Photolyse du butyne-1 dans la région de 147 à 174 nm

1980 ◽  
Vol 58 (19) ◽  
pp. 2100-2107 ◽  
Author(s):  
Hélène Deslauriers ◽  
Jovette Deschênes ◽  
Guy J. Collin
Keyword(s):  
Quantum Yield ◽  
Radical Scavenging ◽  
Hydrogen Iodide ◽  
Radical Scavengers ◽  
Methyl Radical ◽  
Radical Intermediate ◽  
Scavenging Effect ◽  
Radical Scavenging Effect ◽  
Propargyl Radicals

We have studied the 147, 163, and 174 nm photolysis of 1-butyne. Several products from C1 to C5 were observed under various conditions such as in the presence of additives, or at different pressures between 0.5 and 100 Torr (65 to 13 300 N m−2). The methyl radical is the most important radical intermediate. Acetylene, ethylene, and vinylacetylene are produced in the presence of radical scavengers and are probably the result of the fragmentation of the photoexcited molecule. Propargyl radicals are thought to be produced but appear not to be scavenged by hydrogen iodide. Polymerization was observed even in the presence of radical scavengers. Secondary processes are numerous and make the interpretation of our results difficult; for example, the ethylene quantum yield increased upon addition of 10% oxygen, the simple radical scavenging effect of this additive does not explain such an effect.

scholarly journals Antibacterial, Antioxidant and Cytotoxic Properties of Crinum asiaticum Bulb Extract

2012 ◽  
Vol 28 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Md Atiar Rahman ◽  
Rumana Sharmin ◽  
Md Nazim Uddin ◽  
Md Sohel Rana ◽  
Nazim Uddin Ahmed
Keyword(s):  
Radical Scavenging ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Scavenging Effect ◽  
Ic50 Value ◽  
Radical Scavenging Effect ◽  
Dpph Scavenging ◽  
Crinum Asiaticum

Antibacterial effect of Crinum asiaticum bulb extract (1mg/disc) was tested on four Gram- positive and six Gram-negative bacteria by disc diffusion method using kanamycin (30 ìg/disc) as standard antibiotic disc. The bulb extract (250-1000mg/disc) showed significant zone of inhibition against all Gram-positive and Gram-negative bacteria ranging from 12-14 mm in diameter. Antioxidant potential of the same extract was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging method. The extract showed remarkable free radical scavenging effect (95.96%) providing the IC50 value of 5.62 for the bulb extract and 5.46 for ascorbic acid (standard antioxidant) at the concentration of 1000 ìg/ml. The bulb extract was found to be (LC50 value 94.06 ?g/ml) in Brine-Shrimp lethality test. DOI: http://dx.doi.org/10.3329/bjm.v28i1.11801 Bangladesh J Microbiol, Volume 28, Number 1, June 2011, pp 1-5

scholarly journals Anti-oxidative and antimicrobial activities of Hieracium pilosella L. extracts

2008 ◽  
Vol 73 (5) ◽  
pp. 531-540 ◽  
Author(s):  
Ljiljana Stanojevic ◽  
Mihajlo Stankovic ◽  
Vesna Nikolic ◽  
Ljubisa Nikolic
Keyword(s):  
Salmonella Enteritidis ◽  
Radical Scavenging ◽  
Antimicrobial Activities ◽  
Diffusion Method ◽  
Quantitative Composition ◽  
Minimal Inhibitory Concentrations ◽  
Qualitative And Quantitative ◽  
Scavenging Effect ◽  
Hieracium Pilosella ◽  
Radical Scavenging Effect

The anti-oxidative and antimicrobial activities of different extracts from Hieracium pilosella L. (Asteraceae) whole plant were investigated. The total dry extracts were determined for all the investigated solvents: methanol, dichloromethane, ethyl acetate and dichloromethane: methanol (9:1). It was found that the highest yield was obtained by extraction with methanol (12.9 g/100 g of dry plant material). Qualitative and quantitative analysis were performed by the HPLC method, using external standards. Chlorogenic acid, apigenin-7-O-glucoside and umbelliferone were detected in the highest quantity in the extracts. The qualitative and quantitative composition of the extracts depends on the solvent used. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect of the extracts was determined spectrophotometrically. The highest radical scavenging effect was observed in the methanolic extract, both with and without incubation, EC50 = 0.012 and EC50 = 0.015 mg ml-1, respectively. The antimicrobial activities of the extracts towards the bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Salmonella enteritidis and Klebsiella pneumoniae) and the fungi (Aspergillus niger and Candida albicans) were determined by the disc diffusion method. The minimal inhibitory concentrations were determined for all the investigated extracts against all the mentioned microorganisms.

IN-SILICO AND IN VITRO ASSESSMENT OF SYNTHESIZED DIAZENYLSULFONAMIDES AS APOPTOSIS INDUCERS AND RADICAL SCAVENGERS

INDIAN DRUGS ◽  
2020 ◽  
Vol 57 (06) ◽  
pp. 49-59
Author(s):  
Priyambada Kshiroda Nandini Sarangi ◽  
Jyotirmaya Sahoo ◽  
Chita Ranjan Sahoo ◽  
Sudhir Kumar Paidesetty ◽  
Guru Prasad Mohanta
Keyword(s):  
Cell Line ◽  
Cancer Cell ◽  
Radical Scavenging ◽  
Cancer Cell Line ◽  
Scavenging Effect ◽  
Ic50 Values ◽  
Radical Scavenging Effect ◽  
The Individual ◽  
Mcf 7

A series of eight quinoline-thiazole hybrid-bearing diazenylsulfonamides, 4a-4h, were synthesized and characterized by UV-Vis, FT/IR, 1H NMR and lC-MS. These compounds were formed when two prepared intermediate precursors of Schiff-base compounds, (E)-N-((2-chloroquinolin-3-yl)methylene)-4phenylthiazol-2-amine (3a) and (E)-N-((2-chloroquinolin-3-yl)methylene)-4-chlorophenylthiazol-2-amine (3b) were converted to the corresponding diazenyl compounds 4a-4h by treating and coupling with the individual diazonium salts of sulfa-drugs. The results of in vitro cytotoxic activity of the synthesized compounds in two cancer cell lines MCF 7 (human breast cancer cell line) and K562 (myelogenousleukemia cell line) have shown the IC50 values as given: 4b against MCF 7 19.52 and against K562 20.55µM; 4d against MCF 7 15.96 and against K562 13.05µM. Moreover, the compound 4-(((Z)-(2-chloroquinolin-3yl)(4-phenylthiazol-2-ylimino)methyl)diazenyl)benzenesulfonic acid (4d) induced maximum percentage of apoptosis. Furthermore, the in vitro antioxidant activity study revealed that among all the synthesized compounds, compound 4d has an excellent radical scavenging effect. Molecular docking was additionally performed to investigate the binding affinity of H-bonding interaction of synthesized compounds with a targeted enzyme and to compare it with the anticancer drugs, dasatinib, bosutinib and dacarbazine.

scholarly journals Detection and Identification of Antibacterial and Antioxidant Components of Essential Oils by TLC-Biodetection and GC-MS

2016 ◽  
Vol 11 (11) ◽  
pp. 1934578X1601101 ◽  
Author(s):  
Ágnes M. Móricz ◽  
Györgyi Horváth ◽  
Andrea Böszörményi ◽  
Péter G. Ott
Keyword(s):  
Essential Oils ◽  
Solid Phase ◽  
Radical Scavenging ◽  
Gas Chromatography Mass Spectrometry ◽  
Cinnamon Bark ◽  
Scavenging Effect ◽  
Detection And Identification ◽  
Radical Scavenging Effect ◽  
Direct Bioautography ◽  
Layer Chromatography

Components of cinnamon bark, rosemary, clove and thyme essential oils were screened for antioxidant and antibacterial activity utilizing thin-layer chromatography (TLC) coupled with the DPPH• test and direct bioautography using Bacillus subtilis cells. The compounds in the active chromatographic zones were identified by solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) after their elution. Seven antibacterial components were found: cinnamaldehyde and eugenol in cinnamon bark oil, 1,8-cineole, camphor, borneol and α-terpineol in rosemary oil, eugenol in clove oil and thymol in thyme oil. Only two of them, thymol and eugenol displayed a free radical scavenging effect.

scholarly journals Effects of Antioxidants in Reducing Accumulation of Fat in Hepatocyte

2018 ◽  
Vol 19 (9) ◽  
pp. 2563 ◽  
Author(s):  
Jung-Pyo Yang ◽  
Ji-Hun Shin ◽  
Seung-Hwan Seo ◽  
Sang-Gyun Kim ◽  
Sang Lee ◽  
...  
Keyword(s):  
Er Stress ◽  
Inflammatory Responses ◽  
Radical Scavenging ◽  
Gene Expressions ◽  
Fat Accumulation ◽  
Scavenging Effect ◽  
Radical Scavenging Effect ◽  
Vitro Model ◽  
Liver Hepatocellular Carcinoma

The progress of the hepatic steatosis (HS), a clinicopathological status, is influenced by cellular oxidative stress, lipogenesis, fatty acid (FA) oxidation, and inflammatory responses. Because antioxidants are gaining attention as potent preventive agents for HS, we aimed to investigate anti-lipogenic effects of the antioxidants vitamin C (VC), N-acetylcysteine (NAC), and astaxanthin (ATX) using hepatocytes. For this, we established an in vitro model using 1 mM oleic acid (OA) and human liver hepatocellular carcinoma (HepG2) cells; 10 μM antioxidants were evaluated for their ability to reduce fat accumulation in hepatocytes. Our results showed that all three antioxidants were effective to reduce fat accumulation for the molecular targets such as reduction in lipid droplets, triglyceride (TG) concentration, reactive oxygen species (ROS) production, and cell apoptosis, as well as in gene expressions of endoplasmic reticulum (ER) stress-related effectors, lipogenesis, and inflammatory cytokines. There were simultaneous increases in diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effect, cell survival, AMPK phosphorylation, NRF2-related gene expression for cellular defense, and FA β-oxidation. However, among these, ATX more effectively inhibited ER stress and lipogenesis at the intracellular level than VC or NAC. Consequently, ATX was also more effective in inhibiting cell death, lipotoxicity, and inflammation. Our result emphasizes that ATX achieved greater lipotoxicity reduction than VC and NAC.

scholarly journals Investigation into the Antioxidant and Antidiabetic Potential of Moringa stenopetala: Identification of the Active Principles

2015 ◽  
Vol 10 (3) ◽  
pp. 1934578X1501000 ◽  
Author(s):  
Solomon Habtemariam
Keyword(s):  
Potential Role ◽  
Therapeutic Potential ◽  
Radical Scavenging ◽  
Nutritional Supplement ◽  
Inhibitory Effect ◽  
Β Cells ◽  
Moringa Stenopetala ◽  
Scavenging Effect ◽  
Neochlorogenic Acid ◽  
Radical Scavenging Effect

The fresh leaves of Moringa stenopetala (family, Moringaceae) are commonly eaten as cabbage while dried leaves are used as nutritional supplement and for treating a variety of disease conditions including diabetes. The present investigation into the therapeutic potential of the leaves and seeds of the plant revealed no inhibitory effect against α-glucosidase enzyme up to the concentration of 200 μg/mL but the leaves extract displayed potent DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging effect (IC50, 59.5 ± 4.1 μg/mL). An activity directed fractionation and isolation procedure resulted in the identification of the major antioxidant compound as rutin and minor active component, neochlorogenic acid. Both the crude extract (0.8–200 μg/mL) and rutin (0.8–200 μM) but not neochlorogenic acid displayed a concentration-dependent protection of human pancreatic β-cells (1.4E7 cells) from oxidant-induced cell death. The identification of these compounds along with their potential role in the nutritional and medicinal significance of the plant is discussed.

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