Design, Synthesis, Anti-Inflammatory Activity, DFT Modeling and Docking Study of New Ibuprofen Derivatives.

A new ibuprofen derivative, (E)-2-(4-isobutylphenyl)-N'-(4-oxopentan-2-ylidene) propane hydrazide (IA), was synthesized, along with its metal complexes with Co, Cu, Ni, Gd, and Sm, to investigate their anti-inflammatory efficacy and COX-2 inhibition potential. Comprehensive characterization, including 1H NMR, MS, FTIR, UV-vis spectroscopy, and DFT analysis, were employed to determine the structural configurations, revealing unique motifs for Gd/Sm (capped square antiprismatic/tricapped trigonal prismatic) and Cu/Ni/Co (octahedral) complexes. Molecular docking with the COX-2 enzyme (PDB code: 5IKT) and pharmacokinetic assessments through SwissADME indicated that these compounds have superior binding energies and pharmacokinetic profiles, including BBB permeability and gastrointestinal absorption, compared to the traditional ibuprofen standalone. Their significantly lower IC50 values further suggest a higher efficacy as anti-inflammatory agents and COX-2 inhibitors. These research findings not only introduce promising ibuprofen derivatives for therapeutic applications but also set the stage for future validation and exploration of this new generation of ibuprofen compounds.

Stable isotope dilution mass spectrometry quantification of hydrogen sulfide and thiols in biological matrices.

BACKGROUND: Hydrogen sulfide (H2S), a gaseous signaling molecule that impacts multiple physiological processes including aging, is produced via select mammalian enzymes and enteric sulfur-reducing bacteria. H2S research is limited by the lack of an accurate internal standard-containing assay for its quantitation in biological matrices. METHODS: After synthesizing [34S]H2S and developing sample preparation protocols that avoid sulfide contamination with the addition of thiol-containing standards or reducing reagents, we developed a stable isotope-dilution high performance liquid chromatography tandem-mass spectrometry (LC-MS/MS) method for the simultaneous quantification of Total H2S and other abundant thiols (cysteine, homocysteine, glutathione, glutamylcysteine, cysteinylglycine) in biological matrices, conducted a 20-day analytical validation/normal range study, and then both analyzed circulating Total H2S and thiols in plasma from 400 subjects, and within 20 volunteers before and after antibiotic-induced suppression of gut microbiota. RESULTS: Using the new assay, all analytes showed minimal interference, no carryover, and excellent intra- and inter-day reproducibility (≤7.6%, and ≤12.7%, respectively), linearity (r2 > 0.997), recovery (90.9%-110%) and stability (90.0%-100.5%). Only circulating Total H2S levels showed significant age-associated reductions in both males and females (p < 0.001), and a marked reduction following gut microbiota suppression (mean 33.8 ±â€¯17.7%, p < 0.001), with large variations in gut microbiota contribution among subjects (range 6.0-66.7% reduction with antibiotics). CONCLUSIONS: A stable-isotope-dilution LC-MS/MS method is presented for the simultaneous quantification of Total H2S and multiple thiols in biological matrices. We then use this assay panel to show a striking age-related decline and gut microbiota contribution to circulating Total H2S levels in humans.

Cobalt(II) Diphenylazodioxide Complexes Induce Apoptosis in SK-HEP-1 Cells.

The cobalt(II) complex salts [Co(bpy)(az)2](PF6)2 and [Co(az)4](PF6), each bearing the unusual cis-N,N'-diphenylazodioxide ligand, were both screened as possible anticancer agents against SK-HEP-1 liver cancer cells. Both compounds were found to induce substantial apoptosis as an increasing function of concentration and time. Measurement of apoptosis-related proteins indicated that both the extrinsic and intrinsic pathways of apoptosis were activated. The apoptotic activity induced by these salts is not displayed either by simple cobalt(II) salts or complexes or by the free nitrosobenzene ligand. Additionally, these compounds did not induce apoptosis, as assessed by poly(adenosine diphosphate-ribose) polymerase cleavage, in several other cell lines.

Synthesis and Characterization of Cobalt(II) N,N'-Diphenylazodioxide Complexes.

Removal of chloride from CoCl2 with TlPF6 in acetonitrile, followed by addition of excess nitrosobenzene, yielded the eight-coordinate cobalt(II) complex salt [Co{Ph(O)NN(O)Ph}4](PF6)2, shown by single-crystal X-ray analysis to have a distorted tetragonal geometry. The analogous treatment of the bipyridyl complex Co(bpy)Cl2 yielded the mixed-ligand cobalt(II) complex salt [Co(bpy){Ph(O)NN(O)Ph}2](PF6)2, whose single-crystal X-ray structure displays a trigonal prismatic geometry, similar to that of the iron(II) cation in the previously known complex salt [Fe{Ph(O)NN(O)Ph}3](FeCl4)2. The use of TlPF6 to generate solvated metal complex cations from chloride salts or chlorido complexes, followed by the addition of nitrosobenzene, is shown to be a useful synthetic strategy for the preparation of azodioxide complex cations with the noncoordinating, diamagnetic PF6 - counteranion. Coordination number appears to be more important than d electron count in determining the geometry and metal-ligand bond distances of diphenylazodioxide complexes.

Melanin-based coatings as lead-binding agents.

Interactions between metal ions and different forms of melanin play significant roles in melanin biochemistry. The binding properties of natural melanin and related synthetic materials can be exploited for nonbiological applications, potentially including water purification. A method for investigating metal ion-melanin interactions on solid support is described, with lead as the initial target. 2.5 cm discs of the hydrophobic polymer PVDF were coated with synthetic eumelanin from the tyrosinase-catalyzed polymerization of L-dopa, and with melanin extracted from human hair. Lead (Pb(2+)) binding was quantified by atomic absorption spectroscopy (flame mode), and the data was well fit by the Langmuir model. Langmuir affinities ranged from 3.4 · 10(3) to 2.2 · 10(4) M(-1). At the maximum capacity observed, the synthetic eumelanin coating bound ~9% of its mass in lead. Binding of copper (Cu(2+)), zinc (Zn(2+)), and cadmium (Cd(2+)) to the synthetic-eumelanin-coated discs was also investigated. Under the conditions tested, the Langmuir affinities for Zn(2+), Cd(2+), and Cu(2+) were 35%, 53%, and 77%, respectively, of the Langmuir affinity for Pb(2+). The synthetic-eumelanin-coated discs have a slightly higher capacity for Cu(2+) on a per mole basis than for Pb(2+), and lower capacities for Cd(2+) and Zn(2+). The system described can be used to address biological questions and potentially be applied toward melanin-based water purification.

A step beyond the Feltham-Enemark notation: spectroscopic and correlated ab initio computational support for an antiferromagnetically coupled M(II)-(NO)- description of Tp*M(NO) (M = Co, Ni).

Multiple spectroscopic and computational methods were used to characterize the ground-state electronic structure of the novel {CoNO}(9) species Tp*Co(NO) (Tp* = hydro-tris(3,5-Me(2)-pyrazolyl)borate). The metric parameters about the metal center and the pre-edge region of the Co K-edge X-ray absorption spectrum were reproduced by density functional theory (DFT), providing a qualitative description of the Co-NO bonding interaction as a Co(II) (S(Co) = 3/2) metal center, antiferromagnetically coupled to a triplet NO(-) anion (S(NO) = 1), an interpretation of the electronic structure that was validated by ab initio multireference methods (CASSCF/MRCI). Electron paramagnetic resonance (EPR) spectroscopy revealed significant g-anisotropy in the S = ½ ground state, but the linear-response DFT performed poorly at calculating the g-values. Instead, CASSCF/MRCI computational studies in conjunction with quasi-degenerate perturbation theory with respect to spin-orbit coupling were required for obtaining accurate modeling of the molecular g-tensor. The computational portion of this work was extended to the diamagnetic Ni analogue of the Co complex, Tp*Ni(NO), which was found to consist of a Ni(II) (S(Ni) = 1) metal center antiferromagnetically coupled to an S(NO) = 1 NO(-). The similarity between the Co and Ni complexes contrasts with the previously studied Cu analogues, for which a Cu(I) bound to NO(0) formulation has been described. This discrepancy will be discussed along with a comparison of the DFT and ab initio computational methods for their ability to predict various spectroscopic and molecular features.

Cobalt-mediated, enantioselective synthesis of C(2) and C(1) dienes.

The asymmetric C-H functionalization of norbornene and norbornadiene with five-, six-, and seven-membered cyclic enones mediated by the reactive intermediate [{η(5)-((t)BuMe(2)Si)C(5)H(4)}Co(NO)(2)] is reported. A novel base mixture derived from enantiopure ammonium salts and NaHMDS was used as a source of chirality, and this enantioselective desymmetrization of C(s) alkenes has been applied to the asymmetric synthesis of C(2)- and C(1)-symmetric diene ligands in high regioselectivity (3.7-20:1 anti/syn), near perfect diastereoselectivity (>99:1 dr), and high enantioselectivity (90-96% ee).

Cobalt dinitrosoalkane complexes in the C-H functionalization of olefins.

The use of cobalt dinitrosoalkane complexes in the C-H functionalization of alkenes has been demonstrated. Reaction of a series of alkenes with Me4CpCo(CO)2 in the presence of NO generates intermediate cobalt dinitrosoalkane complexes that can be deprotonated alpha to the nitrosyl group and added to various Michael acceptors. The resultant products can then undergo retrocycloaddition reactions in the presence of the original alkene to regenerate the starting cobalt dinitrosoalkane complex and release the functionalized alkene.