• Natural Product Sciences
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• v.29 no.1
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• pp.10-16
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• 2023

We previously reported that dried Lysimachia christinae whole plant extract exerted significant neuroprotective activity. In this study, we tried to isolate neuroprotective compounds of L. christinae. We evaluated the neuroprotective activity of the four fractions (hexane, chloroform, ethyl acetate, and n-butanol fractions) of methanol extract. Among them, ethyl acetate and n-butanol fractions showed most potent neuroprotective activity against glutamate excitotoxicity. Nine compounds were isolated from ethyl acetate and n-butanol fractions of L. christinae extract and identified as cynaroside (1), (3,4,5,6-tetrahydroxytetrahydro-2H-pyran-2-yl)methyl-3-hydroxy-2-octyldopentaconta-23,33-dienoate (2), androst-16-ene-3,6-diol (3), 2-hydroxy-24-propoxytetracos-4-enoic acid (4), 2-hydroxy-24-methoxytetracos-4-enoic acid (5), 12-(stearoyloxy)octadec-9-enoic acid (6), β-sitosterol (7), (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl palmitate (8) and (1S,2S,3R,4R)-4-(((2S,3R,4R,5R,6S)-2-(((2R,3R,4S,5R,6R)-2-(3,4-dimethoxyphenethoxy)-3,5-dihydroxy-6-(hydroxymethyl) tetrahydro-2H-pyran-4-yl)oxy)-4,5-dihydroxy-6-methyltetrahydro-2H-pyran-3-yl)oxy)cyclohexane-1,2,3-triol (9) by spectroscopic data such as UV, IR, NMR, Mass spectroscopy. Their neuroprotective activity was evaluated by MTT assay. Cynaroside (1) and androst-16-ene-3,6-diol (3) had significant neuroprotective activity against glutamate-injured HT22 cells. The neuroprotective efficacy of cynaroside (1) and androst-16-ene-3,6-diol (3) was related to their anti-oxidative activity.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.196-202
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• 2007

Mutations in the cystathionine ${\beta}$-synthase (CBS) gene cause homocystinuria, the most frequent inherited disorder in sulfur metabolism. CBS is the unique enzyme using both heme and pyridoxal 5-phosphate (PLP) for activity. Among the reported 140 mutations, one of the most common disease-causing alterations in human CBS is G307S mutation. To investigate the pathogenic mechanism of G307S by spectroscopic methods, we engineered the full length and the truncated G247S mutation of yeast CBS that is corresponding mutation to human G307S. Yeast CBS does not contain heme and thus gives a merit to study the spectroscopic properties. The UV-visible spectra of the purified full length and the truncated G247S yeast CBSs showed the total absence of PLP in the protein. The absence of PLP in G247S mutation was also confirmed by the PLP-cyanide adduct formation experiment, which was conducted by the incubation of the purified enzyme with KCN. The adducts were detected using a circular dichroism (CD) and a spectrofluorimeter. Radio isotope activity assay of full length and truncated G247S proteins also gave no activity. Our yeast G247S mutation data suggested that G307S might make the distortion of the active site so that cofactor PLP and substrate can not fit inside the active site. Our yeast CBS study addressed the reason why the G307S mutation in human CBS makes the enzyme inactive that consequently leads to severe clinical phenotype.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1067-1074
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• 2008

In this study, the organic carbon normalized-sorption coefficients (Koc) for the binding affinity of phenanthrene (PHE) to 16 different soil humic and fulvic acids of various origins were determined by fluorescence quenching. The humic and fulvic acids used in this study were isolated from 6 different domestic soils including Mt. Hanla soil, IHSS standard soil and peat as well as Aldrich humic acid and characterized by elemental composition, ultraviolet absorption at 254 nm, composition of main structural fragments determined by CPMAS $^{13}$C NMR. The Koc values($\times$10$^4$, L/kg C) for each of HA and FA samples were in the range of 1.48$\sim$8.65 and higher in HA compared to that of FA(3.13$\sim$8.65 vs 1.48$\sim$2.48) in the experimental condition([PHE]/[HS] = 0.02$\sim$0.2(mg/L)/(mg-OC/L), pH 6). The correlation study between the structural descriptors of humic and fulvic acids and log Koc values of phenanthrene, show that the magnitude of Koc values positively correlated with the UV$_{254}$ absorptivity([ABS]$_{254}$) and two $^{13}$C NMR descriptors (C$_{Ar-H,C}$, $\sum$C$_{Ar}$/$\sum$C$_{Alk}$), while negatively correlated with the independent descriptors of the(N+O)/C atomic ratios and $^{13}$C NMR descriptors (I$_{C-O}$/I$_{C-H,C}$). These results confirmed that the binding affinity for the hydrophobic organic compound, phenanthrene are significantly influenced by the polarity and aromaticity of soil humc and fulvic acids.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.412-417
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• 2011

A series of homobinuclear complexes of the type [$M_2L(NO_3)_n(H_2O)_m$] where M=$UO_2$(VI), ZrO(IV), Th(IV); L=3-benzylidine-imino-5-p-sulphonamido phenyl azo-2-thiohyatoin(bispt), 3-furfurylidine-imino-5-p-sulphonamido phenyl azo-2-thiohydantoin(fispt),3-pyridyl-2'-methylene-imino-5-p-sulphonamido phenyl azo-2-thiohydantoin(pmispt) and 3-thienyl-2'-methylene-imino-5-p-sulphoanamido phenyl azo-2-thiohydantoin(tmispt); n=8 for Th(IV) and 4 for others, m=4 for bispt and 3 for others have been synthesized and characterized on the basis of elemental analysis, thermal analysis, molar conductance, magnetic moment and spectroscopic data (IR, electronic and $^1H$-NMR). In the light of this information, the ligands can be visualized as tetradentate co-ordinating through azomethine nitrogen, carbonyl oxygen to one metal centre where as azo nitrogen and thioimido nitrogen to the other metal centre yielding homo binuclear complexes of the above composition. The fungi toxicity of the ligands & their zirconyl complexes against some fungal pathogen has been studied.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.777-783
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• 1997

$TiO_2$ powders were synthesized via hydrolysis reaction of titanium n-propoxide in n-propanol solvent and the reaction rates were studied by use of UV-vis spectroscopic method. Concentration of water, reaction temperature, reaction time and acid-base effects of the solution were investigated to determine the optimum conditions for $TiO_2$ powder synthesis. The reaction were controlled to proceed to pseudo-first orders reaction in the presence of excess water in n-propanol solvent. The rate constants which varied with temperature and concentration of water were calculated by Guggenheim method. Reaction using $D_2O$ was also carried out to determine the catalytic character of water. $TiO_2$ powders were synthesized only in the neutral and basic solution and those were almost spheric forms having average particle size of $0.4-0.7{\mu}m$ diameter. Particle size decreased with increasing concentration of water and reaction temperature, however, increased with increasing reaction time. Associative $S_N2$ mechanism for the hydrolysis was proposed from the data of n-value in the transition state and thermodynamic parameter. $D_2O$ solvent isotope effect showed that $H_2O$ molecules reacted as nucleophilic catalysis.

• Analytical Science and Technology
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• v.24 no.6
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• pp.519-526
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• 2011

Chemometrics using near-infrared (NIR) and Raman spectroscopy have found significant uses in a variety quantitative and qualitative analyses of pharmaceutical products in complex matrixes. Most of the pharmaceutical can be measured directly with little or no sample preparation using these spectroscopic methods. During pharmaceutical manufacturing process, analytical techniques with no or less sample preparation are very critical to confirm the quality. This study showed NIR and Raman spectroscopy with principal component analysis (PCA) was very effective for the blending processing control. It is of utmost importance to evaluate critical parameters related to quality of products during pharmaceutical processing. The blending is confirmed by off-line determination of active pharmaceutical ingredient (API) by a conventional method such as high performance liquid chromatography (HPLC) and UV spectroscopy. These analytical methods are time-consuming and ineffective for real time control. This study showed the possibility for the determination of blend uniformity end-point of CR tablets with the use of both NIR and Raman spectroscopy. The samples were acquired from six positions during blending processing with U-type blender from 0 to 30 min. Using both collected NIR and Raman spectral data, principal component analysis (PCA) was used to follow the uniformity of blending and finally determine the end-point. The variation of homogeneity of six samples during blending was clearly found and blend uniformity end-point was successfully confirmed in the domains of principal component (PC) scores.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.182-182
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• 1996

Annexin I is a member of the annexin family of calcium dependent phospholipid binding proteins and has anti-inflammatory activity by inhibiting phospholipase A$_2$ (PLA$_2$). Recent X-ray crystallographic study of annexin I identified six Ca$\^$2+/ binding bites, which was different types (type II, III) from the well-known EF-hand motif (type I). In this work, the structure of annexin I was studied at atomic level by using $^1$H, $\^$15/N and $\^$l3/C NMR(nuclear magnetic resonance) spectroscopy, and the effect of Ca$\^$2+/ binding on the structure of annexin I was studied, and compared with that of Mg$\^$2+/ binding, When Ca$\^$2+/ was added to annexin I, NMR peak change was occured in high- and low-field regions of $^1$H-NMR spectra. NMR peak change by Ca$\^$2+/ binding was different from that by Mg$\^$2+/ binding. Because annexin I is a larger protein with 35 kDa molecular weight, site-specific (amide-$\^$15/N, carbonyl-$\^$l3/C) labeling technique was also used. We were able to detect methionine, tyrosine and phenylalanine peaks respectively in $\^$13/C-NMR spectra, and each residue was able to be assigned by the method of doubly labeling annexin I with [$\^$13/C] carbonyl-amino acid and [$\^$15/N] amide-amino acid. In $\^$l3/C-NMR spectra of [$\^$13/C] carbonyl-Met labeled annexin I, we observed that methionine residues spatially located near Ca$\^$2+/ binding Sites Were Significantly effected by Ca$\^$2+/ binding. From UV spectroscopic data on the effect of Ca$\^$2+/ binding, we knew that Ca$\^$2+/ binding sites of annexin I have cooperativity in Ca$\^$2+/ binding. The interaction of annexin I with PLA$_2$ also could be detected by using heteronuclear NMR spctroscopy. Consequently, we expect that the anti-inflammatory action mechanism of annexin I may be a specific protein-protein interaction. The residues involved in the interaction with PLA$_2$ can be identified as active site by assigning NMR peaks effected by PLA$_2$ binding.

• Journal of Microbiology and Biotechnology
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• v.25 no.9
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• pp.1433-1441
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• 2015

Pollution resulting from the discharge of textile dyes into water systems has become a major global concern. Because peroxidases are known for their ability to decolorize and detoxify textile dyes, the peroxidase activity of Vitreoscilla hemoglobin (VHb) has recently been studied. It is found that VHb and variants of this enzyme show great promise for enzymatic decolorization of dyes and may play a role in achieving their successful removal from industrial wastewater. The level of VHb peroxidase activity correlates with two amino acid residues present within the conserved distal pocket, at positions 53 and 54. In this work, sitedirected mutagenesis of these residues was performed and resulted in improved VHb peroxidase activity. The double mutant, Q53H/P54C, shows the highest dye decolorization and removal efficiency, with 70% removal efficiency within 5 min. UV spectral studies of Q53H/P54C reveals a more compact structure and an altered porphyrin environment (λ_Soret = 413 nm) relative to that of wild-type VHb (λ_Soret = 406), and differential scanning calorimetry data indicate that the VHb variant protein structure is more stable. In addition, circular dichroism spectroscopic studies indicate that this variant's increased protein structural stability is due to an increase in helical structure, as deduced from the melting temperature, which is higher than 90℃. Therefore, the VHb variant Q53H/P54C shows promise as an excellent peroxidase, with excellent dye decolorization activity and a more stable structure than wild-type VHb under high-temperature conditions.

• Applied Biological Chemistry
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• v.51 no.2
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• pp.136-141
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• 2008

The chromatographic separation of organic solvent extracts of liverwort led to the isolation of six compounds. 2-Chromenone (1), 3, 4-dihydroxy-cinnamic acid (2), 3, 3', 4', 5, 7-pentahydroxy-2-phenylchromen-4-one (3), kaemperol-3-O-${\beta}$-D-glucopyranoside (4), 3-[[3-(3,4-Dihydroxyphenyl)-1-oxo-2-propenyl]oxy]-1, 4, 5-trihydroxycyclohexane carboxylic acid (5) and quercetin-3-O-rutinoside (6) were isolated from the methanolic extracts of the all part of Climacium dendroides. Their structure were established by chemical and spectroscopic methods. All compounds were isolated for the first time from this plant Climacium dendroides.

• Journal of the Korean Chemical Society
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• v.31 no.3
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• pp.258-270
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• 1987

A series of new thorium nitrate complexes with crown ethers have been synthesized from the reaction of the hydrated thorium nitrate, with the appropriate crown ethers of different cavity sizes in various solvents such as methanol, ethanol, butanol, methylacetate, acetone, tetrahydrofuran and acetylacetone. CHN elemental analysis, ICPAS, thermal analysis and Karl-Fischer method have been used to characterize their compositions, and the spectroscopic methods of IR, UV, $^1H-NMR$, and X-ray diffraction have been employed to determine the structures and solvolysis phenomena of these complexes. and the electrical conductances were measured in DMSO, and water solvent. The solvolysis have been observed only in the complexes synthesized in acetylacetone solvent. In the solvated complexes of 15-crown-5 and 18-crown-6, the mole ratio of $Th^{4+}$: ligand : acetylacetone is found to be 1:1:1, but in the non-solvated complexes of 12-crown-4 and 15-crown-5, the mole ratios of Th:L are 1:2 and 2:3, respectively, and that in the complexes of both 18-crown-6 and dicyclohexano-18-crown-6 is 1:1. All complexes which were not solvated have shown $n{\to}{\sigma}^{\ast}$ electronic transitions of crown ether whereas complexes solvated have exhibited both $n{\to}{\sigma}^{\ast}$ of crown ether and $n{\to}{\pi}^{\ast}$ transitions of acac. The dissociation mole ratio of $Th^{4+}$ and nitrate ion is found to be 1:1 in aprotic solvent, and 1:4 in protic solvent like water.