• Corrosion Science and Technology
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• 제5권5호
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• pp.160-167
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• 2006

S-Acetyl Isothiourea Acetate (S-AITA) was synthesized in the laboratory and this influence on the inhibition of corrosion of mild steel in 1.11 N hydrochloric and 1.12 N sulphuric acids was investigated by weight loss and potentiostatic polarization techniques at 303K, 353K and 403K. These results were confirmed by the impedance technique. The inhibition efficiency increased with increase in concentration of inhibitor and decreased with rise in temperature from 303K to 403K. The maximum inhibition efficiency of S-AITA was found to be 99.95% (0.5% of S-AITA) at 303K in sulphuric acid. The adsorption of this compound on the mild steel surface from the acids has been found to obey Temkin's adsorption isotherm. The potentiostatic polarization results revealed that S-AITA was a mixed type inhibitor. Some thermodynamic parameters i.e., activation energy (Ea), free energy of adsorption (${\Delta}G_{ads}$), enthalpy of adsorption (${\Delta}H$) and entropy of adsorption (${\Delta}S$) were also calculated from weight loss data.

• Archives of Pharmacal Research
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• 제29권11호
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• pp.1061-1065
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• 2006

A new chiral derivatization agent with sugar moiety, 2,3,4,6-tetra-O-acetyl-${\beta}$-D-galactopyranosyl isothiocyanate (GATC) was synthesized. Several ${\beta}-blockers$ were investigated for the possible separation of the enantiomers by reversed-phase HPLC after derivatization with this new chiral derivatization agent (GATC). GATC was reacted readily with ${\beta}-blockers$ at room temperature and the reaction mixture could directly be injected into the HPLC system. The corresponding diastereomers were well resolved on an ODS column with acetonitrile-ammonium acetate buffer as a mobile phase and monitored at UV 254 nm. The optimization of the derivatization procedure (concentration of GATC, reaction temperature and time) and HPLC conditions (pH and ionic strength of mobile phase) were investigated and compared with GITC.

• 한국연초학회지
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• 제6권1호
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• pp.25-31
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• 1984

The volatile aroma components were isolated from Korean flue-cured tobacco (N.C. 2326) by using a vacuum steam distillation method. Individual aroma components were identified by GCIMS and comparison of gas chromatowaphic retention time with those of the authentic samples. Sensory analysis showed that a vacuum steam-distilled product of Flue-cured tobacco had a typical haylike, floral and fruity aroma. Among 62 compounds identified, major compounds included neophytadiene, benzyl alcohol, ethyl acetate, phenyl ethyl alcohol, ethyl alcohol, ethyl formate, acetic acid, solanone, 2-acetyl pyrrole, $\beta$-ionone epoxide, 2, 4-heptadienal (2 isomers), megastigmatrienone (4 isomers), furfural and total amounts of 13 compounds were about 80%.

• Bulletin of the Korean Chemical Society
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• 제3권1호
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• pp.34-36
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• 1982

N-Methacryloyl-L-histidine and N-methacryloyl-L-histidine methyl ester were synthesized and polymerized to obtain polymeric catalysts with different functions. In the presence of each of these polymers the solvolytic reactions of p-nitrophenyl acetate (PNPA), 3-nitro-4-acetoxybenzoic acid(NABA), 3-acetoxy-N-trimethylanilinium iodide(ANTI) and 3-nitro-4-decanoyloxybenzoic acid(NDBA) were performed in 20% aqueous ethanol. For the purpose of comparison the low molecular weight analogs(LMWA's), L-histidine, L-histidine methyl ester and N-acetyl-L-histidine were also subjected to catalyze the solvolyses of above substrates. In the solvolysis of PNPA the polymeric catalysts exhibited lower activities than the LMWA's. However the ionic substrates, NABA and ANTI were solvolyzed at anomalous rate by polymeric catalyst, indicating that electrostatic effects are operative in the catalysis by polymers. Furthermore in the solvolysis of hydrophobic monomer NDBA, polymeric catalysts exhibited highly enhanced activities compared with the LMWA's implying that hydrophobic interaction can be the most important contribution to the high catalytic activity of imidazole-containing polymers.

• Journal of Applied Biological Chemistry
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• 제57권4호
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• pp.295-299
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• 2014

뽕나무(Morus alba L.) 뿌리껍질을 실온에서 80% MeOH 수용액으로 추출하고 이 추출물을 EtOAC 분획, n-BuOH 분획, $H_2O$ 분획으로 나누었다. EtOAc 분획에 대하여 silica gel과 ODS column chromatography를 반복 실시하여 5종의 triterpenoid를 분리, 정제하였다. NMR, IR, 및 EI/MS 등을 해석하여, ${\alpha}$-amyrin (1), ${\alpha}$-acetyl amyrin (2), lupeol (3), betulinic acid (4) 그리고 glutinol (5)로 구조동정 하였다. 화합물 중 a-amyrin (1), lupeol (3) 그리고 glutinol (5)은 상백피로부터는 이번 실험에서 처음으로 분리되었다.

• 생명과학회지
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• 제22권6호
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• pp.852-856
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• 2012

한약재의 원료 및 전세계적 외래종으로 알려져 있는 녹조류 청각(Codium fragile)의 디클로로메탄, 에탄올, 열수 추출물을 대상으로 하여 생쥐에서의 항 염증, 해열, 및 진통 활성을 조사하였다. 청각의 디클로로메탄과 에탄올 추출물은 phorbol 12-myristate 13-acetate로 유도된 생쥐 귀의 부종과 충혈에 대한 염증 증상을 74% 이상의 높은 저해 작용을 보였으며, 이들 추출물은 acetyl salicylic acid와 유사하게 발열증상을 억제하였다. 청각으로부터 주된 항 염증 활성물질은 eicosapentaenoic acid인 것으로 분리되었다. 이러한 결과는 청각이 여러 염증 관련 증상에 대처할 약제로서도 사용되어 질 수 있다는 사실을 뒷받침해 준다.

• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1203-1210
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• 2011

Function-driven metagenomic analysis is a powerful approach to screening for novel biocatalysts. In this study, we investigated lipolytic enzymes selected from an alluvial soil metagenomic library, and identified two novel esterases, EstDL26 and EstDL136. EstDL26 and EstDL136 reactivated chloramphenicol from its acetyl derivates by counteracting the chloramphenicol acetyltransferase (CAT) activity in Escherichia coli. These two enzymes showed only 27% identity in amino acid sequence to each other; however both preferentially hydrolyzed short-chain p-nitrophenyl esters (${\leq}C_5$) and showed mesophilic properties. In vitro, EstDL136 catalyzed the deacetylation of 1- and 3-acetyl and 1,3-diacetyl derivates; in contrast, EstDL26 was not capable of the deacetylation at $C_1$, indicating a potential regioselectivity. EstDL26 and EstDL136 were similar to microbial hormone-sensitive lipase (HSL), and since chloramphenicol acetate esterase (CAE) activity was detected from two other soil esterases in the HSL family, this suggests a distribution of CAE among the soil microorganisms. The isolation and characterization of EstDL26 and EstDL136 in this study may be helpful in understanding the diversity of CAE enzymes and their potential role in releasing active chloramphenicol in the producing bacteria.

• Asian-Australasian Journal of Animal Sciences
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• 제4권1호
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• pp.91-97
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• 1991

Twenty five 75% Holstein Friesian cross bred bullocks fed rice straw (Oryza sativa) of long form, were fed with the following five treatments. 1. Rice straw, untreated (RS) 2. RS + water (1:1), stored for 24 hours (WRS) 3. RS (100 kg) + urea solution (4 kg urea/100 litre water) and dried (USRS) 4. RS (100 kg) + urea solution (as in 3) stored in wet condition for 24 hours (UWRS) 5. RS (100 kg) + urea solution (as in 3) stored in pit for 21 days (UTRS). Potential digestibility of treatments of RS was evaluated by monitoring (in vitro) Simulating Rumen like Fermentation (SRLF). The results indicated that Dry Matter Intake (DMI), digestibility of nutrients, N utilization were of the order UTRS > UWRS > USRS > WRS and RS (p < 0.05 to p < 0.01). SRLF index was high (255.84) for UTRS and least (145.58) for USRS. It was intermediary (199.66) for UWRS. The acetyl content (AC) of UTRS with higher hemicellulose (HCE) digestibility (80.8%) was low compared to UWRS, USRS, RS and WRS. The acetate content was of the order UTRS < UWRS < USRS < WRS and RS thereby indicating that reduction in acetyl content was an index of positive response of urea-treatment of RS. In addition, the ratio of HCE/AC in faeces of UTRS was 0.87 as against the ratios (2.26-2.48) observed in other treatments recording reduction in AC due to urea-treatment. Among the treatments, USRS only supplemented N while UTRS in addition to utilization N, increased the digestibility of structural carbohydrates. Reduction in treatment time from 21 days to 1 day (UWRS) resulted in improvements similar to those of UTRS.

• Journal of the Korean Wood Science and Technology
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• 제42권6호
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• pp.740-746
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• 2014

꾸지뽕나무 미숙과를 50% 발효주정으로 추출하고, 농축한 추출용액을 n-hexane, chloroform, ethyl acetate, butanol로 순차적으로 분액하여 수용성 조추출물을 얻었다. 수용성 조추출물을 분취용 겔 투과 크로마토그래피(Gel Permeation Chromatography, GPC)를 실시하여 다당류(F1)를 분리하였다. F1을 가수분해하여 단당 성분 분석을 실시한 결과 glucose, galactose, arabinose, xylose 등 4가지로 구성되어 있었으며, 그 조성비는 6.1 : 1.8 : 3.1 : 1.0이었다. F1에 acetyl 기의 치환여부와 uronic acid의 존재 유무를 확인하기 위해 FT-IR로 측정하고 염산 가수분해 한 다음 HPLC 분석을 실시한 결과, 두 가지 모두 없는 것으로 분석되었다. 결합 위치 확인을 위해 permethylation, 산 가수분해, 환원, silylation을 순차적으로 실시하여 얻은 partially methylated alditol silylate (PMAS)들을 GC-MS 분석을 실시한 결과, 1,5-di-O-trimethylsilyl-2,3,4-tri-O-methyl xylose, 1,5-di-O-trimethylsily-2,3,4-tri-O-methyl arabinose, 1,4,5-tri-O-trimethylsily-2,3-di-O-methy arabinose, 1,3,5-tri-O-trimethylsily-2,4,6-tri-O-methyl glucose, 1,4,5-tri-O-trimethylsily-2,3,6-tri-O-methyl galactose, 1,4,5-tri-O-trimethylsily-2,3,6-tri-O-methyl glucose, 1,3,5,6-tetra-O-trimethylsily-2,4-di-O-methyl galactose, 1,3,5,6-tetra-O-trimethylsily-2,4-di-O-methyl glucose로 구성되어 있었고 그 조성비는 1.1 : 1.0 : 4.9 : 7.5 : 3.0 : 3.1 : 1.4 : 1.5였다.

• Biomolecules & Therapeutics
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• 제24권4호
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• pp.438-445
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• 2016

Cyperi Rhizoma (CR), the rhizome of Cyperus rotundus L., exhibits neuroprotective effects in in vitro and in vivo models of neuronal diseases. Nevertheless, no study has aimed at finding the neuroactive constituent(s) of CR. In this study, we identified active compounds in a CR extract (CRE) using bioactivity-guided fractionation. We first compared the anti-oxidative and neuroprotective activities of four fractions and the CRE total extract. Only the ethyl acetate (EA) fraction revealed strong activity, and further isolation from the bioactive EA fraction yielded nine constituents: scirpusin A (1), scirpusin B (2), luteolin (3), 6'-acetyl-3,6-diferuloylsucrose (4), 4',6' diacetyl-3,6-diferuloylsucrose (5), p-coumaric acid (6), ferulic acid (7), pinellic acid (8), and fulgidic acid (9). The activities of constituents 1-9 were assessed in terms of anti-oxidative, neuroprotective, anti-inflammatory, and anti-amyloid-${\beta}$ activities. Constituents 1, 2, and 3 exhibited strong activities; constituents 1 and 2 were characterized for the first time in this study. These results provide evidence for the value of CRE as a source of multi-functional neuroprotectants, and constituents 1 and 2 may represent new candidates for further development in therapeutic use against neurodegenerative diseases.