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   2013| June  | Volume 12 | Issue 1  
    Online since July 18, 2014

 
 
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ORIGINAL ARTICLES
Influence of formulation parameters on the physicochemical properties of meloxicam-loaded solid lipid nanoparticles
Rawia M. Khalil, Ahmed Abd El-Bary, Mahfoz A. Kassem, Mamdouh M. Ghorab, Mona Basha
June 2013, 12(1):63-72
DOI:10.7123/01.EPJ.0000428643.74323.d9   
Objective

The aim of this research was to investigate novel particulate carrier systems such as solid lipid nanoparticles (SLNs) for topical delivery of a lipophilic drug, meloxicam (MLX).

Methods

MLX-loaded SLNs were prepared using a modified high-shear homogenization and ultrasonication technique using different types of lipids and surfactants. Lipid nanoparticles were characterized in terms of entrapment efficiency, particle size, Zeta potential, differential scanning calorimetry, transmission electron microscopy, and in-vitro release studies.

Results

The lipid nanoparticles showed mean diameters of 210–730 nm, whereas the entrapment efficiency ranged from 50 to 84% depending on emulsifier and lipid concentration or type. MLX-loaded SLNs showed spherical particles with Zeta potentials varying from −15.7 to −30.5 mV. A differential scanning calorimetry study revealed that MLX encapsulated in SLNs was in the amorphous form. All nanoparticle formulations exhibited sustained release characteristics, and the release pattern followed the Higuchi’s equation. The analysis of results revealed that the type and concentration of the emulsifier or lipid used had a significant effect on the physicochemical properties on the investigated SLNs formulations.

Conclusion

The present study indicates that SLNs could potentially be exploited as carrier systems for MLX, with improved drug loading capacity and controlled drug release.

  2,146 262 -
REVIEW ARTICLE
D2M-dopaminergic receptor and 5-HT3 serotoninergic receptor antagonists having antiemetic profile
Mohamed N. Aboul-Enein, Aida A. EL-Azzouny, Yousreya A. Maklad, Mohamed I. Attia, Mohamed Abd EL-Hamid Ismail, Walaa H.A. Abd EL-Hamid
June 2013, 12(1):1-10
DOI:10.7123/01.EPJ.0000428875.20180.de   

Metoclopramide is the prototype of the orthopramide family and is used clinically as a stimulant of upper gastrointestinal motility and as an antiemetic. Its antiemetic potential is attributed mainly to the antagonist activity at D2-dopaminergic receptors in the chemoreceptor trigger zone of the central nervous system. Besides, ondansetron was the first selective 5-HT3 serotoninergic receptor antagonist used in clinics as an antiemetic. Herein, the antiemetic profile of different chemical classes of D2-dopaminergic receptor and 5-HT3 serotoninergic receptor antagonists will be discussed, which may be helpful in the development of potent antiemetic agents.

  2,017 194 -
ORIGINAL ARTICLES
Effect of pollution on the chemical content and secondary metabolites of Zygophyllum coccineum and Tamarix nilotica
Hanan E. Osman, Reham K. Badawy
June 2013, 12(1):73-82
DOI:10.7123/01.EPJ.0000428268.89779.59   
Objectives

This study investigated the uptake and translocation pattern of trace metals from two medicinal plant species namely: Zygophyllum coccineum and Tamarix nilotica from two contaminated sites and a noncontaminated (NC) site. The effects of heavy metals on the amino acids and secondary metabolites of the tested plant species were assessed.

Materials and methods

Medicinal plant samples and soil samples were collected from three different sites: two contaminated and one NC site. The concentration levels (mg/kg) of the selected trace metals (Al, B, Cr, Cu, Fe, Mn, Mo, Pb, V, and Zn) were estimated in the tested plant species and associated soil.

Results

Heavy metal contents in the investigated plant species reflected the metal concentration in the soil samples. The highest content of the determined heavy metals were detected in both tested plants from contaminated sites in comparison with those from the NC site.

The concentrations of free amino acids in T. nilotica and Z. coccineum plants from the contaminated sites were higher compared with those in plants from the NC site. Moreover, the concentration of free amino acids in plants from the wastewater-contaminated sites was higher compared with that in plants from the Suez industrial emission site.

The content of secondary metabolites (tannins, saponins, and alkaloids) was decreased in plants from polluted sites compared with those from the NC site. The concentration of tannins ranged from 0.07 to 0.33 g, saponins from 9.99 to 8.22%, and alkaloids from 7.95 to 1.00%. Moreover, the maximum tannins and alkaloid content was detected in Z. coccineum from the noncontaminated site.

Conclusion

The plants collected from the investigated sites pose a serious danger. However, a periodical assessment of plants used for traditional medicine should be encouraged as this will assist in ensuring their quality and safety in herbal use, especially for people living in urban areas where the level of pollution may be very high.

  1,860 260 -
Synthesis and DPPH radical-scavenging activity of some new 5-(N-substituted-1H-indol-3-yl)-5H-thiazolo[4,3-b]-1,3,4-thiadiazole derivatives
Heba M. Abo-Salem, Manal Sh. Ebaid, Eslam R. El-Sawy, Abd El-Nasser El-Gendy, Adel H. Mandour
June 2013, 12(1):11-19
DOI:10.7123/01.EPJ.0000426585.93667.87   
Background and objectives

Heterocyclic systems with thiadiazole nucleus show a wide spectrum of biological activities such as antioxidant, analgesic, antitumor, and anti-inflammatory activities. The aim of this study is to describe the synthesis of some new 5-(N-substituted-1H-indol-3-yl)-5H-thiazolo[4,3-b]-1,3,4-thiadiazole derivatives and to evaluate their antioxidant activity using 2,2º-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity.

Materials and methods

A one-pot reaction of N-substituted-1H-indol-3-carboxaldehyde 1a,b with thioglycolic acid and thiosemicarbazide in concentrated sulfuric acid yielded novel 2-amino-5-(N-substituted-1H-indol-3-yl)-5H-thiazolo[4,3-b]-1,3,4-thiadiazoles 2a,b. The reaction of 2a,b with some benzenesulfonyl chlorides and/or benzoyl chlorides yielded sulfonamides 3a,b and 4a,b and benzamide 5a,b and 6a,b derivatives, respectively, whereas, the reaction of 2a,b with chloroacetyl chloride yielded chloroacetamide derivatives 7a,b, which, on cyclization with potassium thiocyanate, yielded thiazolidinone derivatives 8a,b. The reaction of 2a,b with sodium azide yielded tetrazole derivatives 9a,b. However, the reaction of 2a,b with benzaldehyde yielded Schiff bases 10a,b, which cyclized with chloroacetyl chloride and/or phenacyl bromide to yield azetidinone derivatives 11a,b and 12a,b, respectively. However, the reaction of 10a,b with sodium cyanide, followed by acid hydrolysis yielded the α-amino acid derivatives 14a,b. Diazotization of 2a,b yielded diazonium salt A, which, on coupling with sodium azide, yielded the azido derivatives 15a,b. Cyclization of 15a,b with ethylacetoacetate yielded tetrazole derivatives 16a,b, whereas the coupling reaction of A with malononitrile yielded dicyano derivatives 17a,b, which, on cyclization with hydrazine hydrate, yielded 3,5-diaminopyrazole derivatives 18a,b. The newly synthesized compounds were screened for their antioxidant activity using 2,2º-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity.

Results and conclusion

4-{5-[(1H-Indol-3-yl)-5H-thiazolo[4,3-b]-1,3,4-thiadiazol-2-yl]diazo}-1H-pyrazole-3,5-diamine (18a) was highly active with radical-scavenging activity (IC50 of 69.14 μg/ml) compared with ascorbic acid (IC50 of 6.50 μg/ml).

  1,251 276 -
Synthesis and antihypertensive activity of certain substituted dihydropyridines and pyrimidinones
Wageeh S. El-Hamouly, Kamelia M. Amine, Hanaa A. Tawfik, Dina H. Dawood
June 2013, 12(1):20-27
DOI:10.7123/01.EPJ.0000426587.41764.d4   
Background and objective

Some bulky substituted aromatic aldehydes reacted with urea and ethyl acetoacetate in the presence of acetic acid as a catalyst to yield solely substituted dihydropyridines (Hantzsch-type molecule). In the presence of p-toluene sulfonic acid as a catalyst, the products were only dihydropyrimidines (Biginelli compounds). The same aldehydes yielded dihydropyrimidinones on using acetyl acetone instead of ethyl acetoacetate whatever the catalyst used. These two classes of molecules represent a heterocyclic system of a remarkable antihypertensive effect. The aim of this study was to synthesize certain dihydropyridine and pyrimidinone derivatives with aromatic moiety with bulky substituents to be evaluated for their antihypertensive effect.

Methods

The aldehydes 3-(substituted-phenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde 35, 4-oxo-4H-chromene-3-carbaldehyde (6), and substituted phenylazo-benzaldehyde 79 reacted with ethyl acetoacetate and urea in ethanol in the presence of acetic acid to yield dihydropyridines 1015. Aldehydes 39 reacted with ethyl acetoacetate and urea in the presence of p-toluene sulfonic acid to yield dihydropyrimidinones 1622. Furthermore, the reaction of the aldehydes 39 with ethyl acetoacetate and urea in the presence of either acetic acid or p-toluene sulfonic acid yielded the corresponding dihydropyrimidinones 2329.

Results and conclusion

The hypotensive activity of compounds 1014 and 1620 indicated that the 4-aryl-dihydropyridine derivatives 1014 showed higher activity than the pyrimidinones 1620. The most active compound was 4-(1,3-diphenyl-1H-pyrazol-4-yl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylic acid diethyl ester (10) at dose levels of 0.6, 1.2, and 2.4 mg/kg. It showed more or less similar hypotensive activity as the reference drug nifedipene at doses of 1.2 and 2.4 mg/kg. Its LD50=298 mg/kg body weight.

  1,245 206 -
SHORT COMMUNICATION
Chemical constituents from the aerial parts of Salsola inermis
Fatma S. Elsharabasy, Ahlam M. Hosney
June 2013, 12(1):90-94
DOI:10.7123/01.EPJ.0000428060.24957.95   
Background and objective

The hydroalcoholic extract from the aerial parts of Salsola inermis exhibited antioxidant, anti-inflammatory, and antinociceptive effects. The present study deals with the isolation and identification of the chemical constituents of this hydroalcoholic extract.

Materials and methods

The aerial parts of S. inermis (Forsskal) were collected from wild plants growing near the El-Alamein area in October 2005. Air-dried and powdered aerial parts of S. inermis were extracted with 70% alcohol in H2O. The extract was partitioned successively with CHCl3, EtOAc, and n-BuOH. The structures of the isolated compounds were determined by chemical and spectroscopic analyses.

Results and conclusion

Phytochemical investigation of the alcoholic extract from the aerial parts of S. inermis revealed 12 compounds, identified as long chain hydroxyl fatty acid 9,12,13-trihydroxydecosan–10,15,19-trienoic acid; trans-N-feruloyl tyramine-4ººº-O-β-D-glucopyranoside; umbelliferone; scopoletin; 3-methyl kaempferol; olean-12-en-3,28-diol; olean-12-en-28-oic acid; stigmasterol-3-β-O-D-glucopyranoside; 3-O-[β-D-glucopyranosyl]oleanolic acid; kaempferol 3-O-β-glucopyranoside; and isorhamnetin 3-O-β-glucopyranoside, in addition to β-sitosterol, stigmasterol, and stigmastanol.

Some of these compounds have hydroxyl groups, which help in scavenging free radicals and inhibit COX and various mediators involved in the pathogenesis of pain relief.

  1,139 183 -
ORIGINAL ARTICLES
Immobilization of Mucor racemosus NRRL 3631 lipase and characterization of silica-coated magnetite (Fe3O4) nanoparticles
Abeer A. El-Hadi, Hesham I. Saleh, Samia A. Moustafa, Hanan M. Ahmed
June 2013, 12(1):28-35
DOI:10.7123/01.EPJ.0000427102.64865.32   
Introduction and purpose

The uncoated magnetite (M) and silica-coated magnetite (MS) nanoparticles have been suggested as carriers for the immobilization of enzymes to improve their activity and stability. The objective of this study was to demonstrate the potential use of magnetic nanoparticles in bioengineering applications, using Mucor racemosus NRRL 3631 lipase as the model enzyme.

Materials and methods

The magnetite (Fe3O4) particles were synthesized by the chemical coprecipitation technique, that is, Massart’s process with minor modifications, using stable ferrous and ferric salts with ammonium hydroxide as the precipitating agent. The uncoated and coated magnetite nanoparticles for immobilizing the lipase were characterized according to the particle sizes, as measured from the transmission electron microscope images. The infrared and X-ray powder diffraction spectra can well explain the bonding interaction and crystal structures of various samples, respectively.

Results and conclusion

Different concentrations of silica-coated magnetite (MS) nanoparticles were used as cross-linking agents. A silica concentration of 1% was proven to be more suitable, with an immobilization efficiency of 96%. The transmission electron microscope images revealed the diameters of the uncoated magnetite particles to be 10–16 nm and those of the coated particles to be about 11 nm. The optimal pH and temperature of the immobilized lipase were 5–6 and 40πC, respectively. There was a slight decrease in the residual activity of the immobilized lipase at 60πC for 1 h. The kinetic constants Vmax and Km were determined to be 250 U/mg protein and 20 mmol/l, respectively, for the immobilized lipase. The residual activity of the immobilized lipase remained over 51% despite being used repeatedly seven times. It can be concluded that Fe3O4 magnetic nanoparticles and silica-coated magnetite (MS) nanoparticles have been successfully prepared with excellent properties using the chemical coprecipitation technique with some modifications. The silica coating appeared to be effective in protecting the magnetite from being converted to other oxide species. The results of the X-ray powder diffraction indicate that the composites were in the nanoscopic phase. The resulting immobilized lipase had better resistance to pH and temperature inactivation compared with free lipase and exhibited good reusability.

  1,145 160 -
Extracellular polysaccharides produced by the newly discovered source Scopularis spp.
Siham A Ismail
June 2013, 12(1):36-39
DOI:10.7123/01.EPJ.0000427067.33748.ea   
Background

Microorganisms are better and cheaper sources for the production of polysaccharides. Therefore, there has been an increasing interest in isolating and identifying new microbial polysaccharides.

Objective

The aim of this study was to produce new extracellular polysaccharides, with better rheological properties and varied applications, from the newly discovered fungal strain Scopularis spp., using different carbon sources.

Methods

Fourier transform infrared spectroscopy, carbohydrate analysis, and thin layer chromatography were the methods used for the preliminary characterizing of the produced polysaccharides.

Results

Among the 10 examined carbon sources, fructose, raffinose, sucrose, and maltose were found to produce an appreciable amount of extracellular polysaccharides (0.90, 0.87, 0.86, and 0.74 g/l, respectively), whereas arabinose, lactose, and mannitol produced a minimal amount of extracellular polysaccharides (0.22, 0.17, 0.12 g/l, respectively). However, all the tested sugars enhanced the growth of the fungal strain. The analytical method proved that the polymer was a heteropolysaccharide with six sugar moieties, all different in their relative ratios from one carbon source to another. Glucose was found to be the most abundant monosugar in all the polymer samples. Galactose, rhamnose, and glucuronic acid also appeared on the thin layer chromatography plate.

Conclusion

A new extracellular heteropolysaccharide was produced from the new source, Scopularis spp. The produced polysaccharide contained glucose, galactose, glucuronic acid, rhamnose, and two other unidentified sugars as indicated from the thin layer chromatography plate.

  1,132 163 -
DNA fingerprinting and profile of phenolics in root and root calli of Arctium lappa L. grown in Egypt
Elsayed A. Aboutabl, Mona El-Tantawy, Nadia Sokkar, Manal M. Shams
June 2013, 12(1):57-62
DOI:10.7123/01.EPJ.0000428269.66909.9a   
Aim

The aim of this study was the establishment of an efficient and promising protocol for callus production from Arctium lappa L. roots (family Asteraceae) and comparison of the metabolic profile of their phenolic and flavonoid content. DNA fingerprinting of A. lappa L. was carried out using the molecular generic marker technique (random amplification of polymorphic DNA-PCR), which was newly introduced in Egypt, for identification and authentication of the plant.

Methods

The effect of different concentrations of benzyladenine and naphthalene acetic acid added to MS media on initiation of root callus production and mass of callus produced was investigated. The presence or absence of various secondary metabolites of the root and calli was also determined using colorimetric methods and high performance liquid chromatography.

Results and conclusion

The growth parameters of the callus were determined. Each callus differs from the root in the profile of phenolic and flavonoid content. The calli have a higher phenolic content than the root and differ in the flavonoid profile.

  1,098 148 -
Biotransformation of soybean saponin to soyasapogenol B by Aspergillus parasiticus
Hala A. Amin, Yousseria M. Hassan, Soad M. Yehia
June 2013, 12(1):40-45
DOI:10.7123/01.EPJ.0000427332.31862.10   
Objectives

The aim of this study was to select of the most potent fungus that is able to hydrolyze soybean saponin (SS) to soyasapogenol B (SB). The selected fungus was cultivated under different physiological conditions to evaluate its ability to transform SS to achieve the maximal conversion output.

Materials and methods

Within 72 h, the biotransformation of SS by Aspergillus parasiticus, followed by isolation and purification of SB as a main product were carried out. The identity of SB was established by determination of its RF value and IR, mass spectra, and NMR spectra. Furthermore, different sets of experiments were carried out to enhance the activity of the tested organism and consequently, SB production.

Results and conclusion

Screening of different fungal isolates for transformation of SS to SB revealed that A. parasiticus produced the highest yield of SB. The maximum SB yield was obtained using a production medium composed of (%, w/v): malt extract, 4; yeast extract, 2; KH2PO4, 0.2; (NH4)2SO4, 0.2; MgSO4·7H2O, 0.03; CaCl2·2H2O, 0.03; galactose, 0.5; and SS, 3 (pH 8). The medium was inoculated with 6% (v/v) inoculum of a 72 h old culture and incubated on a rotary shaker (150 rpm) at 30πC for 72 h. Under these optimal conditions, the cell biotransformation efficiency was increased from 13.44 to 65%.

  1,002 144 -
Characterization of ternary solid dispersions of nimesulide with Inutec SP1 and β-cyclodextrin and evaluation of anti-inflammatory efficiency in rats
Rawia M. Khalil, Mamdouh M. Ghorab, Noha Abd El Rahman, Silvia Kocova El-Arini
June 2013, 12(1):46-56
DOI:10.7123/01.EPJ.0000427333.85411.b9   
Objective

The objective of this investigation is to enhance the physicochemical properties of nimesulide (NS) and the stability of NS solid dispersions in order to improve the anti-inflammatory activity of the drug.

Background

NS – a NSAID – is sparingly soluble in water and this low aqueous solubility in addition to its poor wettability leads to variability in the bioavailability of the drug.

Materials and methods

In the present study, ternary dispersions of NS were investigated using a new polymeric carrier, Inutec SP1 (Inutec), in combination with β cyclodextrin (β-CD). The ternary dispersions were prepared using different ratios of NS and β-CD (2 : 1; 1 : 1; 1 : 2), to which a fixed amount of Inutec (20% w/w of total formula) was added using different methods of incorporation of the drug. Physical mixtures of equivalent compositions were prepared by physically mixing the ingredients. The optimal formulation obtained with a full factorial experimental design was used for the evaluation of anti-inflammatory activity.

Results

In the ternary dispersions, the dissolution behavior improved in comparison with the physical mixtures and was found to be dependent on the technique of incorporation of the drug, the method of preparation, and the molar ratio of drug to β-CD. Physical characterization of the ternary dispersions by infrared spectroscopy (FTIR), differential scanning calorimetry, and X-ray powder diffraction indicated a decrease in crystallinity because of partial inclusion in β-CD and the effect of Inutec, which promoted the formation of microcrystals or partial amorphization of the drug during the processing of the dispersions by kneading. Differential scanning calorimetry and X-ray powder diffraction curves of the dispersions prepared by the solvent method indicated the presence of a polymorphic form of NS with a lower melting point. The optimized ternary dispersion predicted by the full factorial design showed good physical stability following an accelerated stability test. The ternary dispersion of NS, Inutec, and β-CD was found to show better anti-inflammatory efficiency in rats compared with a commercial tablet of NS.

Conclusion

It can be concluded that the dissolution properties and the anti-inflammatory efficacy of the ternary dispersions of NS with β-CD and Inutec were enhanced because of a secondary solubilization of the inclusion by the polymeric surfactant.

  991 122 -
Optimization of growth conditions and continuous production of inulinase using immobilized Aspergillus niger cells
Nagwa A. Atwa, Enas N. Danial
June 2013, 12(1):83-89
DOI:10.7123/01.EPJ.0000428964.32893.44   
Aim

The aim of the study was the optimization of growth conditions for the production of inulinase as well as the continuous production of the enzyme in an airlift bioreactor using Aspergillus niger cells.

Methods

First, inulinase production by A. niger cells, using different carbon and nitrogen sources, was studied on a shake flask level. Second, the cells were adsorbed onto different carriers, and their production over several successive batches was tested. Finally, the economically-favorable continuous production of inulinase by A. niger cells immobilized onto linen fibers was carried out in an airlift bioreactor using crude inulin juice as the fermentation medium.

Results

Although all tested substances resulted in the biosynthesis of certain amounts of inulinase enzyme, the highest titer of 163.5 U/ml was obtained when the producing cells were incubated for 96 h at 27πC and 180 rpm in a fermentation medium containing both inulin and peptone as sole carbon and nitrogen sources, respectively. Moreover, when the cells of the tested microorganism were adsorbed onto different carriers, especially linen fibers, their productivity was also successfully maintained, to different extents, for five successive batches. However, as commercially pure inulin is very expensive and available in only small quantities, the fermentation medium was later substituted by a crude inulin extract obtained by mechanical crushing and filtration of Jerusalem artichoke tubers. The crude inulin juice was able to sustain inulinase production during the second batch cultivation of A. niger cells that were immobilized by their adsorption onto linen fibers to a satisfactory level of about 122 U/ml. Furthermore, the use of the previously mentioned crude inulin preparation was also compared with the use of either complete or minimal media, composed solely of 1% pure inulin, for the continuous production of inulinase enzyme by A. niger cells that were immobilized in their maximum production phase and packed inside an external loop airlift bioreactor. The results of this experiment were very encouraging as, using this technique, an inulinase production of about 838 U/ml over an incubation period of 48 h was obtained compared with a production of about 996 and 1013 U/ml, which resulted from the use of either minimized or complete media, respectively, for the same incubation period.

Conclusion

The method adopted in this study for inulinase production is simple, economic, time saving, and nontoxic to the microorganism. Moreover, the loaded linen fiber pads are reusable.

  853 109 -
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