Design, synthesis and biological evaluation of rasagiline-clorgyline hybrids as novel dual inhibitors of monoamine oxidase-B and amyloid-ß aggregation against Alzheimer's disease.

A series of rasagiline-clorgyline hybrids was designed, synthesized and investigated in vitro for their inhibition of monoamine oxidase and amyloid-ß aggregation. Most of compounds were found to be selective and highly potent hMAO-B inhibitors showing IC50 values in the nanomolar, and exhibited a moderate inhibition of amyloid-ß aggregation. 7-((5-(methyl(prop-2-yn-1-yl)amino) pentyl)oxy)chroman-4-one (6j) was the most interesting compound identified in this research, endowed with higher hMAO-B potency (IC50 = 4 nM) and selectivity (SI > 25000) compared to the reference selective inhibitor rasagiline (IC50 = 141 nM, SI > 355), and exhibited good inhibitory activity against Aß1-42 aggregation (40.78%, 25 µM). Kinetic and molecular modeling studies revealed that 6j was a competitive reversible inhibitor for hMAO-B. Moreover, compound 6j displayed low toxicity and good neuroprotective effects in SH-SY5Y cell assay, and could penetrate the blood-brain barrier according to the parallel artificial membrane permeability assay. Pharmacokinetics assay revealed that compound 6j possessed good pharmacokinetic profiles after intravenous and oral administrations. Overall, these results highlighted that compound 6j was an effective and promising multitarget agent against Alzheimer's disease.

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.

A reversed-phase high performance liquid chromatography method for quantification of methotrexate in cancer patients serum.

A simple, rapid and sensitive reversed-phase high performance liquid chromatography (HPLC) method has been developed for the determination of methotrexate in human serum. After deproteinization of the serum with 40% silver nitrate solution, methotrexate and internal standard (IS) were separated on a reversed-phase column with a mobile phase consisting of 10mM sodium phosphate buffer (pH6.40)-methanol (78:22%, v/v) and ultraviolet detection at 310nm. The linearity is evaluated by a calibration curve in the concentration range of 0.05-10.0µg/mL and presented a correlation coefficient of 0.9995. The absolute recoveries were 97.52±3.9% and 96.87±3.7% for methotrexate and ferulic acid (internal standard), respectively. The intra- and inter-day precision were less 6.19 and 5.89%, respectively (n=6). The limit of quantitation was 0.02µg/mL and the limit of detection was 0.006µg/mL. The complete analysis was achieved less than 10min with no interference from endogenous components or 22 examined drugs. This method was validated by using serum samples from high-dose methotrexate treated patients with osteosarcoma, breast cancer, acute leukemia and lymphoma. The method was demonstrated to be a simple, rapid and reliable approach in quantification of methotrexate in serum samples from patients with high-dose methotrexate therapy.

Effects of long-term tea polyphenols consumption on hepatic microsomal drug-metabolizing enzymes and liver function in Wistar rats.

AIM: To investigate the effects of long-term tea polyphenols (TPs) consumption on hepatic microsomal drug-metabolizing enzymes and liver function in rats. METHODS: TPs were administered intragastrically to rats at the doses of 833 mg.kg(-1).d(-1) (n=20) and 83.3 mg.kg(-1).d(-1) (n=20) respectively for six months. Controlled group (n=20) was given same volume of saline solution. Then the contents of cytochrome P450, b5, enzyme activities of aminopyrine N-demethylase (ADM), glutathione S-transferase (GST) and the biochemical liver function of serum were determined. RESULTS: The contents of cytochrome P450 and b5 in the livers of male rats in high dose groups (respectively 2.66 +/- 0.55, 10.43 +/- 2.78 nmol.mg MS pro(-1)) were significantly increased compared with the control group (1.08 +/- 1.04, 5.51 +/- 2.98 nmol.mg MS pro(-1); P<0.01, respectively). The enzymatic activities of ADM in the livers of female rats in high dose groups (0.91 +/- 0.08 mmol.mg MS pro(-1)min(-1)) were increased compared with the control group (0.82 +/- 0.08 mmol.mg MS pro(-1).min(-1); P<0.05). The GST activity was unchanged in all treated groups, and the function of liver was not obviously changed. CONCLUSION: The antidotal capability of rats' livers can be significantly improved after long-term consumption of TPs. There are differences in changes of drug-metabolizing enzymes between the sexes induced by TPs and normal condition.

[Platelet phospholipase A2 mRNA content changes and cDNA cloning in rat blood with bacteria infection].

AIM: To explore the changes of rat platelet phospholipase A2 (PLA2) mRNA content in bacteria infected rat and study the cDNA and amino acid sequences of the PLA2 structure to lay a good foundation for the development of new antibiotics. METHODS: The PLA2 mRNA level in blood was determined by RT-PCR. The DNA sequence was cloned and analyzed. RESULTS: After injection of bacteria in rats, the mRNA level of PLA2 in blood increased markedly. The cDNA and amino acid sequence were highly homologous to other PLA2 cDNA from different tissues of the rat. CONCLUSION: Platelet PLA2 in blood responded quickly to bacteria infection in gene level. Therefore, the PLA2 protein was produced increasingly which was shown to control the infection with bacteria. Although there are little difference between PLA2 cDNA cloned from blood and other sources in DNA and amino acid sequences, the catalytic site for enzymatic activity and basic structure are identical.