Antioxidant properties of chitosan from crab shells

Crab chitosan was prepared by alkaline N-deacetylation of crab chitin for 60, 90 and 120 min and its antioxidant properties studied. Chitosan exhibited showed antioxidant activities of 58.3–70.2% at 1 mg/mL and showed reducing powers of 0.32–0.44 at 10 mg/mL. At 10 mg/mL, the scavenging ability of chitosan C60 on 1,1-diphenyl-2-picrylhydrazyl radicals was 28.4% whereas those of other chitosans were 46.4–52.3%. At 0.1 mg/mL, scavenging abilities on hydroxyl radicals were 62.3–77.6% whereas at 1 mg/mL, chelating abilities on ferrous ions were 82.9–96.5%. All EC₅₀ values of antioxidant activity were below 1.5 mg/mL. With regard to antioxidant properties assayed, the effectiveness of chitosans C60, C90 and C120 correlated with their N-deacetylation times. Overall, crab chitosan was good in antioxidant activity, scavenging ability on hydroxyl radicals and chelating abilities on ferrous ions and may be used as a source of antioxidants, as a possible food supplement or ingredient in the pharmaceutical industry.     

Extraction of polysaccharides and the antioxidant activity from the seeds of Plantago asiatica L

The extraction conditions of polysaccharides from Plantago asiatica L. seeds were investigated. Four parameters affecting the polysaccharides extraction, extraction times, water to sample, extraction temperature and single extraction time, were determined by orthogonal experiments. Under the optimized conditions, the polysaccharides yield of P. asiatica L. seeds was 2.467%. The antioxidant activities of the polysaccharides were investigated. The reducing power of the polysaccharides was dose dependent, and the reducing capacity of the polysaccharides was inferior to butylated hydroxytoluene, which is known to be a strong reducing agent. The scavenging rates of the polysaccharides on superoxide and 1,1-diphenyl-2-picrylhydrazyl radicals were79.7% and 81.4%, at polysaccharides concentration of 0.75 mg/mL, respectively, a scavenging rates approximately similar to that of 0.75 mg/mL ascorbic acid (83.5% and 85.1%, respectively). Furthermore, it exhibited a moderate concentration-dependent ABTS radical scavenging activity, ferrous ion chelating potency and H₂O₂ scavenging activity. The data obtained in the in vitro models clearly establish the antioxidant potency of the polysaccharides extracted from Semen Plantaginis.     

The influence of the cation of quaternized chitosans on antioxidant activity

Various quaternized chitosans (QCSs) were synthesized according to previous method. Their reducing power and antioxidant potency against hydroxyl radicals (OH) and hydrogen peroxide (H₂O₂) were explored by the established systems in vitro. The QCSs exhibited markedly antioxidant activity, especially TCEDMCS, whose IC₅₀ on hydroxyl radicals was 0.235 mg/mL. They showed 65–80% scavenging effect on hydrogen peroxide at a dose of 0.5 mg/mL. Generally, the antioxidant activity decreased in the order TCEDMCS > TBEDMCS > EDMCS > PDMCS > IBDMCS > Chitosan. Furthermore, the order of their OH and H₂O₂ scavenging activity was consistent with the electronegativity of different substituted groups in the QCSs. The QCSs showed much stronger antioxidant activity than that of chitosan may be due to the positive charge density of the nitrogen atoms in QCSs strengthened by the substituted groups.     

Characterization and antimicrobial activity of water-soluble N-(4-carboxybutyroyl) chitosans against some plant pathogenic bacteria and fungi

Water-soluble N-(4-carboxybutyroyl) chitosan derivatives with different degrees of substitution (DS) were synthesized to enhance the antimicrobial activity of chitosan molecule against plant pathogens. Chitosan in a solution of 2% aqueous acetic acid-methanol (1:1, v/v) was reacted with 0.1, 0.3, 0.6 and 1 mol of glutaric anhydride to give N-(4-carboxybutyroyl) chitosans at DS of 0.10, 0.25, 0.48 and 0.53, respectively. The chemical structures and DS were characterized by ¹H and ¹³C NMR spectroscopy, which showed that the acylate reaction took place at the N-position of chitosan. The synthesized derivatives were more soluble than the native chitosan in water and in dilute aqueous acetic acid and sodium hydroxide solutions. The antimicrobial activity was in vitro investigated against the most economic plant pathogenic bacteria of Agrobacterium tumefaciens and Erwinia carotovora and fungi of Botrytis cinerea, Pythium debaryanum and Rhizoctonia solani. The antimicrobial activity of N-(4-carboxybutyroyl) chitosans was strengthened than the un-modified chitosan with the increase of the DS. A compound of DS 0.53 was the most active one with minimum inhibitory concentration (MIC) of 725 and 800 mg/L against E. carotovora and A. tumefaciens, respectively and also in mycelial growth inhibiation against B. cinerea (EC₅₀ = 899 mg/L), P. debaryanum (EC₅₀ = 467 mg/L) and R. solani (EC₅₀ = 1413 mg/L).     

Physico-chemical characterization, antioxidant and anticancer activities in vitro of a novel polysaccharide from Melia toosendan Sieb. Et Zucc fruit

A novel water-soluble polysaccharide pMTPS-3, obtained from Melia toosendan Sieb. Et Zucc fruit by hot-water extraction and ethanol precipitation, was fractionated by DEAE-52 cellulose anion-exchange and Sephadex G-100 gel filtration chromatography. Its primary structural features and molecular weight were characterized by Fourier infrared spectrometry (FTIR), gel permeation chromatography (GPC) and gas chromatography (GC). And the antioxidant activities of pMTPS-3 in vitro were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, superoxide radical scavenging assay and hydroxyl radical scavenging assay. The results suggested that pMTPS-3 was a heteropolysaccharide, composed of arabinose, glucose, mannose, and galactose in the molar ratio of 17.3:28.3:41.6:12.6 with molecular weight 26 100 Da. The purified pMTPS-3 was revealed to have notable scavenging activity against DPPH radical in a concentration-dependent manner and present a moderate inhibition of superoxide radicals with an IC₅₀ (5.6 mg/ml), and potent inhibiting power for hydroxyl radical compared with crude polysaccharide. Further, it exhibited strong inhibition effect in vitro on the growth of human gastric cancer BGC-823 cells. It is strongly evidenced that pMTPS-3 purified from the crude polysaccharides of Melia toosendan Sieb. Et Zucc could be explored as a potential antioxidant and therapeutics.     

Chitosan gallate as a novel potential polysaccharide antioxidant: an EPR study

A novel biopolymer-based antioxidant, chitosan conjugated with gallic acid (chitosan galloylate, chitosan-GA), is proposed. Electron paramagnetic resonance (EPR) demonstrates a wide range of antioxidant activity for chitosan-GA as evidenced from its reactions with oxidizing free radicals, that is, 1,1-diphenyl-2-picryl-hydrazyl (DPPH), horseradish peroxidase (HRP)-H₂O₂, carbon-centered alkyl radicals, and hydroxyl radicals. The EPR spectrum of the radical formed on chitosan-GA was attributed to the semiquinone radical of the gallate moiety. The stoichiometry and effective concentration (EC₅₀) of the DPPH free radical with chitosan-GA show that the radical scavenging capacity is maintained even after thermal treatment at 100 °C for an hour. Although the degree of substitution of GA on chitosan was about 15%, its antioxidant capacity, that is, the reaction with carbon-centered and hydroxyl radicals, is comparable to that of GA.     

Enhanced antioxidant and antitumor activities of Antrodia cinnamomea cultured with cereal substrates in solid state fermentation

Growing exclusively on stout camphor trees in Taiwan, Antrodia cinnamomea is known for its extraordinary antioxidant and antitumor activities. As an alternative to the limited supply of natural source, cultured A. cinnamomea from solid state or submerged liquid fermentation still offers many of its medicinal effects. To further enhance the production of functional compounds and corresponding activities, oat, wheat, buckwheat and pearl barley were used as substrates for solid state fermentation of A. cinnamomea in this study. Among these cereal-based culturing, the methanol extract of A. cinnamomea mycelia grown on oats showed stronger overall antioxidant properties. EC₅₀ for the antioxidant activity (conjugated diene method), the DPPH radicals scavenging ability and reducing power were estimated to be around 0.57 mg/mL, 1.07 mg/mL and 0.31 mg/mL, respectively. Incubating cultured cells with 150 ppm of the oat-cultured mycelial extract for 24 h greatly reduced the viability of MCF-7 breast cancer cells and HepG2 hepatocellular carcinoma cells to 29% and 76%, while 3T3 normal fibroblasts were virtually unaffected. In general, cereal-based solid state fermentation of A. cinnamomea produced more of the secondary metabolites and their methanolic extracts showed stronger antioxidant and anti-tumor activities than extracts obtained from liquid fermentation at the same concentration.     

Carbohydrate-based anti-adhesive inhibition of Vibrio cholerae toxin binding to GM1-OS immobilized into artificial planar lipid membranes

We have studied ‘food grade’ sialyloligosaccharides (SOS) as anti-adhesive drugs or receptor analogues, since the terminal sialic acid residue has already been shown to contribute significantly to the adhesion and pathogenesis of the Vibrio cholerae toxin (Ctx). GM1-oligosaccharide (GM1-OS) was immobilized into a supporting POPC lipid bilayer onto a surface plasmon resonance (SPR) chip, and the interaction between uninhibited Ctx and GM1-OS-POPC was measured. SOS inhibited 94.7% of the Ctx binding to GM1-OS-POPC at 10 mg/mL. The SOS EC₅₀ value of 5.521 mg/mL is high compared with 0.2811 μg/mL (182.5 ρM or 1.825 × 10⁻¹⁰ M) for GM1-OS. The commercially available sialyloligosaccharide (SOS) mixture Sunsial E^® is impure, containing one monosialylated and two disialylated oligosaccharides in the ratio 9.6%, 6.5% and 17.5%, respectively, and 66.4% protein. However, these inexpensive food-grade molecules are derived from egg yolk and could be used to fortify conventional food additives, by way of emulsifiers, sweeteners and/or preservatives. The work further supports our hypothesis that SOS could be a promising natural anti-adhesive glycomimetic against Ctx and prevent subsequent onset of disease.     

Purification and evaluation of a novel antioxidant peptide from corn protein hydrolysate

In the present study, corn protein hydrolysate (CPH) with antioxidant activity was obtained by enzymatic hydrolysis. Corn gluten meal (CGM) was hydrolyzed using two proteases (Alcalase and Protamex) to produce the antioxidant peptide. Extrusion and starch removal of corn protein were used as pretreatment procedures before proteolysis. Hydrolysis by Alcalase has more remarkable digesting efficiency on corn protein than that by Protamex. Therefore, the hydrolysate catalyzed by Alcalase was fractionated by ultrafiltration, and peptide with the highest antioxidant activity was purified from <6 kDa molecular weight fraction. The amino acid sequence of the novel peptide was Gln-Gln-Pro-Gln-Pro-Trp as identified by a quadrupole time-of-flight mass spectrometer (Q-TOF2), with molecular weight of 782.34 Da, which was matched to γ-zein f (50–55). The new peptide was further synthesized by Fmoc solid-phase method. It showed scavenging activity against DPPH, ABTS, and hydroxyl free radicals in dose dependent manner with EC₅₀ values of 0.95, 0.0112 and 4.43 mg/mL, respectively. It also exhibited notable reducing power of 0.54 at 2.0 mg/mL, but showed weaker Fe²⁺-chelating capacity with EC₅₀ value of 6.27 mg/mL. These results suggest that the hexapeptide is a potential natural antioxidant that can be used as drug or functional food ingredient.     

Evaluation of in vitro free radical scavenging potential of Streptomyces sp. AM-S1 culture filtrate

The present study was carried out to determine the free radical scavenging potential of culture filtrate of Streptomyces sp. AM-S1. Antioxidant activity of culture filtrate, lyophilized culture filtrate and ethyl acetate extract of Streptomyces sp. AM-S1 was determined by various in vitro assays such as ferric reducing power assay, phosphomolybdenum reduction, DPPH and ABTS radical scavenging activities. The results revealed that the culture filtrate of Streptomyces sp. AM-S1 effectively scavenged DPPH (IC₅₀ 90.2 μl/ml) and ABTS (IC₅₀ 13.2 μl/ml) radicals in a concentration dependent manner. In all the assays, ethyl acetate extract registered higher antioxidant activity when compared with the lyophilized culture filtrate (LCF). In addition, ethyl acetate extract (1123.4 μmole Fe(II)/mg extract) exhibited higher ferric reducing activity than the standard BHA (814.4 μmole Fe(II)/mg extract). Further works are needed on the isolation and identification of antioxidant molecules from the ethyl acetate extract of Streptomyces sp. AM-S1 culture filtrate.     

In vitro propagation of the medicinal plant Ziziphora tenuior L. and evaluation of its antioxidant activity

Ziziphora tenuior L. (Lamiaceae) is an aromatic herb used for its medicinal values against fungi, bacteria. Micropropagation can be used for large-scale multiplication of essential oil producing plants thus avoiding an overexploitation of natural resources. This work aims to develop a reliable protocol for the in vitro propagation of Z. tenuior, and to compare the antioxidant activity between in vitro propagated and wild plants.The explants were sterilized and cultured on MS medium containing different concentrations of growth regulators naphthalene acetic acid (NAA) or indole-3-butyric acid (IBA) with 0.5 mg/L of kinetin (Kin) callus formation was 70.2% after 45 days of incubation in dark on medium supplemented with 1.5 mg/L of NAA. After one month of callus culture on medium supplemented with 2 mg/L BA the shoot number was 5.12 and for the multiplication stage. The shoot number was 4.21 and length was 6.17 cm on medium supplemented with 1 mg/L Kin + 0.1 mg/L NAA.DPPH• reagent was used to test the antioxidant activity. The aqueous and methanol extracts of in vitro plants which were treated with 1.5 and 1 mg/L of kin plus 0.1 mg/L of NAA showed a strong DPPH• scavenging activity where IC₅₀ was 0.307 and 0.369 mg/ml, respectively, while the IC₅₀ of aqueous and methanol extracts of wild plants was 0.516 and 9.229 mg/ml, respectively. Our results suggested that plant growth regulators and in vitro culture conditions increased the antioxidant activity.     

Functionalization of chitosan by laccase-catalyzed oxidation of ferulic acid and ethyl ferulate under heterogeneous reaction conditions

Chitosan particles were functionalized with ferulic acid (FA) and ethyl ferulate (EF) as substrates using laccase from Myceliophtora thermophyla as biocatalyst. The reactions were performed with chitosan particles under an eco-friendly procedure, in a heterogeneous system at 30 °C, in phosphate buffer (50 mM, pH 7.5).The FA-chitosan derivative presented an intense yellow-orange color stable while the EF-chitosan derivative was colorless. The spectroscopic analyses indicated that the reaction products bound covalently to the free amino groups of chitosan exhibiting a novel absorbance band in the UV/Vis spectra between 300 and 350 nm, at C-2 region by the duplication of C-2 signal in the ¹³C NMR spectrum, via Schiff base bond (NC) exhibiting novel bands in the FT-IR spectrum at 1640 and 1620 cm⁻¹. Additionally, antioxidant capacities of chitosan derivatives showed that the chitosan derivatives presented improved antioxidant properties, especially for FA-chitosan derivative (EC₅₀ were 0.52 ± 0.04, 0.20 ± 0.02 mg/ml for DPPH and ABTS⁺ scavenging, respectively).     

Optimisation of exopolysaccharide production by Gomphidius rutilus and its antioxidant activities in vitro

The production conditions of the Gomphidius rutilus exopolysaccharides (GREP) in submerged culture were optimised, and the antioxidant activities of GREP in vitro were evaluated. The optimal culture medium constituents were determined as follows: 30 g/L sucrose, 3.0 g/L soybean meal, 0.25 g/L MgSO₄, 1.5 g/L K₂HPO₄, 0.5 g/L KH₂PO₄, 0.03 g/L ZnSO₄, and 0.01 g/L FeSO₄. The optimum parameters for the liquid fermentation were as follows: temperature, 25 °C; cultivation time, 6 d; initial pH, 8.0; volume of medium, 150 mL; and rotary speed, 180 rpm. GREP content and dry cell weight in optimised conditions were 540.1 ± 15.9 mg/L and 8.2 ± 0.3 g/L, respectively. GREP content under the optimised conditions was 2.5 times than that under the basic culture medium and initial conditions. GREP demonstrated positive antioxidant potential on superoxide anion radical, 1,1-diphenyl-2-picrylhydrazyl, and hydroxyl radical scavenging, and reducing power.     

Bursera fagaroides, effect of an ethanolic extract on ornithine decarboxylase (ODC) activity in vitro and on the growth of Entamoeba histolytica

The effect of an ethanolic extract from the stem bark of Bursera fagaroides on ornithine decarboxylase (ODC) activity in vitro and on the growth of Entamoeba histolytica was evaluated. For this purpose, increasing concentrations of the extract, up to 8.0 mg/mL, were added to amoeba cultures or ODC reaction mixtures, which were incubated at 37 °C. Metronidazole and G418 were added as controls. After 1.5 and 72 h, the ODC activity in vitro and growth, respectively, were determined. Results revealed a strong inhibition of growth with IC₅₀ values on the order of 0.05 mg/mL. ODC activity, on the other hand, was inhibited by 12% and 50% at concentrations of 4.0 and 8.0 mg/mL, respectively.     

Investigations of anticholinestrase and antioxidant potentials of methanolic extract,subsequent fractions,crude saponins and flavonoids isolated from Isodon rugosus

Background

Based on the ethnomedicinal uses and the effective outcomes of natural products in various diseases, this study was designed to evaluate Isodon rugosus as possible remedy in oxidative stress, alzheimer’s and other neurodegenerative diseases. Acetylecholinestrase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of crude methanolic extract (Ir.Cr), resultant fractions (n-hexane (Ir.Hex), chloroform (Ir.Cf), ethyl acetate (Ir.EtAc), aqueous (Ir.Aq)), flavonoids (Ir.Flv) and crude saponins (Ir.Sp) of I. rugosus were investigated using Ellman’s spectrophotometric method. Antioxidant potential of I. rugosus was determined using DPPH, H₂O₂ and ABTS free radicals scavenging assays. Total phenolic and flavonoids contents of plant extracts were determined and expressed in mg GAE/g dry weight and mg RTE/g of dry sample respectively.

Results

Among different fractions Ir.Flv and Ir.Cf exhibited highest inhibitory activity against AChE (87.44 ± 0.51, 83.73 ± 0.64%) and BChE (82.53 ± 0.71, 88.55 ± 0.77%) enzymes at 1 mg/ml with IC₅₀ values of 45, 50 for AChE and 40, 70 μg/ml for BChE respectively. Activity of these fractions were comparable to galanthamine causing 96.00 ± 0.30 and 88.61 ± 0.43% inhibition of AChE and BChE at 1 mg/ml concentration with IC₅₀ values of 20 and 47 μg/ml respectively. In antioxidant assays, Ir.Flv, Ir.Cf, and Ir.EtAc demonstrated highest radicals scavenging activities in DPPH and H₂O₂ assays which were comparable to ascorbic acid. Ir.Flv was found most potent with IC₅₀ of 19 and 24 μg/ml against DPPH and H₂O₂ radicals respectively. Whereas antioxidant activates of plant samples against ABTS free radicals was moderate. Ir.Cf, Ir.EtAc and Ir.Cr showed high phenolic and flavonoid contents and concentrations of these compounds in different fractions correlated well to their antioxidant and anticholinestrase activities.

Conclusion

It may be inferred from the current investigations that the Ir.Sp, Ir.Flv and various fractions of I. rugosus are good sources of anticholinesterase and antioxidant compounds. Different fractions can be subjected to activity guided isolation of bioactive compounds effective in neurological disorders.     

Antioxidant and anticholinesterase investigations of Rumex hastatus D. Don: potential effectiveness in oxidative stress and neurological disorders

Background

Rumex species are traditionally used for the treatment of neurological disorders including headache, migraine, depression, paralysis etc. Several species have been scientifically validated for antioxidant and anticholinestrase potentials. This study aims to investigate Rumex hastatus D. Don crude methanolic extract, subsequent fractions, saponins and flavonoids for acetylcholinestrase, butyrylcholinestrase inhibition and diverse antioxidant activities to validate its folkloric uses in neurological disorders. Rumex hastatus crude methanolic extract (Rh. Cr), subsequent fractions; n-hexane (Rh. Hex), chloroform (Rh. Chf), ethyl acetate (Rh. EtAc), aqueous fraction (Rh. Aq), crude saponins (Rh. Sp) and flavonoids (Rh. Fl) were investigated against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) at various concentrations (125, 250, 500, 1000 μg/mL) using Ellman’s spectrophotometric analysis. Antioxidant potentials of Rh. Sp and Rh. Fl were evaluated using DPPH, H₂O₂ and ABTS free radical scavenging assays at 62.5, 125, 250, 500, 1000 μg/mL.

Results

All the test samples showed concentration dependent cholinesterase inhibition and radicals scavenging activity. The AChE inhibition potential of Rh. Sp and Rh. Fl were most prominent i.e., 81.67 ± 0.88 and 91.62 ± 1.67 at highest concentration with IC₅₀ 135 and 20 μg/mL respectively. All the subsequent fractions exhibited moderate to high AChE inhibition i.e., Rh. Cr, Rh. Hex, Rh. Chf, Rh. EtAc and Rh. Aq showed IC₅₀ 218, 1420, 75, 115 and 1210 μg/mL respectively. Similarly, against BChE various plant extracts i.e., Rh. Sp, Rh. Fl, Rh. Cr, Rh. Hex, Rh. Chf, Rh. EtAc and Rh. Aq resulted IC₅₀ 165, 175, 265, 890, 92, 115 and 220 μg/mL respectively. In DPPH free radical scavenging assay, Rh. Sp and Rh. Fl showed comparable results with the positive control i.e., 63.34 ± 0.98 and 76.93 ± 1.13% scavenging at 1 mg/mL concentration (IC₅₀ 312 and 104 μg/mL) respectively. The percent ABTS radical scavenging potential exhibited by Rh. Sp and Rh. Fl (1000 μg/mL) were 82.58 ± 0.52 and 88.25 ± 0.67 with IC₅₀ 18 and 9 μg/mL respectively. Similarly in H₂O₂ scavenging assay, the Rh. Sp and Rh. Fl exhibited IC₅₀ 175 and 275 μg/mL respectively.

Conclusion

The strong anticholinesterase and antioxidant activities of Rh. Sp, Rh. Fl and various fractions of R. hastatus support the purported ethnomedicinal uses and recommend R. hastatus as a possible remedy for the treatment of AD and neurodegenerative disorders.     

Phytochemical analysis,antioxidant and antimicrobial activity of wild and in vitro derived plants of Ceropegia thwaitesii Hook – An endemic species from Western Ghats,India

Ceropegia thwaitesii Hook (Asclepiadaceae), an endemic plant species, due to habitat destruction and over exploitation has a very restricted distribution in the Western Ghats of Tamil Nadu, India. The present wrok aimed to determine the chemical composition, the total phenolic (TPC), flavonoid (TFC) and tannin content (TEC), and to assess the antioxidant properties of various extracts of in vivo plants (IVP) and in vitro regenerated plants (IRP) of C. thwaitesii. Some phenolic compounds like gallic acid, cathechol, vanillin and salicylic acid were identified and quantified by HPLC. All the extracts possessed relevant radical scavenging activity on DPPH, Superoxide radical scavenging activity, and Nitric oxide radicals as well as total antioxidant ability. DPPH assay of in vitro methanol stems extracts and ethanol leaves extracts revealed the best antioxidant properties with important IC₅₀ values of 0.248?±?0.45?µg/mL and 0.397?±?0.67?µg/mL, respectively, whereas in vivo chloroform stems extracts showed a lower antioxidant activity (IC₅₀ of 10.99?±?0.24?µg/mL). The IRP methanol extracts of stem and leaves had good inhibitory activity against all tested microorganisms in a dose-dependent manner. These results suggested that in vitro raised plants of C. thwaitesii are an excellent source of antioxidant compounds to be exploited on an industrial level as food additive.     

Trichinella spiralis: Differential effect of host bile on the in vitro invasion of infective larvae into epithelial cells

The differential effect of fox and pig bile and its corresponding low molecular weight fraction (LMW) was investigated on the in vitro invasion of MDCK-AA7 epithelial cell monolayers by Trichinella spiralis muscle larvae. Seven invasion experiments were performed and a total of 274 cell monolayers were examined. Fox and pig raw bile at 1:10 and 1:20 dilution and their LMW fractions at 1:10 dilution activated T. spiralis larvae to invade the cell monolayers. In addition, fox raw bile caused significantly larger cell damage than pig raw bile at both dilutions. The area of cell damage was larger at 1:10 than at 1:20 dilution for both fox and pig raw bile (p < 0.05). On the other hand, there was no significant difference between the areas of cell damage caused by the LMW fractions of fox and pig bile. It is concluded that differences between host bile actions may account for differences in host susceptibility to T. spiralis.     

Butane-2,3-dionethiosemicarbazone: an oxime with antioxidant properties

Oximes are compounds generally used to reverse the acetylcholinesterase (AChE) inhibition caused by organophosphates (OPs). The aim of this study was to examine the capacity of the butane-2,3-dionethiosemicarbazone oxime to scavenge different forms of reactive species (RS) in vitro, as well as counteract their formation. The potential antioxidant and toxic activity of the oxime was assayed both in vitro and ex vivo. The obtained results indicate a significant hydrogen peroxide (H₂O₂), nitric oxide (NO) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity at 0.275, 0.5 and 5 μM of oxime, respectively (p ≤ 0.05). The oxime exhibited a powerful inhibitory effect on dihydroxybenzoate formation (25 μM) (p ≤ 0.05) and also decreased deoxyribose degradation induced by Fe²⁺ and via Fenton reaction (0.44 and 0.66 mM, respectively) (p ≤ 0.05). The oxime showed a significant inhibitory effect on σ-phenantroline reaction with Fe²⁺ (0.4 mM) suggesting a possible interaction between the oxime and iron. A significant decrease in the basal and pro-oxidant-induced lipid peroxidation in brain, liver, and kidney of mice was observed both in vitro and ex vivo (p ≤ 0.05). In addition, in our ex vivo experiments the oxime did not depict any significant changes in thiol levels of liver, kidney and brain as well as did not modify the δ-aminolevulinate dehydratase (δ-ALA-D) activity in these tissues. Taken together our results indicate an in vitro and ex vivo antioxidant activity of the oxime possibly due to its scavenging activity toward different RS and a significant iron interaction.     

Antioxidant activity of differently regioselective chitosan sulfates in vitro

Differently regioselective chitosan sulfates were prepared according to Hanno Baumann's methods. Their antioxidant potencies were investigated employing various established in vitro systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH)/superoxide/hydroxyl radicals scavenging, reducing power, iron ion chelating and total antioxidant activity. All kinds of sulfated chitosans (HCTS, TSCTS, SCTS, TCTS) showed strong inhibitory activity toward superoxide radical by the PMS-NADH system compared to Vc. According to the above-mentioned order their IC50 were 0.012, 0.040, 0.015, 0.022 mg/mL, respectively, however, scavenging activity of Vc on superoxide radical was 68.19% at 2.0 mg/mL. Scavenging activity of superoxide radical was found to be in the order of HCTS>SCTS>TCTS>TSCTS>Vc. Furthermore, all kinds of sulfated chitosans exhibited strong concentration-dependent inhibition of deoxyribose oxidation. Except for HCTS, others had stronger scavenging activity on hydroxyl radical than Vc. Scavenging effect of TSCTS on 1,1-diphenyl-2-picrylhydrazyl radical was little lower than that of BHA, but better than that of others. All kinds of sulfated chitosans were efficient in the reducing power, especially TSCTS. TSCTS and TCTS showed considerable ferrous ion chelating potency. The data obtained in vitro models clearly establish the antioxidant potency of all kinds of sulfated chitosans. These in vitro results suggested the possibility that sulfated chitosans could be effectively employed as ingredient in health or functional food, to alleviate oxidative stress. However, comprehensive studies need to be conducted to ascertain the in vivo safety of sulfated chitosans in experimental animal models.