Extracts from Acacia catechu suppress HIV-1 replication by inhibiting the activities of the viral protease and Tat

Background: Acacia catechu (Mimosa family) stem bark extracts have been used traditionally as a dietary supplement as well as a folk medicine given its reported anti-inflammatory, immunomodulatory, hepatoprotective, antioxidant, anti-microbial and anti-tumor activities. The present study was undertaken to evaluate the anti-HIV-1 activity of the extracts from stem bark of A. catechu. Methods. The aqueous and 50% ethanolic extracts of A. catechu stem bark were prepared and 50% ethanolic extract was further fractioned by successively partitioning with petroleum ether, chloroform and n-butanol. All the extracts and fractions were evaluated for cytotoxicity and anti-HIV-1 activity using different in vitro assays. The active n-butanol fraction was evaluated for its inhibition against HIV-1 reverse transcriptase, integrase, protease, pro-viral genome integration and viral Tat protein mediated transactivation. The effect of n-butanol fraction on the induction of pro-inflammatory cytokines secretion in Vk2/E6E7 cells and transepithelial resistance in Caco-2 and HEC-1A cells was investigated. Results: The aqueous and 50% ethanolic extracts of A. catechu showed IC§ssub§50§esub§ values of 1.8 ± 0.18 μg/ml and 3.6 ± 0.31 μg/ml, respectively in cell-free virus based assay using TZM-bl cells and HIV-1§ssub§NL4.3§esub§ (X-4 tropic). In the above assay, n-butanol fraction exhibited anti-HIV-1 activity with an IC§ssub§50§esub§ of 1.7 ± 0.12 μg/ml. The n-butanol fraction showed a dose-dependent inhibition against HIV-1§ssub§NL4.3§esub§ infection of the peripheral blood lymphocytes and against HIV-1§ssub§BaL§esub§(R-5-tropic) as well as two different primary viral isolates of HIV-1 infection of TZM-bl cells. The n-butanol fraction demonstrates a potent inhibitory activity against the viral protease (IC§ssub§50§esub§ = 12.9 μg/ml), but not reverse transcriptase or integrase. Further, in Alu-PCR no effect on viral integration was observed. The n-butanol fraction interfered with the Tat-mediated Long Terminal Repeat transactivation in TZM-bl cells, mRNA quantitation (qRT-PCR) and electrophoretic mobility shift assay (EMSA). The n-butanol fraction did not cause an enhanced secretion of pro-inflammatory cytokines in Vk2/E6E7 cells. Additionally, no adverse effects were observed to the monolayer formed by the Caco-2 and HEC-1A epithelial cells. Conclusions: The results presented here show a potential anti-HIV-1 activity of A. catechu mediated by the inhibition of the functions of the viral protein and Tat. © 2013 Nutan et al.; licensee BioMed Central Ltd

Down-Regulation of NDRG1 Promotes Migration of Cancer Cells during Reoxygenation

One characteristic of tumor microenvironment is oxygen fluctuation, which results from hyper-proliferation and abnormal metabolism of tumor cells as well as disorganized neo-vasculature. Reoxygenation of tumors can induce oxidative stress, which leads to DNA damage and genomic instability. Although the cellular responses to hypoxia are well known, little is known about the dynamic response upon reoxygenation. In order to investigate the transcriptional responses of tumor adaptation to reoxygenation, breast cancer MCF-7 cells were cultured under 0.5% oxygen for 24 h followed by 24 h of reoxygenation in normoxia. Cells were harvested at 0, 1, 4, 8, 12, and 24 h during reoxygenation. The transcriptional profile of MCF-7 cells upon reoxygenation was examined using Illumina Human-6 v3 BeadChips. We identified 127 differentially expressed genes, of which 53.1% were up-regulated and 46.9% were down-regulated upon reoxygenation. Pathway analysis revealed that the HIF-1-alpha transcription factor network and validated targets of C-MYC transcriptional activation were significantly enriched in these differentially expressed genes. Among these genes, a subset of interest genes was further validated by quantitative reverse-transcription PCR. In particular, human N-MYC down-regulated gene 1 (NDRG1) was highly suppressed upon reoxygenation. NDRG1 is associated with a variety of stress and cell growth-regulatory conditions. To determine whether NDRG1 plays a role in reoxygenation, NDRG1 protein was overexpressed in MCF-7 cells. Upon reoxygenation, overexpression of NDRG1 significantly inhibited cell migration. Our results revealed the dynamic nature of gene expression in MCF-7 cells upon reoxygenation and demonstrated that NDRG1 is involved in tumor adaptation to reoxygenation

Synthesis and characterization of CdS and CdSe nanoparticles prepared from novel intramolecularly stabilized single-source precursors

In this note we describe the synthesis of cadmium sulphide and selenide nanoparticles from the corresponding novel single source precursors, M[E(Ox)](2) [E = S (1), Se (2); M = Cd; Ox = 2-(4,4-dimethyl-2- oxazolinyl)benzene] by thermolysing in tri-n-octylphosphine oxide (TOPO) at 280 degrees C, and their characterization by X-ray powder diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM) studies

Synthesis, characterization and molecular structures of monomeric selenolato complexes of mercury with nitrogen-containing chelating ligands

Intramolecularly stabilized divalent mercury selenolates of empirical formula Hg(SeR)(2) [R = 2-Me(2)NCH(2)C(6)H(4) 1, (S)-2-Me(2)NCHMeC(6)H(4)2,(R,S)-(C5H5)Fe(2-Me(2)NCHMeC(5)H(3)) 3 and (S,R)-(C5H5)Fe(2-Me(2)NCHMeC(5)H(3)) 4] have been synthesized in high yield by treating the corresponding diselenides with elemental mercury. The compounds show excellent solubility in non-polar solvents. They were characterized by elemental analysis, H-1, C-13, Se-77 NMR, IR, Fourier-transform Raman and mass spectral techniques. The single-crystal structures of 1 and 4 were determined. Both are monomeric and the Hg atom is four-co-ordinate, being bound to a pair of chelating aminoselenolate ligands with both the six-membered rings having Se-Hg-N co-ordination adopting an envelope conformation. The bond configuration about Hg in 1 can be approximated to distorted tetrahedral, while in 4 it is more square planar with the two Se atoms being mutually trans and the Se-Hg-Se angle 168.6(2)degrees. Compounds 1 and 2 vaporize without decomposition at atmospheric pressure and decompose at higher temperatures to give HgSe while 3 decomposes to HgSe

Time response and stability of porous silicon capacitive immunosensors

The time response of affinity sensors made with nanostructured materials is a topic of considerable interest, since affinity sensors made with nanostructured materials provide greater sensitivities than corresponding planar crystalline devices but at the cost of stability and drift. We present a study of the time response of capacitive immunosensors made using porous silicon and ultrathin room temperature anodic oxide. It was found that sensor drift can be substantial but can be reduced by subjecting the capacitive immunosensor in buffer to an anodic bias that is larger than the bias at which sensor capacitance is measured. By measuring sensor response before the addition of the analyte and using it for baseline correction after addition of the analyte, the effect of nonspecific sensor drift can be further reduced. We observed that after the addition of the analyte to the porous silicon immunocapacitor, there is a fast decrease in capacitance (order of tens of seconds) followed by a slow increase (order of tens of minutes), which models well as a sum of exponents with a fast exponential decay followed by a slow exponential rise. Possible processes that can give rise to such a response are perturbations of the double layer for the fast decay and column resistance switching for the slow rise. (c) 200

Synthesis, structure and reactions of the first tellurium-containing macrocyclic Schiff base

The condensation of bis(2-formylphenyl) telluride 1 with ethane-1,2-diamine yielded the novel macrocyclic tellurium ligand 2 via metal-free dimerisation. Crystals of 2 are triclinic, space group with a = 7.956(3), b = 9.885(2), c = 1.068(2) Angstrom, Z = 1. Hydrogenation of macrocycle 2 provided the corresponding saturated tetraazamacrocycle 3, protonation of which with HBr afforded 4. The co-ordination chemistry of 2 has been studied with 'soft' metal ions such as palladium(II) and mercury(II). N,N'-Bis[(2-chloroteIluranyl)benzylidene]ethane-1,2-diamine has also been characterised by an X-ray diffraction study, with triclinic space group , a = 7.71(1), b = 7.90(1), c = 8.52(1) Angstrom and Z = 1

The influence of aluminium sources on the acidic behaviour as well as on the catalytic activity of mesoporous H-AlMCM-41 molecular sieves

A series of mesoporous molecular sieves (AIMCM-41) were synthesized with varying silicon-to-aluminium ratios and using three different aluminium sources, viz., sodium aluminate, aluminium isopropoxide and aluminium. sulphate. The samples were characterized systematically using XRD, TG-DTA, BET surface area, and ICP-AES. In addition, the extent of framework substitution as well as the nature of acid sites was deduced employing Al-27 MAS-NMR, pyridine FT-IR, and NH3-TPD methods. These studies indicate that in case of samples prepared with sodium aluminate, most of the aluminium existed in tetrahedral positions even after calcination. Also, such samples posses moderate-to-strong (Bronsted) acid sites along with small amounts of structural as well as non-framework Lewis acid sites. The density of non-framework acid sites depended upon the source of aluminium following a trend in the order of sodium aluminate < aluminium sulphate < aluminium isopropoxide. Among the various catalysts investigated, those having a silicon-to-aluminium ratio of around 60 irrespective of aluminum sources exhibited highest conversion and good selectivity for vapour phase tertiary-butylation of phenol. This characteristic is attributed to the presence of larger number of moderate-to-strong acid sites and a smaller number of Lewis acid sites. (C) 200

Deposition of hydrogenated amorphous carbon films with enhanced sp3-C bonding on nanocrystalline palladium interlayer

The present study deals with the deposition of hydrogenated amorphous carbon (a-C:H) films on Si (100) substrates with and without an interlayer of nanocrystalline palladium (nc-Pd) on them, by high-voltage electro-dissociation of N,N-dimethyl formamide (DMF). Significant improvement in the sp3 carbon content has been observed for a-C:H films grown on nc-Pd interlayer as revealed by Fourier transformed infrared (FTIR), Raman, X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopic techniques. It is inferred that H2 activation on palladium sites leads to the stabilization of sp3-C bonding, thereby improving the quality of the deposits grown on them.© Elsevie