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Effects of kojic acid, arbutin and vitamin C on cell viability and melanin synthesis in B16BL6 cells
( Yumi Park ),( Jongsung Lee ),( Junho Park ),( Deokhoon Park ) 대한화장품학회 2003 대한화장품학회지 Vol.29 No.1
Melanin biosynthesis is a human defense mechanism to protect skin from UV irradiation and also determines colors of hair and skin. However, as a interest on skin-whitening increases, researches to prevent pigmentation and hypersynthesis of melanin in skin are being actively in progress. Active components used as a whitening agent in cosmeceuticals are kojic acid, arbutin, vitamin C and hydroquinone. However, until now, because comparison researches among them in the aspect of both melanin formation and cellular toxicity have not been performed, we can't exactly estimate merits and defects of them as a whitening agent. To this end, we performed experiments to compare their effects on cell viability and melanin formation. As a first step, in vitro tyrosinase inhibition assay was done. While kojic acid and hydroquinone showed strong inhibition activities(their IC<sub>50</sub>/s are all < 100uM), arbutin and vitamin C showed weak activities. IC<sub>50</sub>/s of arbutin and vitamin C are 100uM and 400∼500uM, respectively. In B16BL6 melanoma cells, like in vitro tyrosinase inhibition assay, arbutin and kojic acid showed more strong inhibition effect on melanin synthesis than vitamin C. And unlike arbutin, vitamin C and kojic acid induced cell death at high concentration. Although arbutin showed no cytotoxicity, it has side effect to induce morphological change at high concentration.. In this paper, we suggest both kojic acid and arbutin have stronger ability to inhibit melanogenesis than vitamin C. And they also have side effect, that is, kojic acid induces cell death like vitamin C and arbutin changes cell morphology respectively.
( Yumi Park ),( Jae-gook Shin ),( Sun-young Lee ),( Jeong Seong Yang ),( Jake Whang ),( Eun-soon Son ),( Tae Won Jang ),( Je Hun Kim ),( Jee Youn Oh ),( Jusang Kim ),( Hyungwoo Kim ),( Yong-soon Cho ) 대한결핵 및 호흡기학회 2021 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.129 No.0
Background Minimum inhibitory concentration (MIC) of antibiotics has been widely conducted for drug susceptibility test (DST) of most bacterial infectious diseases, except tuberculosis (TB). Current phenotypic DST for TB uses one or two critical concentrations to determine the resistance of anti-TB drugs. The MIC test would be necessary not only for therapeutic drug monitoring-based precision medicine but also for detecting borderline resistance of anti-TB drugs. Here, we present the distribution of MIC of anti-TB drugs in cPMTb cohort Mycobacterium tuberculosis (Mtb) isolates. Methods From 2019-2020, 205 Mtb strains were collected in the cPMTb cohort. Broth microdilution method in 96 well plates were used for the MIC test of anti-TB drugs, except for pyrazinamide (PZA). MGIT960 system was used for PZA MIC determination. Results The proportions of drug-resistant (DR) and drug-susceptible (DS) strains were 13.1% and 86.9%, respectively. Most of the DS MIC were distributed below the critical concentration of the drug. Six discordances between phenotypic or genotypic DST and MIC were found in this study. Two cases of disputed mutation L511P on rpoB were included in the discordance cases. Their MIC of rifampicin was 0.5 ug/ml. It is lower than critical concentration but higher than epidemiological cut-off value. Conclusion MIC of cPMTb cohort 205 strains were distributed mostly below the critical concentration of all drugs. There are 6 cases of discordance between MIC and DST (phenotypic or genotypic). The MIC test could be utilized to overcome the limitation of phenotypic DST using critical concentration and fill the gap between genotypic and phenotypic DST.
( Yumi Park ),( Sun-young Lee ),( Eun-soon Son ),( Jeong Seong Yang ),( Jake Whang ),( Tae Won Jang ),( Je Hun Kim ),( Jee Youn Oh ),( Hyn Kuk Kim ),( Hyo-jung Kim ),( Yong-soon Cho ),( Jae-gook Shin 대한결핵 및 호흡기학회 2020 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.128 No.-
Background Minimum inhibitory concentration (MIC) of antibiotics has been widely conducted for drug susceptibility tests (DST) of most bacterial infectious diseases, except tuberculosis (TB). Current phenotypic DST for TB uses one or two critical concentrations to determine the resistance of anti-TB drugs. The MIC test would be necessary not only for therapeutic drug monitoring-based precision medicine but also for detecting borderline resistance of anti-TB drugs. Here, we present the distribution of MIC of 4 first-line drugs and levofloxacin in cPMTb cohort Mycobacterium tuberculosis (Mtb) isolates. Methods From 2019-2020, 108 Mtb strains were collected in the cPMTb cohort. Broth microdilution Method in 96 well plates was used for the MIC test of anti-TB drugs, except for pyrazinamide (PZA). MGIT960 system was used for PZA MIC determination. Results The proportions of drug-resistant (DR) and drug-susceptible (DS) strains were 15.7% and 84.3%, respectively. Most of the DS MIC were distributed below the critical concentration of the drug. Three discordances between phenotypic DST and MIC were found in isoniazid, which is 2.8% in total. We observed 2 cases (1.9%) of low-level resistance (MIC 0.5 ug/ml), determined as DS for rifampicin in phenotypic DST but DR in genotypic DST. Conclusion MIC of cPMTb cohort 108 strains were distributed mostly below the critical concentration of all drugs. There are 6 cases of discordance between MIC and DST (phenotypic or genotypic). The MIC test could be utilized to overcome the limitation of phenotypic DST using critical concentration and fill the gap between genotypic and phenotypic DST.
Park, Sun Hee,Park, Yumi,Han, Jeong Sik,Jeong, Byung Hun,Han, Hogyu,Kim, Sung Hyun American Chemical Society 2015 ENERGY AND FUELS Vol.29 No.1
<P>We investigated the thermal stability of <I>exo</I>-tetrahydrodicyclopentadiene (<I>exo</I>-THDCP, C<SUB>10</SUB>H<SUB>16</SUB>) in the absence and presence of 5,6,7,8-tetrafluoro-1,2,3,4-tetrahydroquinoxaline (TFQox), a new hydrogen donor (H donor). Conversion of <I>exo</I>-THDCP was slowed in the presence of TFQox but less effectively compared to its analogues, 1,2,3,4-tetrahydroquinoxaline (THQox) and 1,2,3,4-tetrahydroquinoline (THQ). We analyzed the H-donor effects on the thermal decomposition kinetics of <I>exo</I>-THDCP, which explains the relative effect of the H donors on the thermal stability improvement of <I>exo</I>-THDCP.</P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ef5016445'>ACS Electronic Supporting Info</A></P>
( Yumi Park ),( Sung Young Lee ),( Young-kyung Choi ),( Yong-soon Cho ),( Tae Won Jang ),( Je Hun Kim ),( Jee Youn Oh ),( Jaehee Lee ),( Hyewon Seo ),( Jae-gook Shin ) 대한결핵 및 호흡기학회 2020 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.128 No.-
Background Discordancy across phenotypic (pDST) and genotypic drug susceptibility test (gDST) Results of isoniazid (INH) and rifampicin (RIF) has been reported between 5%-15%, depending on the compared Methods. The strain has been considered as resistant to test drugs, either one is shown as resistant. However, the strain would be considered as drug-susceptible (DS) if it was the false-negative in both pgDST. Here we report five discrepancy cases and one case of false-negative INH resistant strain screened by the MIC test. Method Results of pDST, gDST, and minimum inhibitory concentration (MIC) of 108 cPMTb clinical Mycobacterium tuberculosis (Mtb) isolates were compared. DNA sequences of resistant genes were analyzed by Sanger sequencing for discrepant cases. Anti-tuberculosis (TB) drug concentrations and N-acetyltransferase-2 (NAT2) genotypes of patients were analyzed to estimate the effectiveness of anti-TB drugs based on the pharmacokinetic model. Result Six cases (5.6%) of discrepancy were found among 108 cPMTb MIC tested Mtb isolates. Four of gRpS strains were confirmed as rifampicin or isoniazid low-level resistance. The other two (gS)pS strains were confirmed as low-level resistance of ethambutol or isoniazid. The INH gSpS strain was redefined as an INH-resistance via MIC and DNA sequencing. It harbored a rare mutation Q439R in katG. Despite the INH resistance, the patient was exposed to sufficient INH concentration according to our pharmacokinetic simulation. Conclusion The MIC tests screened one-third of discrepancy cases in this study. Currently, the MIC test is not conducted regularly for first-line anti-TB drugs. The discrepancy rate would be increased if the MIC test and DNA sequencing are widely undertaken.
파일럿 규모 연소기에서 밀짚 펠렛 혼소 시 첨가제에 따른 회 점착의 특성 연구
박유미(Yumi Park),임호(Ho Lim),채태영(Taeyoung Chae),이재욱(Jaewook Lee),고대홍(Dae-hong Ko),양원(Won Yang) 한국열환경공학회 2019 한국열환경공학회 학술대회지 Vol.2019 No.춘계
최근 국내 미활용 바이오매스에 대한 관심이 증가하고 있고 미분탄 보일러에 적용 가능성을 타진하고 있다. 그러나 미분탄 보일러에 바이오매스 혼소 적용 시 회 발생은 중요한 문제로 이를 감소시키는 것은 보일러의 효율적인 운전을 위해 반드시 필요하다. 따라서 본 연구의 목적은 회 점착에 영향을 미칠 수 있는 다양한 첨가제에 따라 석탄, 바이오매스 혼소 시 발생하는 회 점착 특성, 특히 증저감 특성을 규명하는 것이다. 본 연구에서 사용된 바이오매스는 초본계로 밀짚 펠렛(straw pellet)이다. 첨가제로는 카올린(Al2Si2O5(OH)4), 황산암모늄((NH4)2SO4), 인산수소칼슘(CaHPO4), 산화 알루미늄 (Al2O3), 산화 칼슘(CaO)을 선택하여 비교하였다. 연료의 공업분석, 원소분석 및 ICP 등의 기초 분석을 수행하여 연료 특성을 확인하였다. 분석 결과를 바탕으로 80kWth 설비를 사용하여 바이오매스와 석탄 혼소 시 회 점착 거동을 조사하였다. 회 점착 생성 정도는 실시간 무게 측정이 가능한 측정 장비(on-line deposit measuring system)를 활용하여 회 점착량을 측정하였으며, 첨가제에 따른 회 점착 무게를 비교하였다. 그리고 다양한 첨가제 사용에 따른 메커니즘을 분석하기 위해 회 점착을 SEM/EDS 분석을 수행하였다. 결과적으로 동일한 연료가 사용되더라도 첨가제의 종류에 따라 회 점착 형성 메커니즘의 차이로 인해 회 점착을 촉진 또는 억제하는 다양한 결과가 발생함을 확인하였다.