Effects of dietary glucosylceramide on dermatitis in atopic dermatitis model mice

The effects of dietary plant and yeast cerebroside (glucosylceramide), a major sphingolipid in plants and yeast, on atopic dermatitis (AD) like symptoms were investigated in a mouse model. After 7 wk of feeding with a diet containing maize glucosylceramide, plasma IgE levels became significantly lower and in contrast, the levels of interleukin (IL)‐12, which induces cellular immunity, became significantly higher in the AD mice than in the controls. However, the sphingolipid constituents of the skin fraction in the maize glucosylceramide fed group did not contain sphingoid bases of plant origin, such as 8‐unsaturated sphingoid bases. The results of the present study indicated that dietary plant glucosylceramide prevented AD‐like symptoms in AD model mice via regulation of Th1/Th2 balance. Practical applications: Dietary plant and yeast glucosylceramides have been shown to suppress AD‐like symptoms in AD model mice via regulation of helper T‐cell Th1/Th2 balance. Glucosylceramide are capable of preventing AD and may be useful in skincare products.     

Microbial transformation of androst‐4‐ene‐3, 17‐dione by Bordetella sp. B4 CGMCC 2229

BACKGROUND: Microbial transformation of steroids has attracted widespread attention, especially the transformation of those steroids synthesized with difficulty by chemical methods. In this study, microbial transformation of androst‐4‐ene‐3, 17‐dione (AD) by Bordetella sp. B4 was investigated, and the effect of temperature on transformation was studied. RESULTS: Three metabolites were purified by preparative TLC and HPLC, and identified as androsta‐1,4‐diene‐3,17‐dione (ADD), 9α‐hydroxyandrost‐4‐ene‐3, 17‐dione (9α‐OH‐AD), and 3‐hydroxy‐9, 10‐secoandrost‐1, 3, 5‐triene‐9, 17‐dione (3‐OH‐SATD) by nuclear magnetic resonance imaging (NMR), Fourier transform infrared spectroscopy (FTIR) and mass spectroscopy (MS). It was first reported that the genus of Bordetella has the capability of AD degradation. Microbial transformation of AD was performed at 30 °C, 37 °C, 40 °C and 45 °C. The 9α‐OH‐AD yield reached a maximum within 16 h when the strain was cultivated in media with AD as sole carbon at 37 °C. Surprisingly, ADD was produced by the strain cultivated at 40 °C but not at 37 °C, which was different from previous reports. It was deduced that the alcohol dehydrogenase that catalyzed the transformation of AD to ADD may be temperature sensitive. CONCLUSION: Androst‐4‐ene‐3,17‐dione was converted into 9α‐hydroxyandrost‐4‐ene‐3, 17‐dione and other metabolites rapidly by Bordetella sp. B4. It is anticipated that the strain Bordetella sp. B4 CGMCC 2229 can be used in the steroids industry. Copyright © 2009 Society of Chemical Industry     

Copper and Zinc Binding to Amyloid‐β: Coordination,Dynamics, Aggregation,Reactivity and Metal‐Ion Transfer

The metal ions copper, zinc and iron have been shown to be involved in Alzheimer's disease (AD). Cu, Zn and Fe ions are proposed to be implicated in two key steps of AD pathology: 1) aggregation of the peptide amyloid‐β (Aβ), and 2) production of reactive oxygen species (ROS) induced by Aβ. There is compelling evidence that Cu and Zn bind directly to Aβ in AD. This formation of Cu/Zn–Aβ complexes is thought to be aberrant as they have been detected only in AD, but not under healthy conditions. In this context, the understanding of how these metal ions interact with Aβ, their influence on structure and oligomerization become an important issue for AD. Moreover, the mechanism of ROS production by Cu–Aβ in relation to its aggregations state, as well as the metal‐transfer reaction from and to Aβ are crucial in order to understand why Aβ oligomers are highly toxic and why Aβ seems to bind Cu and Zn only in AD.     

Enzymatic removal of 3‐monochloro‐1,2‐propanediol (3‐MCPD) and its esters from oils

3‐Monochloro‐1,2‐propanediol (3‐MCPD) is a contaminant in processed food well known for about 30 years. More recently, this compound has observed attendance due to its occurrence as fatty acid esters in edible oils and products derived from them. In this study, the first enzymatic approach to remove 3‐MCPD and its esters from aqueous and biphasic systems by converting it into glycerol is described. First, 3‐MCPD was converted in an aqueous system by an enzyme cascade consisting of a halohydrin dehalogenase from Arthrobacter sp. AD2 and an epoxide hydrolase from Agrobacterium radiobacter AD1 with complete conversion to glycerol. Next, it could also be shown, that the corresponding oleic acid monoester of 3‐monochloropropanediol‐1‐monooleic‐ester (3‐MCPD‐ester) was converted in a biphasic system in the presence of an edible oil by Candida antarctica lipase A to yield free 3‐MCPD and the corresponding fatty acid. Hence, also 3‐MCPD‐esters can be converted by an enzyme cascade into the harmless product glycerol. Practical applications: Since several reports have been recently published on the contamination of foods with 3‐MCPD and its fatty acid esters, there is a great demand to remove these compounds and an urgency to find useful methods for this. In this contribution, we present an easy enzymatic way to remove 3‐MCPD and its esters from the reaction media (i.e., plant oil) by converting it to the nontoxic glycerol. The method requires neither high temperature nor organic solvents.     

Thermodynamic and Kinetic Study of Adsorption of R,S‐α‐Tetralol Enantiomers on the Chiral Adsorbent CHIRALPAK AD

Abstract

Experimental results for the separation of S,R‐α‐Tetralol enantiomers obtained on preparative columns packed with particle size 20 µm of chiral adsorbent CHIRALPAK AD are presented. The total porosity was measured by using the non‐retained compound 1,3,5‐Tri‐tert‐butylbenzene and was 0.61. The permeability of the bed packed with CHIRALPAK AD was calculated as 4.4×10^?13 m². The efficiency of columns was characterized by the height equivalent to a theoretical plate (HETP) and a linear dependency has been found over tested flow rates. The HETP of S‐α‐Tetralol and R‐α‐Tetralol calculated at the flow rate 5.0 cm³/min were 320 µm and 340 µm, respectively. Thermodynamic adsorption parameters enthalpy, ΔH and entropy, ΔS, have been calculated from van't Hoff plot. Equilibrium and kinetics of adsorption of single enantiomers and racemic mixture of α‐Tetralol on CHIRALPAK AD were evaluated as well. The parameters for multicomponent isotherm linear‐Langmuir model are presented. The breakthrough curves of α‐Tetralol enantiomers are simulated with a mathematical model that accounts for axial dispersion and linear driving force for the intraparticle mass transfer.     

The role of polycarbonate molecular weight in the poly(L‐lactide) blends compatibilized with poly(butylene succinate‐co‐L‐lactate)

Poly(butylene succinate‐co‐L ‐lactate) (PBSL)–compatibilized poly(L ‐lactide) (PLLA) polymer blends with two commercial grades of polycarbonate (PC) were investigated. The capillary tests showed that the steady shear viscosity of high molecular weight PC (PC‐L) was 10 times higher than that of low molecular weight PC (PC‐AD) throughout the shear rate range under investigation. Morphologic examination revealed that the shape of the dispersed PC‐L phase in the as‐extruded blends was largely spherical, but the PC‐AD phase was more like a rod and elongated further during injection molding. Notched Izod impact strength (IS) of the unmodified PLLA/PC‐L blend was higher than that of PC‐AD blend. The IS of modified ternary blends increased with PBSL content because of enhanced phase interaction indicated from thermal and morphologic analysis. The PBSL modification also enhanced IS more significantly in PLLA/PC‐L than in PLLA/PC‐AD blends. On the contrary, the heat deflection temperature (HDT) of PLLA/PC‐L binary system was much lower than that of PLLA/PC‐AD. HDT of PBSL‐modified PLLA/PC‐AD blends dropped with increasing PBSL content, which is a ductile polymer. Thermal and dynamic mechanical analysis of the ternary blends showed that individual components were immiscible with distinct T_gs for PC and PLLA and distinct T_ms for PBSL and PLLA. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Cholesterol: A Key in the Pathogenesis of Alzheimer's Disease

Herein we highlight recent advances in our understanding of the role of cholesterol in Alzheimer′s disease (AD). It has been proposed that cholesterol could enhance the risk of AD, and the interaction between cholesterol and amyloid‐β peptide 42 (Aβ42) has been studied extensively, yet until recently, the specific interaction mechanisms between them and how this affects Aβ42 aggregation had not yet been fully explored and had remained ambiguous. Vendruscolo and co‐workers addressed these issues in their recent article entitled “Cholesterol catalyses Aβ42 aggregation through a heterogeneous nucleation pathway in the presence of lipid membranes” (Habchi et al., Nat. Chem. 2018 , 10, 673). In this article, the authors revealed the mechanism behind cholesterol‐catalyzed Aβ42 aggregation, providing the potential to address the molecular origins of AD, thereby opening a new avenue for effective AD therapy.     

Microbial conversion of sterol‐containing soybean oil production waste

Soybean extract residue (scum), a waste of soybean oil production, was examined as a raw material for C₁₇‐ketosteroid production. As a model process, its bioconversion to 9α‐hydroxyandrost‐4‐ene‐3,17‐dione (9‐OH‐AD) by Mycobacterium sp VKM Ac‐1817D was studied. The content of transformable sterols (sitosterol, stigmasterol and campesterol) in scum was estimated at ～14%. The bioconversion of scum to 9‐OH‐AD was characterized by a long lag‐period (300–350 h) followed by 9‐OH‐AD accumulation. The microbial or chemical elimination of fatty non‐identified components resulted in sterol‐enriched scum preparations. Effective conversion of these preparations by Mycobacterium sp was demonstrated: 9‐OH‐AD molar yield ～65% was reached at 60 h from the scum preparation containing 10 g dm^?3 transformable sterols. The process productivity was comparable with that for high quality‐sitosterol of wood origin (tall‐oil sitosterol). Copyright © 2004 Society of Chemical Industry     

New Mono‐Quarternized Bis‐Cinchona Alkaloid Ligands for Asymmetric Dihydroxylation of Olefins in Aqueous Medium: Unprecedented High Enantioselectivity and Recyclability

New mono‐quaternized allyl bromide salts of bis‐Cinchona alkaloid ligands, [(QD)₂PHAL‐Allyl]Br and [(QN)₂PHAL‐Allyl]Br, have been synthesized which can be converted into their highly water‐soluble multihydroxylated derivatives under asymmetric dihydroxylation (AD) conditions and, thus, easily recovered by a simple extraction method after reaction and reused. These mono‐quaternized ligands exhibited superior catalytic efficiency to their neutral counterparts such as (DHQD)₂PHAL and (DHQ)₂PHAL for the AD reactions of mono‐ and disubstituted styrenes under Upjohn conditions. Merely 0.1 mol % of osmium was enough to complete the reactions of mono‐ and disubstituted styrenes and, moreover, these ligands showed the highest enantioselectivities (e.g., for styrene, 97 % ee with [(QD)₂PHAL‐Allyl]Br) among those ever achieved under Upjohn conditions.     

Asymmetric Dihydroxylation of 2‐Substituted 1‐Vinylferrocenes: The First Non‐Enzymatic Kinetic Resolution of Planar‐Chiral Ferrocenes

The first non‐enzymatic kinetic resolution of planar chiral ferrocenes has been achieved by the Sharpless catalytic asymmetric dihydroxylation (AD) of a set of racemic 2‐substituted 1‐ethenylferrocenes 1a – d . The enantioselectivity factor k_rel varies from 20 to 62 [for (DHQD)₂PYR ligands], and from 5 to 27 [for (DHQ)₂PYR ligands]. The stereochemical outcome of the resolution can be easily predicted by the mnemonic device for AD, with the additional hypothesis that in the preferred transition state the olefin group and the upper cyclopentadiene ring of vinylferrocenes exhibit an essentially coplanar geometry.     

Bioconversion of soysterols to androstenedione by Mycobacterium fortuitum subsp. fortuitum NCIM 5239, a mutant derived from total sterol degrader strain

BACKGROUND: The bioconversion of soysterols to androstenedione (AD) by microbial cleavage of C‐17 side chain is of practical interest since AD serves as the starting compound for the production of the majority of pharmaceutically active steroids. A total soysterols degrader strain was subjected to combined mitomycin C and UV treatments and a mutant designated Mycobacterium fortuitum subsp. fortuitum NCIM 5239 was isolated that accumulated AD as major bioconversion product. RESULTS: The maximum bioconversion of soysterols to AD (71.3 mol %) was obtained at 30 °C, pH 5, 15% inoculum grown for 48 h, glycerol (12.68 g L^?1) and urea (1.06 g L^?1) as carbon and nitrogen sources, respectively, at C:N ratio of 10, the use of 10% polypropylene glycol‐400 (PPG‐400) as soysterols carrier solvent and 3 mg mL^?1 concentration of soysterols after 240 h incubation period in shake flask culture. In a laboratory scale fermentor, a maximum of 64.8 mol % bioconversion of soysterols to AD was recorded after 99 h. CONCLUSION: The mutant Mycobacterium fortuitum subsp. fortuitum NCIM 5239 possesses high potential for industrial production of AD from soysterols. Copyright © 2010 Society of Chemical Industry     

Kinetics of thermal degradation studies of some new terpolymers derived from 2,4‐dihydroxypropiophenone,oxamide, and formaldehyde

The terpolymers (2,4‐DHPOF) have been synthesized by the condensation of 2,4‐dihydroxypropiophenone with oxamide and formaldehyde in the presence of 2M HCl as catalyst with varying proportions of reactants. Terpolymer composition has been determined on the basis of their elemental analysis. The terpolymer has been characterized by UV‐visible, IR, and ¹H NMR spectra. The thermal decomposition behavior of some new terpolymers was studied using thermogravimetric analysis in air atmosphere at heating rate of 10°C/min. Thermal decomposition curves are discussed with careful attention to minute details. The Freeman–Carroll and Sharp–Wentworth methods have been used to calculate activation energy and thermal stability. Thermal activation energy (E_a) calculated with the help of these methods are in agreement with each other. Thermodynamic parameters such as free energy change (ΔF), entropy change (ΔS), apparent entropy change (S*), and frequency factor (z) are also determined on the basis of the TG curves and by using data of the Freeman–Carroll method. The Freidman method evaluated the variation in the apparent activation energy changes by isoconversional (model‐free) kinetic methods. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Topical emulsions containing ceramides: Effects on the skin barrier function and anti‐inflammatory properties

The barrier properties of the stratum corneum (SC) are largely dependent on the intactness of the lipid lamellae that surround the corneocytes. Ceramides, fatty acids, and cholesterol together with hydrocortisone (HC) have thus been proposed as protective or therapeutic agents against xerosis and atopic dermatitis (AD). However, topical delivery of these substances is still a challenge because of the excellent barrier function of the skin. The aim of the present study was to develop a formulation with combined anti‐inflammatory/barrier repair properties. In order to achieve this goal, a new non‐ionic O/W emulsion (CerEmulsion) containing skin barrier lipids and HC was prepared. Its physicochemical and microbiological stability and skin permeation performance were compared to a blank emulsion (NoCerEmulsion). Placebos described as PlaceboCerEmulsion and PlaceboNoCerEmulsion of CerEmulsion and NoCerEmulsion, respectively, were also prepared in order to study the transepidermal water loss (TEWL) profiles. The emulsions presented white glossy and pourable characteristics with an acidic pH. CerEmulsion showed smaller droplet sizes and higher viscosity values (5000 mPas) while NoCerEmulsion presented viscosity values of 2000 mPas. Crystalline structures were prominent in both emulsions. The microbiological analysis showed that the results were within the established specification limits. CerEmulsion and NoCerEmulsion have shown similar release profiles and CerEmulsion presented a similar anti‐inflammatory activity in vivo when compared with a commercially available 1% HC emulsion. Both emulsions were chemically, physically, and microbiologically stable. TEWL was significantly lower for the group treated with PlaceboCerEmulsion, suggesting that skin hydration was higher with this ceramide‐containing formulation. Practical applications: In this work, the authors develop and characterize a new non‐ionic HC/ceramide‐dominant O/W emulsion as a topical therapy for the improvement of skin barrier abnormalities in atopic dermatitis (AD). This unique formulation includes high concentrations of three lipids (ceramides, cholesterol, and free fatty acids) and paraffin. Its use is recommended for AD patients ≥6 months of age. It is also indicated for the management and relief of burning and itching associated with various dermatoses, including AD, irritant contact dermatitis, and radiation dermatitis.     

Production of androstenedione using mutants of Mycobacterium sp

Mycobacterium sp VKM Ac‐1815D strain was able to cleave sterol side chain giving androstenedione (AD) as a major product with a molar yield of 63–68%. Clones having altered resistance to antibacterial agents were selected. After treatment with ethyl methane sulfonate or mitomycin C, mutants were obtained that retained the ability to produce AD from sitosterol with molar yields of 70–75%. A mutant strain able to effectively reduce 3,17‐diketosteroids at C‐17 was selected. The 17β‐hydroxy steroid dehydrogenase activity of its crude extract was twice as high as that found for the parent organism. The approach offers the possibility of obtaining improved and labelled biocatalysts for AD or testosterone production from sterols. © 2002 Society of Chemical Industry     

Synthesis and comparative study of thermal stabilities of the imidization of some maleic anhydride copolymers

In the present study, first, maleic anhydride‐styrene (MA‐St), maleic anhydride‐allyl phenyl ether (MA‐APhE), maleic anhydride‐heptene‐1(MA‐Hp), and maleic anhydride‐allyl propionate (MA‐AP) copolymers have been synthesized in different solvents in the presence of azobisisobutyronitrile (AIBN) at 70°C. Then, these four copolymers have been reacted with aniline at 60°C in N,N‐dimethyl formamide (DMF), and maleamidic acid derivatives of these copolymers have been synthesized. Next, they have been obtained from their maleimide derivatives by heating under vacuum at 150°C. All these polymers have been characterized by Fourier Transform infrared spectroscopy (FTIR) and investigated their thermal properties by using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) methods. The analyses results showed that thermal properties of maleimide derivatives of maleic anhydride copolymers changed as depend on the neighbor monomers of maleic anhydride. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2250–2254, 2006     

Effect of epoxy functionalized compatibilizer on the mechanical properties of low‐density polyethylene/plasticized tapioca starch blends

A series of low‐density polyethylene (LDPE) blends with varying proportions of plasticized tapioca starch have been used for the study of their mechanical properties. A functionalized epoxy resin, namely, poly(ethylene‐co‐glycidyl methacrylate) has been used as the compatibilizer. The impact and tensile properties have been measured by standard ASTM methods. The mechanical properties are seen to improve significantly with the addition of the epoxy compatibilizer, approaching values close to those of virgin LDPE. The scanning electron micrographs of the compatibilized blends show ductile failure which evidently contribute to improved mechanical properties. © 2001 Society of Chemical Industry     

The inhibitive effect of poly(p‐toluidine) on corrosion of iron in 1M HCL solutions

In recent years, polymer amines have been recognized as an excellent corrosion inhibitors for iron in acid solutions. In this work, the inhibitive effect of p‐toluidine and poly(p‐toluidine) on corrosion of iron in 1M HCl has been studied by the electrochemical methods such as impedance, linear polarization, Tafel polarization techniques. The effectiveness of poly(p‐toluidine) was found to be high in comparison with that of monomer. The results showed that p‐toluidine and poly(p‐toluidine) suppressed both cathodic and anodic processes of iron dissolution in 1M HCl. The inhibition efficiency of both p‐toluidine and poly(p‐toluidine) were found to increase with the inhibitor concentrations. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

A comparative study of physical properties in Fe3O4 nanoparticles prepared by coprecipitation and citrate methods

Magnetite exhibits unique structural, electronic, and magnetic properties in extreme conditions that are of great research interest. In this work, the effects of preparation technique on X‐ray peak broadening, magnetic and elastic moduli properties of Fe₃O₄ nanoparticles prepared by coprecipitation (FcP‐NPs) and citrate (FC‐NPs) methods have been investigated. The structural characterization of the samples is evidence for a cubic structure with Fd‐3m space group. The Williamson‐Hall analysis was used to study crystallite sizes and lattice strain of the samples and also stress and energy density. In addition, the crystallite sizes are compared with the particle sizes and the magnetic core sizes obtained from TEM and VSM methods, respectively. In addition, the cation distribution obtained from calculated inversion parameter indicate that in the smaller particles, more amount of Fe²⁺ on the tetrahedral sites can be related to higher stress induced in the FcP‐NPs compared to the FC‐NPs. The saturation magnetization of the FcP‐NPs is almost two times bigger than the saturation magnetization of the FC‐NPs. It could be attributed to the decrease in the negative interaction on the octahedral site and also the magnetic moment on the tetrahedral site of the FcP‐NPs. The increase in force constants of the FC‐NPs determined by infrared spectra analysis compared to FcP‐NPs suggests the strengthening of their interatomic bonding. The values of shear and longitudinal wave velocities obtained from force constants have been used to determine the values of Young's modulus, rigidity modulus, bulk modulus, and Debye temperature. By comparison of the elastic results of FC‐NPs with the FcP‐NPs, we can observe that the elastic properties of the F‐NPs have been improved by synthesis method, while Poisson's ratio almost remains constant. In addition, using the values of the compliance s_ij obtained from elastic stiffness constants, the values of Young's modulus and Poisson's ratio along the oriented direction [hkl] have been calculated for the samples.     

Synthesis,characterisation and electrochemical investigation of phthalocyanines with pendant 4‐{2‐[2‐(4‐tert‐butylphenoxy)ethoxy]ethoxy} substituents

In this study, a novel metal‐free phthalocyanine and three metallophthalocyanines carrying four 2‐[2‐(4‐tert‐butylphenoxy)ethoxy groups on the periphery were prepared by cyclotetramerisation of a dinitrile derivative in the presence of the corresponding divalent metal salts [zinc(ii ), cobalt(ii ), copper(ii )]. These new phthalocyanine compounds have been characterised by infrared, ¹H and ¹³C nuclear magnetic resonance and electrospray mass spectroscopies and elemental analysis. The electrochemical properties of the metal‐free, zinc(ii ) and cobalt(ii ) phthalocyanines were investigated by cyclic voltammetry and differential pulse voltammetry methods. The cobalt complex showed a metal‐based reduction process, while the metal‐free and zinc(ii ) phthalocyanines showed ligand‐based electron transfer processes. It has been found that the absorption spectra substantially depend on concentration. It has been shown that these changes are attributable to the association of the phthalocyanine molecule. The number of molecules in the associates and the equilibrium constants for this association are determined.