Sulfur is an essential element for the entire biological kingdom because of its incorporation into amino acids, proteins and other biomolecules. Sulfur atoms are also important in the iron-containing flavoenzymes. Unlike humans, plants can use inorganic sulfur to synthesize sulfur-containing amino acids. Therefore, plants are an important source of sulfur for humans. Sulfur-containing compounds are found in all body cells and are indispensable for life. Some of sulfur-containing antioxidant compounds are, cysteine, methionine, taurine, glutathione, lipoic acid, mercaptopropionylglycine, N-acetylcysteine, and the three major organosulfur compounds of garlic oil, diallylsulfide, diallyldisulfide and diallyltrisulfide. In a comparison of the structure-function relationship among these sulfur-containing antioxidant compounds, dihydrolipoic acid (the reduced form of LA) is the most effective antioxidant. Dihydrolipoic acid contains two sulfhydryl groups and can undergo further oxidation reaction to form lipoic acid. The antioxidative activities of sulfur-containing compounds follow a general trend, the more highly reduced forms are stronger antioxidants and the number of sulfur atoms determine, at least in part, their modulatory activites on the glutathione related antioxidant enzymes. In this article, the antioxidant effects and the antioxidative activities, of sulfur-containing amino acids, are reviewed. In addition, the general antioxidant effects and the structure-function relationship of some sulfur-containing compounds are also reviewed.
Acetylcysteine/pharmacology ; Amino Acids, Sulfur/*pharmacology ; Antioxidants/*pharmacology ; Cysteine/pharmacology ; Glutathione/pharmacology ; Methionine/pharmacology ; Structure-Activity Relationship ; Taurine/pharmacology ; Thioctic Acid/pharmacology ; Thiopronine/pharmacology

Acetaminophen ; poisoning ; Acetylcysteine ; pharmacology ; therapeutic use ; toxicity ; Humans ; Liver Diseases ; drug therapy

N-acetyl-L-cysteine (NAC) capped quantum dots (QDs) were synthesized by a hydrothermal method and coated with 2-amino-2-deoxy-D-glucose (DG), polyethylene glycol (PEG), and 9-D-arginine (9R). The optical properties, morphology and structure of 9R/DG-coated CdTe QDs were characterized by ultraviolet-visible spectrometry, fluorescence spectrum, Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), liquid chromatography-mass spectrometer (LC-MS), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and transmission electron micrographs (TEM). Furthermore, the biocompatibility, tumor targeted ability and transmembrane action of 9R/DG-coated CdTe QDs were studied. Results indicated that 9R/DG-coated CdTe QDs was constructed successfully by ligand exchange. The 9R/DG-coated CdTe QDs with the size of 8-10 nm had good dispersity and the absorbance and fluorescence peaks of CdTe QDs after modification were red shifted from 480 nm to 510 nm and 627 nm to 659 nm, respectively. In addition, the CdTe QDs modified by PEG, DG and 9R displayed good biocompatibility, high targeted ability to the cancer cells with glucose transporter type 1 (GLUT1) receptor high expression and obvious transmembrane ability.
Acetylcysteine ; chemistry ; Cadmium Compounds ; pharmacology ; Humans ; Neoplasms ; drug therapy ; Polymers ; chemistry ; Quantum Dots ; chemistry ; Spectrophotometry, Ultraviolet ; Tellurium ; pharmacology

This study investigated the effects of N-acetylcysteine (NAC) and ascorbic acid (AA) on hemin-induced K562 cell erythroid differentiation and the role of reactive oxygen species (ROS) in this process. Hemin increased ROS levels in a concentration-dependent manner, whereas NAC and AA had opposite effects. Both NAC and AA eliminated transient increased ROS levels after hemin treatment, inhibited hemin-induced hemoglobin synthesis, and decreased mRNA expression levels of β-globin, γ-globin, and GATA-1 genes significantly. Pretreatment with 5,000 μmol/L AA for 2 h resulted in a considerably lower inhibition ratio of hemoglobin synthesis than that when pretreated for 24 h, whereas the ROS levels were the lowest when treated with 5,000 μmol/L AA for 2 h. These results show that NAC and AA might inhibit hemin-induced K562 cell erythroid differentiation by downregulating ROS levels.
Acetylcysteine ; pharmacology ; Antioxidants ; pharmacology ; Ascorbic Acid ; pharmacology ; Cell Differentiation ; drug effects ; Down-Regulation ; Erythroid Cells ; drug effects ; Hemin ; pharmacology ; Humans ; K562 Cells ; Reactive Oxygen Species ; metabolism

C-terminal farnesyl cysteine carboxyl methylation has been known to be the last step in the post-translational modification processes of several important signal transduction proteins in eukaryotes including ras related GTP binding proteins and the gamma-subunit of heterotrimeric G proteins. Protein farnesyl cysteine carboxyl methyltransferase (PFCCMT; EC, 2.1.1.100) catalyzing the reaction is well characterized as being stimulated by guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) and suppressed by N-acetyl-S-farnesyl-L-cysteine (AFC). As an initial step to understand the physiological significance of the process, we attempted to purify the enzyme, which was partially purified 130-fold (specific activity, 143 pmol of methyl group transferred/min/mg of protein) with yield of 1.8% after purification by fast protein liquid chromatography (FPLC) on a Superdex 75 column. The enzyme was further purified with non denaturing polyacrylamide gel electrophoresis (ND-PAGE) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight of PFCCMT was determined to be about 30 kDa based on Superdex 75 FPLC as well as photoaffinity labelling with S-adenosyl-L-[methyl-3H] methionine ([methyl-3H]SAM). The partially purified enzyme (Superdex 75 eluate) was found to be characteristically affected by GTP gamma S, being activated about 40-fold in 2 mM, in contrast to ATP which did not show any effect on enzyme activity. Meanwhile, the enzyme was found to be markedly inhibited by AFC, reaching 0 activity in 2 mM. These observations strongly suggested that the partially purified enzyme was PFCCMT.
Acetylcysteine/pharmacology ; Acetylcysteine/analogs & derivatives ; Animal ; Brain/enzymology* ; Cattle ; Chromatography, Liquid ; Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology ; Molecular Weight ; Protein Methyltransferases/isolation & purification* ; Protein Methyltransferases/chemistry ; Protein Processing, Post-Translational

BACKGROUND: The purpose of this study was to determine the adequate loading and maintenance doses of N-acetylcyseteine (NAC) for patients suffering from acute ROS-induced injury. METHODS: Concentrations of extra cellular NAC, cysteine (Cys), cystine (Cyst2), and methionine (Met) were measured in vitro, at which more than 50% of the intracellular ROS raised by paraquat were suppressed using Swiss 3T3 fibroblasts. An in vivo pharmacokinetic study followed on a healthy subject to determine the proper loading and maintenance doses of reduced NAC following intravenous administration of 25 mg/kg NAC. RESULTS: In vivo, NAC suppressed ROS in a dose dependant manner. 10 mM of NAC suppressed about 50% of ROS, and was comparable to 10 micro M of Cys and Met and 400 micro M of Cys2. In vitro, the elimination of half-life was achieved at 2.88+/-1.14 h for NAC and at 3.68+/-1.84 h for total NAC. The body clearances were 1.23+/-0.77 L h (-1) kg (-1) and 0.56+/-0.27 L h (-1) kg (-1) and the volumes of distribution were 3.07+/-0.10 L kg (-1) and 3.00+/-0.11 L kg (-1), respectively. The loading and maintenance NAC doses used to reach the target concentration of 10 mM, were 5010 mg. kg (-1) and 2250 mg min (-1) kg (-1), respectively. CONCLUSION: NAC provides an antioxidant effect on ROS produced by paraquat in vivo. However, in vitro, our results showed that the intravenous NAC dose could not be estimated from NAC plasma concentration or its metabolites.
Sulfur/*blood ; Reactive Oxygen Species ; Humans ; Glutathione/blood ; Amino Acids/*blood/chemistry ; Acetylcysteine/*administration & dosage/pharmacokinetics/pharmacology

Acetylcysteine ; pharmacology ; Adolescent ; Adult ; Aged ; Female ; Hepatitis, Viral, Human ; blood ; Humans ; Interleukin-18 ; blood ; Male ; Middle Aged

Acetaminophen ; administration & dosage ; poisoning ; Acetylcysteine ; administration & dosage ; pharmacology ; therapeutic use ; Brunei ; Drug Overdose ; drug therapy ; physiopathology ; Humans

OBJECTIVETo study the effect of epigallocatechin gallate (EGCG) against lactacystin induced PC12 cell injury.

METHODSThe inoculated rat PC12 cells were cultured for 24 h, followed by intervention. The cells were divided into 5 groups, i.e., the normal control group, 10 micromol/L lactacystin injury group, and the EGCG pretreated groups (at the final concentration of 5, 10, and 50 micromol/L, respectively). The cytoactive was detected by MTT colorimetry. Morphological changes of the cell nucleus were observed by Hoechst 33,258 staining, and the apoptosis ratio was detected by flow cytometry (FCM).

RESULTSEGCG at different doses showed protective effect on lactacystin-induced PC12 cell injury. Compared with the lactacystin injury group [(61.22 +/- 1.02)%], the cytoactive in EGCG pretreated groups at the final concentration of 5, 10, and 50 micromol/L, respectively increased obviously to (66.99 +/- 1.30)%, (66.67 +/- 0.65)%, and (73.4 +/- 0.67)%, respectively. Hoechst 33 258 staining found that more nuclear pyknosis and aggregation occurred in the lactacystin injury group, but less occurred in EGCG pretreated groups. FCM indicated that the apoptosis ratio was reduced by EGCG pretreatment. It was 3.0%, 60.4%, 59.8%, 57.5%, and 38.6%, respectively in the normal control group, the lactacystin injury group, and EGCG pretreated groups (at the final concentration of 5, 10, and 50 micromol/L, respectively).

CONCLUSIONEGCG could attenuate lactacystin induced PC 12 cell injury.

Acetylcysteine ; adverse effects ; analogs & derivatives ; Animals ; Apoptosis ; drug effects ; Catechin ; analogs & derivatives ; pharmacology ; Flow Cytometry ; PC12 Cells ; Rats

Curcumin( Cur) is a natural active substance extracted from the roots or tubers of traditional Chinese medicinal materials. It has anti-inflammatory and anti-tumor activities on brain diseases. Due to the poor stability,low solubility,poor absorption and low bioavailability of curcumin,N-acetyl-L-cysteine( NAC) was used as an absorption enhancer and mixed with curcumin to improve the absorption of curcumin in the body. In this paper,curcumin was smashed by airflow pulverization,and Cur-NAC mixtures were prepared by being grinded with liquid. Then,the raw material and the product were analyzed by differential scanning calorimetry( DSC),X-ray diffraction( XRD) for structural characterization. The dissolution was determined by high performance liquid chromatography( HPLC) analysis. The characteristic peaks of the samples prepared by grinding method were similar to those of the raw materials,while the melting temperature and the accumulated dissolution degree were not significantly changed. The crystal forms of the products were not changed,and no new crystal form was formed after grinding. After the administration of intranasal powder,blood samples were collected from the orbit,while the whole brain tissues were removed from the skull and dissected into 10 anatomical regions. The concentrations of curcumin in these samples were determined by UPLC-MS/MS. The concentrations of curcumin in plasma and brain were compared at different time points. After intranasal administration of two drugs,it was found that the concentration of curcumin after sniffing up the mixtures in plasma was high,and the concentration of the drug in the olfactory bulb,hippocampus,and pons was increased significantly. Within 0. 083-0. 5 h,the olfactory bulb,piriform lobe and hippocampus remained high concentrations,the endodermis,striatum,hypothalamus and midbrain reached high concentrations within 1-3 h; and the cerebellum,pons and brain extension maintained relatively high concentrations within 3-7 h. The experiment showed that nasal administration of Cur-NAC mixtures can significantly improve the bioavailability of curcumin,and lead to significant differences in brain tissue distribution.
Acetylcysteine ; pharmacology ; Administration, Intranasal ; Animals ; Biological Availability ; Brain ; Brain Chemistry ; Chromatography, Liquid ; Curcumin ; pharmacokinetics ; Rats ; Tandem Mass Spectrometry ; Tissue Distribution