Clioquinol Protects Against Cell Death in Parkinson’s Disease Models In Vivo and In Vitro. In: Groenewegen HJ, Voorn P, Berendse HW, Mulder AB, Cools AR, editors. The Basal Ganglia IX. New York: Springer; 2009. pp. 431-42. [DOI: 10.1007/978-1-4419-0340-2_33]

C-2 derivatized 8-sulfonamidoquinolines as antibacterial compounds

A series of C-2 derivatized 8-sulfonamidoquinolines were evaluated for their antibacterial activity against the common mastitis causative pathogens Streptococcus uberis, Staphylococcus aureus and Escherichia coli, both in the presence and absence of supplementary zinc (50 µM ZnSO₄). The vast majority of compounds tested were demonstrated to be significantly more active against S. uberis when in the presence of supplementary zinc (MICs as low as 0.125 µg/mL were observed in the presence of 50 µM ZnSO₄). Compounds 5, 34-36, 39, 58, 79, 82, 94 and 95 were shown to display the greatest antibacterial activity against S. aureus (MIC ≤ 8 µg/mL; both in the presence and absence of supplementary zinc), while compounds 56, 58 and 66 were demonstrated to also exhibit activity against E. coli (MIC ≤ 16 µg/mL; under all conditions). Compounds 56, 58 and 66 were subsequently confirmed to be bactericidal against all three mastitis pathogens studied, with MBCs (≥3log₁₀ CFU/mL reduction) of ≤ 32 µg/mL (in both the presence and absence of 50 µM ZnSO₄). To validate the sanitizing activity of compounds 56, 58 and 66, a quantitative suspension disinfection (sanitizer) test was performed. Sanitizing activity (>5log₁₀ CFU/mL reduction in 5 min) was observed against both S. uberis and E. coli at compound concentrations as low as 1 mg/mL (compounds 56, 58 and 66), and against S. aureus at 1 mg/mL (compound 58); thereby validating the potential of compounds 56, 58 and 66 to function as topical sanitizers designed explicitly for use in non-human applications.

The Pivotal Role of Copper in Neurodegeneration: A New Strategy for the Therapy of Neurodegenerative Disorders

Copper is an essential trace element for the human body since it is a cofactor of several enzymes and proteins and plays a pivotal role in several biological functions (e.g., respiration, protection from oxidative damage, iron metabolism, etc.), also including the central nervous system development and functioning (e.g., synthesis of neurotransmitters, myelination, activation of neuropeptides, etc.). Therefore, copper dysmetabolism is associated with different toxic effects, mainly represented by oxidative stress, and it has been reported in many neurodegenerative disorders, such as Wilson's disease, Menkes disease, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. This paper shows a detailed report of how copper is involved in the pathophysiology of these diseases. Moreover, a hint on novel therapeutic approaches based on restoring copper homeostasis through metal chelators will be pointed out.

Effect of 8-hydroxyquinoline and derivatives on human neuroblastoma SH-SY5Y cells under high glucose

8-Hydroxyquinoline and derivatives exhibit multifunctional properties, including antioxidant, antineurodegenerative, anticancer, anti-inflammatory and antidiabetic activities. In biological systems, elevation of intracellular calcium can cause calpain activation, leading to cell death. Here, the effect of 8-hydroxyquinoline and derivatives (5-chloro-7-iodo-8-hydroxyquinoline or clioquinol and 8-hydroxy-5-nitroquinoline or nitroxoline) on calpain-dependent (calpain-calpastatin) pathways in human neuroblastoma (SH-SY5Y) cells was investigated. 8-Hydroxyquinoline and derivatives ameliorated high glucose toxicity in SH-SY5Y cells. The investigated compounds, particularly clioquinol, attenuated the increased expression of calpain, even under high-glucose conditions. 8-Hydroxyquinoline and derivatives thus adversely affected the promotion of neuronal cell death by high glucose via the calpain-calpastatin signaling pathways. These findings support the beneficial effects of 8-hydroxyquinolines for further therapeutic development.

An N-heterocyclic amine chelate capable of antioxidant capacity and amyloid disaggregation

Alzheimer's disease is a neurodegenerative disorder characterized by the development of intracellular neurofibrillary tangles, deposition of extracellular amyloid beta (Aβ) plaques, along with a disruption of transition metal ion homeostasis in conjunction with oxidative stress. Spectroscopic, transmission electron microscopy, and scanning electron microscopy imaging studies show that 1 (pyclen) is capable of both preventing and disrupting Cu(2+) induced AB(1-40) aggregation. The pyridine backbone of 1 engenders antioxidant capacity, as shown by cellular DCFH-DA (dichlorodihydrofluorescein diacetate) assay in comparison to other N-heterocyclic amines lacking this aromatic feature. Finally, 1 prevents cell death induced by oxidative stress as shown by the Calcein AM assay. The results are supported using density functional theory studies which show that the pyridine backbone is responsible for the antioxidant capacity observed.