Dose concentration and spatial memory and brain mitochondrial function association after 3,4-methylenedioxymethamphetamine (MDMA) administration in rats.

MDMA-induced impairments of memory performance have been reported in different human and animal studies. However, the correlation between spatial memory impairment, brain mitochondrial function, and concentrations of MDMA and its metabolites has not yet been investigated despite it being needed for comparison with human studies. Therefore, the aim of this study was to investigate the dose concentration and spatial memory as well as brain mitochondrial function association after MDMA administration in rats. We assessed the effects of MDMA [0.5, 2.5, 5, 10 and 15 mg/kg; intraperitoneally (I.P)] on spatial memory of male Wistar rats in the Morris water maze test (MWM) and brain mitochondrial function (i.e., reactive oxygen species, mitochondrial membrane potential, swelling and outer membrane damage, cytochrome c release, and ADP/ATP ratio). Concentrations of MDMA and its metabolite, MDA, were determined in plasma, cerebrospinal fluid (CSF) and brain which was obtained immediately after probe test of MWM (i.e., 4 h after last training trial). The results of this study indicate nonlinear kinetics of MDMA after I.P adminstration. Also, an insignificant correlation was observed between MDMA doses and the MDA/MDMA ratio in plasma, CSF, and brain. Moreover, the results showed that MDMA, but not MDA, accumulated in brain tissue by increasing the administered doses. Beside, MDMA-induced impairments of spatial memory and brain mitochondrial function were significantly correlated with the concentrations of both MDMA and MDA in plasma, CSF, and brain. Therefore, it can be suggested that MDMA and its metabolite, MDA, affect spatial memory and brain mitochondrial function.

A structural model of the anaphase promoting complex co-activator (Cdh1) and in silico design of inhibitory compounds.

Anaphase promoting complex (APC) controls cell cycle and chromosome segregation. The APC activation occurs after binding of co-activators, cdh1 and cdc20. Cdh1 plays a role in cancer pathogenesis and is known as a potential drug target. The main aim of this study was prediction of 3D structure of cdh1 and designing the inhibitory compounds based on the structural model. First, 3D structure of cdh1 was predicted by means of homology modelling and molecular dynamics tools, MODELLER and Gromacs package, respectively. Then, inhibitory compounds were designed using virtual screening and molecular docking by means AutoDock package. The overall structure of cdh1 is propeller like and each DW40 repeat contains four anti-parallel beta-sheets. Moreover, binding pocket of the inhibitory compounds was determined. The results might be helpful in finding a suitable cdh1 inhibitor for the treatment of cancer.

In vitro antibacterial activity of some Iranian medicinal plant extracts against Helicobacter pylori.

Helicobacter pylori infection causes lifelong chronic gastritis, which can lead to peptic ulcer, mucosa-associated lymphoid tissue (MALT) lymphoma and gastric cancer. The growing problem of antibiotic resistance by the organism demands the search for novel candidates from plant-based sources. In the present study, we evaluated the in vitro anti-H. pylori activity of some selected medicinal plants on clinical isolates of H. pylori. Gastric biopsy samples were obtained from patients presenting with gastroduodenal complications. Helicobacter pylori was isolated from the specimens following standard microbiology procedures. The disc-diffusion method was used to determine the susceptibility of three H. pylori isolates to methanol extracts of 23 Iranian plants. All tests were performed in triplicate. Among them, the extracts of Punica granatum and Juglans regia had remarkable anti-H. pylori activity with mean of inhibition zone diameter of 39 and 16 mm at 100 µg disc⁻¹, respectively. In view of the results obtained with P. granatum (pomegranate), the peel extracts of nine cultivars of pomegranate (Shirin-e-Pust Sefid, Agha Mohammad Ali-e-Shirin, Sefid-e-Shomal, Sefid-e-Torsh, Shirin-e-Malase, Tabestani-e-Torsh, Shirin-e-Saveh Malase, Alak-e-Shirin, Pust Siyah) were further assayed against the clinical isolates of H. pylori. The results revealed that all Iranian pomegranate cultivars, except for Alak-e-Shirin, showed significant in vitro anti-H. pylori activity against the clinical isolates of H. pylori (mean of inhibition zone diameter ranging from 16 to 40 mm at 50 µg disc⁻¹).

Core shell methyl methacrylate chitosan nanoparticles: In vitro mucoadhesion and complement activation.

BACKGROUND AND THE PURPOSE OF THE STUDY: Studies show that chitosan nanoparticles increase mucoadhesivity and penetration of large molecules across mucosal surface. The aim of the present study was to investigate the use of thiolated chitosan in the development of polysaccharide-coated nanoparticles in order to confer specific functionality to the system. METHODS: Methyl methacrylate nanoparticles were coated with thiolated chitosan using a radical polymerization method. Thiolation was carried out using glutathione (GSH) to improve mucoadhesivity and permeation enhancing properties of chitosan. Mucoadhesion studies were carried out by calculating the amount of mucin adsorbed on nanoparticles in a specific period of time. Complement consumption was assessed in human serum (HS) by measurement of the hemolytic capacity of the complement system after contact with nanoparticles. RESULTS: The FT-IR and (1)HNMR spectra both confirmed the synthesis and showed the conjugation of thiolated chitosan to methyl methacrylate (MMA) homopolymer. Nanoparticles were spherical having a mean diameter within the range of about 334-650 nm and their positive zeta potential values indicated the presence of the cationic polysaccharide at the nanoparticle surface. Increasing the amount of thiolated chitosan led to mucoadhesivity and complement activation. However there was not dose dependent correlation between these phenomenons and the absence of thiolated chitosan led to particles with larger size, and without ability to activate complement process. MAJOR CONCLUSION: It can be concluded that nanoparticles could be used for the mucosal delivery of peptides and proteins. Results show that the thiolated chitosan had higher mucoadhesion and complement activation than unmodified chitosan.

Development and validation of a rapid HPLC- fluorescence method for simultaneous determination of venlafaxine and its major metabolites in human plasma.

BACKGROUND AND THE PURPOSE OF THE STUDY: To develop a simple, rapid and accurate HPLC method for the measurement of the venlafaxine and its main metabolites, O-desmethylvenlafaxine and O,N-didesmethylvenlafaxine in pharmacokinetic studies and therapeutic drug monitoring. METHOD: Chromatographic separation was achieved with a ChromolithTM Performance RP-18e 100 mm×4.6 mm column equipped with a Fluorescence detectore (λ(ex) 200 nm/λ(em) 300 nm) The mobile phase of methanol:water (35:65, v/v) adjusted to pH 2.5 by phosphoric acid was passed through the column in an isocratic mode at flow rate of 2 ml/min. The sample preparation involved a simple, one-step, extraction with ethyl acetate. RESULTS: The calibration curves were linear in the concentration range of 1-300 ng/ml for all analytes (r2>0.998). The lower limit of quantification was 1 ng/ml for all analytes. Within and between day precisions in the measurement of quality control (QC) of samples were in the range of 1.8-14.1% for all analytes. CONCLUSION: The developed procedure was used to assess the pharmacokinetics of venlafaxine and its main metabolites following oral administration of 75 mg venlafaxine to a healthy subject.

Synthesis and cloxacillin antimicrobial enhancement of 2-methylsulfonylimidazolyl-1,4-dihydropyridine derivatives.

BACKGROUND AND THE PURPOSE OF THE STUDY: Hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) has been a major problem worldwide in chemotherapy of infection disease. This study was designed to assess the enhancing effects of a new group of dihydropyridine-3,5dicarboxamides, in combination with cloxacillin with distinctly different mechanisms of action against MRSAs. MATERIAL AND METHODS: Dihydropyridine-3,5-dicarboxamides with 2-methylsulfonylimidazole at 4 position 6a-k were synthesized by the reaction of corresponding aldehyde 5 with different N-aryl acetoacetamides 3 in the presence of ammonium hydroxide. Agar disc diffusion method was used to determine the antibacterial and potentiating activity of different synthetic compounds in the presence and absence of cloxacillin to evaluate their activity as modulators of multidrugresistant (MDR). RESULTS AND MAJOR CONCLUSION: The antibacterial effect of cloxacillin was enhanced by compounds 6g and 6h against cloxacillin-resistant strains (MRSA(1) and MRSA(2)). The potentiation was found 1 2 to be statistically significant (p<0.01). Compound 6g at concentration of 1000 µg/disc, caused a 329 percent potentiation of the activity of cloxacillin against MRSA(1).

Synthesis and cytotoxic activity of some 2-amino-4-aryl-3-cyano-7-(dimethylamino)-4H-chromenes.

A series of 2-amino-4-aryl-3-cyano-7- (dimethylamino)-4H-chromenes was synthesized by condensation of 3- (dimethylamino) phenol, an aromatic aldehyde and malonitrile in ethanol containing piperidine. The assignments of the structure of all synthesized compounds were based on spectral data (IR, Mass and(1)H NMR). The cytotoxic activities of the synthesized compounds against six human tumor cell lines were determined by MTT assay. Several compounds showed significant cytotoxic activity.

Evaluation of anti-inflammatory and analgesic activity of a novel rigid 3, 4-dihydroxy chalcone in mice.

There have been many reports indicating the analgesic and anti-inflammatory effects of 3,4-dihydroxychalcones. We have designed and synthesized a rigid 3,4-dihydroxychalcone (RDHC) as a possible drug effecting inflammation and nociception. The analgesic and anti-inflammatory effects were evaluated by formalin and hot-plate tests, respectively. The results showed that RDHC induced significant antinociceptive and anti-inflammatory effects (P < 0.01). Maximum analgesia (63.7%) was observed at 37.5 mg/kg in the first phase of the formalin test. The effect of RDHC was higher in the chronic phase (inflammation phase) of the formalin test (86.4%, P < 0.01). In addition, a significant analgesia (maximum possible effect; MPE = 30.1%) was observed in the hot plate test 45 min after injection of 37.5 mg/kg RDHC (P < 0.01). As a result of our findings, this new RDHC could be suggested for further pharmacological studies.

Structure-activity relationship study of a series of N-substituted piperazinyl-fluoroquinolones as anti-Helicobacter pylori agents.

Helicobacter pylori is now recognized as the primary etiological factor associated with gastritis, peptic ulcer disease and gastric cancers. Fluoroquinolones have been shown to be active against H. pylori. For develop new anti-H. pylori agents, we have investigated the SAR of a series of N-(phenethyl)piperazinyl quinolones for their antimicrobial activity against H. pylori. The anti-H. pylori activity of synthesized compounds along with commercially available anti-H. pylori agents such as metronidazole, and parent quinolones was evaluated by the disc diffusion bioassay. The results indicated that the potency and anti-H. pylori activity profile of the quinolones is highly dependent on the type of substituent at N-1 and the structure of phenethyl unit on piperazine ring. Most compounds containing a cyclopropyl at N-1 exhibited good activity against H. pylori strains. Among them, ciprofloxacin derivative 13 containing 2-methoxyimino-2-(2-chlorophenyl)ethyl moiety was the most active compound.

Effects of novel antituberculosis agents on OmpF channel activity.

Nanopore forming proteins spanning the outer membrane mediate in the diffusion of hydrophilic chemicals through the hydrophobic bacterial cell wall. In this study, the effects of two novel anti-TB derivatives, ethyl alpha-[5-(5-nitro-2-thienyl)-1,3,4-thiadiazole-2-ylthio] acetates and propyl alpha-[5-(5-nitro-2-thienyl)-1,3,4-thiadiazole-2-ylthio] acetates, on OmpF channel reconstituted in artificial bilayers were evaluated by voltage clamp technique. Surprisingly, ethyl derivative (MIC > or = 6.75 microg/ml) showed no effects on OmpF channel activity but the propyl derivative (MIC=0.39 microg/ml) reduced the channel conductance considerably and changed the gating pattern of the channel. The findings obtained here at molecular level, might shed light on better understanding of the actual mechanism(s) by which the novel anti-TB agents permeate through the cell wall of the Mycobacterium tuberculosis.

Antituberculosis agents. IX. In vitro antimycobacterial activity of N-(2-phenyl-2-oxoethyl) and N-[2-(4-fluorophenyl)-2-oxoethyl]ciprofloxacin derivatives against some drug-resistant strains of Mycobacterium tuberculosis and Mycobacterium avium isolates.

The in vitro antimycobacterial activity of two ciprofloxacin analogues (2a and 2b) containing 2-phenyl-2-axoethyl and 2-(4-fluorophenyl)-2-axoethyl groups attached to N-4 position of piperazin ring, was evaluated against M. tuberculosis strains resistant to Isoniazid (MIC 2a and 2b = 3.13 micrograms/ml), Ethambutol (MIC 2a and 2b = 1.56 micrograms/ml), Rifampin (MIC 2a and 2b = 1.56 micrograms/ml), Kanamycin (MIC 2a and 2b = 1.56 micrograms/ml) and ciprofloxacin (MIC 2a and 2b > 25 micrograms/ml). Furthermore, the minimum bactericidal concentration (MBC) of 2a and 2b was determined against M. tuberculosis H37Rv (MBC2a = 6.25 and 2b = 25 micrograms/ml) and strains resistant to isoniazid (MBCs > 25 micrograms/ml) and rifampin (MBC2a = 3.13 and 2b = 6.25 micrograms/ml). Also, in this study the activity of 2a and 2b was determined against a strain of M. avium (%Inhibition 2a = 89 and 2b = 95%). Expanded primary screening was conducted for 2b (having MIC < 6.25 micrograms/ml) against five clinical isolates of M. avium using the MABA and BACTEC 460 systems (MIC = 2-4 micrograms/ml). The significant anti-Mycobacterium avium activity of 2b suggested further M. avium assays and so, 2b was then retested at lower concentrations against 30 strains of M. avium including five strains resistant to claritromycin (MIC = 2-16 micrograms/ml).

Antituberculosis agents IV: in vitro antimycobacterial activity and cytotoxicity of N-piperazinyl quinolone derivatives containing 2-thienyl and 2-furyl moiety.

A series of N-[2-(2-furyl)-2-oxoethyl], N-[2-(2-furyl)-2-oxyiminoethyl], N-[2-oxo-2-(2-thienyl)ethyl] and N-[2-oxyimino-2-(2-thienyl)ethyl] piperazinyl quinolones (1a-h; 2a-h) were evaluated for antituberculosis activity against M. tuberculosis H37Rv using the BACTEC 460 radiometric system and BACTEC 12B medium. Our results indicated that compounds 1a, 1e and 1g were efficient antimycobacterial agents showing MIC values ranging from 0.78 to 6.25 microg/ml. In general, ciprofloxacin derivatives were more active than norfloxacin derivatives and the oxime analogues were less active than corresponding ketones. Active compounds (1a, 1e and 1g) were also screened by serial dilution to assess toxicity to VERO cell line. The cytotoxicity of tested compounds indicated that compound 1a was the less toxic compound (IC50 > 62.5 microg/ml). This compound was tested for efficacy in vitro in TB-infected macrophage model (EC90 = 3.25 microg/ml).

Antituberculosis agents. VII. Synthesis and in vitro evaluation of antimycobacterial activity and cytotoxicity of some N-piperazinyl quinolone derivatives.

A series of N-[2-(2,4-dichlorophenyl)-2-oxoethyl] and N-[2-aryl-2-benzyloxyimino ethyl]piperazinyl quinolones (5-13) have been prepared as part of a study to examine the relationship between structural modification at 7-position and activity against Mycobacterium tuberculosis. Primary screening was conducted at concentration of 6.25 micrograms/ml against M. tuberculosis H37Rv using BACTEC 460 radiometric system and BACTEC 12B medium. The actual minimum inhibitory concentrations (MIC) were determined for compounds demonstrating at least 90% inhibition in the primary screening. The results demonstrate that substitution of phenyl ring with 4- fluoro, 2, 4-difluoro and 2,4-dichloro groups resulted in variable inhibition percentage (Inh% = 7-101). Despite the significant antituberculosis activity of ciprofloxacin and norfloxacin derivatives containing 2-(2,4-dichlorophenyl)-2-oxoethyl moiety (MIC = 0.39 & 6.25 micrograms/ml), compounds with 2-aryl-2-(hydroxyimino)ethyl, 2-aryl-2-(benzyloxyimino)ethyl and 2-aryl-2-(4-chlorobenzyloxyimino)ethyl did not show any activity (MIC > 6.25 micrograms/ml, Inh% = -7 to 75). Active compounds were also screened by serial dilution to assess toxicity to a VERO cell line. While the most active compound 5a was not soluble in tissue culture media, compound 5b showed IC50 = 5.3 micrograms/ml.

Synthesis and evaluation of in vitro antimycobacterial activity of some 5-(5-nitro-2-thienyl)-2-(piperazinyl, piperidinyl and morpholinyl)-1,3,4-thiadiazole derivatives.

A new series of 5-(5-nitro-2-thienyl)-2-(piperazinyl, piperidinyl and morpholinyl)-1,3,4-thiadiazole derivatives(5a-g) have been synthesized and evaluated against Mycobacterium tuberculosis H37Rv as apart of TAACF TB screening program under direction of the US National Institute of Health, NIAID division. Primary screening was conducted at the single concentration, 6.25 mg/ml against Mycobacterium tuberculosis H37Rv (ATCC 27294) in BACTEC 12B medium using a broth microdilution assay, the Microplate Alamar Blue Assay (MABA). The minimum inhibitory concentration (MIC) determined for compounds demonstrating 90% growth inhibition in the primary screening. The tested compounds showed a varying degree of inhibitory activity (Inhibition = 0-100%). The most active compounds were 4-methyl and 4-benzoylpiperaxinyl analogues(5b and 5g) with the same MIC value of 3.13 micrograms/ml.

Antituberculosis agents. VI. Activity of a new ciprofloxacin derivative against Mycobacterium avium and some drug-resistant strains of Mycobacterium tuberculosis.

The in vitro antimycobacterial activity of a new quinolone derivative, 1a containing 2-(2-furyl)-2-oxoethyl group at N-4 position of piperazine ring of Ciprofloxacin was tested for efficacy in vitro in TB-infected macrophage model (EC90 = 3.25 micrograms/ml and EC99 > 12.5 micrograms/ml). The MIC values of 1a were determined against M. tuberculosis strains resistant to Isoniazid (MIC = 1.56 micrograms/ml), Rifampin (MIC = 1.56 micrograms/ml), Ethambutol (MIC = 0.78 microgram/ml), Kanamycin (MIC = 0.78 microgram/ml) and Ciprofloxacin (MIC > 25 micrograms/ml). Furthermore, the MIC and selectivity index (SI) of 1a were evaluated against M. avium. Also, in this study the minimum bactericidal concentration (MBC) of 1a was determined against M. tuberculosis H37Rv (MBC = 6.25 micrograms/ml) and strain resistant to Rifampim (MBC = 25 micrograms/ml) and Isoniazid (MBC = 25 micrograms/ml).

Antituberculosis agents. III. In vitro evaluation of antimycobacterial activity and cytotoxicity of some N-piperazinyl quinolone derivatives.

A series of N-[2-oxo-2-(4-substitutedphenyl)ethyl]piperazinyl quinolones(1a-e,2a-e and 3a-c) and N-[2-hydroxyimino-2-(4-substitutedphenyl)ethyl]piperazinyl quinolones(1f-j,2f-j and 3d-f) were evaluated for antituberculosis activity against Mycobacterium tuberculosis H37R, using the BACTEC 460 radiometric system and BACTEC 12B medium. Active compounds were also screened by serial dilution to assess toxicity to a VERO cell line. Nine compounds were efficient antimycobacterial agents showing MIC values ranging from 0.78 to 6.25 micrograms/ml. Generally, ciprofloxacin derivatives were more active than norfloxacin and enoxacin derivatives and the oxime analogues were less active than corresponding ketones. The most selective and less toxic compound 1a was tested for efficacy in vitro in TB-infected macrophage model (EC90 = 3.68 micrograms/ml, EC99 = 9.18 micrograms/ml).

Synthesis and calcium channel antagonist activity of nifedipine analogues with methylthioimidazole substituent.

Various diester analogues of nifedipine, in which the orthonitrophenyl group at position 4 is replaced by 1-methyl-2-methylthio-5-imidazolyl substituent, were synthesized and evaluated as calcium channel antagonists on guinea-pig ileal smooth muscle. Nifedipine was used as standard. Comparison of the activities of symmetrical esters (3a-e) indicate that increasing the length of alkyl chain in C3 and C5 ester substituents increases the antagonist activity and the n-propyl ester being preferred (IC50= 2.66 x 10(-9) M). In asymmetrical series (6a-g), compound 6g having ethyl and n-butyl ester at C3 and C5 positions of basic dihydropyridine structure was found to be the most active (IC50= 1.32 x 10(-9) M).

Antituberculosis agents II. Evaluation of in vitro antituberculosis activity and cytotoxicity of some 2-(1-methyl-5-nitro-2-imidazolyl)-1,3,4-thiadiazole derivatives.

Using the radiometric BACTEC 460-TB methodology, the minimum inhibitory concentration (MIC) of a series of 2-(1-methyl-5-nitro-2-imidazolyl-1,3,4-thiadiazole-5-alkylsulfides, alkylsulfoxides and alkylsulfones which had been reported previously as antifungal agents, were determined. Active compounds were also screened by serial dilution to assess toxicity to a VERO cell line. The results indicate that compounds bearing a primary alkylthio substitution displayed good antituberculosis activity (MIC = 3.13-6.25 microg/ml). Oxidation to sulfone abolished the antituberculosis activity in methyl and propyl derivatives while the ethylsulfonyl analogue was active (MIC = 1.56 microg/ml). The cytotoxic effects indicate that 2-(1-methyl-5-nitro-2-imidazolyl)-5-methylthio-1,3,4-thiadiazole was the least toxic compound (IC50 > 10 microg/ml). Generally, all compounds showed a low selectivity index.

Antituberculosis agents, I: Synthesis and antituberculosis activity of 2-aryl-1,3,4-thiadiazole derivatives.

The design, synthesis and antituberculosis activity of a series of 2-aryl-5-methylthio-1,3,4-thiadiazoles (5a-b), ethyl alpha-(5-aryl)-1,3,4-thiadiazole-2-ylthio)acetates (8a-b) and related compounds are described. All of the compounds were tested against Mycobacterium tuberculosis strain H37Rv in comparison to rifampicin. Six compounds exhibited a very good activity (MIC < 6.25 micrograms/ml, % Inhibition = 100).