ($N_2O$) was monitored for 9 days in three different treatments; 1) control (only pig slurry application), 2) DCD treatment (pig slurry + DCD), and 3) HQ treatment (pig slurry + HQ). Most $NH_3$ emission occurred after 4~5 days in three treatments. Total $NH_3$ emission, expressed as a cumulative amount throughout the measurement time, was $1.33kg\;N\;ha^{-1}$ in the control. The DCD and HQ treatment decreased total $NH_3$ emission by 16.3% and 25.1%, respectively, compared to the control. Total $N_2O$ emission in the control was $47.1g\;N\;ha^{-1}$. The DCD and HQ treatment resulted in a reduction of 67.9% and 41.8% in total $N_2O$ emission, respectively, compared to the control. The present study clearly indicated that nitrification and urease inhibitor exhibited positive roles in reducing N losses through $NH_3$ and $N_2O$ emission.