scholarly journals Inhibitory effect of glutathione on the generation of hydroxyl radicals in the reaction system of glutathione-alloxan.

1991 ◽  
Vol 39 (3) ◽  
pp. 737-742 ◽  
Author(s):  
Koichi SAKURAI ◽  
Taketo OGISO
1970 ◽  
Vol 33 (11) ◽  
pp. 1231-1233 ◽  
Author(s):  
KUNIO HIWADA ◽  
TATSUO KOKUBU ◽  
YUICHI YAMAMURA

1972 ◽  
Vol 28 (2) ◽  
pp. 165-166 ◽  
Author(s):  
T. Kokubu ◽  
K. Hiwada ◽  
E. Ueda ◽  
Y. Yamamura

2004 ◽  
Vol 57 (3) ◽  
pp. 243
Author(s):  
Yu-Fei Song

In an effort to investigate the use of short peptide chains as carriers of new antitumour agents, four tripeptide cytotoxic agent conjugates, namely DMQ–MA–Lys(DMQ–MA)–Lys(Cbz)–Arg–OMe, DMQ–MA–Lys(DMQ–MA)–Phe–Arg–OMe, DMQ–MA–Lys(DMQ–MA)–Ile–Arg–OMe, and DMQ–MA–Lys(DMQ–MA)–Val–Arg–OMe, were synthesized. The cytotoxic agent conjugated to the N-terminal, and the ξ-amino group of lysine of the tripeptides was 2,6-dimethoxyhydroquinone–3-mercaptoacetic acid (DMQ–MA). The tripeptides were synthesized by coupling protected amino acid residues in solution according to Pfp/DCC methods (where Pfp refers to pentafluorophenol and DCC refers to N,N′-dicyclohexylcarbodiimide). DNA scission chemistry showed that these compounds were able to cleave supercoiled DNA into open-circular form in drug concentrations as low as 5–20 μM without addition of H2O2 or UV irradiation. DNA cleavage was clearly inhibited when hydroxyl radical scavengers such as glycerol and sodium benzoate were added to the reaction system. When the drugs were added to rhodamine B, the UV absorbance and fluorescence intensity of rhodamine B decreased quickly due to the degradation caused by the hydroxyl radicals. Electron paramagnetic resonance (EPR) experiments employing the spin-trap agent 5,5-dimethyl-1-pyrroline N-oxide (DMPO) showed that the signal intensity of the hydroxyl radicals generated from these newly synthesized DMQ–MA–peptide compounds was a non-linear function of ascorbic acid concentration. Deoxyribonucleic acid binding constants of these compounds were in the 104 M–1 range. It was concluded that DNA cleavage was not related to the ability of these drugs to produce hydroxyl radicals exclusively; indeed, it was related to their ability to produce various radicals and reactive species.


Author(s):  
Yunjie Zhu ◽  
Yanan Shao ◽  
Min Wei ◽  
Kefu Yu ◽  
Yuanyuan Zhang ◽  
...  

Abstract Sulfate radical (•SO4−)-based advanced oxidation processes are widely used for wastewater treatment. This study explored the potential use of UV/persulfate (UV/PS) system for the degradation of 17β-estradiol (E2). The pH of the reaction system can affect the degradation rate of E2 by UV/PS and the optimum pH was 7.0; Br− and Cl− in water can promote the degradation rate, HCO3− has an inhibitory effect on the reaction, SO42− and cations (Na+, Mg2+, K+) have no effect on the degradation rate. The degradation of E2 by UV/PS was a mineralization process, with the mineralization rate reaching 90.97% at 8 h. E2 in the UV/PS system was mainly degraded by hydroxylation, deoxygenation, and hydrogenation. E2 reaction sites were mainly located on benzene rings, mainly carbonylation on quinary rings, and bond breakage between C10 and C5 resulted in the removal of benzene rings and carboxyl at C2 and C3 sites. In the presence of halogen ions, halogenated disinfection by-products were not formed in the degradation process of E2 by UV/PS. E2 in the UV/PS system could inhibit the formation of bromate. The results of this study suggest that UV/PS is a safe and reliable method to degrade E2.


2016 ◽  
Vol 24 (4) ◽  
pp. 413-422 ◽  
Author(s):  
Chuangpeng Shen ◽  
Liping Huang ◽  
Hua Xiang ◽  
Minzhen Deng ◽  
Huahong Gao ◽  
...  

Abstract Cassia mimosoides Linn has been used from ancient times and used for treating hepatitis for its supposedly medically beneficial properties. In this study, different constituents of the Cassia mimosoides Linn (β-Sitosterol, Oleanolic Acid, Emodin, Carotene, Resorcinol, Luteolin, and α-L-Rhamnose) were evaluated for potential anti-HMG-CoA reductase effect. The inhibitory effects of HMG-CoA reductase of Cassia mimosoides Linn extracts and Pravastatin inhibitor at different concentrations (at doses of 1, 5, 25 or 125 μg/mL, respectively) in reaction system (70 mmol/L phosphate buffer, 200mmol/L NADPH, 5 μg HMG-CoA reductase, 2 mmol/L EDTA, 2 mmol/L cysteamine, 0.06% BSA) into 37°C preheat HMG-CoA for initiating this reaction, and then determined the change of HMG-CoA reductase activity (ΔAΔt) at 340 nm, the inhibition ratio of HMG-CoA reductase activity and its dynamic change of inhibitory effect within 15 min and the descent rate of NADPH. Emodin, Luteolin, β-Sitosterol, Oleanolic Acid, α-L-Rhamnose and Carotene showed good inhibition of HMG-CoA reductase activity. Among them, only the Emodin (1 and 5 μg/mL) groups showed a significant decrease of HMG-CoA reductase activity compared to the Pravastatin (1 and 5 μg/mL) groups respectively. In addition, the HMG-CoA reductase activity in the Emodin and Luteolin (25 and 125 μg/mL) groups was clearly lower than the Pravastatin (25 and 125 μg/mL) groups respectively. And the Emodin and Luteolin (1, 5, 25 or 125 μg/mL) groups exhibited a stable effect on inhibiting the HMG-CoA reductase within 15 min. These findings further support the exploration of Cassia mimosoides Linn as a potential agent for the treatment of hepatitis in future studies.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Masoud Reza Shishehbore ◽  
Ali Sheibani ◽  
Masoumeh Eslami

A simple, selective, and inexpensive kinetic method was developed for the determination of hydrazine based on its inhibitory effect on the thionine-bromate system in sulfuric acid media. The reaction was monitored spectrophotometrically at 601 nm by a fixed time method. The effect of different parameters such as concentration of reactants, ionic strength, temperature, and time on the rate of reaction was investigated, and the optimum conditions were obtained. Under optimum conditions, the calibration curve was linear in the concentration range from 0.8–23.0 μg mL−1of hydrazine, and the detection limit of the method was 0.22 μg mL−1. The relative standard deviation for five replicate determinations of 1.0 μg mL−1of hydrazine was 0.74%. The potential of interfering effect of foreign species on the hydrazine determination was studied. The proposed method was successfully applied for the determination of hydrazine in different water samples.


Sign in / Sign up

Export Citation Format

Share Document