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Med Chem [journal]
- Chemometric Studies on Potential Larvicidal Compounds against Aedes aegypti. [JOURNAL ARTICLE]
- Med Chem 2013 May 13.
The mosquito Aedes aegypti (Diptera, Culicidae) is the vector of yellow and dengue fever. In this study, chemometric tools, such as, Principal Component Analysis (PCA), Consensus PCA (CPCA), and Partial Least Squares Regression (PLS), were applied to a set of fifty five active compounds against Ae. aegypti larvae, which includes terpenes, cyclic alcohols, phenolic compounds, and their synthetic derivatives.The calculations were performed using the VolSurf+ program. CPCA analysis suggests that the higher weight blocks of descriptors were SIZE/SHAPE, DRY, and H2O. The PCA was generated with 48 descriptors selected from the previous blocks. The scores plot showed good separation between more and less potent compounds. The first two PCs accounted for over 60% of the data variance. The best model obtained in PLS, after validation leave-one-out, exhibited q2 = 0.679 and r2 = 0.714. External prediction model was R2 = 0.623. The independent variables having a hydrophobic profile were strongly correlated to the biological data. The interaction maps generated with the GRID force field showed that the most active compounds exhibit more interaction with the DRY probe.
- Design, Synthesis and Biological Evaluation of Novel Non-Peptide Boronic Acid Derivatives as Proteasome Inhibitors. [JOURNAL ARTICLE]
- Med Chem 2013 May 13.
A series of novel non-peptide boronic acid derivatives were designed and synthesized via rational drug design principles. All target compounds were screened for the proteasome inhibitory activities in vitro. Selected compounds (6a and 7j) were evaluated for their cytotoxic activities in vitro. Among these tested compounds, two (6a, 7j) displayed better proteasome inhibitory activities than that of the lead compound PI-083, and compound 6a was the most potent one with IC50 value of 161.90±29.46 nM. However, both of the two compounds (6a, 7j) exhibited weak cytotoxic activities, the discrepancy may lie in the compensatory pathways of the ubiquitin-proteasome pathway that promote tumor cell survival.
- QSAR and Docking Based Semi-Synthesis and In Vitro Evaluation of 18 β-Glycyrrhetinic Acid Derivatives against Human Lung Cancer Cell Line A-549. [JOURNAL ARTICLE]
- Med Chem 2013 May 8.
For the prediction of anticancer activity of glycyrrhetinic acid (GA-1) analogs against the human lung cancer cell line (A-549), a QSAR model was developed by forward stepwise multiple linear regression methodology. The regression coefficient (r2) and prediction accuracy (rCV2) of the QSAR model were taken 0.94 and 0.82, respectively in terms of correlation. The QSAR study indicates that the dipole moments, size of smallest ring, amine counts, hydroxyl and nitro functional groups are correlated well with cytotoxic activity. The docking studies showed high binding affinity of the predicted active compounds against the lung cancer target EGFR. These active glycyrrhetinic acid derivatives were then semi-synthesized, characterized and in-vitro tested for anticancer activity. The experimental results were in agreement with the predicted values and the ethyl oxalyl derivative of GA-1 (GA-3) showed equal cytotoxic activity to that of standard anticancer drug paclitaxel.
- Imidazole incorporated semicarbazone derivatives as a new class of anticonvulsants: design, synthesis and in-vivo screening. [Journal Article]
- Med Chem 2013 Jun 1; 9(4):571-80.
A series of novel imidazole incorporated semicarbazones was synthesized using an appropriate synthetic route and characterized by spectral analysis (IR, 1H NMR, 13C NMR and Mass). The anticonvulsant activity of the synthesized compounds was determined using doses of 30, 100, and 300 mg kg-1 against maximal electroshock seizure (MES), subcutaneous pentylenetetrazole (scPTZ) induced seizure and minimal neurotoxicity test. Six compounds exhibited protection in both models and 2-(1-(4-chlorophenyl)-2-(1H-imidazol-1-yl)ethylidene)-N-p-tolylsemicarbazone emerged as the most active compound of the series without any neurotoxicity and significant CNS depressant effect. Liver enzyme estimations (SGOT, SGPT, Alkaline phosphatase) of the compound also showed no significant change in the enzymes levels. Moreover, it caused 80% elevation of γ-amino butyric acid (GABA) levels in the whole mice brain, thus indicating that it could be a promising candidate in designing of a potent anticonvulsant drug.
- Ramoplanin Imaging Conjugates - Synthesis and Evaluation. [JOURNAL ARTICLE]
- Med Chem 2013 May 3.
In a previous study we found that fluorescence-marked vancomycin - a glycopeptide antibiotic - is taken up into human tumor cells. To expand on these investigations we now used the lipoglycodepsipeptide antibiotic ramoplanin. Compared to vancomycin it is a bigger molecule but it also has two potential binding sites for coupling to the imaging agents. Three different ramoplanin imaging conjugates were synthesized, two used for fluorescence imaging and one for magnetic resonance imaging. The two fluorescent dyes used in confocal laser scanning microscopy (CLSM) and fluorescence activated cell sorting (FACS) were fluorescein isothiocyanate (FITC) and rhodamine isothiocyanate (RITC). The third was the magnetic resonance imaging (MRI) contrast agent gadolinium-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid (GdDOTA). The uptake of ramoplanin conjugates, their specificity for different cell lines and the accessibility of the conjugates by imaging methods was evaluated on 8 human cell lines (two benign, six malignant) by CLSM, FACS and MRI experiments. Cytotoxicity of the ramoplanin conjugates was determined in the FACS experiments with the propidium iodide and Annexin-V-Fluos indicating any disruption in the cell membranes. Cytoplasmic uptake of the ramoplanin conjugates was observed in confocal laser scanning images and was measured using FACS and MRI experiments. Compared to the vancomycin conjugates the ramoplanin conjugates showed much weaker and slower uptake. Additionally, uptake of the ramoplanin conjugates led to strong membrane disruption and cell death.
- Design, Synthesis and Docking Studies Of Novel 2,4-Disubstituted Oxazole Derivatives As Potential Anti-Tumor Agents. [JOURNAL ARTICLE]
- Med Chem 2013 Apr 30.
A novel series of 2,4-disubstituted oxazole derivatives were synthesized. A series of chiral α-amino acid derivatives 6-15 were synthesized by coupling of various L-acylated amino acid azide 3. The synthesized compounds were evaluated for their in vitro antitumor activity against MCF-7, TK-10 and UACC-62 cell lines. Compound 6 exhibited the strongest inhibitory activity against TK cell lines while compound 12 showed the highest activity against MCF-7 cell lines. Compound 14 was the most active against UACC-62 cell lines. Furthermore, a molecular docking study of the most active compounds were carried out using EGFR x-ray 3D structure (PDB id 1M17). Docking results revealed that compound 6 showed the highest binding energy of ΔG= -78.17 Kcal/mol.
- Pharmacological Properties of Novel Cyclic Pentapeptides with μ-Opioid Receptor Agonist Activity. [JOURNAL ARTICLE]
- Med Chem 2013 Apr 23.
In our previous paper we have reported the synthesis and biological activity of a cyclic analog, Tyr-c(D-Lys-Phe-Phe-Asp)-NH2, based on endomorphin-2 (EM-2) structure. This analog displayed high affinity for the μ-opioid receptor, was much more stable than EM-2 in rat brain homogenate and showed remarkable antinociceptive activity after intracerebroventricular (i.c.v.) injection. Even more importantly, the cyclic analog elicited weak analgesia also after peripheral administration, giving evidence that it was able to cross, at least to some extent, the blood-brain barrier (BBB). Here we describe further modifications of this analog aimed at enhancing brain delivery by increasing lipophilicity. Two new cyclic pentapeptides, Tyr-c(D-Lys-D-1-Nal-Phe-Asp)-NH2 and Tyr-c(D-Lys-D-2-Nal-Phe-Asp)-NH2 (where 1-Nal=1-naphthyl-3-alanine, 2-Nal=2-naphthyl-3-alanine) were synthesized and evaluated in biological assays. Both analogs showed high μ-opioid receptor affinity and agonist activity and were stable in the rat brain homogenates. Unfortunately, the increase of lipophilicity was achieved at the expense of water solubility. The analog with D-2-Nal residue showed strong analgesic effect when given i.c.v. but could not be tested after intraventricular (i.v.) administration where higher concentrations of the compound are required. However, this analog showed inhibitory effect on gastrointestinal (GI) motility in vivo, providing an interesting approach to the development of peripherally restricted agents that could be useful for studying gastrointestinal disorders in animal models.
- Alkyl Caffeates as Anti-Helicobacter pylori and Scavenger of Oxidants Produced by Neutrophils. [JOURNAL ARTICLE]
- Med Chem 2013 Apr 23.
Helicobacter pylori pathogenic action involves the colonization of the gastrointestinal tract and a large production of reactive oxygen species (ROS) by the neutrophils attracted to the site of infection. The aim of this study was to evaluate caffeic acid and its alkyl esters as inhibitors of the release of ROS by Helicobacter pylori activated neutrophils and their bactericidal effect. The increased hydrophobicity caused by esterification had direct consequence in their efficiency as bactericidal agents against H. pylori and inhibitors of the production of ROS by neutrophils. The minimum inhibitory concentration (MIC) decreased from higher than 1000 mg/mL (caffeic acid) to 250 mg/mL to butyl and heptyl caffeate. The release of total ROS, superoxide anion and hypochlorous acid by activated neutrophils was also significantly decreased and the esters were more efficient than the acid precursor. In conclusion, the alkyl esters of caffeic acid have two properties that are complementary for the treatment of H. pylori infections: bactericidal activity and inhibitory effect upon generation of ROS by neutrophils. Hence, we propose that these easily synthesized and non-expensive substances should be applied to in vivo experimental models of H. pylori induced gastric infections.
- Structural Analysis for Colchicine Binding Site-Targeted ATCAA Derivatives as Melanoma Antagonists. [JOURNAL ARTICLE]
- Med Chem 2013 Apr 23.
Melanoma is the fatal form of skin cancer. Herein, a three-dimensional quantitative structure-activity relationship study on a series of 105 colchicine binding site-targeted 2-arylthiazolidine-4-carboxylic acid amides (ATCAA) derivatives as melanoma antagonists was conducted. The optimal CoMSIA model yields a Q2 of 0.556, R2ncv of 0.833 and R2pred of 0.757, while the CoMFA yields a Q2 of 0.569, R2ncv of 0.812 and R2pred of 0.589. In addition, molecular docking was also carried out. The study results demonstrated that: (1) Bulky substituents in Rings C and D significantly increase the biological activity of compounds while decrease the activity at Rings A and B; (2) Electropositive groups at Rings A and B as well as electronegative groups at Ring C help to increase the activity; (3) HB donor favors Rings A and D while HB acceptor favors Rings B and C. Besides, a statistical analysis of the key amino acids as well as the ones forming HB with various antagonists of the colchicine binding site was conducted based on 34 essays and found HB to be the key interaction that MTAs have with the colchicine binding site and that Ala 250, Asn 258, Thr 179, Lys 254 and Lys 352 are vital in the composition of the site and the formation of HB. The results of this study provide useful information on designing antagonists with improved activity and insight on the composition of the colchicine binding site.
- Synthesis and Biological Evaluation of Some Novel Thieno[2,3-d]pyrimidine Derivatives as Potential Anti-inflammatory and Analgesic Agents. [JOURNAL ARTICLE]
- Med Chem 2013 Apr 19.
A novel series of thienopyrimidine derivatives bearing various substituents or linked to various heterocyclic moieties through atoms spacers were prepared starting from 5-methyl-4-oxo-3,4-dihydrothieno[2,3-d]pyrimidine-6-carboxamide potassium salt 3. Twelve out of the prepared compounds were selected and evaluated for their anti-inflammatory activity using the formalin-induced paw edema and the turpentine oil-induced granuloma pouch bioassays using diclofenac sodium as a reference standard. The ulcerogenic effects and acute toxicity (ALD50) values of these compounds were also determined. In addition, the analgesic activity of the same compounds was evaluated using the rat tail withdrawal technique. The results revealed that compounds 5a, 13, 14b, 15a, 16a and 16b showed high anti-inflammatory effect comparable to diclofenac sodium, whereas compounds 5a, 14a, 15a and 16a revealed pronounced analgesic activity that equal or higher than that of the reference. All of the tested compounds revealed high GI safety profile and were well tolerated by the experimental animals with high safety margin (ALD50 > 3.0g/Kg).