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Introduction
Published in Nicola Loprieno, Alternative Methodologies for the Safety Evaluation of Chemicals in the Cosmetic Industry, 2019
According to their potential toxic effects, they are classified as: Coloring agents allowed in all cosmetic products;Coloring agents allowed in all cosmetic products except those intended to be applied in the vicinity of the eye: in particular eye make-up and eye make-up removers;Coloring agents allowed exclusively in cosmetic products intended not to come into contact with the mucous membranes;Coloring agents allowed exclusively in cosmetic products intended to come into contact with the skin only briefly.Coloring agents which include nitro dyes, azo compounds, tryphenylmethane, xanthene, quinoline, anthraquinone, indigo, etc.
Methods of Protein Iodination
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
An acyl group is the univalent group, , where R is any organic group attached to one bond of the bivalent carbonyl group ,. The alkyl group has already been defined in Section C.1.a. An aryl group is an organic group derived from an aromatic hydrocarbon by the removal of a hydrogen (e.g., the phenyl group, C6H5-, derived from benzene, C6H6). Amines are organic derivatives of ammonia (NH3) formed by the replacement of one, two, or three of the hydrogen atoms by an alkyl or aryl group; correspondingly, the resulting aliphatic and aromatic (and other) amines are classified as primary (RNH2), secondary (R2NH), or tertiary (R3N) amines. Amides are carboxylic acid derivatives obtained by the replacement of the OH group of an acid by an amino group (NH2). Azo compounds are organic compounds which contain the group, -N:N-, attached to two alkyl or aryl groups (e.g., azobenzene, C6H5-N:N-C6H5). In contrast, only one of the two N atoms bonded together in diazo compounds is attached to a carbon of an organic structure (RN=N, see further below). Imines, containing the grouping, -CH=N-, arise from the condensation of primary amines with aldehydes (or ketones) through the loss of H2O. Imides are nitrogen analogs of anhydrides:
Tools for Microanalysis of the Neurotransmitter Location in Plant Cells
Published in Akula Ramakrishna, Victoria V. Roshchina, Neurotransmitters in Plants, 2018
Color reactions for cholinesterases were originated from the experiments related to the animal nervous system. Recent experiments for similar determination of the cholinesterase activity with thiocholine as substrate were based on the ferricyanide/ferrocyanide reaction of Karnovsky-Roots (Karnovsky and Roots 1964) where the product was red-brown Hettchet’s pigment (copper ferrocyanide) and was well seen on isolated enzymes from electric eel (Budantsev and Roshchina 2005, 2007). First histochemical research in animals was also based on the color reactions with some azo compounds (Menten et al. 1944; Nachlas and Seligman 1949). Some authors applied azo dye Fast Red TR for determination of spot (band) of cholinesterase reacting with β-naphthyl acetate as substrate in gel-electrophoresis (Harris et al. 1962).
Gut microbiota in ALS: possible role in pathogenesis?
Published in Expert Review of Neurotherapeutics, 2019
Pamela A. McCombe, Robert D. Henderson, Aven Lee, John D. Lee, Trent M. Woodruff, Restuadi Restuadi, Allan McRae, Naomi R. Wray, Shyuan Ngo, Frederik J. Steyn
Microbial metabolism can also result in the production of toxic molecules from dietary components. Well-characterized examples include the transformation of AZO compounds (derivatives of diazene where both hydrogens are substituted by hydrocarbyl groups), metals (e.g. Bismuth), certain drugs, heterocyclic amines and polycyclic aromatic hydrocarbons (PAHs). Data from several studies have shown that azoreductases from the gut microbiota catalyze the AZO-bond cleavage of numerous AZO compounds to generate toxic aromatic amines [188, 189]. Another example is bismuth. Studies have shown that human fecal samples can readily metabolize bismuth into trimethylbismuth, which is a known neurotoxin [190]; the methylation pathway of bismuth is proposed to occur via Methanoarchaea [191].
Antioxidant activity and photostability assessment of trans-resveratrol acrylate microspheres
Published in Pharmaceutical Development and Technology, 2019
Rosario Pignatello, Tiziana M. G. Pecora, Giuseppa G. Cutuli, Alfio Catalfo, Guido De Guidi, Barbara Ruozi, Giovanni Tosi, Simona Cianciolo, Teresa Musumeci
Before ORAC analysis, the RSV samples were solubilized in phosphate buffer solution (PBS, 0.075 M, pH =7.4) and incubated at room temperature for different days. The original ORAC method with few modifications was used (Ninfali et al. 2005). The water-soluble azo compound AAPH was used as a radical initiator to generate free radicals at a constant rate. FL was used as a probe to assess the antioxidant activity. The final reaction mixtures for the assay were:A positive control (90 µL of 1.5 µM FL solution, 90 µL of Trolox solution at 20–40 µM concentration range, 2820 µL PBS and 45 mg of AAPH);a negative control (90 µL 1.5 µM FL solution and 2910 µL of PBS);samples of neat RSV (90 µL of 1.5 µM FL solution, 2.88 µL of RSV in different concentration, 2907 µL PBS and 45 mg of AAPH);Eudragit®-associated RSV samples (90 µL of 1.5 µM FL solution, 4.75 µL of a microparticle suspension at different RSV ratio, 2905 µL PBS and 45 mg of AAPH).
Insights into biological activity of ureidoamides with primaquine and amino acid moieties
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2018
Josipa Vlainić, Ivan Kosalec, Kristina Pavić, Dimitra Hadjipavlou-Litina, Eleni Pontiki, Branka Zorc
Free radicals play an important role in the inflammatory process and several diseases, as well as in potential damage of cellular compounds such as DNA, proteins and lipids. Consequently, compounds with antioxidative properties could be expected to offer protection and therapeutic treatment. LOX inhibitors are potential agents for the treatment of inflammatory and allergic diseases, certain types of cancer, and cardiovascular diseases32. Thus, to evaluate the antioxidative potential of PQ-derivatives 5a–f, we have used three different antioxidant assays: (a) the interaction with the stable free radical DPPH, (b) the interaction with the water-soluble azo compound AAPH and (c) the inhibition of soybean lipoxygenase in vitro. DPPH interaction of the tested compounds was examined at a 100 µM concentration after 20 and 60 min. As shown in Table 3, DPPH-reducing ability of all tested compounds was very low, possibly due to stereochemical reasons.