Chemopreventive effects of diverse dietary phytochemicals against DMBA-induced hamster buccal pouch carcinogenesis via the induction of Nrf2-mediated cytoprotective antioxidant, detoxification, and DNA repair enzymes.

Identifying agents that activate nuclear factor erythroid-2 related factor-2 (Nrf2), a key regulator of various cytoprotective antioxidant, and detoxifying enzymes has evolved as a promising strategy for cancer chemoprevention. In the present study, we investigated the effect of dietary supplementation of structurally diverse phytochemicals- astaxanthin, blueberry, chlorophyllin, ellagic acid, and theaphenon-E on Nrf2 signaling, and xenobiotic-metabolizing and antioxidant enzymes in the 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis model. We observed that these phytochemicals induce nuclear accumulation of Nrf2 while downregulating its negative regulator, Keap-1. This was associated with reduced expression of CYP1A1 and CYP1B1, the cytochrome P450 isoforms involved in the activation of DMBA, and the oxidative stress marker 8-hydroxy-2'-deoxyguanosine coupled with upregulation of the phase II detoxification enzymes glutathione S-transferases and NAD(P)H:quinone oxidoreductase 1 and the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase. In addition, these dietary phytochemicals also enhanced the DNA repair enzymes 8-oxoguanine glycosylase 1 (OGG1), xeroderma pigmentosum D (XPD), xeroderma pigmentosum G (XPG), and x-ray repair cross complementing group 1 (XRCC1). Our data provide substantial evidence that the dietary phytochemicals inhibit the development of HBP carcinomas through the activation of Nrf2/Keap-1 signaling and by upregulating cytoprotective enzymes. The extent of the chemopreventive effects of the phytochemicals was in the order: chlorophyllin > blueberry > ellagic acid > astaxanthin > theaphenon-E. Thus these dietary phytochemicals that function as potent activators of Nrf2 and its orchestrated response are novel candidates for cancer chemoprevention.

Dietary chlorophyllin inhibits the canonical NF-κB signaling pathway and induces intrinsic apoptosis in a hamster model of oral oncogenesis.

Chlorophyllin, a water-soluble, semi-synthetic derivative of the ubiquitous green pigment chlorophyll is shown to exert potent anticarcinogenic effects. In the present study, we investigated the chemopreventive effects of chlorophyllin on 7,12-dimethylbenz(a)anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis by analyzing the expression of NF-κB family members and markers of intrinsic apoptosis. Dietary administration of chlorophyllin (4 mg/kg bw) suppressed the development of HBP carcinomas by inhibiting the canonical NF-κB signaling pathway by downregulating IKKß, preventing the phosphorylation of IκB-α, and reducing the expression of nuclear NF-κB. Inactivation of NF-κB signaling by chlorophyllin was associated with the induction of intrinsic apoptosis as evidenced by modulation of Bcl-2 family proteins, enforced nuclear localization of survivin, upregulation of apoptogenic molecules, activation of caspases, and cleavage of PARP. The results of the present study demonstrate that chlorophyllin inhibits the development of DMBA-induced HBP carcinogenesis by targeting NF-κB and the intrinsic apoptotic pathway. Thus, dietary agents such as chlorophyllin that simultaneously target divergent pathways of cell survival and cell death are novel candidates for cancer chemoprevention.

Modulation of lipopolysaccharide-induced pro-inflammatory mediators by an extract of Glycyrrhiza glabra and its phytoconstituents.

OBJECTIVE: To evaluate the inhibitory property of de-glycyrrhizinated extract of Glycyrrhiza glabra root and its phytoconstituents (glabridin, isoliquiritigenin and glycyrrhizin) on LPS-induced production of pro-inflammatory mediators. MATERIALS AND METHODS: Inhibitory effect of G. glabra extract and its phytoconstituents were studied on lipopolysaccharide (LPS)-induced nitric oxide (NO), interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) levels in J774A.1 murine macrophages. RESULTS: G. glabra and isoliquiritigenin significantly inhibited LPS stimulated NO, IL-1 beta and IL-6 production. Glabridin showed significant inhibition of NO and IL-1 beta release, but failed to attenuate IL-6 levels at the tested concentrations. In addition, glycyrrhizin did not exhibit inhibitory response towards any of the LPS-induced pro-inflammatory mediators at the tested concentrations. CONCLUSION: From the results we speculate that the inhibitory effect of G. glabra extract on LPS-induced pro-inflammatory mediators is influenced by glabridin and isoliquiritigenin and is not contributed by glycyrrhizin.

Dual inhibitory effect of Glycyrrhiza glabra (GutGard™) on COX and LOX products.

Glycyrrhiza glabra and its phytoconstituents have been known to possess widespread pharmacological properties as an anti-inflammatory, anti-viral, antitumour and hepatoprotective drug. In this study, we examined the inhibitory potential of extract of G. glabra (GutGard™) root and its phytoconstituents (glabridin, glycyrrhizin, and isoliquiritigenin) on both cyclooxygenase (COX) and lipoxygenase (LOX) products in order to understand the mechanism of its anti-inflammatory action. Inhibitory effect of GutGard™ and its phytoconstituents on lipopolysaccharide (LPS) induced prostaglandin E(2) (PGE(2)), calcimycin (A23187) induced thromboxane (TXB(2)), and leukotriene (LTB(4)) release was studied using murine macrophages (J774A.1) and human neutrophil (HL-60) cells. Results revealed that, G. glabra and glabridin significantly inhibited PGE(2), TXB(2) (COX) and LTB(4) (LOX), while, isoliquiritigenin exerted inhibitory effect only against COX products but failed to suppress LOX product. However, glycyrrhizin at the tested concentrations failed to exhibit inhibitory effect on both COX and LOX products. Here, we report for the first time that G. glabra (almost devoid of glycyrrhizin) exhibits anti-inflammatory property likely through the inhibition of PGE(2), TXB(2) and LTB(4) in mammalian cell assay system, which could be influenced in part by glabridin and isoliquiritigenin.

In vitro modulation of LPS/calcimycin induced inflammatory and allergic mediators by pure compounds of Andrographis paniculata (King of bitters) extract.

The aim of the current study is to probe the anti-inflammatory/anti-allergic potential of seven phytoconstituents (andrographolide, neoandrographolide, isoandrographolide, andrograpanin, 14-deoxy-11,12-didehydroandrographolide, 7-O-methylwogonin and skullcapflavone-I) isolated from Andrographis paniculata (King of bitters) on the production of key inflammatory/allergic mediators (NO, PGE(2), IL-1 beta, IL-6, LTB(4), TXB(2) and histamine). The results demonstrated that andrographolide, isoandrographolide, 7-O-methylwogonin and skullcapflavone-I significantly inhibited LPS stimulated NO and PGE(2) release in J774A.1 macrophages. Andrographolide, isoandrographolide and 7-O-methylwogonin showed considerable inhibition of IL-1 beta production in LPS elicited macrophages. LPS induced IL-6 production was significantly inhibited by andrographolide, isoandrographolide and skullcapflavone-I in a concentration dependent manner. The results revealed that andrographolide, isoandrographolide and skullcapflavone-I significantly decreased TXB(2) release in A23187 activated HL-60 promyelocytic cells. Furthermore, the anti-allergic properties of the phytoconstituents was investigated on A23187 induced LTB(4) production (HL-60 cells) and histamine release (RBL-2H3 basophilic cells). The results showed that only skullcapflavone-I and 7-O-methylwogonin showed marked inhibitory effect on LTB(4) production, however, only 7-O-methylwogonin exerted dose-dependent inhibition towards histamine release. Therefore, this study indicates that some of these phytoconstituents exhibit potent anti-inflammatory/anti-allergic effects by modulating different inflammatory/allergic mediators. Hence, these phytoconstituents might provide useful phytomedical treatment against variety of inflammatory and allergic disorders.

Solvent-free fabrication of rare LaCO3OH luminescent superstructures.

Lanthanum hydroxycarbonate (LaCO(3)OH) superstructures [LHS] decorated with carbon spheres are synthesized by a solvent-free, one-pot Reactions under Autogenic Pressure at Elevated Temperature (RAPET) process, dissociating a single lanthanum acetate hydrate (LAH) precursor. The structure of the as-synthesized LHS are studied by powder X-ray diffraction, high-resolution transmission electron microscopy, morphology by field-emission scanning electron microscopy, and the composition by energy dispersive X-ray analysis, elemental mapping, as well as FT-IR spectroscopy. The photoluminescence results showed an emission band centered at 465 nm (lambda = exc. 360 nm) for the hexagonal phase of LHS. The mechanistic elucidation for the fabrication of LaCO(3)OH decorated with carbon spheres is developed on the basis of obtained thermal [TGA and DTA] data on initial LAH reactant.

Superconducting nanocrystalline tin protected by carbon.

Nanosized pure Sn crystals protected by in situ formed carbon synthesized by the thermolysis of allyltriphenyltin in an inert atmosphere under its autogenic pressure in closed reactor showed superconductivity at 3.7 K.

Evaluation of the genotoxic potential and acute oral toxicity of standardized extract of Andrographis paniculata (KalmCold).

Andrographis paniculata is used in the traditional medicine for cold and influenza remedy. The main endeavor in this study was to assess the genotoxicity of the standardized extract of A. paniculata (KalmCold) through three different in vitro tests: Ames, chromosome aberration (CA), and micronucleus (MN). Ames test was performed at 5000 microg/ml, 1581 microg/ml, 500 microg/ml, 158 microg/ml, 50 microg/ml, 16 microg/ml, while the clastogenicity tests were performed at 80 microg/ml, 26.6 microg/ml, 8.8 microg/ml for short-term treatment without S9; 345 microg/ml, 115 microg/ml, 38.3 microg/ml for short-term treatment with S9; and 46 microg/ml, 15.3 microg/ml, 5.1 microg/ml for long-term without S9 using DMSO as a vehicle control. Results of Ames test confirmed that KalmCold did not induce mutations both in the presence and absence of S9 in Salmonella typhimurium mutant strains TA98 and TAMix. In CA and MN, KalmCold did not induce clastogenicity in CHO-K1 cells in vitro. Based on our results, it is evident that KalmCold is genotoxically safe. Additionally in acute oral toxicity study, female rats were treated at 5000 mg/kg of KalmCold and observed for signs of toxicity for 14 days. KalmCold did not produce any treatment-related toxic effects in rats.

Methodical thermolysis of [Ba2Ti2(thd)4(OnPr)8(nPrOH)2] under autogenous pressure followed by combustion for the synthesis of dielectric tetragonal BaTiO3 nanopowder.

The tetragonal BaTiO(3) nanopowder is synthesized in a solvent-less, efficient process by the thermolysis of a single [Ba(2)Ti(2)(thd)(4)(OnPr)(8)(nPrOH)(2)] precursor in a closed reactor at 700 degrees C under autogenous pressure, followed by combustion. This paper compiles the synthesis of the [Ba(2)Ti(2)(thd)(4)(OnPr)(8)(nPrOH)(2)] precursor, its analysis by mass spectrometry, and implementation for the fabrication of dielectric tetragonal BaTiO(3) nanopowder by controlled efficient thermal decomposition. The as-prepared, intermediate, and final forms of the obtained nanomaterials are systematically analysed by XRD, Raman, and EDS measurements to gain structural and compositional information. Employing HR-SEM, TEM, and HR-TEM techniques, the morphological changes during the structural evolution of all the phases are pursued. The mechanistic elucidation for the fabrication of BaTiO(3) nanopowder is developed on the basis of TGA and DTA data obtained for the initial [Ba(2)Ti(2)(thd)(4)(OnPr)(8)(nPrOH)(2)] reactant as well as the as-prepared BaCO(3) with amorphous Ti phase.

Synthesis of new red-emitting single-phase europium oxycarbonate.

A fascinating one-pot solvent-, catalyst-, and template-free synthesis process to facilitate a single-phase crystalline hexagonal type-II luminescent Eu(2)O(2)CO(3) organization comprised of nanoplates is demonstrated. The thermolysis (700 degrees C) of europium acetate in a closed stainless steel reactor under autogenic pressure [approximately 3 MPa] yielded Eu(2)O(2)CO(3) superstructures. Powder X-ray diffraction, high-resolution transmission electron microscopy, and Raman measurements confirmed the structure. Fourier transform infrared spectroscopy, energy-dispersive spectrometry, and CHNS analysis verified the composition. Scanning electron microscopy corroborated the morphology of the new Eu(2)O(2)CO(3) compound, and the primary luminescence properties are accounted.

Facile synthesis of novel photoluminescent ZnO micro- and nanopencils.

A single-step solvent-, catalyst-, and template-free synthesis process to prepare photoluminescent pencils of ZnO either in micro- or in nanosize diameters from a single precursor is demonstrated. The thermolysis of Zn's acetate dihydrate (ZAD) precursor in a closed stainless steel reactor at 700 degrees C under autogenic pressure (6.5 MPa), yielded carbon sphere-decorated ZnO micropencils (ZnO-M's). The ZnO-M's have novel room-temperature photoluminescence (PL) with well-defined emission peaks at the green, yellow, orange, and red regions of the visible spectra while suppressing the blue region. On the contrary, the thermolysis of ZAD in a closed stainless steel reactor at 700 degrees C with released pressure yielded uniformly carbon-coated ZnO nanopencils (ZN's). The coated carbon in ZN's quenches the complete UV-vis PL; however, after annealing ZN's at 600 degrees C/2 h in air, the UV PL is dominant, and the visible PL is suppressed. The carbon coating (partly or completely) on the one-dimensional (1D) ZnO surfaces plays an important role to modify PL properties. The insight into the reaction mechanism was gained through in situ mass spectrometry measurements. The as-prepared ZnO-M's and ZN's have been systematically characterized to determine their morphology, structure, and composition.

pH- and temperature-dependent phase behavior of a PEO-PPO-PEO-based pentablock copolymer in aqueous media.

We investigated the structural features of micelles formed by the self-association of the pentablock copolymer poly[ N,N -(diethyl amino)ethyl methacrylate]-block-poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethyleneoxide)-block-poly[ N,N -(diethylamino)ethyl methacrylate] (PDEAEM-PEO-PPO-PEO-PDEAEM) in aqueous solutions by using small-angle neutron scattering SANS. The pentablock copolymer solutions exhibit micellar and gel phases in response to changes in both the temperature and pH by virtue of (1) the lower critical solution temperature of the PPO blocks and (2) the polyelectrolyte character of the pendant PDEAEM blocks. Two modeling schemes were employed to describe the SANS data of semidilute copolymer solutions at higher temperature as they contain interacting charged micelles at pH<7.5 and interacting neutral micelles at higher pH. We have elucidated the structures of the micelles in terms of size, shape, polydispersity, association number, number density, and surface charge. At low pH the charged spherical micelles are less packed with the copolymers presumably due to the electrostatic repulsion between the charged pendant groups. On the other hand, at higher pH the hydrophobic character of the neutral pendant groups enable them to sequester within the micelle core along with the PPO, thus increasing the number density and the core size of the spherical micelles. At higher copolymer concentration reversible thermoresponsive sol-gel transitions were observed at all pH conditions and the rheological behavior of the gels nicely correlates with different organization of micelles with different shapes.

Neutron and X-ray structural studies of short hydrogen bonds in photoactive yellow protein (PYP).

Photoactive yellow protein (PYP) from Halorhodospira halophila is a soluble 14 kDa blue-light photoreceptor. It absorbs light via its para-coumaric acid chromophore (pCA), which is covalently attached to Cys69 and is believed to be involved in the negative phototactic response of the organism to blue light. The complete structure (including H atoms) of PYP has been determined in D(2)O-soaked crystals through the application of joint X-ray (1.1 A) and neutron (2.5 A) structure refinement in combination with cross-validated maximum-likelihood simulated annealing. The resulting XN structure reveals that the phenolate O atom of pCA accepts deuterons from Glu46 O(epsilon2) and Tyr42 O(eta) in two unusually short hydrogen bonds. This arrangement is stabilized by the donation of a deuteron from Thr50 O(gamma1) to Tyr42 O(eta). However, the deuteron position between pCA and Tyr42 is only partially occupied. Thus, this atom may also interact with Thr50, possibly being disordered or fluctuating between the two bonds.

Effect of interfacial interaction on the cross-sectional morphology of tobacco mosaic virus using GISAXS.

We have investigated the effect of the interfacial interaction on the cross-sectional morphology of the tobacco mosaic virus (TMV) in solution and on two types of solid substrates, SiOx (polar) on Si(100) and polystyrene film (nonpolar) on Si(100), using small-angle X-ray scattering (SAXS) and grazing incidence small-angle X-ray scattering (GISAXS), respectively. Results reveal that the flexible chains at the outer surface of TMV either expand or contract depending on the nature of the substrate. Although the unfavorable interaction between the TMV and the PS causes a minimal effect, the stronger attractive interaction between the outer protein surface of TMV and the SiOx substrate induces pronounced deformation of its cross-sectional morphology.

Macroscale assembly of peptide nanotubes.

Simple oligopeptides that self-assemble into homogeneous nanotubes can be directed to further assemble into macroscale parallel arrays through protein "salting out" strategies.

Assembly of tobacco mosaic virus into fibrous and macroscopic bundled arrays mediated by surface aniline polymerization.

One-dimensional (1D) polyaniline/tobacco mosaic virus (TMV) composite nanofibers and macroscopic bundles of such fibers were generated via a self-assembly process of TMV assisted by in-situ polymerization of polyaniline on the surface of TMV. At near-neutral reaction pH, branched polyaniline formed on the surface of TMV preventing lateral association. Therefore, long 1D nanofibers were observed with high aspect ratios and excellent processibility. At a lower pH, transmission electron microscopy (TEM) analysis revealed that initially long nanofibers were formed which resulted in bundled structures upon long-time reaction, presumably mediated by the hydrophobic interaction because of the polyaniline on the surface of TMV. In-situ time-resolved small-angle X-ray scattering study of TMV at different reaction conditions supported this mechanism. This novel strategy to assemble TMV into 1D and 3D supramolecular composites could be utilized in the fabrication of advanced materials for potential applications including electronics, optics, sensing, and biomedical engineering.

Fully reduced ribonuclease A does not expand at high denaturant concentration or temperature.

The dimensions of a denatured protein, fully reduced ribonuclease A (r-RNase A), have been measured using synchrotron-based small angle X-ray scattering. The radius of gyration, 34-35 A, is unchanged from 0-6 M guanidinium chloride and from 20-90 degrees C at pH 2.5, and agrees with the known scaling behavior for a multitude of chemically denatured states. The polypeptide is behaving as a statistical coil in the non-interacting, high-temperature limit.

Dynamics and internal stress at the nanoscale related to unique thermomechanical behavior in polymer nanocomposites.

A small amount of alumina nanoparticles in polymethylmethacrylate causes a sharp depression of the glass transition temperature (Tg) accompanied by a toughening of the composite. We investigated this phenomenon using multispeckle x-ray photon correlation spectroscopy. Measurements reveal a dynamic structure factor that has the form exp[-(t/taua)beta], with beta greater than 1. We show for the first time that beta(T) tracks the internal stress at the polymer-particle interface. The internal stress, which we propose arises due to the entropic penalty that the polymer faces in the presence of the nanoparticles, engenders temporally heterogeneous dynamics. In the jammed glassy state, we show that the dominant fast relaxation mode--taumax--aided by a weak dewetting interface relieves the stress and follows the variations in Tg.

Surfactant copolymers prevent aggregation of heat denatured lysozyme.

We investigated the ability of certain triblock copolymer surfactant poloxamers of the form polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO), to prevent formation of stable aggregates of heat denatured hen egg lysozyme. Differential scanning calorimetry (DSC) and synchrotron small angle x-ray scattering (SAXS) experiments were performed to study the thermodynamics and solution structures of lysozyme at temperatures between 20 and 90 degrees C in the presence and absence of poloxamers with various molecular weights (8.4-14.3 kDa), but similar hydrophile/hydrophobe (PEO:PPO) ratio of 80%. Poloxmer 188 was found to be very effective in preventing aggregation of heat denatured lysozyme and those functioned as a synthetic surfactant, thus enabling them to refold when the conditions become optimal. For comparison, we measured the ability of 8 kDa polyethylene glycol (PEG) to prevent lysozyme aggregation under same conditions. The results of these studies suggest that poloxamers are more efficient than PEG in preventing aggregation of heat denaturated lysozyme. To achieve equivalence, more than an order of magnitude higher concentration of PEG concentration was needed. Apparently, the presence of a hydrophobic segment in the poloxamers increases their ability to target the hydrophobic region of the unfolded proteins and protect them from self association. Given their biocompatibility and the low concentrations at which they effectively facilitate refolding of denatured proteins, they may be useful in the treatment of burns and other conditions resulting in the denaturation of proteins.

Supramolecular self-assembly of multiblock copolymers in aqueous solution.

A unique pH-dependent phase behavior from a copolymer micellar solution to a collapsed hydrogel with micelles ordered in a hexagonal phase was observed. Small-angle neutron scattering (SANS) was used to follow the pH-dependent structural evolution of micelles formed in a solution of a pentablock copolymer consisting of poly((diethylaminoethyl methacrylate)-b-(ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide)-b-(diethylaminoethyl methacrylate)) (PDEAEM25-b-PEO100-b-PPO65-b-PEO100-b-PDEAEM25). Between pH 3.0 and pH 7.4, we observed the presence of charged spherical micelles. Increasing the pH of the micelle solution above pH 7.4 resulted in increasing the size of the micelles due to the increasing hydrophobicity of the PDEAEM blocks above their pKa of 7.6. The increase in size of the spherical micelles resulted in a transition to a cylindrical micelle morphology in the pH range 8.1-10.5, and at pH >11, the copolymer solution undergoes macroscopic phase separation. Indeed, the phase separated copolymer sediments and coalesces into a hydrogel structure that consists of 25-35 wt % water. Small-angle X-ray scattering (SAXS) clearly indicated that the hydrogel has a hexagonal ordered phase. Interestingly, the process is reversible, as lowering of the pH below 7.0 leads to rapid dissolution of the solid into homogeneous solution. We believe that the hexagonal structure in the hydrogel is a result of the organization of the cylindrical micelles due to the increased hydrophobic interactions between the micelles at 70 degrees C and pH 11. Thus we have developed a pH-/temperature-dependent, reversible hierarchically self-assembling block copolymer system with structures spanning nano- to microscale dimensions.