• 약학회지
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• 제47권4호
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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.

• 대한화학회지
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• 제26권2호
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• pp.107-113
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• 1982

티안트렌양이온 자유라디칼의 아세토니트릴 용액에 의해 티오크잔틴이 산화되어 생성된 티오크잔틸이움 이온에 디메돈을 넣어주면 9-(4,4-dimethylcyclohexane-2,6-dionyl)thioxanthylium 과염소산염(2)이 생성되나 순서를 바꾸어 넣어주면 초기에 9-(4,4-dimethylcyclohexane-2,6-dionyl)thioxanthene (1)이 생성되며 이것은 계속 반응하여 2를 만든다. 화합물 2는 물이 섞인 아세톤에서 쉽게 탈 수소화되어 9-(4,4-dimethylcyclohexane-2,6-dionylidene)thioxanthene (3)이 된다. 그러나 물이 섞인 아세토니트릴용액중에서 관찰된 219, 289, 348 nm의 isobestic point는 3이 2와 평형상태로 존재함을 말한다. 3의 380nm 근처에 있는 흡수띠의 위치와 강도는 용매에 따라 변하는데 이것은 용매-용질 사이의 상호작용으로 설명한다.

• 동아시아식생활학회지
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• 제20권5호
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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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• 제33권6호
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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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• 제20권10호
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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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• 제64권4호
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• pp.407-411
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• 2021

인삼(Panax ginseng)과 전칠삼(Panax notoginseng)의 30% (v/v) 에탄올 추출물의 항산화 활성을 확인하였다. 인삼과 전칠삼 추출물의 폴리페놀 함량은 각각 10.3±0.3 및 10.4±0.4 mg/g-추출물이었다. 인삼과 전칠삼 추출물은 농도의존적으로 항산화 활성을 나타내었다. 인삼과 전칠삼 추출물의 양이온라디칼에 대한 EC₅₀값은 4.76±0.12 및 6.24±0.14 mg/mL이었고, 환원력에 대한 EC₅₀값은 1.99±0.01 및 3.13±0.05 mg/mL이었으며, 아질산염에 대한 EC₅₀값은 4.78±0.31 및 3.52±0.10 mg/mL이었다.

• Bulletin of the Korean Chemical Society
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• 제15권2호
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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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• 제13권2호
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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.

• 한국식품영양과학회지
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• 제32권5호
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• pp.723-727
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• 2003

본 연구에서는 일상생활에서 손쉽게 음용할 수 있는 차 추출물에 대해 항산화력과 항산화 성분의 함량을 측정함으로써 그 상관관계를 알아보고자 하였다. 차 추출물의 항산화력은 ABTS 와 DPPH radical을 사용하여 측정하였으며, 항산화력 성분은 총 폴리페놀, 총 플라보노이드, 총 비타민 C 함량을 각각 측정하였다. 총 폴리페놀 함량은 홍차, 허브티 I, 녹차 I, 허브티 II, 녹차 II, 한차 I에서 101.51~62.60 mg범위로 다른 차에 비하여 높게 나타났으며, 총 플라보노이드 함량은 허브티 II, 한차 I, 홍차에서 높은 함량을 나타내었다. 반면 총 비타민 C의 경우 한차 I이 15.78 mg을 나타낸 제품을 제외 하고 다른 것들은 모두 낮은 함량을 나타내었다. 항산화력이 높게 나타난 차는 주로 녹차류와 홍차였으며 이들의 항산화력에 기여하는 물질이 주로 비타민 C나 플라보노이드가 아닌 폴리페놀성 화합물임을 알 수 있었다.

• Journal of Applied Biological Chemistry
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• 제54권2호
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• pp.89-93
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• 2011

오이풀 아세톤 추출물로부터 용매분획물의 기능성 화장품 소재로 활용하기 위하여 항산화 효과를 측정한 후 화장품 소재로서의 가능성을 검증하였다. 항산화 효과를 확인하기 위하여 electron donating ability을 측정한 결과 ethyl actate 층과 n-butyl alcohol 층이 전 농도에서 대조군 BHA와 유사한 활성을 나타내었으며, ABTS radical cation decolorization assay 결과 ethyl acetate 층, n-butyl alcohol 층, water 층 모두 전 농도에서 99% 이상의 효과를 나타내어 BHA와 유사하였다. hydrogen peroxide scavenging assay 결과 ethyl acetate 층, n-butyl alcohol 층이 대조군 ascorbic acid 보다 효과가 높았다. Superoxide dismutase (SOD) 유사 활성 측정 결과, n-butyl alcohol 층이 1,000 ${\mu}g/mL$ 농도에서 50% 이상의 효능이 있었으며, Superoxide anion 라디칼 소거능은 n-butyl alcohol 층의 1,000 ${\mu}g/mL$에서 45%의 효과가 있었다. 이상의 결과로 미루어 보아 오이풀 아세톤 추출물의 분획물 중 ethyl acetate 층과 n-butyl alcohol 층에서 항산화 효과가 있었으며, 새로운 항산화 화장품의 소재로서 가능성을 확인 할 수 있었다.