Physicochemical Characterization and Antimicrobial Properties of Inulin Acetate Obtained by Microwave-Assisted Synthesis

Microwave-assisted irradiation was performed for esterification of chicory inulin with high degree of polymerization with acetic anhydride without a solvent only with a catalyst.The resulting esters were characterized by melting point,hydrophilic-lipophilic balance,thin-layer chromatography,ultraviolet spectroscopy,Fourier transform infrared spectroscopy(FTIR)and nuclear magnetic resonance(NMR)spectroscopy.Inulin acetate demonstrated a high degree of acetylation(2.5-3.0)and presented a white,water-insoluble substance with bitter taste.The FTIR and NMR spectra confirmed esterification and demonstrated the incorporation of hydrophobic residue to the water soluble inulin backbone.Swelling capacity,water holding,oil-holding capacities,the foamability,foam stability and emulsifying properties were also evaluated.Inulin acetate showed promising foam stability 52%for 60 min and formed stable emulsions at concentration 0.2 g/L with 50 and 80%oil phases.Its water holding capacity was lower than the oil holding capacity.In addition to this,for the first time,the antimicrobial potential of inulin acetate was tested against seventeen microorganisms(Gram-positive and Gram-negative bacteria,yeasts and fungi).Inulin acetate(10 mg/ml)inhibited the growth of Bacillus cereus,Escherichia coli ATCC 8739,Salmonella abony,Candida albicans and Penicillium sp.However,inulin acetate demonstrated antimicrobial activity at concentration 1 mg/ml against Listeria monocytogenes 863,Escherichia coli 3398,Candida albicans 8673,Fusarium oxysporum and Aspergillus niger.The current study demonstrated the applications of“green”synthesized inulin acetate as a foaming agent,oil-in-water emulsion stabilizer and antimicrobial substance in pharmaceutical,agricultural and cosmetic preparations.

Microwave-Assisted Isolation and Acetylation of Inulin from Helianthus Tuberosus L Tubers

Jerusalem artichoke (Helianthus tuberosus L.) tubers are industrial crop considered as a promising source forinulin production. “Green” method was performed for accelerated inulin extraction from Helianthus tuberosus L.tubers by the application of microwave irradiation. Further pretreatment of the water extract with acetone andethanol yielded inulin (20%) with purity 89% and degree of polymerization 18. Jerusalem artichoke inulin wascharacterized by FTIR and NMR spectroscopy. For the first time eco-friendly synthesis of acetylated Jerusalemartichoke inulin was performed by the reaction with acetic anhydride, without toxic solvent, but only withsodium acetate as catalyst under microwave irradiation for 60 s. The degree of acetylation (DA=2.1) and thestructure of inulin esters were confirmed by 1H and 13C NMR. The suggested microwave acetylation shortenssignificantly the esterification reaction.

Preparation,Characterization and Catalytic Activity of Palladium Nanoparticles Embedded in the Mesoporous Silica Matrices

Novel in-situ reduction approach was applied for the synthesis of palladium nanoparticles in the pores of mesoporous silica materials with grafted siliconhydride groups. Matrices possessing different structural properties (MCM-41, SBA-15 and Silochrom) were used. Samples were studied by nitrogen adsorption-desorption method, low-angle X-ray diffraction, transmission electron microscopy (TEM) and FT-IR/PAS spectroscopy. The temperature-programmed oxidation (TPO) and reduction (TPR) methods were applied to examine reducibility of palladium species. Palladium containing catalysts were tested in methane oxidation reaction. It was demonstrated that relatively large pores in SBA-15 type silica facilitated formation of well-dispersed palladium nanoparticles confined in the pores channels. In the case of MCM-41 support, metallic palladium nanoparticles were formed on the external surface. The obtained materials showed high catalytic activity. Lower activity of the samples containing small crystallites located in the pore volume at high temperatures was related to worse accessibility of active sites to the reation mixture.

Determination of Mercuric Ion in Water Samples with a LED Exciting and CCD Based Portable Spectrofluorimeter

The fluorescent characteristics of a fluorimetric chemosensor for mercuric ion, Hg2+, employing a synthesized Rhodamine 6G derivative, have been analyzed. For that, a portable spectrofluorimeter composed of a 515 nm LED as excitation source, two fiber-optics and a CCD camera as detector, has been used, intended for “in situ” analysis. A highly selective Rhodamine based probe for Hg2+, that is water soluble and gives a positive response upon analyte binding, is reported. The reagent is bearing a monothiospirolactone group in a Rhodamine 6G architecture and the thiol atom served for the direct attack of thiophilic Hg2+. The fluorescence enhancement is attributed to the spirolactone ring opening and the coordination of two sulphur atoms to Hg2+ giving a 2:1 reagent: Hg2+ stoichiometry complex.

Microwave Synthesis of Inulin Acetate as Potential Bio- Based Additive for Poly(Vinyl Chloride)

The paper presents the findings of an experimental study on the microwave synthesis (MW) of inulin acetateand its possible application as bio-additive in poly(vinyl chloride) (PVC). The obtained inulin acetate has beenidentified and characterized by spectroscopic methods. Advantages of the MW compared with the conventionalsynthesis were defined. In order to evaluate possible application of the product as bio-based additive forpolymers, effect of the inulin ester on PVC behavior and characteristics has been investigated by differentialscanning calorimetry (DSC) and deformation upon extension. Experimental results show that in concentrationrange up to 30.0 wt. % the inulin ester influences positively the properties of PVC causing effect similar toplasticizing one. At concentration over 30 wt.% the ester shows more specific behavior, which will be furtherinvestigated. Conclusions about potential application of MW synthesized inulin acetate as bio-based additive forPVC have been drawn.

The Thermal Stability of (CaTiO3)1-x (Cr3/4Fe5/4O3)x Ceramic Composites in the Microwave Region

The thermal stability, structural and dielectric properties of the (CaTiO3)1-x(Cr3/4Fe5/4O3)x ceramic composites with x = 0, 0.1, 0.5, 0.9 and 1 have been examined in microwave region. The samples were produced via the solid-state reaction. The orthorhombic structural phase of CaTiO3 and trigonal structural phase of Cr3/4Fe5/4O3 were confirmed by the X-Ray Powder Diffraction (XRPD). The XRPD patterns for composites reveal the quantities of each original phase present. The infrared spectra of the samples reinforce this structural verification indicating no or minimal occurrence of unwanted reactions. The first sample (x = 0) and last sample (x = 1) in this series exhibit the maximum and the minimum of the relative dielectric permittivity and values range from 140.1 to 8.3 respectively. The measured temperature coefficient of the matrix CaTiO3 was +921 ppm·℃-1 and for the matrix Cr3/4Fe5/4O3 was -56 ppm·℃-1. With the study of series of composites, it was possible to make a mathematical prediction for a composition reach the temperature coefficient near zero. The proposed ceramic has potential use as thermostable material in the microwave region and can be applied to resonators, low-noise amplifiers, filters, and so on.

Mangiferin,a natural xanthone,accelerates gastrointestinal transit in mice involving cholinergic mechanism

AIM:To investigate the effects of mangiferin on gastrointestinal transit(GIT) in normal and constipated mice,together with the possible mechanism.METHODS:Intragastrically-administered charcoal mealwas used to measure GIT in overnight starved Swiss mice.In the first experiments,mangiferin(3 mg/kg,10 mg/kg,30 mg/kg,and 100 mg/kg,po) or tegaserod(1 mg/kg,ip) were administered 30 min before the charcoal meal to study their effects on normal transit.In the second series,mangiferin(30 mg/kg) was tested on delayed GIT induced by several different pharmacological agonists(morphine,clonidine,capsaicin) or antagonists(ondansetron,verapamil,and atropine) whereas in the third series,mangiferin(30 mg/kg,100 mg/kg and 300 mg/kg) or tegaserod(1 mg/kg) were tested on 6 h fecal pellets outputted by freely fed mice.The ratio of wet to dry weight was calculated and used as a marker of fecal water content.RESULTS:Mangiferin administered orally significantly(P < 0.05) accelerated GIT at 30 mg/kg and 100 mg/kg(89% and 93%,respectively),similarly to 5-hydroxytryptamine4(5-HT4) agonist tegaserod(81%) when compared to vehicle-treated control(63%).Co-administered mangiferin(30 mg/kg) totally reversed the inhibitory effect of opioid agonist morphine,5-HT3-receptor antagonist ondansetron and transient receptor potential vanilloid-1 receptor agonist capsaicin on GIT,but only to a partial extent with the GIT-delay induced by 2-adrenoceptor agonist clonidine,and calcium antagonist verapamil.However,co-administered atropine completely blocked the stimulant effect of mangiferin on GIT,suggesting the involvement of muscarinic acetylcholine receptor activation.Although mangiferin significantly enhanced the 6 h fecal output at higher doses(245.5 ± 10.43 mg vs 161.9 ± 10.82 mg and 227.1 ± 20.11 mg vs 161.9 ± 10.82 mg of vehicle-treated control,at 30 and 100 mg/kg,P < 0.05,respectively),the effect of tegaserod was more potent(297.4 ± 7.42 mg vs 161.9 ± 10.82 mg of vehicle-treated control,P < 0.05).Unlike tegaserod,which showed an enhanced water content in fecal pellets(59.20% ± 1.09% vs 51.44% ± 1.19% of control,P < 0.05),mangiferin evidenced no such effect,indi-cating that it has only a motor and not a secretomotor effect.CONCLUSION:Our data indicate the prokinetic action of mangiferin.It can stimulate the normal GIT and also overcome the drug-induced transit delay,via a cholinergic physiological mechanism.

Preparation and Microstructural Characterization of Activated Carbon-Metal Oxide Hybrid Catalysts:New Insights into Reaction Paths

In catalysis processes, activated carbon （AC） and metal oxides （MOs） are widely used either as catalysts or as catalyst supports because of their unique properties. A combination of AC and MO nanoparticles in a single hybrid material usually entails both chemical and microstructural changes, which may largely influence the potential catalytic suitability and performance of the resulting product. Here, the prepa- ration of a wide series of AC-MO hybrid catalysts is studied. Three series of such catalysts are prepared by support first of MO （Al2O3, Fe2O3, SnO2, TiO2, WO3, and ZnO） precursors on a granular AC by wet impregnation and oven-drying at 120 ℃, and by subsequent heat treatment at 200 or 850℃ in inert atmosphere. Both the chemical composition and microstructure are mainly investigated by powder X-ray diffraction. Yield and ash content are often strongly dependent on the MO precursor and heat treatment temperature, in particular for the Sn catalysts. With the temperature rise, trends are towards the transformation of metal hydroxides into metal oxides, crystallinity improvement, and occurrence of drastic composition changes, ultimately leading to the formation of metals in elemental state and even metal carbides. Reaction paths during the preparation are explored for various hybrid catalysts and new insights into them are provided.

Vibrio spp.from Macrobrachium amazonicum prawn farming are inhibited by Moringa oleifera extracts

Objective:To investigate the in vitro antimicrobial potential of extracts of stem,leaves,flowers,pods and seeds of Moringu okifera(M.okifera) against Vibrio spp.from hatchery water and the prawn Mmrobrachium amazonicum.Methods:The ethanol extracts of stem,leaves,pods and seeds and chloroform extract of flowers of M.oleifera were tested against Vibrio cholerue(V.cholerae) serogroups non-O1/non-O139(n=4).Vibrio vulnificus(n=l) and Vibrio mimicus(n=1).Escherichia coli(E.coli)(ATCC(?) 25922) was used as quality control.Vibrio species were obtained from Macmbrachium amazonicum prawns and from hatchery water from prawn farming.The Minimum Inhibitory Concentration(MIC) was determined by broth microdilution method.Results:The best result was obtained with the ethanol extract of pods,which inhibited three strains of the V.choleme,Vibrio vulnificus,Vibrio minimis and E.coli(MIC range 0.312-5.000 mg/mL).The chloroform extract of flowers was effective against all V.chokrae strains and E.coli(MIC range 0.625-1.250 mg/mL).However,the ethanol extracts of stem and seeds showed low effectiveness in inhibiting the bacterial growth.Conclusions:The extracts of pods,flowers and leaves of M.oleifera have potential for the control of Vibrio spp.Further studies are necessary to isolate the bioaetive compounds responsible for this antimicrobial activity.

α,β-amyrin, a natural triterpenoid ameliorates L-arginine-induced acute pancreatitis in rats

AIM: To study the benef icial effects of triterpene α,β-amyrin and the underlying mechanisms in an experimental pancreatitis model. METHODS: Acute pancreatitis was induced in five groups of rats (n = 8) by L-arginine (2 × 2.5 g/kg, intraperitoneal, 1 h apart) and 1 h later, they received a single oral dose of α,β-amyrin (10, 30 and 100 mg/kg),methylprednisolone (30 mg/kg) and vehicle (3% Tween 80). A saline (0.9% NaCl) treated group served as a normal control. Efficacy was assessed at 24 h by determination of serum levels of amylase, lipase and proinflammatory cytokines [tumor necrosis factor (TNF)-α and interleukin (IL)-6], pancreatic myeloperoxidase (MPO) activity, lipid peroxidation [thiobarbituric acid reactive substances (TBARS)], nitrate/nitrite levels, and the wet weight/body weight ratio. Tissue histology and the immunoreactivity for TNF-α and inducible nitric oxide synthetase (iNOS) were performed. RESULTS: α,β-amyrin and methylprednisolone treatments significantly (P < 0.05) attenuated the L-arginine-induced increases in pancreatic wet weight/body weight ratio, and decreased the serum levels of amylase and lipase, and TNF-α and IL-6, as compared to the vehicle control. Also, pancreatic levels of MPO activity, TBARS, and nitrate/nitrite were signifi cantly lower. Histological f indings and TNF-α and iNOS immunostaining further confirmed the amelioration of pancreatic injury by α,β-amyrin. CONCLUSION: α,β-amyrin has the potential to combat acute pancreatitis by acting as an anti-in? ammatory and antioxidant agent.