• YAKHAK HOEJI
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• v.47 no.4
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• pp.224-229
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• 2003

We have investigated the transport characteristics of synthetic antioxidant and free radical scavenger, $\alpha$-phenyl-n-tert-butyl nitrone (PBN) at the blood-brain barrier (BBB) by in vitro uptake study in conditionally immortalized rat brain capillary endothelial cell line (TR-BBB). Also, the efflux of PBN from brain to blood is estimated using the brain efflux index (BEI) method. Choline is a charged organic cation, including nitrogen-methyl group and shows the carrier-mediated distribution to the brain. [$^3$H]Choline uptake by TR-BBB cells was significantly inhibited by PBN with $IC_{50}$/ of 1.2 mM, which appears to be due to similar structures between choline and PBN. And, PBN was microinjected into Par2 of the rat brain by BEI method, and was eliminated from the brain with an apparent elimination half-life of about 2 min. Also, [$^3$H]choline efflux was significantly inhibited by PBN using BEI method. In conclusion, the efflux transport of PBN takes place across the BBB and PBN may be transported into the brain and eliminated from the brain by BBB choline transporter.

• Journal of the Korean Chemical Society
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• v.26 no.2
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• pp.107-113
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• 1982

Addition of dimedone to thioxanthylium ion generated from the oxidation of thioxanthene by thianthrene cation radical perchlorate in acetonitrile gave 9-(4,4-dimethylcyclohexane-2,6-dionyl)thioxanthylium perchlorate (2), whereas from the reverse addition between two reactants was obtained initially 9-(4,4-dimethylcyclohexane-2,6-dionyl)thioxanthene (1), which then underwent further reaction to give 2. The compound 2 was readily deprotonated in aq acetone to give 9-(4,4-dimethylcyclohexane-2,6-dionylidene)thioxanthene (3). However, 3 turned out to be in equilibrium with 2 in which three isosbestic points at 219, 289, and 348 nm were recorded in aq acetonitrile. The intensity and the position of the maximum absorption of 3 near 380 nm vary depending on the solvents which has been explained in terms of the solvent-solute interactions.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.5
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• pp.751-758
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• 2010

Prunus mume is well known contain many functional materials that play beneficial roles in the human body. Studies have found that many organic acids and polyphenol compounds exist in Prunus mume. In this study, content of total polyphenols and flavonoids, antioxidative activity and cytotoxicity of ethanol extract from Prunus mume were measured Contents of total polyphenolic and total flavonoid compounds in ethanol extract from Prunus mume were 16.92 mg/g and 59.95 mg/g, respectively. The $IC_{50}$ of ethanol extract from Prunus mume were $237.72 {\mu}g$/assay and $239.58 {\mu}g$/assay by DPPH and ABTS radical cation scavenging test, respectively. Additionally, ferric ion reducing antioxidant power (FRAP) value of ethanol extract from Prunus mume was 0.94 mM ($FeSO_4$ eq.) by $800 {\mu}g$/assay. Cytotoxicity of Prunus mume against five kinds of cancer cell lines increased as the extract concentration increased Especially, cytotoxicity of the ethanol extract against A-549 (lung cancer line) was higher than that against any other cancer cell line by both MTT and SRB assay. These results show that ethanol extract of Prunus mume has considerably high antioxidative and cytotoxic activities.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.1949-1954
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• 2012

We have developed a novel and eco-friendly synthetic route for the preparation of a two-dimensional layered zinc hydroxide with intercalated nitrate anions. The layered zinc hydroxide nitrate, called 'zinc basic salt', was, in general, successfully synthesized, using an electron beam irradiation technique. The 2-propanol solutions containing hydrated zinc nitrate were directly irradiated with an electron-beam at room temperature, under atmospheric conditions, without stabilizers or base molecules. Under electron beam irradiation, the reactive OH radicals were generated by radiolysis of water molecules in precursor metal salts. After further radiolytic processes, the hydroxyl anions might be formed by the reaction of solvated electrons and the OH radical. Finally, the $Zn_5(OH)_8(NO_3)_2{\cdot}2H_2O$ was precipitated by the reaction of zinc cation and hydroxyl anions. Structure and morphology of obtained compounds were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and high resolution transmission electron microscopy (HR-TEM). The chemical components of the products were determined by Fourier transform infrared spectroscopy (FT-IR) and elemental analysis (EA). The thermal behavior of products was studied by thermogravimetric (TG) and differential thermal analysis (DTA).

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1177-1180
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• 1999

The ab initio SCF MO and density functional theory (DFT) studies are carried out on the electrophilic (1a) and electron transfer (1b) addition reactions to the vinyl double bond of aryl vinyl sulfides and ethers. In the electrophilic addition processes, a double bond shift from C3 = C4 to X = C3 occurs with occupation number (1.97) close to the normal two. Due to this shift direct conjugation between the cationic center, X = S or O, and the para electron-donor substituent becomes impossible so that the reaction energies (or log K) are correlated with σ rather than σ+. By contrast, radical cation formation leads to delocalization of the SOMO, a lone-pair πorbital on X, with four major resonance structures in which cationic charge as well as spin density is delocalized over C4 , X and C7 atoms. As a result, partial πbonds are formed over C1 -X and C3 - C4 with occupation numbers (0.82) lower than one. In two of the cannonical structures, III(Ⅹ) and III(X+), direct conjugation between the cationic center, X, and the para substituent is achieved so that a better correlation with σ+ rather than σis obtained. The SCF MO energies at the HF/3-21G* and HF/6-31G* levels lead to very much inferior Hammett correlations in the σ/ σ+ diagnostic criterion. In contrast, the ρvalues evaluated with the DFT energies can give reliable diagnostic distinction between the two addition mechanisms.

• Journal of Applied Biological Chemistry
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• v.64 no.4
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• pp.407-411
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• 2021

In vitro antioxidant potential of 30% (v/v) ethanolic extracts from Panax ginseng and Panax notoginseng roots was investigated. The polyphenol contents of Panax ginseng and Panax notoginseng extracts were 10.3±0.3 and 10.4±0.4 mg/g-extract, respectively. The extracts of Panax ginseng and Panax notoginseng possessed an antioxidant potential in a concentration-dependent manner. EC₅₀ values of Panax ginseng and Panax notoginseng extracts for cation radical, reducing power, and nitrite were 4.76±0.12 and 6.24±0.14 mg/mL, 1.99±0.01 and 3.13±0.05 mg/mL, and 4.78±0.31 and 3.52±0.10 mg/mL, respectively.

• Bulletin of the Korean Chemical Society
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• v.15 no.2
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• pp.154-161
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• 1994

Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethylthioalkyl)phthalimides (alkyl=ethyl, n-propyl, n-butyl, n-pentyl, and n-hexyl). Photocyclizations occur in methanol in modest to high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from sulfur in the ${\alpha}$-silylmethylthioalkyl groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate ${\alpha}$ -silylmethylthio cation radicals and cyclization by radical coupling is proposed. In contrast, photoreactions of N-(trimethylsilylmethylthioalkyl)phthalimides in acetone follow different reaction routes to produce another cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon ${\alpha}$ to silicon and sulfur atoms via triplet carbonyl hydrogen abstraction pathway. The normal singlet SET pathway dominates this triplet process for photoreactions of these substances in methanol while the triplet process dominates the singlet SET pathway for those in acetone. The efficient and regioselective cyclization reactions observed for photolyses in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.

• Bulletin of the Korean Chemical Society
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• v.13 no.2
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• pp.166-172
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• 1992

Studies have been conducted to explore single electron transfer (SET) induced photocyclization reactions of N-(trimethylsilylmethoxyalkyl)phthalimides(alkyl=E thyl, n-propyl, n-butyl, n-pentyl, and n-octyl). Photocyclizations occur in methanol in high yields to produce cyclized products in which phthalimide carbonyl carbon is bonded to the carbon of side chain in place of the trimethylsilyl group. Mechanism for these photocyclizations involving intramolecular SET from oxygen in the $\alpha-silylmethoxy$ groups to the singlet excited state phthalimide moieties followed by desilylation of the intermediate $\alpha-silylmethoxy$ cation radicals and cyclization by radical coupling are proposed. In contrast, photoreaction of N-(trimethylsilylmethoxyethyl) phthalimide in acetone follows different reaction routes to produce two cyclized products in which carbon-carbon bond formation takes place between the phthalimide carbonyl carbon and the carbon $\alpha$ to silicon and oxygen atoms via triplet carbonyl hydrogen abstraction triplet carbonyl silyl group abstraction pathways. The normal singlet SET pathway dominates these triplet processes for photoreaction of this substance in methanol. The efficient and regioselective cyclization reactions observed for photolysis in methanol represent synthetically useful processes for construction of medium and large ring heterocyclic compounds.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.5
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• pp.723-727
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• 2003

The antioxidant activities and their antioxidant compounds of a group of teas obtained in local markets were investigated. A total of 18 teas were tested for their antioxidant activities based on their ability to scavenge ABTS (2,2'-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) cation radical and DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical. The former was expressed as mg of ascorbic acid equivalents per 1 tea bag (L-ascorbic acid equivalent antioxidant capacity, AEAC) and the latter was expressed as percentage of electron donating activity (EDA%). A good correlation of AEAC and EDA was observed between the two methods. The concentrations of total polyphenolics and flavonoids in tea extracts were measured by spectrophotometric methods. Total ascorbic acid was determined via the 2,6-dicholoroindophenol titrimetric method. According to the AEAC value and EDA, black tea, brown rice green tea, green tea, herb tea and malva tea showed relatively high antioxidant activities. Polyphenolic compounds were the major naturally occurring antioxidant compounds found in teas and the high concentrations of polyphenolic compounds were observed in black tea, green tea and herb tea. Overall, six teas out of 18 teas tested in the study showed better antioxidant activities and higher amounts of total polyphenolic compounds.

• Journal of Applied Biological Chemistry
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• v.54 no.2
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• pp.89-93
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• 2011

The solvent extracts of Sanguisorbae officinalis L. were investigated for the activities of antioxidants as a functional ingredient for cosmetic products. The electron donating effect of ethyl acetate layer and n-butyl alcohol layer was appeared similar activity with positive control butylated hydroxy anisole (BHA) at all concentrations. In addition, in 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging assay, ethyl acetate layer, n-butyl alcohol layer and water layer were over 99% effect at all concentrations and higher than that of BHA. Also in hydrogen peroxide scavenging assay, ethyl acetate layer and n-butyl alcohol layer were higher than that of positive control ascorbic acid. The measured superoxide dismutase (SOD)-like activity of n-butyl alcohol was more than 50% at concentration of 1,000 ${\mu}g/mL$ and superoxide anion radical scavenging ability showed more than 45% at 1,000 ${\mu}g/mL$ of n-butyl alcohol layer. All these findings suggested that ethyl acetate layer and n-butyl alcohol layer have a great potential as a cosmeceutical ingredient with an antioxidant effect.