Design, synthesis and biological evaluation of new coumarin-dithiocarbamate hybrids as multifunctional agents for the treatment of Alzheimer's disease.

A series of new coumarin-dithiocarbamate hybrids were designed, synthesized and evaluated as multifunctional agents for the treatment of Alzheimer's Disease (AD). The biological assays indicated that most of them showed potent inhibition and excellent selectivity towards acetylcholinesterase (AChE), and could inhibit self-induced ß-amyloid (Aß) aggregation. Especially, compound 4n presented the highest ability to inhibit AChE (IC50, 0.027 µM for hAChE) and good inhibition of Aß aggregation (40.19% at 25 µM). Kinetic and molecular modeling studies revealed that 4n was a mixed-type inhibitor, which could interact simultaneously with the catalytic active site (CAS) and peripheral anionic site (PAS) of AChE. In addition, it also possessed specific metal-chelating ability, good BBB permeability and low toxicity on SH-SY5Y neuroblastoma cells. Moreover, compound 4n did not exhibit any acute toxicity in mice at doses up to 1000 mg/kg, and could reverse the cognitive dysfunction of scopolamine-induced AD mice. As far as we know, 4n was the first reported dithiocarbamate derivative with multifunctional activity. Its excellent profiles in vitro and effectivity in vivo highlight this structurally distinct compound as a potential lead compound in the research of innovative multifunctional drugs for AD.

Chitosan-Zn chelate increases antioxidant enzyme activity and improves immune function in weaned piglets.

This experiment was performed in order to investigate the effects of chitosan-Zn chelate (CS-Zn) on activities of antioxidant enzymes and immune function in weaned piglets. One hundred and twenty weaned piglets (Duroc × Landrace × Yorkshire) with 7.12 ± 0.25 kg body weight were allotted to four treatments. A basal diet without Zn supplementation was used as control group. The other three treatments were fed the control diet supplemented with 100 mg/kg Zn as ZnSO4, 100 mg/kg Zn as CS-Zn, 100 mg/kg Zn as ZnSO4 and chitosan (the content of chitosan was the same as that of CS-Zn), respectively. The feeding trial lasted 30 days. Spleen index of pigs fed dietary CS-Zn was higher (p < 0.05) than that of control pigs. Thymus index and lymph node index did not differ among the pigs fed any diets (p > 0.05). T-AOC levels, Cu-ZnSOD, and GSH-PX activities in serum or liver of the pigs receiving CS-Zn diet were higher than those of the pigs fed CS+ZnSO4 or ZnSO4 diets (p < 0.05). These pigs fed dietary CS-Zn also showed lower MDA content in liver compared with the pigs fed other diets (p < 0.05). Serum IgA, complement 3, and complement 4 levels of pig fed dietary CS-Zn was higher than those of the pigs fed other diets (p < 0.05). Supplemental dietary Zn did not change serum IgG and IgM levels (p > 0.05). The ALP activity of pigs fed dietary CS-Zn was higher than those of the pigs fed other three diets (p < 0.05). No significant differences were founded in serum GOT or GPT activities of pigs fed dietary Zn (p > 0.05). The results of the present study indicated that chitosan-Zn chelate could increase antioxidant capacity and improve immune function in weaned piglets compared with ZnSO4 or chitosan.

Development and validation of an LC-ESI-MS/MS method for the determination of nitidine chloride in rat plasma.

A new liquid chromatography-electrospray ionization-mass/mass spectrometry (LC-ESI-MS/MS) assay method has been developed and validated for the quantification of nitidine chloride (NC), an anti-cancer bioactive substance of Zanthoxylum nitidum (Roxb.) DC. plants, in rat plasma using carbamazepine as an internal standard (I.S.). The NC and I.S. were extracted from rat plasma by acetonitrile protein procedure. Chromatographic separation was carried out with a C(18) column (2.1 mm × 150 mm, 3 µm) with a security guard C18 column (4 mm × 20 mm, 3 µm). The mobile phase consisted of acetonitrile-10 mM ammonium acetate buffer solution-formic acid (35:65:0.2, v/v/v) and delivered at the flow rate of 0.25 mL/min. LC-ESI-MS/MS was performed on a triple-quadrupole mass spectrometry equipped with electrospray ionization (ESI) and positive multiple reaction monitoring (MRM). Target ions were monitored at [M](+)m/z 348.2 for NC and [M]⁺ m/z 237.2 for I.S. The method was linear over the concentration range of 5.0-1500.0 ng/mL. The intra- and inter-day relative standard deviations of the assay were less than 5.0%. The lower limit of quantification was 5.0 ng/mL. The developed method was successfully applied to the estimation of the pharmacokinetic parameters of NC by intravenous administration to rats.

Changes of porcine growth hormone and pituitary nitrogen monoxide production as a response to cadmium toxicity.

The present study was designed to investigate the effects of various cadmium concentrations on porcine growth hormone (GH) secretion in serum and cultured pituitary cells and to explore the possible mechanisms of cadmium toxicity. In feeding trial, 192 barrows (Duroc x Landrace x Yorkshire), with similar initial body weights, were randomly divided into four different treatment groups with three replicates for each treatment. The diets were supplemented for 83 days with 0, 0.5, 5.0, and 10.0 mg/kg cadmium (as CdCl2). For the cell culture trial, dispersed pituitary cells were incubated with graded doses of cadmium (0, 5, 10, 15, or 20 microM) for 24 h. Pigs treated with 10 mg/kg cadmium had significantly decreased serum GH content. 3-(4,5-dimethyl-2-yl)-2,5-diphenyl tetrazolium bromide assay showed that Cd toxicity was dose-dependent. Cell viability was reduced to 50% at 15 microM concentration. Administration of cadmium significantly reduced GH secretion, whereas cellular NO content and inducible nitric oxide synthase activity increased to a certain extent. These findings suggest that the decrease of GH might be related to NO production and to a change of NO signal pathway caused by cadmium.

Effect of cadmium on lipid peroxidation and activities of antioxidant enzymes in growing pigs.

Malondialdehyde (MDA), glutathione (GSH) content, total antioxidant capacity (T-AOC) levels, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione transferase (GST) activities were studied in serum, liver, and kidney of growing pigs after graded doses of cadmium administration in diets. One hundred ninety-two barrows (Duroc x Landrace x Yorkshire), with similar initial body weight 27.67 +/- 1.33 kg, were randomly allotted into 4 different treatments with 3 replications (16 pigs per replication). The treatments received the same basal diet added with 0, 0.5, 5.0, and 10.0 mg/kg cadmium (as CdCl2), respectively. The results showed pigs treated with 10 mg/kg cadmium significantly decreased average daily gain (ADG) (p<0.05) and increased feed/gain ratio (F/G) (p<0.05) compared to the control. In this treatment, the contents of MDA increased significantly (p<0.05), GSH concentrations, T-AOC levels, and the activities of SOD, GSH-PX, and GST decreased significantly (p<0.05). The results indicate 10 mg/kg cadmium could decrease pig antioxidant capacity after extended exposure and cadmium-induced increase lipid peroxidation might not be only the result of the possibility of lower level of GSH but could also be as a result of direct action of cadmium on peroxidation reaction.