Seven new 4-hydroxybenzyl-substituted glutathione derivatives (2-8), together with a known analogue (1), were isolated from the aqueous extract of Gastrodia elata Blume rhizomes. Their structures were determined by using spectroscopic and chemical methods. The absolute configurations of 1-8 were assigned by using Marfey's method, combined with comparing the NMR and CD spectroscopic data of sulfoxide moieties in 3-6 with those of S-(4-hydroxybenzyl)cysteine sulfoxide stereoisomers (9-12) synthesized as authentic samples. The configurations of 9-12 were confirmed by electronic CD calculations based on the quantum-mechanical time-dependent density functional theory. Furthermore, the structures of 1, 3, 5, 7, and 8 were verified by synthesis. Compound 3 was active against serum deprivation-induced PC12 cell damage and synthetic 9-14 exhibited activity against Fe2+-cysteine induced rat liver microsomal lipid peroxidation.
Moringin and Its Structural Analogues as Slow H<sub>2</sub>S Donors: Their Mechanisms and Bioactivity
作者:Yuyun Lu、Xingyi Wang、Haoliang Pu、Yi Lin、Dan Li、Shao Quan Liu、Dejian Huang
DOI:10.1021/acs.jafc.0c02358
日期:2020.7.8
These isothiocyanates rapidly formed cysteine adducts, which underwent intramolecular cyclization followed by slowly releasing (a) organic amine and raphanusamic acid and (b) H2S and 2-carbylamino-4,5-dihydrothiazole-4-carboxylic acids. The product distributions are highly dependent on para-substituents on the phenyl group. Moringin has higher cytotoxicity to cancer cells and is a more potent anti-inflammatory
Bletilla striata is consumed as food and herbal medicine. Militarine (MLT) is a major ingredient in B. striata. Previous studies demonstrated that MLT showed teratogenic toxicity to zebrafish embryos. The present study aimed to identify reactive metabolites possibly involved in the cytotoxicity of MLT and determine the metabolic pathways involved. MLT was found to be hydrolyzed to p-hydroxybenzyl alcohol (HBA) by β-glucosidase and esterases. The resulting HBA further underwent spontaneous dehydration to form quinone methide. HBA was also metabolized to the corresponding sulfate, followed by departure of the sulfate to generate a quinone methide. The resultant quinone methide reacted with hepatic glutathione (GSH) and protein to form the corresponding GSH conjugate and protein adduction. Additionally, inhibition of sulfotransferases (SULTs) attenuated the susceptibility of hepatocytes to the toxicity of MLT. This study provides that the hydrolytic enzymes β-glucosidase, esterases, and SULTs participate in the metabolic activation of MLT.
Thermally Sensitive Protecting Groups for Cysteine for Peptide Cyclization and Selective Disulfide Bond Formation
申请人:University of Windsor
公开号:US20220153749A1
公开(公告)日:2022-05-19
In a preferred embodiment, there is provided a protecting group for protecting the thiol side chain of a cysteine residue, the protecting group comprising a Diels-Alder cycloadduct of a furan and a maleimide, and optionally, a linker interposed between the thiol side chain and the Diels-Alder cycloadduct.
Studies on peptides. LXXXIII. Behavior of S-substituted cysteine sulfoxides under deprotecting conditions in peptide synthesis.
Sulfoxides of Cys (S-p-methoxybenzyl) and Cys (S-benzyl) were prepared by oxidation with sodium perborate. Hydrogen fluoride and methanesulfonic acid converted the former sulfoxide to S-p-methoxyphenylcysteine or S-p-hydroxyphenylcysteine in the presence of anisole or phenol, respectively, while the latter sulfoxide resisted the actions of these deprotecting reagents. Thiophenol appears to be useful as a powerful reducing reagent for protected cysteine sulfoxides.
作者:Qing-Lan Guo、Ya-Nan Wang、Cheng-Gen Zhu、Ming-Hua Chen、Zhi-Bo Jiang、Nai-Hong Chen、Xiu-Yun Song、Mei-Jin Zhang、Jian-Gong Shi
DOI:10.1080/10286020.2015.1040000
日期:2015.5.4
Seven new 4-hydroxybenzyl-substituted glutathione derivatives (2-8), together with a known analogue (1), were isolated from the aqueous extract of Gastrodia elata Blume rhizomes. Their structures were determined by using spectroscopic and chemical methods. The absolute configurations of 1-8 were assigned by using Marfey's method, combined with comparing the NMR and CD spectroscopic data of sulfoxide moieties in 3-6 with those of S-(4-hydroxybenzyl)cysteine sulfoxide stereoisomers (9-12) synthesized as authentic samples. The configurations of 9-12 were confirmed by electronic CD calculations based on the quantum-mechanical time-dependent density functional theory. Furthermore, the structures of 1, 3, 5, 7, and 8 were verified by synthesis. Compound 3 was active against serum deprivation-induced PC12 cell damage and synthetic 9-14 exhibited activity against Fe2+-cysteine induced rat liver microsomal lipid peroxidation.