Synthesis, characterization, biological activity and electrochemistry studies of iron(III) complex with curcumin-oxime ligand

Recent advances in the antioxidant activity of metal-curcumin complexes: a combined computational and experimental review

Curcumin, an extensively studied phytochemical compound, has gained attention for its potential therapeutic applications across a spectrum of diseases. Its notable attributes include its relatively high tolerability within the human body and its perceived absence of adverse side effects. This review article presents a comprehensive overview of the antioxidant effects exhibited by complexes formed by curcumin and curcumin derived ligands with metals like Mn, Cu, Fe, Zn, Ga and In, which leads to toxic effects beyond a certain limit, based on both experimental and theoretical findings. Additionally, the discussion delves into metal-curcumin complexes characterized by stoichiometries of 1:1 and 1:2, exploring their geometric arrangements and corresponding antioxidant activity, as highlighted in recent studies. These complexes hold the promise of improving curcumin's solubility, stability, and bioavailability, potentially augmenting its overall therapeutic potential and expanding its scope for medical applications.

Curcumin Electrochemistry-Antioxidant Activity Assessment, Voltammetric Behavior and Quantitative Determination, Applications as Electrode Modifier

Curcumin (CU) is a polyphenolic compound extracted from turmeric, a well-known dietary spice. Since it has been shown that CU exerts beneficial effects on human health, interest has increased in its use but also in its analysis in different matrices. CU has an antioxidant character and is electroactive due to the presence of phenolic groups in its molecule. This paper reviews the data reported in the literature regarding the use of electrochemical techniques for the assessment of CU antioxidant activity and the investigation of the voltammetric behavior at different electrodes of free or loaded CU on various carriers. The performance characteristics and the analytical applications of the electrochemical methods developed for CU analysis are compared and critically discussed. Examples of voltammetric investigations of CU interaction with different metallic ions or of CU or CU complexes with DNA as well as the CU applications as electrode modifiers for the enhanced detection of various chemical species are also shown.

Neuroprotective Effects of the Lithium Salt of a Novel JNK Inhibitor in an Animal Model of Cerebral Ischemia–Reperfusion

The c-Jun N-terminal kinases (JNKs) regulate many physiological processes, including inflammatory responses, morphogenesis, cell proliferation, differentiation, survival, and cell death. Therefore, JNKs represent attractive targets for therapeutic intervention. In an effort to develop improved JNK inhibitors, we synthesized the lithium salt of 11H-indeno[1,2-b]quinoxaline-11-one oxime (IQ-1L) and evaluated its affinity for JNK and biological activity in vitro and in vivo. According to density functional theory (DFT) modeling, the Li⁺ ion stabilizes the six-membered ring with the 11H-indeno[1,2-b]quinoxaline-11-one (IQ-1) oximate better than Na⁺. Molecular docking showed that the Z isomer of the IQ-1 oximate should bind JNK1 and JNK3 better than (E)-IQ-1. Indeed, experimental analysis showed that IQ-1L exhibited higher JNK1-3 binding affinity in comparison with IQ-1S. IQ-1L also was a more effective inhibitor of lipopolysaccharide (LPS)-induced nuclear factor-κB/activating protein 1 (NF-κB/AP-1) transcriptional activity in THP-1Blue monocytes and was a potent inhibitor of proinflammatory cytokine production by MonoMac-6 monocytic cells. In addition, IQ-1L inhibited LPS-induced c-Jun phosphorylation in MonoMac-6 cells, directly confirming JNK inhibition. In a rat model of focal cerebral ischemia (FCI), intraperitoneal injections of 12 mg/kg IQ-1L led to significant neuroprotective effects, decreasing total neurological deficit scores by 28, 29, and 32% at 4, 24, and 48 h after FCI, respectively, and reducing infarct size by 52% at 48 h after FCI. The therapeutic efficacy of 12 mg/kg IQ-1L was comparable to that observed with 25 mg/kg of IQ-1S, indicating that complexation with Li⁺ improved efficacy of this compound. We conclude that IQ-1L is more effective than IQ-1S in treating cerebral ischemia injury and thus represents a promising anti-inflammatory compound.

Role of Iron in the Molecular Pathogenesis of Diseases and Therapeutic Opportunities

Iron is an essential mineral that serves as a prosthetic group for a variety of proteins involved in vital cellular processes. The iron economy within humans is highly conserved in that there is no proper iron excretion pathway. Therefore, iron homeostasis is highly evolved to coordinate iron acquisition, storage, transport, and recycling efficiently. A disturbance in this state can result in excess iron burden in which an ensuing iron-mediated generation of reactive oxygen species imparts widespread oxidative damage to proteins, lipids, and DNA. On the contrary, problems in iron deficiency either due to genetic or nutritional causes can lead to a number of iron deficiency disorders. Iron chelation strategies have been in the works since the early 1900s, and they still remain the most viable therapeutic approach to mitigate the toxic side effects of excess iron. Intense investigations on improving the efficacy of chelation strategies while being well tolerated and accepted by patients have been a particular focus for many researchers over the past 30 years. Moreover, recent advances in our understanding on the role of iron in the pathogenesis of different diseases (both in iron overload and iron deficiency conditions) motivate the need to develop new therapeutics. We summarized recent investigations into the role of iron in health and disease conditions, iron chelation, and iron delivery strategies. Information regarding small molecule as well as macromolecular approaches and how they are employed within different disease pathogenesis such as primary and secondary iron overload diseases, cancer, diabetes, neurodegenerative diseases, infections, and in iron deficiency is provided.