• Bulletin of the Korean Chemical Society
• /
• 제35권9호
• /
• pp.2704-2710
• /
• 2014

Catalase (CAT) decomposes hydrogen peroxide that is toxic to the body. In this study, simple and sensitive detector has been developed for observing catalase activity using liquid crystal droplet system. Microscale LC droplet patterns are formed by spreading aldehyde-doped nematic liquid crystal on pre-treated glass slides. When hydrogen peroxide is added, aldehyde is oxidized and amphiphiles are formed. Dodecanoates cause the pattern to transit from bright to dark as they self-assemble to form a carboxyalte monolayer at the interface. When a drop of pre-incubated CAT and hydrogen peroxide mixture is placed onto the pattern, bright fan-shape is observed. This planar optical appearance indicates that catalase has decomposed hydrogen peroxide. Compared to the detectors that have been previously developed, this system is more sensitive with detection limit of 1fM. This research suggests further studies to be on LC droplet patterning to develop highly sensitive and methodologically simple sensors for various chemicals.

• 대한본초학회지
• /
• 제38권4호
• /
• pp.11-19
• /
• 2023

Objectives : The aim of this study was to investigate the effect of baicalein (BA) on the production of hydrogen peroxide and nitric oxide (NO) in RAW 264.7 mouse macrophages stimulated with polyinosinic-polycytidylic acid (poly-IC) and lipoteichoic acid. Methods : RAW 264.7 co-stimulated with poly-IC and lipoteichoic acid were incubated with baicalein at concentrations of 25 and 50 μM. Incubation time is 16 h, 18 h, 20 h, 22 h, and 24 h. After incubation, The production of hydrogen peroxide in RAW 264.7 was measured with dihydrorhodamine 123 assay. Chrysin was used as a comparative material. NO production was evaluated by griess assay. Results : For 16 h, 18 h, 20 h, 22 h, and 24 h incubation, BA at the concentration of 25 and 50 μM significantly inhibited the production of hydrogen peroxide in RAW 264.7 stimulated by poly-IC and lipoteichoic acid (p <0.001). In details, production of hydrogen peroxide in 'poly-IC and lipoteichoic acid'-stimulated RAW 264.7 treated for 16 h with BA at concentrations of 25 and 50 μM was 82.36% and 77.24% of the control group treated with poly-IC and lipoteichoic acid only, respectively; the production of hydrogen peroxide for 18 h was 83.15% and 77.91%, respectively;production of hydrogen peroxide for 20 h was 82.88% and 77.82%, respectively; production of hydrogen peroxide for 22 h was 83.27% and 78.17%, respectively; production of hydrogen peroxide for 24 h was 83.54% and 78.35%, respectively. Additionally, BA at the concentration of 50 and 100 μM significantly inhibited NO production in lipoteichoic acid-induced RAW 264.7 (p <0.001). Conclusions : BA might have anti-oxidative activity related to its inhibition of hydrogen peroxide production in 'poly-IC and lipoteichoic acid'-stimulated RAW 264.7 macrophages.

• 치위생과학회지
• /
• 제8권4호
• /
• pp.255-260
• /
• 2008

본 연구는 전문가 미백제로 많이 사용되고 있는 35% hydrogen peroxide를 사용하여 인공적으로 변색시킨 법랑질에 노출시킨 후 법랑질의 색, 경도 및 표면변화에 미치는 영향을 평가하여 다음과 같은 결론을 얻었다. 1. 35% HP 미백처리군의 색조변화량(${\Delta}E^*$)은 시간의 경과에 따라 색조 변화를 보였으며 통계적으로도 유의한 차이를 나타냈으며 NBS unit로 환산해본 결과 30분 노출군에서는 appreciable에 해당이 되며 1시간, 2시간 노출군에서 각각 much, very much에 해당이 되어 임상적인 의미를 지니는 것으로 나타났다(p < 0.05). 2. 법랑질 표면의 경도를 분석한 결과 대조군에서는 3주동안 거의 변화를 보이지 않은 반면 미백제 노출군에서는 법랑질 표면경도가 매우 낮게 나타났다. 특히 2시간 노출군에서 각 주마다 큰 변화를 보였으며 통계적으로도 유의한 차이를 나타냈다(P < 0.05). 3. 미백처리 전 후의 법랑질 표면에 대한 미세구조를 분석하기 위해 주사전자현미경을 이용하여 관찰한 결과 미백 후 노출시간이 길수록 법랑질 표면의 불규칙한 표면양상을 관찰할 수 있었으며 EDX를 사용하여 법랑질 표면의 성분 분석을 시행해본 결과 모든 군에서 Ca, P의 전반적인 감소를 볼 수 있었으나 통계적으로는 유의한 차이를 보이지 않았다(P > 0.05). 이상의 결과를 종합해 볼 때 35% HP 치아 미백은 미백노출 시간이 길어질수록 법랑질 표면에 영향을 미쳐 술후 치아의 시림이나 거칠어짐과 같은 부작용을 야기 할수 있으므로 짧은 기간 동안 정확한 방법으로 전문가에 의하여 시행되어야 할 것으로 사료된다.

• Bulletin of the Korean Chemical Society
• /
• 제35권2호
• /
• pp.629-630
• /
• 2014

• Restorative Dentistry and Endodontics
• /
• 제19권1호
• /
• pp.114-123
• /
• 1994

The purpose of this study was to examine the shear bond strength of resin-enamel bond formed at specific time intervals after the termination ov vital bleaching. A total of 72 human extracted maxillary premolars were divided into nine groups : untreated control (group 1) ; enamel treated with 35% hydrogen peroxide(group 2, 3, 4, 5) ; and enamel reated with 15% carbamide peroxide gel (group 6, 7, 8, 9). After the treatment with 35% hydrogen peroxide for 2 hours and 15% carbamide peroxide for 24 hours, adhesion of a resin to bleached enamel was formed at 1 hour (group 2, 6) and 24 hours(group 3, 7) ; 3days(group 4, 8) and 7 days(group 5, 9) post-termination of bleaching treatment. A $3{\times}3mm$ mold was filled with Scotchbond Multi-Purpose and Z100. After 24 hours later, the specimens were shear-tested at crosshead speed 1mm/min and analyzed statistically. Fractured specimens from group 1,2, 6 were gold-coated with Eiko ion coater and observed under Scanning electron microscope at 25KV. The following results results were obtained : 1. Bonds formed at 1 hour post-termination of 35 % hydrogen peroxide(P<0.01) and 15 % carbamide peroxide bleaching treatment groups(P<0.05) showed significantly lower shear bond strength than untreated group. 2. Bonds formed at 24 hours, 3 days and 7 days post-termination of 35% hydrogen peroxide and 15 % carbamide peroxide bleaching treatment groups showed no significant differences in shear bond strength with untreated group(p>0.05). 3. SEM examinations of the untreated fracture specimen indicated cohesive fracture within enamel and exposed enamel prisms, but the bleached fracture specimens indicated adhesive fracture.

• 대한본초학회지
• /
• 제36권5호
• /
• pp.117-123
• /
• 2021

Objectives : The aim of this study is to investigate the effect of wogonin on the production of hydrogen peroxide in polyinosinic:polycytidylic acid (poly I:C)-stimulated TM4 mouse sertoli cells. Methods : TM4 were treated with poly I:C (50 ug/mL) and wogonin at concentrations of 5, 10, 25, and 50 µM for 30 min, 2 hr, 12 hr, 18 hr, and 24 hr. The production of intracellular hydrogen peroxide was measured by dihydrorhodamine 123 assay. Results : For 30 min, 2 hr, 12 hr, 18 hr, and 24 hr treatment, wogonin significantly inhibited intracellular hydrogen peroxide productions of TM4 at the concentration of 5, 10, 25, and 50 µM (p<0.05). In details, production of hydrogen peroxide in poly I:C-stimulated TM4 treated for 30 min with wogonin at concentrations of 5, 10, 25, and 50 µM was 95.67%, 92.69%, 92.05%, and 91.97% of the control group treated with poly I:C only, respectively; the production of hydrogen peroxide for 2 hr was 94.44%, 94.41%, 93%, and 92.98%, respectively; production of hydrogen peroxide for 12 hr was 96.78%, 95.32%, 94.33%, and 93.17%, respectively; production of hydrogen peroxide for 18 hr was 94.7%, 93.4%, 93.38%, and 93.35%, respectively; and production of hydrogen peroxide for 24 hr was 95.75%, 94.77%, 94.58%, and 92.8%, respectively. Conclusions : Wogonin might have anti-viral property related with its inhibition of intracellular hydrogen peroxide production in poly I:C-stimulated TM4 cells.

• 치위생과학회지
• /
• 제11권4호
• /
• pp.375-380
• /
• 2011

This study evaluated whether fluoride treatment can affect recovery of the irregularity of enamel surface after tooth whitening with a high concentration of hydrogen peroxide (HP) activated by plasma arc light. A total of 36 bovine teeth stained with coke were used in this experiment. The specimens were classified into following three groups (two different commercial plasma arc groups and a control group without light curing source): (1) 35% HP gel only, (2): 35% HP gel and Plasma arc A, and (3) 35% HP gel and Plasma arc B. To measure color changes and surface morphologies before and after the bleaching, colorimeter and scanning electron microscopy were used, respectively. When the specimens were bleached with hydrogen peroxide and plasma arc lights, the bleaching effect was greater than when only hydrogen peroxide gels were used (Kruskal-Wallis test, p<0.05). In addition, plasma arc B showed the more color changes than plasma arc A (Bonferroni post-hoc test, p<0.05). The surfaces of the teeth treated with fluoride gel after the whitening treatment came to be smooth. Therefore, the results of this study suggested that the fluoride application for patients who got tooth whitening therapy with a high concentration of hydrogen peroxide gels activated by plasma arc light will be effective to recover rough enamel surfaces.

• 한국식품영양학회지
• /
• 제35권4호
• /
• pp.259-267
• /
• 2022

The purpose of this study was to evaluate the antioxidative activities of jeolpyun containing Cnidium officinale M extract (2%, 4%, 6%, 8%) by total polyphenol contents, electron donating ability on 2,2-diphenyl-1-picrylhydrazyl (DPPH), scavenging ability of superoxide anion radical and decomposing ability of hydrogen peroxide. In chromaticity analysis, the brightness significantly decreased with increasing Cnidium officinale M extract content. Jeolpyun containing 8% Cnidium officinale M extract revealing the highest value for the redness and the yellowness, 1.07, 12.70, respectively. The total polyphenol contents of jeolpyun containing 8% Cnidium officinale M extract were the highest content of 4,213 ㎍ gallic acid equivalent (GAE)/mL. The total polyphenol contents revealed significant difference (p<0.05). Jeolpyun containing 8% Cnidium officinale M extract revealing the highest electron donating ability (83.55%). The electron donating abilities were significantly related at p<0.05. The scavenging abilities of superoxide anion radical for jeolpyun containing 4% Cnidium officinale M extract revealed the highest ability (0.01676). There was no significant difference. The hydrogen peroxide decomposing ability for jeolpyun containing 8% Cnidium officinale M extract revealed the most hydrogen peroxide decomposing ability (-0.193) and the hydrogen peroxide decomposing ability revealed a significant difference (p<0.05).

• 미생물학회지
• /
• 제31권2호
• /
• pp.166-174
• /
• 1993

Streptomyces coelicolor (Muller) 의 세포에 $100 \mu$M 의 과산화수소를 1시간 동안 처리하여 과산화수소 스트레스중에 생성되는 단백질을 L-[$^{35}S$] methionine 을 이용하여 순간 표지하였다. 단백질을 추출하여 2차원 겔 전기영동으로 분석한 결과 지수 성장기의 세포가 가지는 총세포 단백질 중 약 100개의 단백질의 합성이 과산화수소에 의해 증가되는 것을 관찰하였다. 이들을 Pin(peroxide inducible) 단백질이라고 명명하고 과상화수소 처리 후 발현이 증가되는 시간에 따라 세 그룹으로 나누었다. 약 60 개의 Pin 단백질은 과산화수소 처리후 20분 이내에 발현이 증가하여 1시간동안 지속적으로 다량 합성되었다. 정체 성장기의 세포에서는 62개의 단백질의 합성이 과산화수소에 의해 증가되었으며, 이 중 21 개의 단백질은 지수성장기의 Pin 단백질과 일치하였다. 과산화수소에 대한 저항성이 증가한 세가지 돌연변이체의 단백질을 지수 성장기에서 추출하여 2 차원 겔 전기영동으로 분석한 결과, 각각의 경우 15, 17, 15개의 Pin 단백질을 야생형보다 항상적으로 다량합성하는 것을 관찰하였다. 이 pin 단백질 중 9개 (D74.7 a, E76.0c, E23.3, F50.7, F47.2a, F25.5, G39.6b, G24.0, H39.6a) 는 두가지 돌연변이체 모두에게 증가되었다. 따라서 이 단백질들은 S. coelicolor 가 과산화수소 스트레스에 대응하는데 있어 중요한 역할을 담당한다고 추정된다.

• 약학회지
• /
• 제56권6호
• /
• pp.390-394
• /
• 2012

A series of new pyridazinyl sulfoxides 3a~e and pyridazinyl sulfones 4a were synthesized for development of candidates to retain anticancer activity. The utility of sulfoxides and sulfones in both laboratory and industrial practice was quickly recognized, and these species have been extensively utilized, including as pharmaceutical intermediates and anticancer agents. Alkylthiopyridazines 2a~e were prepared from the 3,6-dichloropyridazine using allylthiolation with alkyl mercaptan. Sulfides could be oxidized to sulfoxides or sulfones using 1~3 equivalents of hydrogen peroxide as an oxidant. The oxidation of sulfoxides to sulfones was also accomplished with aqueous hydrogen peroxide. Formation of 3a~e and 4a was undertaken with stirring using 35% hydrogen peroxide at room temperature in acetic acid for 18~72 h. Synthetic compounds were identified using NMR spectrum.