Natural Xanthones from Garcinia mangostana with Multifunctional Activities for the Therapy of Alzheimer's Disease.

Natural xanthones have diversity pharmacological activities. Here, a series of xanthones isolated from the pericarps of Garcinia mangostana Linn, named α-Mangostin, 8-Deoxygartanin, Gartanin, Garciniafuran, Garcinone C, Garcinone D, and γ-Mangostin were investigated. Biological screening performed in vitro and in Escherichia coli cells indicated that most of the xanthones exhibited significant inhibition of self-induced ß-amyloid (Aß) aggregation and also ß-site amyloid precursor protein-cleaving enzyme 1, acted as potential antioxidants and biometal chelators. Among these compounds, α-Mangostin, Gartanin, Garcinone C and γ-Mangostin showed better antioxidant properties to scavenge Diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) free radical than Trolox, and potent neuroprotective effects against glutamate-induced HT22 cell death partly by up-regulating HO-1 protein level and then scavenging reactive oxygen species. Moreover, Gartanin, Garcinone C and γ-Mangostin could be able to penetrate the blood-brain barrier (BBB) in vitro. These findings suggest that the natural xanthones have multifunctional activities against Alzheimer's disease (AD) and could be promising compounds for the therapy of AD.

Berberine protects homocysteic acid-induced HT-22 cell death: involvement of Akt pathway.

Berberine (BBR), one of the major constituents of Chinese herb Rhizoma coptidis, has been reported to exert beneficial effects to various diseases, including Alzheimer's disease (AD). In the present work, we aimed to investigate the effects of BBR on neuronal cell death induced by homocysteic acid (HCA), which was considered as a risk of AD. BBR significantly reduced HCA-induced reactive oxygen species (ROS) generation, lactate dehydrogenase release and subsequent cell death. LY294002, the PI3K inhibitor, blocked the protection as well as the up-regulation of Akt phosphorylation of BBR. Taken together, our results indicate that BBR protects HCA-induced HT-22 cell death partly via modulating Akt pathway, suggesting BBR may be a promising therapeutic agent for the treatment of HCA-related diseases, including AD.

Systematic Investigation of the Physical and Electrochemical Characteristics of the Vanadium (III) Acidic Electrolyte With Different Concentrations and Related Diffusion Kinetics.

Owing to the lack of systematic kinetic theory about the redox reaction of V(III)/V(II), the poor electrochemical performance of the negative process in vanadium flow batteries limits the overall battery performance to a great extent. As the key factors that influence electrode/electrolyte interfacial reactivity, the physicochemical properties of the V(III) acidic electrolyte play an important role in the redox reaction of V(III)/V(II), hence a systematic investigation of the physical and electrochemical characteristics of V(III) acidic electrolytes with different concentrations and related diffusion kinetics was conducted in this work. It was found that the surface tension and viscosity of the electrolyte increase with increasing V(III) concentration, while the corresponding conductivity shows an opposite trend. Both the surface tension and viscosity change slightly with increasing concentration of H2SO4, but the conductivity increases significantly, indicating that a lower V(III) concentration and a higher H2SO4 concentration are conducive to the ion transfer process. The electrochemical measurements further show that a higher V(III) concentration will facilitate the redox reaction of V(III)/V(II), while the increase in H2SO4 concentration only improves the ion transmission and has little effect on the electron transfer process. Furthermore, the diffusion kinetics of V(III) have been further studied with cyclic voltammetry and chronopotentiometry. The results show that an elevated temperature facilitates the V(III)/V(II) redox reaction and gives rise to an increased electrode reaction rate constant (k s) and diffusion coefficient [D V(III)]. On this basis, the diffusion activation energy (13.7 kJ·mol-1) and the diffusion equation of V(III) are provided to integrate kinetic theory in the redox reaction of V(III)/V(II).

Construction of multifunctional electrochemical sensor based on electroactivity-adjustable poly (ionic liquids)/reduced graphene oxide.

In this article, a novel electroactivity-adjustable poly (ionic liquids)/reduced graphene oxide (PIL-GP) was developed and utilized for the fabrication of multifunctional, high stable electrochemical sensors. The structure, morphology and surface charge properties of PIL-GP have been systematically studied. And the selective detection performance of dopamine (DA) on PIL-GP modified glassy carbon electrode (GCE) were further explored by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). More importantly, by virtue of the anion exchange property of PIL, electroactive Fe(CN)63-/PIL-GP/GCE and Polyoxometalates (PWA)/PIL-GP/GCE were easily fabricated and their electrochemical detection performance of ascorbic acid (AA) and bromate were investigated respectively. The results showed that PIL-GP/GCE based electrochemical sensors provided higher sensitivity, lower detection limits and outstanding anti-interference ability in certain detection system. It was indicated that this general approach to construct electroactivity-adjustable sensors with various electroactive anions possessed a broad application prospect.