Crystal structure, DFT, antimicrobial, anticancer and molecular docking of (4E)-4-((aryl)methyleneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one

Favorable Heteroaromatic Thiazole-Based Polyurea Derivatives as Interesting Biologically Active Products

This research sought to synthesize a new set of heteroaromatic thiazole-based polyurea derivatives with sulfur links in the polymers' main chains, which were denoted by the acronyms PU_1-5. Using pyridine as a solvent, a diphenylsulfide-based aminothiazole monomer (M2) was polymerized via solution polycondensation with varied aromatic, aliphatic, and cyclic diisocyanates. Typical characterization methods were used to confirm the structures of the premonomer, monomer, and fully generated polymers. The XRD results revealed that aromatic-based polymers had higher crystallinity than aliphatic and cyclic derivatives. SEM was used to visualize the surfaces of PU₁, PU₄, and PU₅, revealing spongy and porous shapes, shapes resembling wooden planks and sticks, and shapes resembling coral reefs with floral shapes at various magnifications. The polymers demonstrated thermal stability. The numerical results for PDTmax are listed in the following order, ranked from lowest to highest: PU₁ < PU₂ < PU₃ < PU₅ < PU₄. The FDT values for the aliphatic-based derivatives (PU₄ and PU₅) were lower than those for the aromatic-based ones (616, 655, and 665 °C). PU₃ showed the greatest inhibitory impact against the bacteria and fungi under investigation. In addition, PU₄ and PU₅ demonstrated antifungal activities that, in contrast with the other products, were on the lower end of the spectrum. Furthermore, the intended polymers were also tested for the presence of the proteins 1KNZ, 1JIJ, and 1IYL, which are frequently utilized as model organisms for E. coli (Gram-negative bacteria), S. aureus (Gram-positive bacteria), and C. albicans (fungal pathogens). This study's findings are consistent with the outcomes of the subjective screening.

Synthesis, characterization, anticancer, and antioxidant activities of chitosan Schiff bases bearing quinolinone or pyranoquinolinone and their silver nanoparticles derivatives

In this work, new chitosan-based Schiff bases were synthesized by the reaction of chitosan with quinolinone and pyranoquinolinone giving CSQ, and CSP, respectively. The novel Chitosan Schiff bases were grafted on silver nanoparticles providing CSQ/Ag, CSP/Ag structures. Characterization of isolated compounds was carried out by FT-IR, TGA, XRD, SEM, and TEM. The target compounds CSQ, CSP, CSQ/Ag, and CSP/Ag were evaluated as antitumor agents against three cancer cell lines, liver (HepG-2), colon (HCT-116), and breast (MCF-7). Compound CSQ/Ag disclosed potent cytotoxic effect with IC50 values in the range of 41.9–55.1 μg/ml in comparison with 5-fluorouracil against different cancer cell lines. Besides, the antioxidant activity of chitosan and its quinolinone and pyranoquinolinone analogues was assessed as radical scavengers versus 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH%). The compound CSQ/Ag emerged as the most active member in scavenging the DPPH radicals. The obtained findings proved that the new Schiff bases/silver nanoparticles of chitosan showed higher antiproliferative and antioxidant activities than the blank CS and would be highly applicable in biomedical fields.

Graphical abstract

A Review on the Advancements in the Field of Metal Complexes with Schiff Bases as Antiproliferative Agents

Metal complexes play an essential role in pharmaceutical sciences for their multiple and important activities. Schiff bases are versatile pharmacophores able to form chelating complexes with several metals in different oxidation states. Complexes with Schiff bases are widely described in the literature for their multiple actions and numerous advantages, such as low cost and easy synthesis. They show multiple biological activities, including antimicrobial, antioxidant, antimalarial, antinflammatory and antitumor. Schiff bases may also form complexes with lanthanides and actinides acting as catalysts (e.g., in various synthetic processes) and antitumor agents. This review intends to extend on our previous paper regarding Schiff bases as antitumorals, highlighting the importance, in the field of the anticancer agents, of these tools as ligands of metal complexes.