Modern research has revealed that dietary consumption of flavonoids and flavonoids-rich foods significantly improve cognitive capabilities, inhibit or delay the senescence process and related neurodegenerative disorders including Alzheimer’s disease (AD). The flavonoids rich foods such as green tea, cocoa, blue berry and other foods improve the various states of cognitive dysfunction, AD and dementia-like pathological alterations in different animal models. The mechanisms of flavonoids have been shown to be mediated through the inhibition of cholinesterases including acetylcholinesterase (AChE), and butyrylcholinesterase (BChE), β-secretase (BACE1), free radicals and modulation of signaling pathways, that are implicated in cognitive and neuroprotective functions. Flavonoids interact with various signaling protein pathways like ERK and PI3-kinase/Akt and modulate their actions, thereby leading to beneficial neuroprotective effects. Moreover, they enhance vascular blood flow and instigate neurogenesis particularly in the hippocampus. Flavonoids also hamper the progression of pathological symptoms of neurodegenerative diseases by inhibiting neuronal apoptosis induced by neurotoxic substances including free radicals and β-amyloid proteins (Aβ). All these protective mechanisms contribute to the maintenance of number, quality of neurons and their synaptic connectivity in the brain. Thus flavonoids can thwart the progression of age-related disorders and can be a potential source for the design and development of new drugs effective in cognitive disorders.

BackgroundThe medicinal importance of a novel plant Olax nana Wall. ex Benth. (family: Olacaceae) was revealed for the first time via HPLC-DAD finger printing, qualitative phytochemical analysis, antioxidant, cholinesterase, and α-glucosidase inhibitory assays.MethodsThe crude methanolic extract of O. nana (ON-Cr) was subjected to qualitative phytochemical analysis and HPLC-DAD finger printing. The antioxidant potential of ON-Cr was assessed via 1,1-diphenyl,2-picrylhydrazyl (DPPH), 2,2-azinobis[3-ethylbenzthiazoline]-6-sulfonic acid (ABTS) and hydrogen peroxide (H2O2) free radical scavenging assays. Furthermore, acetylcholinesterase (AChE) & butyrylcholinesterase (BChE) inhibitory activities were performed using Ellman’s assay, while α- glucosidase inhibitory assay was carried out using a standard protocol.ResultsThe qualitative phytochemical analysis of ON-Cr revealed the presence of secondary metabolites like alkaloids, flavonoids, tannins, sterols, saponins and terpenoids. The HPLC-DAD finger printing revealed the presence of 40 potential compounds in ON-Cr. Considerable anti-radical activities was revealed by ON-Cr in the DPPH, ABTS and H2O2 free radical scavenging assays with IC50 values of 71.46, 72.55 and 92.33 μg/mL, respectively. Furthermore, ON-Cr showed potent AChE and BChE inhibitory potentials as indicated by their IC50 values of 33.2 and 55.36 μg/mL, respectively. In the α-glucosidase inhibition assay, ON-Cr exhibited moderate inhibitory propensity with an IC50 value of 639.89 μg/mL.ConclusionsThis study investigated Olax nana for the first time for detailed qualitative phytochemical tests, HPLC-DAD finger printing analysis, antioxidant, anticholinesterase and α-glucosidase inhibition assays. The antioxidant and cholinesterase inhibitory results were considerable and can provide scientific basis for further studies on the neuroprotective and anti-Alzheimer’s potentials of this plant. ON-Cr may further be subjected to fractionation and polarity guided fractionation to narrow down the search for isolation of bioactive compounds.

The family Polygonaceae is known for its traditional use in the management of various neurological disorders including Alzheimer’s disease (AD). In search of new anti-AD drugs, β-sitosterol isolated from Polygonum hydropiper was subjected to in vitro, in vivo, behavioral and molecular docking studies to confirm its possibility as a potential anti-Alzheimer’s agent. The in vitro AChE, BChE inhibitory potentials of β-sitosterol were investigated following Ellman’s assay. The antioxidant activity was tested using DPPH, ABTS and H2O2 assays. Behavioral studies were performed on a sub-strain of transgenic mice using shallow water maze (SWM), Y-maze and balance beam tests. β-sitosterol was tested for in vivo inhibitory potentials against cholinesterase’s and free radicals in the frontal cortex (FC) and hippocampus (HC). The molecular docking study was performed to predict the binding mode of β-sitosterol in the active sites of AChE and BChE as inhibitor. Considerable in vitro and in vivo cholinesterase inhibitory effects were observed in the β-sitosterol treated groups. β-sitosterol exhibited an IC50 value of 55 and 50 μg/ml against AChE and BChE respectively. Whereas, the activity of these enzymes were significantly low in FC and HC homogenates of transgenic animals. Molecular docking studies also support the binding of β-sitosterol with the target enzyme and further support the in vitro and in vivo results. In the antioxidant assays, the IC50 values were observed as 140, 120, and 280 μg/ml in the DPPH, ABTS and H2O2 assays respectively. The free radicals load in the brain tissues was significantly declined in the β-sitosterol treated animals as compared to the transgenic-saline treated groups. In the memory assessment and coordination tasks including SWM, Y-maze and balance beam tests, β-sitosterol treated transgenic animals showed gradual improvement in working memory, spontaneous alternation behavior and motor coordination. These results conclude that β-sitosterol is a potential compound for the management of memory deficit disorders like AD.

Co3O4 nanocube-doped chitosan-grafted-polyaniline nanocomposites have been successfully synthesised. The synthesised polymeric nanocomposite was stable and exhibits greater photocatalytic activity to degrade MB efficiently within a short duration of time.

This work demonstrates the high performance graphene oxide (GO)/PEDOT:PSS doubled decked hole transport layer (HTL) in the PCDTBT:PC71BM based bulk heterojunction organic photovoltaic device. The devices were tested on merits of their power conversion efficiency (PCE), reproducibility, stability and further compared with the devices with individual GO or PEDOT:PSS HTLs. Solar cells employing GO/PEDOT:PSS HTL yielded a PCE of 4.28% as compared to either of individual GO or PEDOT:PSS HTLs where they demonstrated PCEs of 2.77 and 3.57%, respectively. In case of single GO HTL, an inhomogeneous coating of ITO caused the poor performance whereas PEDOT:PSS is known to be hygroscopic and acidic which upon direct contact with ITO reduced the device performance. The improvement in the photovoltaic performance is mainly ascribed to the increased charge carriers mobility, short circuit current, open circuit voltage, fill factor, and decreased series resistance. The well matched work function of GO and PEDOT:PSS is likely to facilitate the charge transportation and an overall reduction in the series resistance. Moreover, GO could effectively block the electrons due to its large band-gap of ~3.6 eV, leading to an increased shunt resistance. In addition, we also observed the improvement in the reproducibility and stability.

Green synthesis and biological activities of gold nanoparticles functionalized with Salix alba, Arabian Journal of Chemistry (2015), doi: http://dx. Abstract:This study reports a facile and reproducible green extracellular synthetic route of highly stable gold nanoparticles. The aqueous gold ions when exposed to Salix alba L. leaves extract were bioreduced and resulted in the biosynthesis of gold nanoparticles (Au-WAs). The nanoparticles were characterized by UV-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and scanning electron microscopy (SEM).Their stability was evaluated against varying volumes of pH and sodium chloride as well as at elevated temperature along with enzymes inhibition, antibacterial, antifungal, anti-nociceptive, muscle relaxant and sedative activities. The UV-Vis spectra of the gold nanoparticles gave surface plasmon resonance at 540 nm while the AFM and SEM nanoparticles analyses revealed the particle size of 63 nm and 50-80 nm respectively. FTIR spectra confirmed the involvement of amines, amide and aromatic groups in capping and reduction of the gold nanoparticles. Au-WAs showed remarkable stability in different volumes of salt and various pH solutions however, AuWAs were relatively unstable at elevated temperature. Au-WAs possessed good antifungal activity and showed significant antinociceptive and muscle relaxant properties. These results revealed that the leaves extract of Salix alba is a very good bio-reductant for the synthesis of gold nanoparticles that have potential for various biomedical and pharmaceutical applications.

We report a facile one-pot hydrothermal synthesis of reduced graphene oxide-cobalt oxide nanocubes@platinum (rGO-Co 3 O 4 @Pt) nanocomposite and its application toward the electrochemical detection of nitric oxide (NO). The rGO-Co 3 O 4 @Pt nanocomposite was characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) mapping, X-ray diffraction (XRD) and Raman analyses. The nanocomposite modified glassy carbon (GC) electrode was used for the electrochemical oxidation of nitric oxide (NO) and it showed better catalytic performance in terms of catalytic peak current and shift in overpotential when compared to rGO, Co 3 O 4 nanocubes and rGO-Co 3 O 4 nanocomposite modified electrodes. The rGO-Co 3 O 4 @Pt nanocomposite modified electrode showed a better sensing ability toward the in-situ generated NO in NO 2 containing phosphate buffer solution (PBS) than the other controlled modified electrodes. The Pt nanoparticles present in the nanocomposite could enhance the sensing performance and the limit of detection (LOD) was found as 1.73 µM with signal-to-noise (S/N) ratio ~3 using amperometric i-t curve. Further, the nanocomposite modified electrode showed the selectivity toward the detection of NO in the presence of 100-fold higher concentration of other physiologically important analytes. The proposed sensor was stable, reproducible and selective toward the detection of NO.

Cobalt oxide nanocubes incorporated reduced graphene oxide prepared by hydrothermal method and used for the electrocatalytic oxidation of methanol. AbstractHerein, we report a facile hydrothermal method for the preparation of cobalt oxide nanocubes incorporated reduced graphene oxide (rGO-Co 3 O 4 nanocubes) for electrocatalytic oxidation of methanol. The synthesized rGO-Co 3 O 4 nanocubes were characterized using transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Raman techniques. The electrochemical behavior of rGO-Co 3 O 4 nanocubes modified electrode was studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The electrocatalytic performances of rGO-Co 3 O 4 nanocube-modified electrodes with different wt. % of GO were investigated in relation to methanol oxidation in an alkaline medium. The rGO-Co 3 O 4 nanocubes modified electrode showed enhanced current density due to oxidation of methanol when compared to the bare Pt, rGO, and Co 3 O 4 nanocubes modified electrodes. The optimal GO content for an rGO-Co 3 O 4 nanocube-modified electrode to achieve a high electrocatalytic oxidation of methanol was 2 wt. %, and it showed an anodic peak current density of 362 µA/cm 2 . IntroductionThe constantly increasing energy demand due to the depletion of conventional fossil fuel reserves and the rapid growth of environmental issues have led to search for alternative power sources. 1,2 These include direct methanol fuel cells (DMFCs) as alternative green, environmentally friendly, and sustainable power sources that can directly convert the chemical energy of methanol into electrical energy. 3,4 A polycrystalline Pt electrode is the most commonly used electrode material in DMFCs. However, its high cost, rarity, low power density, and poor CO-poisoning tolerance significantly hinder their commercialization and practical application. 5,6 In order to reach a high power density and low production cost for DMFCs, well-designed and fabricated high-performance electrocatalysts with controlled compositions and morphologies have been emerged as a key point for realizing high device performance. 5,6 In this area, carbon-based nanomaterials, including activated carbon, carbon nanotubes (SWCNT, DWCNT, MWCNT), GO, and rGO have enormous potential to boost the performance of DMFCs. 3,7,8 Among these, graphene plays a crucial role in the fabrication of advanced composite/hybrid electrocatalysts for high performance DMFCs because of its unique physicochemical properties, including a high specific surface area, superior electronic conductivity, and excellent stability. 8-13 Several attempts have been made to apply metal and metal oxide nanomaterials incorporated graphene modified electrodes in DMFC applications to attain a high power density. 14,15 Metal oxide incorporated graphene composite gained tremendous attention because of their low-cost, facile synthesis, high electrocatalytic activity, and durability in DMFC application...