• Journal of Ginseng Research
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• 제27권2호
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• pp.52-55
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• 2003

The present experiment was perf'3rmed to investigate the protective effects of ginseng total saponin (GTS) and possible mechanisms on the hepatocytotoxicity induced by tert-butylhydroperoxide (t-BuOOH), 4-Bromo-calciumu ionophore A23187 (Br-A23187) and KCN. Hepatocytes were isolated by collagenase perfusion of livers from fasted male Sprague Dawley rats and cultured overnight. After various treatments in Krebs-Ringer-HEPES buffer at pH 7.4, cell viability was determined by propidium iodide using fluorocytometry. GTS (5-20 ${\mu}$M) inhibited cell killing induced by t-BuOOH, and KCN, dose-dependently. However, GTS did not inhibit Br-A23187-induced cell killing. These findings support that GTS could protect the hepatocytoxicity induced by some toxic chemicals. The mechanisms of these protective effects by GTS seem to be associated with antioxidant activity and increase of cellular ATP.

• Applied Biological Chemistry
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• 제41권5호
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• pp.390-394
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• 1998

맥문동 괴근을 80% MeOH 수용액으로 추출하고, 얻어진 추출물을 EtOAc, n-BuOH 및 $H_2O$로 용매 분획하였다. 암세포 A549, SK-OV-3, SK-Mel-2, XF-498 및 HCT-15에 대한 각 분획물의 생장억제활성을 SRB 법으로 측정한 결과 n-BuOH 분획에서 암세포 생장억제활성이 높게 나타났다. n-BuOH 분획으로부터 Amberlite XAD-II 및 silica gel column chromatography를 반복하여 2종의 사포닌을 분리하였고, NMR, IR 데이터의 해석과 가수분해반응을 이용하여 spicatoside A와 B로 동정하였다. Spicatoside A가 암세포에 대한 생장억제활성을 보여 A549, SK-OV-3, SK-Mel-2, XF-498 및 HCT-15에 대한 $IC_{50}$ 값이 각각 17.3, 21.7, 14.9, 18.8 및 $15.6\;{\mu}g/ml$를 나타내었다.

• 한국환경과학회지
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• 제12권3호
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• pp.337-344
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• 2003

The photodegradation of pyrene, chrysene and benzo［a］pyrene, that were similar in structure among poly-cyclic aromatic hydrocarbons (PAMs), were investigated in water irradiated with a low-pressure mercury lamp (wavelength of 253.7 nm and UV output of 1.35 ${\times}$ 10$\^$-3/J/s). The effects of several factors (t-BuOH, HCO$_3$$\^$-/ and pH) on photodegradation of above three PAHs were also examined. The photodegradation rates of PAHs decreased with increasing the concentration of t-BuOH, but decreased little with increasing the concentration of HCO$_3$$\^$-/ under the concentrations used in this study. The photodegradation rates of PAHs decreased with increasing pH, but their change were greater in case of pH increase from acid to neutral and were little in case of pH increase from neutral to base. The photodegradation rates of PAMs fitted a first-order kinetic model and their photodegradation rates decreased in the following sequences: pyrene>chrysene>benzo[a]pyrene among the PAHs used.

• Macromolecular Research
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• 제17권7호
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• pp.522-527
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• 2009

A photocrosslinkable polyphosphazene was used for molecular imprinting. We synthesized polyphosphazene (3) having urea groups for complexation with N-carbobenzyloxyglycin (Z-Gly-OH, template) and chalcone groups for cross-linking reaction. As substituents, 4-hydroxycha1cone (1) and N-(4-hydroxyphenyl)-N'-ethylurea (2) were prepared. Choloro groups of poly(dichlorophosphazene) were replaced by the sequential treatment with sodium salts of compounds 1 and 2, and trifluoroethanol. The template molecule was complexed with the urea groups on the polymer chains via hydrogen bonding. A thin polymer film was prepared by casting a solution of the complex of polymer 3 and the template in dimethylformamide on a quartz cell and irradiated with 365 nm UV light to yield a cross-linked film with a thickness of about $16{\mu}m$. The template molecules in the film were removed by Soxhlet extraction with methanol/acetic acid. The control polymer film was prepared in the same manner for the preparation of the imprinted polymer film, except that the template and triethylamine were omitted. In the rebinding test, the imprinted film exhibited much higher recognition ability for the template than the control polymer. We also investigated the specific recognition ability of the imprinted polymer for the template and its structural analogues. The rebinding tests were conducted using Z-Glu-OH, Z-Asp($O^tBu$)-OH, and Z-Glu-OMe. The imprinted film showed higher specific recognition ability for the template and the lowest response for Z-Asp($O^tBu$)-OH.

• Bulletin of the Korean Chemical Society
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• 제19권3호
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• pp.319-323
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• 1998

The phodissociation dynamics of t-butyl hydroperoxide at 280-285 nm has been investigated by measuring laser induced fluorescence spectra of the fragment OH. Measured fractions of the available energy distributed among the fragments are ft=0.56, fr(OH)=0.044, fint(t-BuO)=0.40, and negligible populations of OH are found in vibrationally excited states. By analyzing the Doppler profiles of the spectra of OH, the positive ν-J vector correlation has been obtained. From the measured ν-J correlation and A" propensity in the two Λ-doublets of OH, it is concluded that the dissociation takes place directly from the repulsive surface induced by the σ* ← n transition with the fragment OH rotating in the plane perpendicular to the dissociating O-O bond axis.

• Bulletin of the Korean Chemical Society
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• 제11권2호
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• pp.134-139
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• 1990

The hydrogenation catalyst precursors $[(L-L)Rh(NBD)]ClO_4\;(L-L=Fe({\eta}^5-C_5H_4PBu^t\;_2)_2,\;Fe({\eta}^5-C_5H_4PPhBu^t)_2$; NBD = norbornadiene) react with $H_2(1\;atm,\;30^{\circ}C$, MeOH) to yield $[(L-L)HRh({\mu}-H)_3RhH(L-L)]ClO_4$. These hydrido species are fluxional, and variable temperature NMR studies show the existence of a number of equilibria involving both fluxional and non-fluxional species. The synthesis, solution structures, and fluxional behaviors of these hydrides are described.

• Natural Product Sciences
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• 제18권3호
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• pp.153-157
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• 2012

Obesity, which is characterized by excessive fat accumulation in adipose tissues, occurs by fat absorption by lipase and sequential fat accumulation in adipocyte through adipocyte differentiation. Thus, inhibition of pancreatic lipase activity and adipocyte differentiation would be crucial for the prevention and progression of obesity. In the present study, we attempted to evaluate anti-adipogenic activity of several algae extracts employing preadipocytes cell line, 3T3-L1 as an in vitro assay system. The effects on pancreatic lipase activity in vitro were also evaluated. Total methanolic extracts of Cladophora wrightiana and Costaria costata showed significant inhibitory activity on adipocyte differentiation as assessed by measuring fat accumulation using Oil Red O staining. Related to pancreatic lipase, C. wrightiana and Padina arborescens showed significant inhibition. Further fractionation of C. wrightiana, which showed the most potent activity, suggested that $CHCl_3$ and n-BuOH fraction are responsible for adipocyte differentiation inhibition, whereas n-BuOH and $H_2O$ fraction for pancreatic lipase inhibition. Our study also demonstrated that n-BuOH fraction was effective both in early and middle stage of differentiation whereas $CHCl_3$ fraction was effective only in early stage of differentiation. Taken together, algae might be new candidates in the development of obesity treatment.

• 대한환경공학회지
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• 제32권6호
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• pp.639-648
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• 2010

본 연구는 극미량의 BPA 분석법을 정립하기 위하여 HPLC-MS/MS를 이용한 BPA 분석 조건을 개발하였고, 초음파를 이용한 BPA의 분해 특성을 조사하였다. HPLC-MS/MS에 의한 BPA의 MDL과 LOQ는 각각 0.13 nM과 1.3 nM로 조사되었는데, 이는 기존의 HPLC-UV (MDL: 81.1 nM, LOQ: 811 nM) 및 FLD (MDL: 4.6 nM, LOQ: 46 nM) 보다 약 620배 및 35배 우수하였으며, U.S. EPA의 음용수 권고기준(1.53 ${\mu}M$ 혹은 350 ${\mu}g/{\ell}$)의 약 1,180배 이하까지 정량분석이 가능하였다. 초음파 조사에 따른 BPA의 분해효율은 저주파(28 kHz)를 제외한 중?고주파 조건(580 and 1000 kHz)에서 반응 30분 이내에 95%이상 제거되었다. 특히 BPA의 분해효율 및 k1의 결과는 580 kHz에서 가장 우수하였는데, 이는 580 kHz 근처의 주파수 영역에서 최적의 초음파 공동현상 및 열분해/산화분해가 일어남을 알 수 있었다. 0.01 mM의 $CCl_4$를 첨가하여 분해효율을 측정한 결과 30분 이내에 BPA 초기농도(1 ${\mu}M$)의 98% 이상까지 제거되었으며, 반응 초기(5분)와 후기(30분)의 $k_1$값은 무첨가 반응에 비해 각각 1.4배 및 1.1배씩 증가하였다. 10 mM의 t-BuOH이 첨가된 결과 무첨가 반응에 비해 약 60% 이상 BPA 분해효율이 감소한 것을 감안할 때 BPA의 주된 초음파 기전은 OH 라디칼에 의한 산화분해임을 알 수 있었다. 그러나 t-BuOH이 첨가된 반응시간 동안(30분) 약 33%의 BPA가 분해가 일어난 것은 OH 라디칼 뿐 아니라 열분해 및 기타 라디칼 등에 의한 분해가 진행되었을 것으로 판단된다.

• Bulletin of the Korean Chemical Society
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• 제24권9호
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• pp.1293-1302
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• 2003

Rate constants at various temperatures and activation parameters are reported for solvolyses of acyl chlorides (RCOCl), with R = Me, Et, i-Pr, t-Bu, cyclopentylmethyl, benzyl, thiophenylmethyl, 2-phenylethyl, diphenylmethyl, and phenylthiomethyl in 100% ethanol, 100% 2,2,2-trifluoroethanol (TFE), 80% v/v ethanol/ water and 97% w/w TFE/water. Additional rate constants for solvolyses with R = Me, t-Bu, and $PhCH_2$ are reported for TFE/water and TFE/ethanol mixtures, and for solvolyses with R = t-Bu, and PhCH2 are reported for 1,1,1,3,3,3-hexafluoropropan-2-ol/water mixtures, as well as selected kinetic solvent isotope effects (MeOH/MeOD and TFE). Taft plots show that electron withdrawing groups (EWG) decrease reactivity significantly in TFE, but increase reactivity slightly in ethanol. Correlation of solvent effects using the extended Grunwald-Winstein (GW) equation shows an increasing sensitivity to solvent nucleophilicity for EWG. The effect of solvent stoichiometry in assumed third order reactions is evaluated for TFE/ethanol mixtures, which do not fit well in GW plots for R = Me, and t-Bu, and it is proposed that one molecule of TFE may have a specific role as electrophile; in contrast, reactions of substrates containing an EWG can be explained by third order reactions in which one molecule of solvent (ethanol or TFE) acts as a nucleophile, and a molecule of ethanol acts as a general base catalyst. Isokinetic relationships are also investigated.

• 생명과학회지
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• 제32권12호
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• pp.979-988
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• 2022

비만은 당뇨, 고혈압, 심근경색 등 심혈관 질환을 유발하는 주요 원인으로 이와 관련된 질환의 발병률이 증가하고 있다. 이로 인해 비만 치료 및 예방에 대한 관심이 급증하는 추세이며, 비만 치료제가 전 세계적으로 개발되고 있지만 많은 부작용을 초래하여 시판이 중단되거나 장기복용이 금지되어 있다. 이러한 문제를 막기 위해 부작용이 적으면서 항비만 효과를 가지는 천연 소재를 활용한 연구가 진행되고 있다. 본 연구에서 사용된 해당화(Rosa rugosa)는 장미과에 속하는 낙엽활엽관목으로서 토혈, 하리, 월경과다 등에 이용되고 있으며, 항염증, 항산화 효과, 노화방지, 혈당 강하작용, 혈청 콜레스테롤 수치 저하작용, HIV protease 저해 등에도 효과가 있는 것으로 알려져 있다. 따라서 본 연구에서는 해당화 추출물 및 분획물 4종(H₂O, n-BuOH, 85% aq. MeOH, n-Hex)의 지방세포분화에 미치는 효과에 대한 연구를 진행하였다. 3T3-L1 지방전구세포를 지방세포로의 분화를 유도하여 Oil-Red O staining으로 지방생성 억제 정도를 측정하였다. 그 결과, 갯완두 추출물 및 분획물 처리군에서 농도 의존적으로 지방세포 형성이 억제되는 것을 확인하였다. 또한 지방세포분화에 관여하는 PPARγ, C/EBPα 및 SREBP1c와 같은 인자의 mRNA 및 단백질 발현에 미치는 효과를 확인한 결과, 지방세포분화 조절인자의 발현이 농도 의존적으로 감소하는 것을 확인하였다. 이는 AMPK 신호전달경로를 통한 지방분화인자의 억제를 통한 것으로 확인되었다. 따라서 본 연구결과로부터 해당화 추출물 및 분획물의 항비만 효과를 확인하였으며, 나아가 비만 치료제의 소재로 개발될 수 있는 가능성을 제시할 것으로 기대된다.