• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1319-1325
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• 2010

Tyrosinase ubiquitously existing from microorganisms to animals and plants is known to be the most critical and rate limiting enzyme during melanin biosynthesis. In order to develop new tyrosinase inhibitor we have synthesized 14 diphenyl ether compounds possessing hydroxyl, bromo, and nitro groups in the structure. Among the compounds prepared, 18 and 19 have shown much stronger inhibition of tyrosinase monophenolase function than arbutin used as a positive control. Both compounds 18 and 19 possess para-hydroxyphenyl moiety in their structure, which might reinforce the importance of p-hydroxyphenyl group in the tyrosinase inhibitory process. In the DPPH radical scavenging activity test, none of the compounds even 18 and 19 showed significant antioxidant activity. The results suggest that elaborate adjustment of diphenyl ether analogues with proper substituents have potential to be developed as new skin whitening agents working on the tyrosinase function.

• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.145-151
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• 2006

The molecular assembly of p-iodo-phenyl octadecyl ether (I-POE), p-iodo-phenyl docosyl ether (I-PDE) and a binary mixture of these two molecules on graphite has been studied using a scanning tunneling microscope. Each molecular system self-assembles on the graphite surface to form a stable monolayer with a head-to-tail configuration. For the binary system, the I-POE and I-PDE molecules do not mix on the surface, preferring instead to form isolated monolayer domains. Here, the I-POE molecules are preferentially adsorbed on the graphite surface, due to the effects of alkyl chain length and the functional group on the monolayer structure.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.235-238
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• 2005

Sulfonated poly(ether sulfone) copolymers (PESs) were synthesized using hydroquinone 2-potassium sulfonate (HPS) with other monomers (bisphenol A and 4-fluorophenyl sulfone). PESs with different $mole\%$ of hydrophilic group were prepared by changing the mole ratio of HPS in the polymerization reaction. The chemical structure and the thermal stability of these polymers were characterized by using $^1H-NMR$, FT-IR and TGA techniques. The PES 60 membrane, which has $60 mole\%$ of HPS unit in the polymer backbone, has a proton conductivity of 0.091 S/cm and good insolubility in boiling water. The TGA showed that PES 60 was stable up to $272^{\circ}C$ with a char yield of about $29\%\;at\;900^{\circ}C\;under\;N_2$ atmosphere. To investigate the single cell performance, the catalyst coated PES 60 membrane was used and a single cell test was carried out using $H_2/O_2$ gases as fuel and oxidant at various temperatures. We observed that the cell performance was enhanced by increasing the cell temperature. A current density of $1400 mA/cm^2$ at 0.60 V was obtained at $70^{\circ}C$.

• YAKHAK HOEJI
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• v.25 no.4
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• pp.153-160
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• 1981

The investigation aimed to study the effect of ginseng on the hepatic glutathion S-transferase activity. The ginseng methanol extract was administered to rats and mice for 10 days and their hepatic gluthatione S-transferase activities were measured by the method of Habig et al. Glutathione S-transferase activities in the rat treated with 100 and 500mg/kg ginseng methanol extract were increased by 13.4% and 17.10%, respectively and their increases were statistically significant. Similar results were also found in the mouse treated with ginseng 100mg/kg methanol extract. To investigate components of the extract which induce the enzyme, the methanol extract was fractionated into ether and butanol fraction and their effect on the enzyme was compared. Glutathione S-transferase activities in the rat treated with ether fraction were increased by 13.1%, similar to that obtained with ginseng methanol extract, whereas, butanol fraction did not show any increase in the enzyme activities. In the rats treated with maltol, one of the components in ether fraction, 5mg/kg for 10 days, activity of glutathione S-transferase was increased by 7.89%, but its increase was not significantly different from control group. Therefore, it may be concluded that ginseng methanol extract and its ether soluble fraction had effect on the elevation of glutathione S-transferase activities, whereas, butanol fraction of ginseng methanol extract had no effect on the enzyme.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3549-3552
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• 2010

The complex formation between diazocalix[4]dipropyl (1) and diazocalix[4]crown-6 ether (2) with alkali, alkaline earth and transition metal ions was investigated by voltammetry. Electrochemical properties of compounds 1 and 2 and their selectivity toward metal ions were evaluated in $CH_3CN$ solution by comparison of voltammetric behaviors of two phenols in each compound. Compounds 1 and 2 showed almost same voltammetric behavior which is two irreversible oxidation peaks caused by intramolecular hydrogen bonding between two phenols in 1 and 2. While, however, upon interacting with various metal ions, 1 with two propyl ether groups showed no significant changes in voltammetry, 2 with crown ether group caused significant voltammetric changes upon the addition of $Ba^{2+}$ to 2. Their behavior is closely related to the complex formation by entrapment of metal ion into crown ether cavity, and ion-dipole interaction between metal ion and two phenolic groups in calix[4]crown-6.

• Journal of Nutrition and Health
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• v.36 no.8
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• pp.793-800
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• 2003

This study was conducted to investigate the antioxidative effects of Paeonia lactiflora (PL) seeds on antioxidative defense system and lipid peroxidation of liver in rats fed high-cholesterol diet. Sprague-Dawley male rats weighing 100 $\pm$10g were randomly assigned into five experimental groups fed 0.5% cholesterol ; HC group which was not supplemented PL seeds extract, 0.1% methanol extract diet group (MP1 group), 0.2% methanol extract diet group (MP2 group), 0.05% ether-souble fraction diet group (EP1 group) and 0.1 % ether-souble fraction diet group (EP2 group). Experimental diets were fed ad libitum to the rats for 3 weeks. The activity of hepatic superoxide dismutase (SOD) was not significantly different among all the high cholesterol diet groups. The hepatic glutathione peroxidase (GSHpx) activity in MP2 group was increased to 27% compared to HC group. The activity of hepatic catalase (CAT) was not significantly different among the all high cholesterol diet groups. The hepatic glutathione S-transferase (GST) activity in the EP1 and EP2 groups were increased to 12% and 13%, respectively, as compared to HC group. The levels of hepatic TBARS in the MP1, MP2, EP1 and EP2 groups were reduced by 18%, 21%, 20% and 23%, respectively, as compared with HC group. The contents of lipofuscin in liver was not significantly different among all the experimental groups. The results indicated that PL seeds extract may be reduced oxidative damage by activating antioxidative defense system of hepatic in rats fed high-cholesterol diets. (Korean J Nutrition 36(8): 793∼800, 2003)

• Korean Journal of Pharmacognosy
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• v.22 no.3
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• pp.183-191
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• 1991

The effects of Ephedrae herba on cellular and humoral immune responses were investigated in mice. Group A and B of mice received intraperitoneal injection of methanol extracts, ether fraction(E), petroleum ether fraction(PE), ethyl acetate fraction(EA) and water fraction(W) for 5 days or 10 days before sensitization. The other group received i.p. injection of ephedrine (Ep) or pseudoephedrine $({\psi}\;Ep)$ for 1 day prior to sensitization. The change of body and spleen weights showed a tendency of decreasing but that of thymus showed increasing. Ear swelling was maximum at 48 hours after challenge and was significantly decreased in the groups treated with EA, W, Ep, and ${\psi}\;Ep$. HA titer was enhanced in EA, W and EP treated groups, HE titer being significantly decreased.

• Bulletin of the Korean Chemical Society
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• v.17 no.2
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• pp.113-114
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• 1996

• Bulletin of the Korean Chemical Society
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• v.16 no.9
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• pp.799-801
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• 1995

• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.151-154
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• 1989

4-Methoxy-4-methylcyclohexa-2,5-dienone 1 in aqueous sulfuric acid underwent the normal dienone-phenol rearrangement with methyl group migration. The fact that methyl is migrating group and methoxy is remaining group can be rationalized by the stabilization of positive charge at C-4 during the transition state. Methoxy methyl dienone 1 $((H_0)_{1/2} = - 4.6)$ is less basic than 4,4-dimethylcyclohexa-2,5-dienone whose half protonation acidity is reported as - 3.15 or - 3.66. This basicity difference comes from the unstabilization of the protonated methoxy methyl dienone 1 due to the electron withdrawing inductive effect of a methoxy group.