Development of an analytical method for dibutyl phthalate determination using surrogate analyte approach

Dibutyl phthalate [DBP] is a phthalic acid ester and is widely used in polymeric products to make them more flexible. DBP is found in almost every plastic material and is believed to be persistent in the environment. Various analytical methods have been used to measure DBP in different matrices. Considering the ubiquitous nature of DBP, the most important challenge in DBP analyses is the contamination of even analytical grade organic solvents with this compound and lack of availability of a true blank matrix to construct the calibration line. Standard addition method or using artificial matrices reduce the precision and accuracy of the results. In this study a surrogate analyte approach that is based on using deuterium labeled analyte [DBP-d4] to construct the calibration line was applied to determine DBP in hexane samples

Study of sedative-hypnotic effects of Aloe vera L. aqueous extract through behavioral evaluations and EEG recording in rats

In the present work sedative and hypnotic effects of aqueous extract of Aloe vera in rats have been investigated. In order to evaluate the overall hypnotic effects of the Aloe vera extract, open field and loss of righting reflex tests were primarily used. The sedative and hypnotic effects of the extract were then confirmed by detection of remarkable raise in the total sleeping time through analysis of electroencephalographic [EEG] recordings of animals. Analysis of the EEG recordings showed that there is concomitant change in Rapid Eye Movement [REM] and None Rapid Eye Movement [NREM] sleep in parallel with the prolonged total sleeping time. Results of the current research show that the extract has sedative-hypnotic effects on both functional and electrical activities of the brain

Evaluation of anxiolytic, sedative-hypnotic and amnesic effects of novel 2-phenoxy phenyl-1,3,4-oxadizole derivatives using experimental models

Benzodiazepines [BZDs] are widely used in clinical practice as anxiolytics, hypnotics, anticonvulsants and muscle relaxants. However, they have some undesired effects including memory problems. In continuing our research on novel benzodiazepine ligands, we are looking for ligands with less adverse effects. Previously, 4 novel derivatives of 2-phenoxy phenyl-1,3,4-oxadiazole were synthesized as agonists of BZD receptors. In this study, the pharmacological effects of novel compounds were evaluated. Pentobarbital induced loss of righting reflex, elevated plus maze, open-field locomotor activity and passive avoidance test were used to evaluate the sedative-hypnotic, anxiolytic and amnesic effects of compounds respectively. The results revealed that the novel compounds with NH[2], SH and SCH[3] substituents at the 2-position of the oxadiazole ring increase righting reflex time significantly. In the elevated plus maze test none of the derivatives increased open arm duration and open arm entry indicating no anxiolytic properties. Moreover, the novel compounds didn't influence step-down latencies in the mice. The fact that the hypnotic activity of these compounds were significantly reduced by flumazenil, confirmed that this effect is mediated by BZD receptors

Cyclic AMP pathway modifies memory through neural cell adhesion molecule alterations in the rat hippocampus

Neural Cell Adhesion Molecules [NCAMs] are known to influence memory by affecting neural cell-cell and cell-extracellular matrix junctions. This study investigated the possible role of cAMP pathway in the expression of hippocampal NCAM and its polysialylated derivative [PSA-NCAM]. The following pharmacological tools were employed for manipulation of cAMP pathway: a] forskolin; the activator of adenylyl cyclase [AC], b] 8-Br-cAMP; a protein kinase A [PKA] agonist, c] 8-pCPT-2'-O-Me-cAMP; a selective enhancer of exchange protein activated by cAMP [Epac] and d] Rp-cAMP; a PKA inhibitor. Memory acquisition was tested by passive avoidance paradigm after injecting the above compounds for three consecutive days into the CA1 region of dorsal hippocampus of rats. Forskolin and 8-Br-cAMP enhanced memory retrieval while Rp-cAMP significantly reduced memory and NCAM levels. 8-pCPT-2'-O-Me-cAMP failed to alter memory performance or NCAM levels as compared to vehicle. We observed no significant changes in PSA-NCAM, however the expression of St8sia4 and St8sia2 [the polysialyltransferase isoforms] were altered. The mRNA levels of St8sia4 was down-regulated by 8-Br-cAMP, Rp-cAMP and 8-pCPT while forskolin led to almost 3 and 5 fold increase in mRNAs of St8sia2 and St8sia4, respectively. The current insight might endorse the predominant role of PKA as compared to Epac in cAMP pathway in expression of NCAM and memory function

Design, synthesis and biological evaluation of 4-benzamidobenzoic acid hydrazide derivatives as novel soluble epoxide hydrolase inhibitors

Inhibitors of soluble epoxide hydrolase [sEH] represent one of the novel pharmaceutical approaches for treating hypertension, vascular inflammation, pain and other cardiovascular related diseases. Most of the potent sEH inhibitors reported in literature often suffer from poor solubility and bioavailability. Toward improving pharmacokinetic profile beside favorable potency, two series of 4-benzamidobenzoic acid hydrazide derivatives with hydrazide group as a novel secondary pharmacophore against sEH enzyme were developed. The designed compounds were synthesized in acceptable yield and their in vitro assay was determined. Most of the synthesized compounds have appropriate physical properties and exhibited considerable in-vitro sEH inhibitory activity in comparison with 12-[3-Adamantan-1-yl-ureido]-dodecanoicacid [AUDA], a potent urea-based sEH inhibitor. 4-[2-[4-[4-chlorobenzamido] benzoyl]hydrazinyl]-4-oxobutanoic acid 6c was found to be the most potent inhibitor with inhibitory activity of 72% targeting sEH enzyme

Optimum conditions of radioligand receptor binding assay of ligands of benzodiazepine Receptors

To obtain drugs which are more selective at benzodiazepine [BZD] receptors, design and synthesis of functionally selective ligands for BZD receptors is the current strategy of our pharmaceutical chemistry department. The affinity of newly synthesized ligands is assessed by radioligand receptor binding assays. Based on our previous studies, 2-phenyl-5-oxo-7-methyl-1,3, 4-oxadiazolo[a,2,3]-pyrimidine [compound A] was chosen for design and synthesis of new triazole derivatives as GABA[A] BZD receptor agonist. The cortical membrane of male Sprague-Dawley rats was prepared as the source of the BZD receptors. Different concentrations of membrane protein and [[3]H]-flumazenil were incubated at room temperature at different time periods to reach the steady-state. To saturate the receptors, increased amounts of radioligand were incubated with membrane protein. The bound and un-bound ligands were separated by centrifugation. The affinity of compound A was measured in competition studies at optimum conditions by displacement of [[3]H]-Flumazenil from rat cortical membrane. Based on results, the optimum conditions of radioligand receptor binding assay of benzodiazepines were 35 min incubation of ligands with 100 micro g cortical membrane protein and 8.6 x 10[-5] nmole [3]H-flumazenil in a final volume of 0.5 mL Tris-HCl buffer [50 mM, pH 7.4] at 30 [degree sign]C. The binding parameters of [[3]H]-flumazenil, B[max] and K[d] were determined through saturation studies as 0.638 +/- 0.099 pmol/mg and 1.35 +/- 0.316 nM respectively. The affinity of compound A was 1.9 nM comparable with diazepam [1.53nM]. This finding makes the compound an interesting lead for further optimization. Starting from this compound, new ligands were synthesized and screened in-vitro by competitive binding assays

Schizophrenia induces oxidative stress and cytochrome C release in isolated rat brain mitochondria: a possible pathway for induction of apoptosis and neurodegeneration

Schizophrenia is a chronic and often debilitating illness which affects about 1% of the world population. Some reagents have been used to simulate schizophrenic disorders in laboratory animals, such as amphetamine and ketamine. Previous studies have suggested that reactive oxygen species [ROS] production, reduced levels of ATP, mitochondrial dysfunction and apoptosis are involved in the pathophysiology and etiology of schizophrenia. In this study we divided Wistar rats in to 2 groups; control group received normal saline and test group received ketamine 30 mg/Kg daily for five consecutive days. Then, locomotor activity including side to side head rocking and arcing of neck, proved schizophrenia in the test group rats. Rats in both control and test groups were then decapitated and brain mitochondria were isolated. Our results showed increased ROS formation, mitochondrial membrane potential collapse, mitochondrial swelling and cytochrome c release in mitochondria of schizophrenic test group. Our findings suggested that mitochondrial ROS formation and apoptosis signaling are likely involved in cellular pathology of Schizophrenia. To our knowledge this is the first report that provides a mechanistic justification between mitochondrial events and neuodegeneration in the Schizophrenia

Evaluation of anti-inflammatory and anti-nociceptive effects of defatted fruit extract of Olea europaea

Fruits of Olea europaea L. have been used for centuries in folk medicine to treat many inflammatory diseases. In order to evaluate the anti-nociceptive activities of the methanolic and aqueous extracts of defatted fruits of O. europaea, formalin test was used and for evaluation of anti-inflammatory effects of the extract, the volume of paw edema was measured. The results revealed that both extracts did not exhibit significant analgesic activity in the first phase of formalin test, whereas methanolic extract at the 600 mg/Kg dose and aqueous extract at the 450 and 600 mg/Kg doses could inhibit induced pain in the second phase of formalin test. Furthermore, the results of paw edema volume measurement indicated that the aqueous extract has anti-inflammatory effects at dose of 600 mg/Kg. Induced anti-nociception by aqueous olive extract was not reversed by naloxone, which indicates that the opioid receptors are not involved in the analgesic effects of the extracts. The present data pointed out that the extracts of olive defatted fruit have anti-nociceptive and anti-inflammatory effects in rats but further studies are needed to elucidate the mechanism[s] of action and active components which are involved in analgesic and anti-inflammatory effects

Evaluation of anti-nociceptive and anti-inflammatory activities of novel chalcone derivatives

Chalcone [1, 3-diarylprop-2-en-1-one] derivatives have been introduced as selective cyclooxygenase-2 inhibitors. In the present study, anti-nociceptive and anti-inflammatory effects of eight novel compounds were evaluated in male mice and Wistar rats by using the writhing and formalin-induced paw edema tests respectively. The activities of the compounds were compared with celecoxib as a reference drug. Then, novel compounds were divided into two regioisomeric groups based on the position of the methyl sulfonyl substitution. Compounds with substituents such as: 1] H, 2] Me, 3] F and 4] Cl at para position of the phenyl ring of [E]-3-[4-Methanesulfonylphenyl]-1-phenylprop-2-en-1-one were selected in the first group. The regioisomer compounds with 5] H, 6] Me, 7] F and 8] OMe substitutions at C-4 of phenyl ring of [E]-1-[4-Methanesulfonylphenyl]-3-phenylprop-2-en-1-one were chosen as second group. All compounds showed dose-dependent anti-nociceptive activity in writhing test. Interestingly, the potency of anti-nociceptive effect of compounds 1, 2, 5 and 6 were significantly higher than celecoxib. The regioisomeric compounds 1 and 5 with high anti-nociceptive effects, showed a significant dose-dependent anti-inflammatory activity in the paw edema test as well. The results showed that compounds with no substituent or small size substituents at para position of the phenyl ring are the most potent compound in writhing test. Our results revealed that the introduction of a bulky group such as methoxy or chlorine at the vicinal aromatic chain of the derivatives decreases the anti-inflammatory/anti-nociceptive effects. The comparison of estimated ED[50] of each pair of the regioisomeric compounds indicates that the relative position of SO[2]Me to carbonyl moiety did not affect the potency

Design, synthesis and pharmacological evaluation of novel 2-[2-[2-chlorophenoxy] phenyl]-1,3,4-oxadiazole derivatives as benzodiazepine receptor agonists

New derivatives of 2-[2-[2-Chlorophenoxy]phenyl]-1,3,4-oxadiazole as candidates for agonistic effect on benzodiazepine receptors were synthesized. Conformational analysis and superimposition of energy minima conformers of the novel compounds on estazolam, a known benzodiazepine agonist, revealed that the main proposed benzodiazepine pharmacophores were well matched. In pharmacological evaluation, anticonvulsant activity of the compounds determined by pentylenetetrazole-induced lethal convulsion and maximal electroshock tests. The results showed that the introduction of an amino substituent in position 5 of 1,3,4- oxadiazole ring generates compound 6 that has a considerable effect. Compound 8 with a hydroxyl substituent on position 5 of 1,3,4- oxadiazole ring showed a relatively mild anticonvulsant activity, which was significantly weaker than that of diazepam and compound 6. Anticonvulsant effects of active compounds were antagonized by flumazenil, an antagonist of benzodiazepine receptors, indicating the involvement of benzodiazepine receptors in these effects.