Design, synthesis and pharmacological evaluation of novel tetrasubstituted thiophene analogues as anti-inflammatory agents

A new series of tetrasubstituted thiophene analogues (4a-4f, 5a-5f and 8a-8i) were designed incorporating the pharmacophoric features of COX-1 (as in fenamates), 5-LOX and the p38 MAP kinase inhibitors. The designed series was synthesized by nucleophilic addition of aryl/aroylisothiocyanate and enamine (2) yielding the addition product l-(alpha-Carbomethoxy-beta-aminothiocrotonoyl)-aryl/aroyl amines (3/7); which on reaction with substituted phenacyl bromides gave the targeted tetrasubstituted thiophene esters (4a-4f / 8a-8i). The tetrasubstituted thiophenes esters (4a-4f ) on hydrolysis with one equivalent of potassium hydroxide solution in methanol at room temperature gave corresponding acids (5a-5f ). All the targeted compounds were evaluated for their anti-inflammatory activity in carrageenin-induced rat hind paw oedema model at the doses of 10, 20 and 40 mg/kg body weight using standard drugs mefanamic acid and ibuprofen. The compounds (4c, 4e, 4f, 5f, 8a- 8i) which gave reasonable protection to the inflamed paw, eliciting good or moderate comparable anti-inflammatory activity were selected for investigating their analgesic activity using acetic acid induced writhing response test in albino mice at 10 mg/kg dose using standard drug ibuprofen and in order to arrive at possible mechanism of their anti-inflammatory activity, in vitro antioxidant nitric oxide radical scavenging assay at the concentrations of 5, 10, 15, 20, 25, 30 and 35 microg/mL were performed using standard drug ascorbic acid.     

The essential role of centrosomal NDE1 in human cerebral cortex neurogenesis

We investigated three families whose offspring had extreme microcephaly at birth and profound mental retardation. Brain scans and postmortem data showed that affected individuals had brains less than 10% of expected size (≤10 standard deviation) and that in addition to a massive reduction in neuron production they displayed partially deficient cortical lamination (microlissencephaly). Other body systems were apparently unaffected and overall growth was normal. We found two distinct homozygous mutations of NDE1, c.83+1G>T (p.Ala29GlnfsX114) in a Turkish family and c.684_685del (p.Pro229TrpfsX85) in two families of Pakistani origin. Using patient cells, we found that c.83+1G>T led to the use of a novel splice site and to a frameshift after NDE1 exon 2. Transfection of tagged NDE1 constructs showed that the c.684_685del mutation resulted in a NDE1 that was unable to localize to the centrosome. By staining a patient-derived cell line that carried the c.83+1G>T mutation, we found that this endogeneously expressed mutated protein equally failed to localize to the centrosome. By examining human and mouse embryonic brains, we determined that NDE1 is highly expressed in neuroepithelial cells of the developing cerebral cortex, particularly at the centrosome. We show that NDE1 accumulates on the mitotic spindle of apical neural precursors in early neurogenesis. Thus, NDE1 deficiency causes both a severe failure of neurogenesis and a deficiency in cortical lamination. Our data further highlight the importance of the centrosome in multiple aspects of neurodevelopment.     

Aromaticity of azines through dyotropic double hydrogen transfer reaction

The thermodynamic stabilities and IR spectra of the three water clusters (H₂O)_20, (H₂O)_54,, and (H₂O)₁₀₀ are studied by quantum-chemical computations. After full optimization of the (H₂O)_20,54,100 structures using the hybrid density functional B3LYP together with the 6-31+G(d,p) basis set, the electronic energies, zero-point energies, internal energies, enthalpies, entropies, and Gibbs free energies of the water clusters at 298 K are investigated. The OH stretching vibrational IR spectra of (H₂O)_20,54,100 are simulated and split into sub-spectra for different H-bond groups depending on the conformations of the hydrogen bonds. From the computed spectra the different spectroscopic fingerprint features of water molecules in different H-bond conformations in the water clusters are inferred.     

Structural Characteristic of the Initial Unfolded State on Refolding Determines Catalytic Efficiency of the Folded Protein in Presence of Osmolytes

Osmolytes are low molecular weight organic molecules accumulated by organisms to assist proper protein folding, and to provide protection to the structural integrity of proteins under denaturing stress conditions. It is known that osmolyte-induced protein folding is brought by unfavorable interaction of osmolytes with the denatured/unfolded states. The interaction of osmolyte with the native state does not significantly contribute to the osmolyte-induced protein folding. We have therefore investigated if different denatured states of a protein (generated by different denaturing agents) interact differently with the osmolytes to induce protein folding. We observed that osmolyte-assisted refolding of protein obtained from heat-induced denatured state produces native molecules with higher enzyme activity than those initiated from GdmCl- or urea-induced denatured state indicating that the structural property of the initial denatured state during refolding by osmolytes determines the catalytic efficiency of the folded protein molecule. These conclusions have been reached from the systematic measurements of enzymatic kinetic parameters (K _m and k _cat), thermodynamic stability (T _m and ΔH _m) and secondary and tertiary structures of the folded native proteins obtained from refolding of various denatured states (due to heat-, urea- and GdmCl-induced denaturation) of RNase-A in the presence of various osmolytes.     

Theoretical insights into thermal cyclophanediene to dihydropyrene electrocyclic reactions; a comparative study of Woodward Hoffmann allowed and forbidden reactions

The thermally allowed electrocyclic reaction syn-cyclophanediene (CPD) to dihydropyrene (DHP) was compared with the disallowed thermal electrocyclic reaction in anti CPD through density functional theory (DFT) calculations at the B3LYP/6-31?+?G(d) level. Moreover, the results were also compared with the electrocyclization of 1,3,5 hexatriene to 1,3-cyclohexadiene . The Woodward-Hoffmann (W-H) allowed thermal reaction in syn CPD 11 has a calculated activation barrier of 6.23 kcal mol^?1, compared with 29 kcal mol^?1 for the electrocyclization of 1,3,5 hexatriene to 1,3-cyclohexadiene. The enhanced acceleration of electrocyclization is believed to arise from geometrically enforced spatially aligned termini of the hexatriene. Substituents at the electrocyclic terminus of cyclophanediene significantly affected (up to three fold) the activation barriers. Mono-substitution of CPD has substituent dependent acceleration or deceleration whereas di-substitution always increased the activation barrier. The activation barrier for electrocyclization in 33 is 4.44 kcal mol^?1, which is the lowest activation barrier for any thermal electrocyclic reaction. Cyclophanedienes (CPDs) substituted with electron-rich substituents cyclized with high activation barriers and vice versa, a phenomenon significantly different from electrocyclic reaction of 1,3,5-hexatriene where no such trend is traceable. Comparison of W-H allowed and forbidden electrocyclization in syn and anti CPDs, respectively, revealed quite similar electronic demand, although the transition states are different in nature. The transition state for a W-H forbidden reaction is biradicaloid, with most of the spin density at the electrocyclic termini; however, the transition state for a W-H allowed reaction has no such contribution. We also believe that this is the first study of its type, where W-H allowed and forbidden reactions are compared on a similar set of molecules, and compared for electronic effect through substituents.     

Changes in circulating levels of immunoreactive follicle stimulating hormone, luteinizing hormone, and testosterone during sexual development in the rhesus monkey, Macaca mulatta

Basal serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) and the responsiveness of these hormones to a challenge dose of luteinizing hormone releasing hormone (LHRH), were determined in juvenile, pubertal, and adult rhesus monkeys. The monkey gonadotrophins were analyzed using RIA reagents supplied by the World Health Organization (WHO) Special Programme of Human Reproduction. The FSH levels which were near the assay sensitivity in immature monkeys (2.4 +/- 0.8 ng/ml) showed a discernible increase in pubertal animals (6.4 +/- 1.8 ng/ml). Compared to other two age groups, the serum FSH concentration was markedly higher (16.1 +/- 1.8 ng/ml) in adults. Serum LH levels were below the detectable limits of the assay in juvenile monkeys but rose to 16.2 +/- 3.1 ng/ml in pubertal animals. When compared to pubertal animals, a two-fold increase in LH levels paralleled changes in serum LH during the three developmental stages. Response of serum gonadotrophins and T levels to a challenge dose of LHRH (2.5 micrograms; i.v.) was variable in the different age groups. The present data suggest: an asynchronous rise of FSH and LH during the pubertal period and a temporal correlation between the testicular size and FSH concentrations; the challenge dose of LHRH, which induces a significant rise in serum LH and T levels, fails to elicit an FSH response in all the three age groups; and the pubertal as compared to adult monkeys release significantly larger quantities of LH in response to exogenous LHRH.     

Towards thermally stable cyclophanediene-dihydropyrene photoswitches

Cyclophanediene dihydropyrenes (CPD-DHP) are photochromic compounds because they change their color by irradiation with lights of different color. Potential use of CPD-DHP photoswitch in memory devices requires a very slow thermal return in the dark in the absence of any side reaction. Herein, thermal return of CPDs to DHPs, and an unwanted sigmatropic shift in DHP is studied through density functional theory calculations at (U)B3LYP/6-31+G(d). The thermal return occurs through symmetry forbidden conrotatory electrocyclic reaction. Dimethyl amino CPD-DHP photoswitch pair has the highest activation barrier for electrocyclization and sigmatropic shifts. The lowest activation barrier for symmetry forbidden electrocyclization is observed for GeBr₃ functionalized CPD. An unprecedented decomposition pathway involving elimination of the internal substituents is predicted for Cl, Br and SMe functionalized DHPs. This study shows great promise in understanding the Woodward Hoffmann forbidden processes and, in reducing the synthetic efforts toward robust photochromes for memory applications.     

Design,synthesis and pharmacological evaluation of novel tetrasubstituted thiophene analogues as anti-inflammatory agents

A new series of tetrasubstituted thiophene analogues (4a-4f, 5a-5f and 8a-8i) were designed incorporating the pharmacophoric features of COX-1 (as in fenamates), 5-LOX and the p38 MAP kinase inhibitors. The designed series was synthesized by nucleophilic addition of aryl/aroylisothiocyanate and enamine (2) yielding the addition product l-(α-Carbomethoxy-β-aminothiocrotonoyl)-aryl/aroyl amines (3/7); which on reaction with substituted phenacyl bromides gave the targeted tetrasubstituted thiophene esters (4a-4f / 8a-8i). The tetrasubstituted thiophenes esters (4a-4f ) on hydrolysis with one equivalent of potassium hydroxide solution in methanol at room temperature gave corresponding acids (5a-5f ). All the targeted compounds were evaluated for their anti-inflammatory activity in carrageenin-induced rat hind paw oedema model at the doses of 10, 20 and 40 mg/kg body weight using standard drugs mefanamic acid and ibuprofen. The compounds (4c, 4e, 4f, 5f, 8a- 8i) which gave reasonable protection to the inflamed paw, eliciting good or moderate comparable anti-inflammatory activity were selected for investigating their analgesic activity using acetic acid induced writhing response test in albino mice at 10 mg/kg dose using standard drug ibuprofen and in order to arrive at possible mechanism of their anti-inflammatory activity, in vitro antioxidant nitric oxide radical scavenging assay at the concentrations of 5, 10, 15, 20, 25, 30 and 35 μg/mL were performed using standard drug ascorbic acid.