China
Africa
Explore chapters and articles related to this topic
Cross Talk Between Heat Shock and Oxidative Stress Inducible Genes During Myocardial Adaptation to Ischemia
Published in John J. Lemasters, Constance Oliver, Cell Biology of Trauma, 2020
Dipak K. Das, Nilanjana Maulik
Superoxide dismutase activity was assayed by its inhibitory action on the superoxide-dependent reduction of ferricytochrome by xanthine-xanthine oxidase.35 The final concentrations in the assay medium (total volume 1 ml) were these: 100 μM cytochrome c, 100 μM hypoxanthine, 10 mM Tris-HCl, and 50 to 80 μg of enzyme protein. The reaction was initiated by addition of 8 mU of xanthine oxidase. Catalase was estimated by measuring the decreases in the absorbance of H2O2 at 240 nm. The final concentrations in the assay medium (total volume 1 ml) were these: 35 mM phosphate buffer, pH 7.2,0.02% Triton X-100, and 30-50 μg of enzyme protein. The reaction was started by the addition of 30 μl of 1 % H2O2 and monitored by the decrease in absorbance of H2O2 at 240 nm. Glutathione peroxidase was estimated by measuring the decrease in absorbance of NADPH at 340 nm. The final concentrations in the assay medium (total volume 1 ml) were these: 62 mM Tris-HCl, pH 7.6, 0.2 mM NADPH, 0.1 mM EDTA, 0.5 mM GSH, and 1 U/ml GSSG-reductase. The reaction was initiated by adding 100 μl 2 mM cumene hydroperoxide. Glutathione reductase activity was estimated by measuring the decrease in absorbance of NADPH at 340 nm. The final concentrations in the assay buffer (1 ml total volume) were these: 90 mM Tris-HCl, pH 7.8, 0.8 mM EDTA, 0.2 mM NADPH, and the decrease in OD was followed at 340 nm for 10 min.
Chemistry of Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Production of shikimates from petrochemicals for commercial use mostly involves straightforward chemistry (Arctander, 1969; Däniker, 1987; Bauer and Panten, 2006; Sell, 2006). Nowadays, the major starting materials are benzene (180) and toluene (181), which are both available in bulk from petroleum fractions. Alkylation of benzene with propylene gives cumene (182), the hydroperoxide of which fragments to give phenol (183) and acetone. Phenol itself is an important molecular building block and further oxidation gives catechol (184). Syntheses using these last two materials will be discussed in the succeeding text. Alkylation of benzene with ethylene gives ethylbenzene, which is converted to styrene (185) via autoxidation, reduction, and elimination in a process known as styrene monomer/propylene oxide (SMPO) process. The epoxide (186) of styrene serves as an intermediate for 2-phenylethanol (47) and phenylacetaldehyde (187), both of which occur widely in essential oils. 2-Phenylethanol is also available directly from benzene by Lewis acid–catalyzed addition of ethylene oxide and as a by-product of the SMPO process. Currently, the volume available from the SMPO process provides most of the requirement. All of these processes are illustrated in Figure 6.31.
A-Z of Standardisation, Pre-Clinical, Clinical and Toxicological Data
Published in Saroya Amritpal Singh, Regulatory and Pharmacological Basis of Ayurvedic Formulations, 2017
Anti-lipid-peroxidative: The effects of Shilajit on lipid liver homogenate were investigated. It inhibited lipid peroxidation induced by cumene hydroperoxide and PDP/Fe++ complex in a dose dependent reduced glutathione content and inhibited ongoing lipid peroxidation, induced by these agents immediately after addition to the incubation system (Tripathi et al. 1996).
Whole-body inhalation exposure to 2-ethyltoluene for two weeks produced nasal lesions in rats and mice
Published in Inhalation Toxicology, 2021
Madelyn C. Huang, Cynthia J. Willson, Sridhar Jaligama, Gregory L. Baker, Alan W. Singer, Yu Cao, Jessica Pierfelice, Esra Mutlu, Brian Burback, Guanhua Xie, David E. Malarkey, Barney Sparrow, Kristen Ryan, Matthew Stout, Georgia K. Roberts
The toxicity of some C9 alkylbenzenes and related isomers is understudied. While inhalation of some C9 alkylbenzenes has been reported to be carcinogenic in rodent studies (cumene and ethylbenzene: NTP 2009, 2013; IARC 2000; NTP 1999) or have reproductive and neurobehavioral effects (trimethyl benzenes: Gralewicz and Wiaderna 2001; Korsak and Rydzyński 1996; EPA 2016b, xylenes: ATSDR 2007), there is little safety data on ethyltoluene (ET) isomers which make up 25–35% of the C9 aromatic fraction of Naphtha (ICCA 2012). The available literature on ethyltoluene isomers is limited to studies of 4-ET. Oral gavage studies of animals with 4-ET show developmental toxicity at doses ≤200 mg/kg and significant changes in liver weight, leukocyte differentials, and clinical pathology at doses ≥100 mg/kg (IRDC 1980, 1981; Borriston 1983; Hazleton 1983). 4-ET was found to cause mild skin and eye irritancy and changes in leukocyte number in bronchiolar lavage with inhalation exposure (Swiercz et al. 2000).
Tandem repeated irritation test (TRIT) studies and clinical relevance: Post 2006
Published in Cutaneous and Ocular Toxicology, 2019
Schliemann et al. investigated the tandem effects of two undiluted organic solvents (octane and cumene) and SLS, a common amphiphilic detergent irritant.12 They used the classical TRIT and measured outcomes of visual scoring, skin color reflectance (chromameter), skin hydration, and TEWL. Individually, n-octane was the more powerful irritant compared to cumene. However, the combined exposure to both organic solvents resulted in increased irritation and erythema more than octane, cumene, and SLS did alone.12 The tandem effect did not exceed the skin changes and skin barrier impairment induced by repeated application of SLS. These findings contrast with studies others to 2006 that show that tandem application of SLS and another organic solvent, toluene, induces skin barrier impairment and increased skin irritation than repeated application of SLS alone.
The Comparative Effects of Inulin and Bacillus clausii on LPS-Induced Endotoxemic Rat Liver
Published in Journal of Investigative Surgery, 2022
Ibrahim Sogut, Fatih Kar, Sevda Tanrikulu-Kucuk, Tarık Talha Gozden, Sumeyye Asena Can, Aslı Kandil
According to Lawrence and Burk, the GSH-Px activity was calculated using cumene hydroperoxide as a substrate [18]. In a total volume of 1 ml, the assay mixture included 50 mm potassium phosphate buffer (pH: 7.0), 1 mm EDTA, 1 mm sodium azide, 0.2 mm NADPH, 1 mm GSH, 0.5 IU/ml glutathione reductase, 1.2 mm cumene hydroperoxide, and diluted postmitochondrial fraction. At 37 °C, the reaction was started with the addition of cumene hydroperoxide and spectrophotometrically monitored at 340 nm. The NADPH’s extinction coefficient (6.22 × 103/[M−1cm−1]) was used to measure the results, which were expressed in nmol/min/mg protein.