• Asian-Australasian Journal of Animal Sciences
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• 제14권9호
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• pp.1216-1220
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• 2001

Effect of hydroquinone (HQ) on rumen urease activity was studied. Hydroquinone at concentrations of 0.01 ppm, 0.1 ppm, 1 ppm, and 10 ppm inhibited urease activity of intact rumen microbes in vitro by 25%, 34%, 55% and 64% respectively. In the presence of low concentrations of $\beta$-mercaptoethanol, rumen urease could be solubilized and partially purified. The Km for the enzyme was $2{\times}10^{-3}$ M with Vmax of $319.4{\mu}moles/mg$ min. The kinetics of inhibition with partially purified rumen urease was investigated. The result showed that the inhibitory effect was not eliminated by increasing urea concentrations indicating a noncompetitive effect in nature with an inhibition constant $1.2{\times}10^{-5}$ M. Hydroquinone at the concentration of 10 ppm produced 64% urease inhibition, did not affect ruminal total dehydrogenase and proteolytic enzyme (p>0.05), but increased cellulase activity by 28% (p<0.05) in vitro. These results indicated that hydroquinone was a effective inhibitor of rumen urease and could effectively delay urea hydrolysis without a negative effect. The inhibitor appeared to offer a potential to improve nitrogen utilization by ruminants fed diets containing urea.

• 한국응용과학기술학회지
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• 제8권2호
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• pp.153-159
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• 1991

The electrochemical oxidation of p-methoxyphenol and hydroquinone for wastewater treatment application was investigated on platinum anode. At the cyclic voltammetry, it was observed that nagative shift of peak potential of p-methoxyphenol and hydroqinone as the pH of electrolytes increases and the peak current showed higher at strong electrolytes than weak electrolytes. In the case of p-methoxyphenol, the optimum electrode potential of controlled potential electrolysis was observed at the potential region of 0.8-1.0 (V vs. SCE) and hydroquinone was showed at the potential of l.0(V vs. SCE). Specially the oxidation rate of p-methoxyphenol and hydroquinone was showed high value in the acid electrolytes.

• 생명과학회지
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• 제24권1호
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• pp.98-103
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• 2014

NQO1은 플라보 단백질 계통의 2 전자 환원 효소이며 NADH 또는 NADPH를 보조인자로 quinone 계통의 화합물을 hydroquinone으로 환원 한다. 암에서 NQO1은 그에 상응하는 정상 조직과 비교하였을 때 비교적 높은 발현을 나타낸다. NQO1의 다양한 기능 중 quinone 물질 대사는 두 가지 형태의 상반되는 기능을 가진다. 이것은 quinone으로부터 전환된 hydroquinone의 상태적 안정성과 불안정성에 기인하며, 불안정한 hydroquinone의 생성은 산화적 손상 야기 및 DNA 손상은 세포의 운명을 바꾸어 놓게 된다. 따라서 암에서 그 발현이 높은 NQO1을 표적으로 작용하는 생체환원 물질은 암 세포 사멸을 강하게 유도하게 되어 암 치료의 가능성을 보여주고 있다. 항암 표적 분자로서 NQO1 특징과 NQO1을 통해 작용하는 생체환원물질 ${\beta}$-lapachone의 항암 효과와 기전에 대하여 살펴보았다.

• Molecules and Cells
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• 제23권2호
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• pp.198-206
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• 2007

Hydroquinone is a toxic compound and a major benzene metabolite. We report that it strongly inhibits the activation of macrophages and associated cells. Thus, it suppressed the production of proinflammatory cytokines [tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-$1{\beta}$, IL-3, IL-6, IL-10, IL-12p40, IL-23], secretion of toxic molecules [nitric oxide (NO) and reactive oxygen species (ROS)] and the activation and expression of CD29 as judged by cell-cell adhesion and surface staining experiments. The inhibition was due to the induction of heme oxygenase (HO)-1 in LPS-activated macrophages, since blocking HO-1 activity with ZnPP, an HO-1 specific inhibitor, abolished hydroquinone's NO inhibitory activity. In addition, hydroquinone and inhibitors (wortmannin and LY294002) of the phosphatidylinositol-3 kinase (PI3K)/Akt pathway had very similar inhibitory effects on LPS-induced and CD29-mediated macrophage responses, including the phoshorylation of Akt. Therefore, our data suggest that hydroquinone inhibits macrophage-mediated immune responses by modulating intracellular signaling and protective mechanisms.

• 대한화장품학회지
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• 제30권3호
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• pp.415-418
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• 2004

알부틴은 glycosylated hydroquinone으로 여러 식물들에서, 고농도로 발견되며 비교적 안정한 물질이다. 이는 멜라닌화를 억제하는 작용이 있는 것으로 보고되어 있고, 베타-글루코시다제에 의해 포도당과 hydroquinone으로 쉽게 가수분해된다. Hydroquinone 역시 우수한 항멜라닌화 작용을 가지나, 여러 가지 부작용들로 인해 그 사용이 제한적이거나 주의를 요한다. 이 연구는 알부틴과 베타-글루코시다제를 포함하는 미백 화장품이 자외선 조사로 유도된 색소 침착을 억제하는 효과를 알아보고자 하였다. 대상은 10명의 건강한 성인으로 등 부위에 자외선 B를 조사하여 색소 침착 병변을 만들었고 이 병변들은 세 그룹: 알부틴과 베타-글루코시다제를 함유하는 미백 화장품 도포군, vehicle 대조군, no-application 대조군으로 나누었다. 알부틴과 베타-글주코시다제를 함유하는 미백 화장품 도포군은 no-application 대조군에 비교하여 색소 침착을 $50.17\%$ 억제하였다(N = 10:P<0.05). 따라서 알부틴과 베타-글루코시다제를 함유하는 미백 화장품이 기미 등 자외선 조사로 유도되거나 악화되는 과색소성 질환에 효과적으로 사용될 수 있겠다.

• 아시안잔디학회지
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• 제12권3호
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• pp.237-248
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• 1998

자생종과 귀화종의 토양 pH를 측정한 결과 자생종의 토양 pH범위는 5.33~7.20인 반면 귀화 종의 토양 pH는 3.95~6.48로 자생종에 비하여 귀화종의 pH가 낮았다. 귀화식물 추출액 50% 농도 이상부터는 잔디의 발아율이 60% 미만으로 급격하게 억제되었으며 망초추출액이 가장 현저한 발아억제를 보인 반면, 자생식물인 차풀의 30%와 50% 추출액농도에서 발아율이 증가하였다. 자생식물과 귀화식물 추출액에 의한 잔디의 유근생장 억제는 각 농도에 따라 큰 차이를 보이지 않았지만 차풀의 경우는 15% 이상의 추출액 농도에서 유근생장이 60% 이상 현저하게 억제되었다. HPLC에 의한 차풀추출액의 성분 분석 결과는 254nm에서 protocatechuic acid, $ ho$-hydroquinone, $\rho$-coumaric acid, ferulic acid가 분석되었고 284nm에서는 vanillic acid, hydroquinone, benzoic acid, cinnamic acid가 분석되었다. Phenolic compound 각 농도로 잔디의 발아와 유근생장을 조사한 결과 ferulic acid와 vanillic acid는 잔디의 발아율을 증가시켰고 $\rho$-coumaric acid는 유근생장을 억제시켰다.

• 한국식품과학회지
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• 제22권6호
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• pp.625-631
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• 1990

사과로부터 추출한 산화효소와 5종의 polyphenol 화합물을 반응시켜 얻어진 사과효소 갈변반응 생성물(AEBRP)들의 항돌연변이 효과를 검토하기 위해 발암물질로 알려져 있는 N-methyl-N'-nitro-N-nitrosoguanidine(MNNG), mitomycin C(MMC), 4-nitroquinoline-1-oxide(4NQO), benzo(${\alpha}$)pyrene(B(${\alpha}$)P) 그리고 3-amino-1,4-dimethyl-5H-pyrido(4,3-b) indole(Trp-P-1)에 대한 다섯 종류의 사과효소 갈변반응 생성물들의 돌연변이 억제효과를 검토하였다. Bacillus subtilis Hl7과 M45 두 균주를 이용하는 spore rec-assay에서 homocate-chol-AEBRP와 hydroquinone-AEBRP는 농도증가에 따라 MMC와 MNNG에 대하여 강한 억제효과를 나타내었으며 Salmonella typhimurium TA98과 TA100 두 균주를 이용한 Antimutagenicity test에서는 hydroxyhydro-quinone-AEBRP와 pyrogallol-AEBRP는 S-9mix 첨가시 두 균주에서 Trp-P-1과 B(${\alpha}$)P에 대하여 강한 억제효과를 나타내었다. 그리고 대부분의 AEBRP들은 MNNG로 유도된 TA98주에서 $50%{\sim}80%$의 억제효과를 나타내었으나 hydroxy-hydroquinone-AEBRP를 제외한 네 종류의 AEBRP들은 TA100 균주에서 약 94%의 억제효과를 나타내었다. 한편, 4NQO에 대한 다섯 종류의 AEBRP들의 돌연변이 억제효과는 일반적으로 약한 편이었으며, 특히 homocatechol-AEBRP는 TA98 균주에서 48%의 억제효과를 보였고 TA100 균주에서는 homocatechol-AEBRP와 hydroquinone-AEBRP가 46%에서 58% 정도의 억제효과를 나타내었다.

• Journal of Electrochemical Science and Technology
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• 제3권1호
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• pp.24-28
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• 2012

The electrocatalytic activities and surface roughness of indium-tin-oxide (ITO) electrodes have been investigated after thermal treatment at 100, 150, or $200^{\circ}C$ for 30 min, 2 h, or 8 h. To check electrocatalytic activities, the electrochemical behavior of four electroactive species (p-hydroquinone, $Ru(NH_3){_6}^{3+}$, ferrocenemethanol, and $Fe(CN){_6}^{4-}$) has been measured. The electron transfer rate for p-hydroquinone oxidation and ferrocenemethanol oxidation increases with increasing the incubation temperature and the incubation period of time, but the rate for $Ru(NH_3){_6}^{3+}$ is similar irrespective of the incubation temperature and period because $Ru(NH_3){_6}^{3+}$ undergoes a fast outer-sphere reaction. Overall, the electrocatalytic activities of ITO electrodes increase with increasing the incubation temperature and period. The surface roughness of ITO electrodes increases with increasing the incubation temperature, and the thermal treatment generates many towering pillars as high as several tens of nanometer.

• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.833-837
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• 2004

DeniLite$^{TM}$ laccase immobilized platinum electrode was used for amperometric detection of hydroquinone (HQ) and homogentisic acid (HGA) by means of substrate recycling. In case of HQ, the obtained sensitivity is 280 nA/ ${\mu}$M with linear range of 0.2-35 ${\mu}$M ($r^2$ = 0.998) and detection limit (S/N = 3) of 50 nM. This high sensitivity can be attributed to chemical amplification due to the cycling of the substrate caused by enzymatic oxidation and following electrochemical regeneration. In case of HGA, the obtained sensitivity is 53 nA/ ${\mu}$M with linear range of 1-50 $[\mu}M\;(r^2$ = 0.999) and detection limit of 0.3 ${\mu}$M. The response times ($t_{90%}$) are about 2 seconds for the two substrates and the long-term stability is 60 days for HQ and around 40-50 days for HGA with retaining 80% of initial activities. The very fast response and the durable long-term stability are the principal advantages of this sensor. pH studies show that optimal pH of the sensor for HQ is 6.0 and that for HGA is 4.5-5.0. This shift of optimal pH towards acidic range for HGA can be attributed to the balance between enzyme activity and accessibility of the substrate to the active site of the enzyme.

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2771-2775
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• 2011

Poly-ethylenedioxypyrrole (PEDOP) coated thiolated multiwall carbon nanotubes palladium nanoparticles (MWCNTs-Pd) modified glassy carbon electrode (GCE) [PEDOP/MWCNTs-Pd/GCE] for the determination of hydroquinone (HQ) and it’s isomer catechol (CA) were synthesized and compared with bare GCE and thiolated multiwall carbon nanotubes (MWCNTs-SH/GCE). The modification could be made by simple processes on a GCE with MWCNTs-Pd covered by PEDOP in a 0.05 M tetrabutylammonium perchlorate (TBAP)/MeCN solution system. A well-defined peak potential evaluation of the oxidation of hydroquinone to quinone at 0.05 V (vs. Ag/AgCl), and electrochemical reduction back to hydroquinone were found by cyclic voltammetry (CV) in phosphate buffered saline (PBS) at pH 7.4. Peak current values increased linearly with increasing hydroquinone contents. The peak separation between the anodic and cathodic peaks at the PEDOP/MWCNTs-Pd/GCE was ${\Delta}Ep$ = 40 mV for HQ and ${\Delta}Ep$ = 70 mV for CA, resulting in a higher electron transfer rate. Moreover, good reproducibility, excellent storage stability, a wide linear range (0.1 ${\mu}M$ - 5 mM for HQ and 0.01 ${\mu}M$ - 6 mM for CA), and low detection limits ($2.9{\times}10^{-8}$ M for HQ and $2.6{\times}10^{-8}$ M for CA; S/N = 3) were determined using differential pulse voltammetry (DPV) and amperometric responses; this makes it a promising candidate as a sensor for determination of HQ and CA.