• Bulletin of the Korean Chemical Society
• /
• v.25 no.11
• /
• pp.1641-1644
• /
• 2004

Several [2]- and [3]rotaxanes bearing some functional groups on their wheel components and spacers with different lengths between two ammonium centers on their dumbbell components were prepared in good yields from dibenzo-24-crown-8-ether derivatives and dumbbell-shaped bis(sec-ammonium salt)s having a centrally located disulfide linkage, by utilizing the reversible thiol-disulfide interchange reaction. The shuttling behaviors of the [2]rotaxanes were investigated by $^1H$ NMR by use of the spin polarization transfer-selective inversion recovery technique. It was found that the change in spacer length in the axle resulted in a drastic change in shuttling rate of the [2]rotaxanes, although the introduction of the functional groups to the wheels did not affect the shuttling behavior at all.

• Journal of Pharmacopuncture
• /
• v.23 no.3
• /
• pp.158-164
• /
• 2020

Objectives: The aim of the present work was to evaluate the possible beneficial effects of F. latisecta on blood glucose, lipids, and diabetes-related changes in the liver and kidney of streptozotocin-induced diabetic rats. Methods: Male Wistar rats were randomly allocated into four groups (n = 6): normal control rats, diabetic control rats, diabetic rats treated for 4 weeks with F. latisecta root (400 mg/kg/day), and diabetic rats treated with F. latisecta aerial parts (400 mg/kg/day). Results: Induction of diabetes significantly (p < 0.05) increased the levels of fasting blood glucose (FBG), triglyceride, total cholesterol, low-density lipoprotein (LDL), blood urea nitrogen (BUN), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). Diabetes also increased (p < 0.05) oxidative stress in the kidney and liver (decrease of thiol and increase of superoxide dismutase). The root and aerial parts of F. latisecta significantly reduced the level of LDL (p < 0.05) and restored the content of thiol (p < 0.05) and superoxide dismutase (p < 0.01) in the kidney and liver. F. latisecta had no significant effect on the levels of FBG, BUN, AST, and ALT. The root of F. latisecta also reduced the serum level of total cholesterol (p < 0.05) and prevented the progression of hyperglycemia. Conclusion: These findings suggest that F. latisecta may improve diabetic dyslipidemia by reducing serum LDL. Further studies are needed to confirm our findings.

• Journal of Pharmacopuncture
• /
• v.22 no.4
• /
• pp.239-247
• /
• 2019

Objectives: Allium jesdianum (Aj) is a medicinal plant that has highlighted pharmacological features. In this study, the effects of Aj extract were examined on acetaminophen (APAP)-induced hepatic failure in rats. Methods: Methanolic fraction of hydro-alcoholic extract of Aj was obtained by silica gel column chromatography method. Animals were randomly divided into four groups each containing six rats and treated by gavage as follows: the first and second groups received normal saline, the third and fourth groups were received with 50 and 100 mg/kg of Aj extract, respectively. After two consecutive weeks, the groups 2-4 were given a single dose of APAP (2 g/kg). After 48 hours, blood and liver samples were collected for biochemical and histological examinations. Results: The findings of the study demonstrated that APAP caused a significant increase in ALT (P < 0.001), AST (P < 0.001), LDH (P < 0.001), ALP (P < 0.001) serum levels, hepatic lipid peroxidation (LPO; P < 0.001) and nitric oxide (NO; P < 0.001). In this regard, APAP led to the depletion of the total antioxidant capacity (TAC; P < 0.001), glutathione and total thiol groups (TTGs; P < 0.001), and structural change in the liver. In the Aj extract groups, a considerable improvement was found in the hepatic function alongside the histopathologic changes. Conclusion: This investigation indicated that the influential effects of Aj extract in APAP-induced hepatic failure might depend on its effect on improving oxidant/antioxidant balance in hepatic tissue.

• Korean Journal of Chemical Engineering
• /
• v.35 no.11
• /
• pp.2220-2231
• /
• 2018

Lipase from Candida rugosa was immobilized on $MgO{\cdot}SiO_2$ hybrid grafted with amine, thiol, cyano, phenyl, epoxy and carbonyl groups. The products were analyzed using Fourier transform infrared spectroscopy, nuclear magnetic resonance, low-temperature $N_2$ sorption and elemental analysis. Additionally, the degree of coverage of the oxide material surface with different functional groups and the number of surface functional groups were estimated. The Bradford method was used to determine the quantity of immobilized enzyme. The largest quantity of enzyme (25-28 mg/g) was immobilized on the hybrid functionalized with amine and carbonyl groups. On the basis of hydrolysis reaction of p-nitrophenyl palmitate to p-nitrophenol, it was determined how the catalytic activity of the obtained biocatalysts is affected by pH, temperature, storage time, and repeated reaction cycles. The best results for catalytic activity were obtained for the lipase immobilized on $MgO{\cdot}SiO_2$ hybrids with amine and carbonyl groups. The biocatalytic system demonstrated activity above 40% in the pH range 4-10 and in the temperature range $30-70^{\circ}C$. Lipase immobilized on the $MgO{\cdot}SiO_2$ systems with amine and epoxy groups retains, respectively, around 80% and 60% of its initial activity after 30 days of storage, and approximately 60-70% after 10 reaction cycles.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.9
• /
• pp.2660-2664
• /
• 2014

A simple method of depositing titanium dioxide ($TiO_2$) nanoparticles onto graphene oxide (GO) as a catalytic support was devised for photocatalytic degradation of methylene blue (MB). Thiol groups were utilized as linkers to secure the $TiO_2$ nanoparticles. The resultant GO-supported $TiO_2$ (GO-$TiO_2$) sample was characterized by transmission electron microscopy (TEM), near-edge X-ray absorption fine structure (NEXAFS), and X-ray photoelectron spectroscopy (XPS) measurements, revealing that the anatase $TiO_2$ nanoparticles had effectively anchored to the GO surface. In the photodegradation of MB, GO-$TiO_2$ exhibited remarkably enhanced photocatalytic efficiency compared with thiolated GO and pure $TiO_2$ nanoparticles. Moreover, after five-cycle photodegradation experiment, no obvious deactivation was observed. The overall results showed that thiolated GO provides a good support substrate and, thereby, enhances the photodegradation effectiveness of the composite photocatalyst.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.1409-1411
• /
• 2006

A new rod-like liquid crystalline monomer having divinyl terminal groups was synthesized and polymerized by using thiol-ene UV polymerization technique. High quality thin film with good retardation value was prepared on a rubbed alignment layer without the inert gas purging. The retardation value of the resulting film was controlled by experimental conditions such as spin speed, concentration, and spin time. From the retardation value and thickness measurement, ${\bigtriangleup}n$ was calculated to be 0.169 for the resulting film having thickness of 815.1 nm.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2002.08a
• /
• pp.305-308
• /
• 2002

Field emission from single-walled carbon nanotubes (SWNTs) aligned on a patterned gold surface is reported. The SWNTs emitters were prepared at room temperature by a self-assembly monolayer technique. SWNTs were cut into sub-micron length by sonication in an acidic solution. Cut SWNTs were attached on the gold surface by the reaction between the thiol groups and the gold surface. The field emission measurement showed that the turn-on field was 4.8 $V/{\mu}m$ at the emission current density of 10 ${\mu}A/cm^2$. The current density was 0.5 $mA/cm^2$ at 6.6 $V/{\mu}m$. This approach provides a novel route for fabricating CNT-based field emission displays.

• Molecules and Cells
• /
• v.39 no.1
• /
• pp.53-59
• /
• 2016

Peroxiredoxins are cysteine-dependent peroxide reductases that group into 6 different, structurally discernable classes. In 2011, our research team reported the application of a bioinformatic approach called active site profiling to extract active site-proximal sequence segments from the 29 distinct, structurally-characterized peroxiredoxins available at the time. These extracted sequences were then used to create unique profiles for the six groups which were subsequently used to search GenBank(nr), allowing identification of ~3500 peroxiredoxin sequences and their respective subgroups. Summarized in this minireview are the features and phylogenetic distributions of each of these peroxiredoxin subgroups; an example is also provided illustrating the use of the web accessible, searchable database known as PREX to identify subfamily-specific peroxiredoxin sequences for the organism Vitis vinifera (grape).

• Toxicological Research
• /
• v.35 no.4
• /
• pp.303-310
• /
• 2019

We are exposed to numerous xenobiotic electrophiles on a daily basis through the environment, lifestyle, and dietary habits. Although such reactive species have been associated with detrimental effects, recent accumulated evidence indicates that xenobiotic electrophiles appear to act as signaling molecules. In this review, we introduce our findings on 1) activation of various redox signaling pathways involved in cell proliferation, detoxification/excretion of electrophiles, quality control of cellular proteins, and cell survival during exposure to xenobiotic electrophiles at low concentrations through covalent modification of thiol groups in sensor proteins, and 2) negative regulation of reactive sulfur species (RSS) in the modulation of redox signaling and toxicity caused by xenobiotic electrophiles.

• Journal of Periodontal and Implant Science
• /
• v.23 no.3
• /
• pp.517-525
• /
• 1993

Glutathione(GSH),a tripeptide thiol, found in virtually all cells, functions in metabolism tranasport and cellular protection. It protects cells against the destructive effects of reactive oxygen intermediates and free radicals. Also ${\gamma}-Glutamyl$ transpeptidase(${\gamma}-GTT$), an enzyme of major importance in GSH metabolism, initiates GSH degradation. In order to explore the $GSH-{\gamma}-GTT$ system as periodontal disease activity indicator, we observed the ${\gamma}-GTT$ and arachidonic acid metabolits according to clinical groups(Control, Adult periodontitis, Rapidly progressive Periodontitis). From the experiments, the following results were obtained. 1. When compared with normal, ${\gamma}-GTT$ of A. P. and R. P. P. were increased, and only the change of ${\gamma}-GTT$ of R. P. P. was statistically significant(P<0. 05). 2. The amounts of arachidonic acid metabolites were not different with statistical significance among the clinical groups. 3. ${\gamma}-GTT$ may by useful adjuncts as new cytoprotective indicator and periodontal disease activity indicator in accordance with positive corelation pocket depth, attachment level and ${\gamma}-GTT$.