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Depigmenting Agents
Published in Vineet Relhan, Vijay Kumar Garg, Sneha Ghunawat, Khushbu Mahajan, Comprehensive Textbook on Vitiligo, 2020
A huge number of phenolic compounds have been tested as inhibitors of melanin synthesis. In one animal study, eight compounds were selected on the basis of their known depigmenting effects, including hydroquinone (H), 4-ethoxyphenol (4-EP), 4-methylcatechol (4-MC), 4-tert-butylcatechol (4-t-BC), monobenzone (M), hydroquinone bis (2-hydroxyethyl)-ether (HHEE), and catechol (C). These compounds were injected into animal skin as 10% and 20% solutions dissolved in 95% ethanol. Six of the eight compounds tested showed positive depigmenting effects at 10% except C and HHEE. Compounds showed increased necrosis at a concentration of 20% [10,38].
Cognition Enhancers
Published in Sahab Uddin, Rashid Mamunur, Advances in Neuropharmacology, 2020
Ramneek Kaur, Rashi Rajput, Sachin Kumar, Harleen Kaur, R. Rachana, Manisha Singh
As BDNF is associated in activity-dependent maturation and short-range functioning of synapse, whose damage is one of the initial changes in AD, and BDNF will be quite efficient as a cognition enhancer. Therefore, the interest is to up-regulate the BDNF levels in the brain. But, BDNF is unable to cross the blood-brain barrier (BBB) (Pardridge et al., 1998). Another activator of TrkB, 7, 8-dihydroxyflavone (Fig. 18.1) is able to cross the BBB and affects the emotional learning in amygdala (Andero et al., 2011; Zeng et al., 2012). Therefore, the emphasis has been on the discovery of small molecules which are the agonists of Trk receptors and small molecules that synthesize NTs. 4-methylcatechol (4-MC) is one such molecule which is reported to synthesize NGF (Kaechi et al., 1993; Kaechi et al., 1995), to increase the mRNA of BDNF, and immunoreactivity by 50% in the brain when administered peripherally to the 10-day old rat (Fukumitsu et al., 1999). Further, when 4-MC was administered intracerebroventricularly, it enhanced memory and spatial learning in rats and caused an anti-depressant effect (Sun and Alkon, 2008). The process by which BDNF is induced is still not known, but, on the whole, it can be stimulated by various transcription factors (TFs) like cAMP response element binding protein (CREB), calcium-response factor and neuronal Per Arnt Sim domain protein 4 (NPAS4) (Calabrese et al., 2013). Evidences suggest that 4-MC stimulates MAP kinases and NT receptors of Trk family directly (Sometani et al., 2002).
Laccase-Mediated Synthesis of Novel Antibiotics and Amino Acid Derivatives
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
The amination of catechols is limited to a few specific examples. If other catechols or ß-lactam antibiotics or other reaction conditions were used, monoaminated products were either not obtained at all or only in low yield, and undesirable side reactions produced a number of by-products. The redox potential difference between Trametes sp. laccase and the substrates 3-methylcatechol (75) and 4-methylcatechol (78) is of around 0.2 V (Table 8.6) and a high activity of laccase with these substrates can be derived. The primary radicals formed by laccase (first reaction step of Fig. 8.5) mainly react to homomolecular dimers and oligomers or products formed by abiotic follow-up reactions with solvent molecules. The formation of heteromolecular dimers (second reaction step, Fig. 8.5) is rather a stroke of lack than the standard. Possible reaction steps during laccase-mediated reactions of catechols.
Qingyi granules ameliorate severe acute pancreatitis in rats by modulating the gut microbiota and serum metabolic aberrations
Published in Pharmaceutical Biology, 2023
Juying Jiao, Jianjun Liu, Fei Luo, Mengxue Shang, Chen Pan, Bing Qi, Liang Zhao, Peiyuan Yin, Dong Shang
Correlation analysis between four key bacteria at the genus level, including Lactobacillus, Helicobacter, Romboutsia and Allobaculum, and differentially abundant metabolites was carried out to investigate the potential gut microbiota-mediated metabolic disturbance in SAP (Figure 6). The level of Allobaculum and Romboutsia, which decreased in SAP rats, were negatively correlated with the levels of a variety of metabolites, including citric acid, malic acid, hydrocinnamic acid, succinic acid, and linoleic acid. In addition, the abundance of Allobaculum was positively correlated with the levels of galactaric acid, glucaric acid, and glycerylphosphorylethanolamine, and the abundance of Romboutsia was positively correlated with the levels of 4-methylcatechol 2-sulfate and o-desmethyltramadol glucuronide. The abundances of Lactobacillus and Helicobacter, which were increased in SAP rats, were positively correlated with the levels of most of the metabolites; in particular, Lactobacillus abundance was significantly correlated with the levels of metabolites such as indole-3-propionic acid, linoleic acid, and 3-indoxyl sulfate, while it was negatively correlated with the levels of galactaric acid, glucaric acid, glycerylphosphorylethanolamine and d-ribulose 5-phosphate. These results suggested that the four key bacteria have an intimate relationship with serum metabolite levels in SAP.
1D NMR WaterLOGSY as an efficient method for fragment-based lead discovery
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2019
Claire Raingeval, Olivier Cala, Béatrice Brion, Marc Le Borgne, Roderick Eliot Hubbard, Isabelle Krimm
The WaterLOGSY factors and the calculated solvent-accessibilities for compounds 1, 4, and 7 are shown in Figure 8. As expected, the protons exhibiting weaker WaterLOGSY factors correspond to the most solvent-exposed protons in the corresponding protein-ligand 3 D structures. For weak-affinity ligands such as fragment-like compounds, the comparison of WaterLOGSY factors between two analogues may be used to assess the impact of a chemical group on the binding mode of the ligand. This is illustrated in Figure 8 for compound 1 (4-methylcatechol, see also Figure 2) and compound 7 (4-tert-butylcatechol) bound to PRDX5. According to the WaterLOGSY factors, the binding mode compound 7 is modified in comparison to that of compound 1. This observation is in agreement with the X-ray structure of the complex of compound 7 with PRDX5, in which two binding modes are observed (while only one binding mode was observed for compound 1) (Figure 8). Depending on the binding modes, the proton H1 is either buried into the protein or solvent-exposed. The experimental WaterLOGSY factor is averaged, and no privileged orientation is observed. This result shows that WaterLOGSY-based structural information can be particularly useful to compare the binding properties of similar compounds.
Lung cancer: active therapeutic targeting and inhalational nanoproduct design
Published in Expert Opinion on Drug Delivery, 2018
Nasser Alhajj, Chin Fei Chee, Tin Wui Wong, Noorsaadah Abd Rahman, Noor Hayaty Abu Kasim, Paolo Colombo
The Mannich reaction is a multicomponent condensation of a non-enolizable aldehyde (such as formaldehyde), a primary or secondary amine and a carbonyl compound or electron-rich aromatic compound to provide aminoalkylated products [114]. Xie et al. (2008) conjugated peptides to nanoparticles using the Mannich reaction (Table 1d) [115]. 4-methylcatecol-functionalized iron oxide nanoparticles are prepared through chelation with the iron. The aromatic ring of 4-methylcatechol on nanoparticles is directly conjugated with the amine moiety of a cyclic peptide, c(RGDyK) in the presence of formaldehyde in N,N-dimethylformamide.