Potentiometric Studies on Binary and Ternary Complexes of Ni(II) and Cu(II) Ions with L-Valine and Paracetamol

The protonation constants of the free ligands and the stability constants of binary and ternary complexes of bivalent metal ions of Ni(II) and Cu(II) with a biologically important amino acid of L-valine, Val, and paracetamol, Para, were studied potentiometrically in aqueous solutions at 313.15 ± 0.1 K and a fixed ionic strength of I = 0.10 M NaCl. The complexation model for each system was established using the Irving-Rossotti equation. The formation of the 1:2 or 1:1 binary complexes and 1:1:1 ternary complexes in which the amino acid Val was used as the primary ligand and Para as the secondary ligand, as inferred from the corresponding potentiometric pH-metric titration curves, and their relative stabilities compared to the corresponding ML and ML2 binary complexes are expressed in terms of statistical parameters ∆logK, logK1 and logK2. The complex stability was found to follow the order of Cu(II) > Ni(II). Through these diagnostic studies, it was possible to give the general formula of compounds prepared from amino acids and paracetamol. Amino acid binds to the central ion through oxygen in the hydroxyl group and nitrogen atom in the amine group (-NH2), whereas paracetamol forms a unipolar bond by binding to the concentrated ion through the oxygen atom in the hydroxyl group. Most of the nickel complexes had octahedral symmetry with valine and paracetamol ligands, while the copper complexes had square or hierarchical to square base symmetry.

NSAID-Based Coordination Compounds for Biomedical Applications: Recent Advances and Developments

After the serendipitous discovery of cisplatin, a platinum-based drug with chemotherapeutic effects, an incredible amount of research in the area of coordination chemistry has been produced. Other transition metal compounds were studied, and several new relevant metallodrugs have been synthetized in the past few years. This review is focused on coordination compounds with first-row transition metals, namely, copper, cobalt, nickel or manganese, or with zinc, which have potential or effective pharmacological properties. It is known that metal complexes, once bound to organic drugs, can enhance the drugs’ biological activities, such as anticancer, antimicrobial or anti-inflammatory ones. NSAIDs are a class of compounds with anti-inflammatory properties used to treat pain or fever. NSAIDs’ properties can be strongly improved when included in complexes using their compositional N and O donor atoms, which facilitate their coordination to metal ions. This review focuses on the research on this topic and on the promising or effective results that complexes of first-row transition metals and NSAIDs can exhibit.

Aspirin-Based Organoiron Dendrimers as Promising Anti-Inflammatory, Anticancer, and Antimicrobial Drugs

Designing nanocarriers with actions directed at a specific organ or tissue is a very promising strategy since it can significantly reduce the toxicity of a bioactive drug. In this study, an organometallic dendrimer was used to synthesize a biocompatible drug delivery system by attaching aspirin to the periphery of the dendrimer. Our goal is to enhance the bioavailability and anticancer activity of aspirin and reduce its toxicity through successive generations of organoiron dendrimers. The biological activity of aspirin-based dendrimer complexes was evaluated. The result of antimicrobial activity of the synthesized dendrimers also demonstrated an increase in their antimicrobial activity with increased generation of the dendrimers for most types of microorganisms. This study reveals for the first time that organoiron dendrimers linked with aspirin exhibit an excellent Gram-negative activity comparable to the reference drug Gentamicin. All synthesized dendrimers were tested for their anticancer activity against breast cancer cell lines (MCF-7), hepatocellular cell lines (Hep-G2), and a non-cancer cell line, Human Embryonic Kidney (HEK293), using the MTT cell viability assay and compared against a standard anticancer drug, Doxorubicin. Compounds G3-D9-Asp and G4-D12-Asp exhibited noticeable activity against both cell lines, both of which were more effective than aspirin itself. In addition, the in vivo anti-inflammatory activity and histopathology of swollen paws showed that the designed aspirin-based dendrimers displayed significant anti-inflammatory activity; however, G2-D6-Asp showed the best anti-inflammatory activity, which was more potent than the reference drug aspirin during the same period. Moreover, the coupling of aspirin to the periphery of organoiron dendrimers showed a significant reduction in the toxicity of aspirin on the stomach.

Novel Synthetic Monothiourea Aspirin Derivatives Bearing Alkylated Amines as Potential Antimicrobial Agents

A new series of aspirin bearing alkylated amines moieties 1–12 were synthesised by reacting isothiocyanate with a series of aniline derivatives in overall yield of 16–56%. The proposed structures of all the synthesised compounds were confirmed using elemental analysis, FTIR, and 1H and  13C NMR spectroscopy. All compounds were evaluated for antibacterial activities against E. coli and S. aureus via turbidimetric kinetic and Kirby Bauer disc diffusion method. Compound 5 bearing meta -CH3 substituent showed the highest relative inhibition zone diameter against tested bacteria compared to ortho and para substituent. Furthermore, aspirin derivatives bearing shorter chains exhibited better bacterial inhibition than longer alkyl chains.