A unique ternary Ce(III)-quercetin-phenanthroline assembly with antioxidant and anti-inflammatory properties.

Quercetin is one of the most bioactive and common dietary flavonoids, with a significant repertoire of biological and pharmacological properties. The biological activity of quercetin, however, is influenced by its limited solubility and bioavailability. Driven by the need to enhance quercetin bioavailability and bioactivity through metal ion complexation, synthetic efforts led to a unique ternary Ce(III)-quercetin-(1,10-phenanthroline) (1) compound. Physicochemical characterization (elemental analysis, FT-IR, Thermogravimetric analysis (TGA), UV-Visible, NMR, Electron Spray Ionization-Mass Spectrometry (ESI-MS), Fluorescence, X-rays) revealed its solid-state and solution properties, with significant information emanating from the coordination sphere composition of Ce(III). The experimental data justified further entry of 1 in biological studies involving toxicity, (Reactive Oxygen Species, ROS)-suppressing potential, cell metabolism inhibition in Saccharomyces cerevisiae (S. cerevisiae) cultures, and plasmid DNA degradation. DFT calculations revealed its electronic structure profile, with in silico studies showing binding to DNA, DNA gyrase, and glutathione S-transferase, thus providing useful complementary insight into the elucidation of the mechanism of action of 1 at the molecular level and interpretation of its bio-activity. The collective work projects the importance of physicochemically supported bio-activity profile of well-defined Ce(III)-flavonoid compounds, thereby justifying focused pursuit of new hybrid metal-organic materials, effectively enhancing the role of naturally-occurring flavonoids in physiology and disease.

In-depth synthetic, physicochemical and in vitro biological investigation of a new ternary V(IV) antioxidant material based on curcumin.

Curcumin is a natural product with a broad spectrum of beneficial properties relating to pharmaceutical applications, extending from traditional remedies to modern cosmetics. The biological activity of such pigments, however, is limited by their solubility and bioavailability, thereby necessitating new ways of achieving optimal tissue cellular response and efficacy as drugs. Metal ion complexation provides a significant route toward improvement of curcumin stability and biological activity, with vanadium being a representative such metal ion, amply encountered in biological systems and exhibiting exogenous bioactivity through potential pharmaceuticals. Driven by the need to optimally increase curcumin bioavailability and bioactivity through complexation, synthetic efforts were launched to seek out stable species, ultimately leading to the synthesis and isolation of a new ternary V(IV)-curcumin-(2,2'-bipyridine) complex. Physicochemical characterization (elemental analysis, FT-IR, Thermogravimetry (TGA), UV-Visible, NMR, ESI-MS, Fluorescence, X-rays) portrayed the solid-state and solution properties of the ternary complex. Pulsed-EPR spectroscopy, in frozen solutions, suggested the presence of two species, cis- and trans-conformers. Density Functional Theory (DFT) calculations revealed the salient features and energetics of the two conformers, thereby complementing EPR spectroscopy. The well-described profile of the vanadium species led to its in vitro biological investigation involving toxicity, cell metabolism inhibition in S. cerevisiae cultures, Reactive Oxygen Species (ROS)-suppressing capacity, lipid peroxidation, and plasmid DNA degradation. A multitude of bio-assays and methodologies, in comparison to free curcumin, showed that it exhibits its antioxidant potential in a concentration-dependent fashion, thereby formulating a bioreactivity profile supporting development of new efficient vanado-pharmaceuticals, targeting (extra)intra-cellular processes under (patho)physiological conditions.

Prevalence and severity of sensorineural hearing loss in patients with exfoliation syndrome.

BACKGROUND AND OBJECTIVES: Exfoliation syndrome is characterized by the production and accumulation of abnormal extracellular material in many ocular and extraocular tissues. The aim of the present prospective case-control clinical study was to evaluate the effect of exfoliation syndrome on prevalence and severity of sensorineural hearing loss. MATERIALS AND METHODS: In the study participated 94 ears of patients with unilateral or bilateral ocular exfoliation syndrome (study group) and 44 ears of individuals without the syndrome (control group). Subjects with a history of conditions affecting hearing function and patients with conductive or mixed hearing loss, glaucoma or ocular hypertension were excluded from the study. All participants underwent pure-tone audiometry with air and bone conduction. During audiometry, the eventual sensorineural hearing loss and its severity was determined for each ear, at frequencies of 250, 500, 1000, 2000, 4000 and 8000 Hz (Hertz). RESULTS: The mean age of participants was 74.7 years in both groups. Differences in age and gender distribution between the two groups were not statistically significant. Compared to control group, study group displayed: (1) Significantly higher prevalence rates of hearing loss at frequencies of 1000, 2000, 4000 and 8000 Hz (p = 0.007). (2) More severe hearing loss at frequencies of 4000 and 8000 Hz (p < 0.001). CONCLUSIONS: The above results demonstrate an effect of exfoliation syndrome on prevalence and severity of sensorineural hearing loss. These findings verify the theory that this syndrome is not only an ocular disease, but also a systemic disorder with potential otological complications.