The impact of chelating compounds on Cu2+, Fe2+/3+, and Zn2+ ions in Alzheimer's disease treatment

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid - β extracellular plaques and tau interfibrillar tangles, leading to memory loss, cognitive decline, and behavioral changes. With dementia posing a growing global health concern, there is an urgent need for comprehensive strategies to address its challenges. The economic burden of dementia is projected to rise significantly, emphasizing the necessity for collaborative efforts in research and healthcare. In the United States alone, millions are affected by AD, with prevalence increasing with age and even affecting younger individuals. The complexity of AD involves intricate biological processes, including the aggregation of amyloid beta, oxidative stress, and metal ion dysregulation. Metal ions, particularly those from copper, iron, and zinc, play pivotal roles in AD pathology, influencing Aβ deposition and tau protein accumulation. Current treatments offer symptomatic relief but do not address the underlying disease mechanisms. This paper explores the potential of various chelating compounds to target metal ions involved in AD pathology. N-acylhydrazones, morpholine, chrysin, quinoline, oxindole, cyclam, catechol-based, and quinazolinone-based derivatives show promising chelation activity and therapeutic effects. Metal chelation therapy offers a targeted approach to AD treatment by addressing the core pathology. By selectively binding to metal ions implicated in disease progression, chelators may minimize side effects associated with broad-spectrum treatments. Additionally, chelators may offer neuroprotective effects beyond metal binding, further enhancing their therapeutic potential. Overall, metal chelation therapy presents a promising strategy in combating AD, with the potential to significantly impact disease progression and improve patient outcomes.

Rationally Designed Molecules Synergistically Modulate Multifaceted Aβ Toxicity, Microglial Activation, and Neuroinflammation

Synergistic modulation of multifaceted toxicity is the key to tackle multifactorial Alzheimer's disease (AD). The etiology of AD includes amyloid β (Aβ) amyloidosis, metal ion dyshomeostasis, reactive oxygen species (ROS), oxidative stress, mitochondrial damage, and neuroinflammation. We rationally designed multifunctional modulators by integrating pharmacophores for metal chelation, antioxidant and anti-inflammatory properties, and modulation of Aβ42 aggregation on the naphthalene monoimide (NMI) scaffold. The in vitro and cellular studies of NMIs revealed that M3 synergistically modulates metal-independent and -dependent amyloid toxicity, scavenges ROS, alleviates oxidative stress, and emulates Nrf2-mediated stress response in neuronal cells. M3 effectively reduced structural and functional damage of mitochondria, reduced Cyt c levels, and rescued cells from apoptosis. The biological atomic force microscopy and Western blot analysis revealed the ability of M3 to suppress microglial activation and neuroinflammation through inhibition of the NF-κβ pathway. The synergistic action of M3 is in agreement with our design strategy to develop a multifunctional therapeutic candidate by integrating multiple pharmacophores with distinct structural and functional elements to ameliorate the multifaceted toxicity of AD.

Synthesis and Antimalarial Activities of New Hybrid Atokel Molecules

The currently spreading resistance of the malaria parasite Plasmodium falciparum to artemisinin-based combination therapies makes an urgent need for new efficient drugs. Aiming to kill artemisinin-resistant Plasmodium, a series of novel hybrid drugs named Atokels were synthesized and characterized. Atokels are based on an 8-amino- or 8-hydroxyquinoline entity covalently bound to a 1,4-naphthoquinone through a polyamine linker. These drugs have been designed to target the parasite mitochondrion by their naphthoquinone moiety reminiscent of the antimalarial drug atovaquone, and to trigger a damaging oxidative stress due to their ability to chelate metal ions in order to generate redox active complexes in situ. The most effective Atokel drug shown a promising antimalarial activity (IC50 =622 nm on an artemisinin-resistant P. falciparum strain) and no cytotoxicity at 50 μm indicating a specific antiplasmodial mode of action.

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.

The polypharmacology of natural products

The once-popular approach of using natural products as a prime source for medicinal chemistry and drug discovery has waned considerably in the past two decades due to the advent of high-throughput screening of small molecule mega libraries. However, the growing appreciation of network pharmacology as the next drug-discovery paradigm suggests that natural products and their unique polypharmacology offer significant advantages for finding novel therapeutics particularly for the treatment of complex and multifactorial diseases. Drug discovery process is awaiting the revitalization of interest in natural products and their derivatives. The current challenge is how to decipher this natural chemical diversity.