The chilean superfruit black-berry Aristotelia chilensis (Elaeocarpaceae), Maqui as mediator in inflammation-associated disorders

The effects of phytochemicals occurred in fractions and extracts of fruits of "Maqui-berry" (Aristotelia chilensis), on the expression of cyclooxygenase-2 (COX-2), inducible-nitric oxide synthases (iNOS) and the production of proinflammatory mediators were investigated in lipopolysaccharide (LPS)-activated murine macrophage RAW-264 cells, as well as their antioxidant activities. The MeOH extract (A), acetone/methanol extract (B), fractions F3, F4, subfractions (SF4-SF6, SF7, SF8-SF10, SF11-SF15, SF16-SF20), quercetin, gallic acid, luteolin, myricetin, mixtures M1, M2 and M3 exhibited potent anti-inflammatory and antioxidant activities. The results indicated that anthocyanins, flavonoids and its mixtures suppressed the LPS induced production of nitric oxide (NO), through the down-regulation of iNOS and COX-2 protein expressions and showed a potent antioxidant activity against SOD, ABTS, TBARS, ORAC, FRAP and DCFH. The inhibition of enzymes and NO production by selected fractions and compounds was dose-dependent with significant effects seen at concentration as low as 1.0-50.0 (ppm) and 5.0-10.0 μM, for samples (extracts, fractions, subfractions and mixtures) and pure compounds, respectively. Thus, the phenolics (anthocyanins, flavonoids, and organic acids) as the fractions and mixtures may provide a potential therapeutic approach for inflammation associated disorders and therefore might be used as antagonizing agents to ameliorate the effects of oxidative stress.

Antioxidant capacity of cocoa beans and chocolate assessed by FTIR

The total antioxidant capacity (TAC) and total phenolic compounds (TPC) of cocoa beans and chocolate produced from spontaneous and inoculated fermentations of different cocoa varieties were evaluated. Fourier transform infrared spectroscopy (FTIR), as well as conventional methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), was used to determine TAC and TPC. Chocolate showed higher (p<0.05) TPC (47.17-57.16mgGAE/g) and TAC (1.66-2.33mMTE/g and 8.86-11.35mMTE/g as measured by DPPH and ABTS, respectively) than cocoa beans (6.30-26.05mgGAE/g, 0.24-1.17mMTE/g and 1.29-4.83mMTE/g for TPC, DPPH and ABTS, respectively). Partial least square (PLS) model for infrared data showed a good calibration coefficient (R²cal>0.94), indicating that the FTIR technique represents a fast and reliable tool to evaluate TPC and TAC in cocoa beans and chocolate.

Validation of three automated assays for total antioxidant capacity determination in canine serum samples

We performed analytical validation of 3 automated assays of the total antioxidant capacity (TAC) in canine serum and evaluated their use in dogs with inflammatory bowel disease. The assays were based on the generation of a 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical cation (ABTS•⁺) in aqueous media, which produces a blue-green color. The antioxidants present in the sample remove the chromogen in proportion to their concentrations. The assays differed mainly in the way in which this radical was produced. All 3 assays produced acceptable results in the analytical validation. However, only 2 of the assays were capable of detecting significantly different TAC values in healthy and diseased animals.

Antioxidant, anticholinesterase and tyrosinase inhibition activities, and fatty acids of Crocus mathewii - A forgotten endemic angiosperm of Turkey

Context We report the first ever chemical/biochemical study on Crocus mathewii Kerndorff (Iridaceae) - a Turkish endemic angiosperm. This plant has never been explored for its phytochemistry and bioactivities. Objective This study explores C. mathewii corm and aerial parts for the chemical and biological properties of hexane, ethyl acetate, methanol and water fractions of the extracts. Material and methods Plant material (20 g) was extracted by methanol (250 mL × 5, 3 days each) and fractioned into hexane, ethyl acetate, methanol and water. All fractions were subjected to β-carotene-linoleic acid, DPPH(·), ABTS(·)(+), CUPRAC, metal chelating and tyrosinase inhibition activities. Hexane fractions were submitted to GC-MS analysis. Results Ethyl acetate fractions showed excellent IC50 values in DPPH(·) (aerial 36.21 ± 0.76 and corm 33.87 ± 0.02 mg/L) and ABTS(·)(+) (aerial 33.01 ± 0.79 and bulb 27.87 ± 0.33 mg/L); higher than the IC50 of the standard α-tocopherol (DPPH 116.25 ± 1.97; ABTS 52.64 ± 0.37 mg/L), higher than BHA in DPPH (57.31 ± 0.25 mg/L), but slightly lower in ABTS (19.86 ± 2.73 mg/L). Methanol extract of aerial parts also showed higher activity than α-tocopherol in DPPH (85.56 ± 11.51 mg/L) but slightly less (72.90 ± 3.66 mg/L) than both the standards in ABTS. Linoleic (aerial 53.9%, corm 43.9%) and palmitic (aerial 22.2%, corm 18%) were found as the major fatty acids. Discussion and conclusion Some fractions of C. mathewii showed higher antioxidant activities than the standards. There is a need to explore more about this plant.

ANTIOXIDANT ACTIVITY AND FT-IR ANALYSIS OF DATURA INNOXIA AND DATURA METEL LEAF AND SEED METHANOLIC EXTRACTS

Background:

Datura (family- Solanaceae), has a long history of being used as herbal medicine. These medicinal effects have been attributed to the phytochemicals present in the plant leaves and seeds, in particular alkaloids, flavonoids and phenolic compounds. The objective of this study was to investigate the methanolic leaf and seed extracts of Datura innoxia (DLP-I & DSP-I) and Datura metel (DLP-M & DSP-M) for their total phenolic, flavonoids and in-vitro antioxidant properties.

Materials and Methods:

Determination of total phenolic content and total flavonoid content and antioxidant activity in terms of total antioxidant assay, ABTS assay, DPPH assay and in-vitro lipid peroxidation inhibiting activity were determined along with the FT-IR (Fourier transform infrared spectroscopy) analysis of the extracts.

Results:

The highest total phenolic and total flavonoid content were registered by the D. innoxia leaf extract (70.26 ±1.12 mg GAE/g and 34.24 ± 1.28 mg RE/g respectively). Maximum DPPH radical scavenging activity was exerted by the leaf extract of D. innoxia (IC50 = 146.69 ± 8.46 μg/mL) among the four different methanolic extracts. The highest activity of the ABTS assay was found in Datura innoxia leaf extract (IC₅₀ value = 149.42 ± 13.43 μg/mL) and the highest total antioxidant capacity was found to be present in D. innoxia leaf extract (221.25 ± 1.06 mg AAE/g) whereas D. metel seed extract registered the maximum lipid peroxidation inhibition activity (IC₅₀ = 112 ± 1.30 μg/mL). The FT-IR data also supported the maximum activity in D. innoxia (leaf and seed) extracts.

Conclusion:

The results thus obtained suggested that the plant Datura innoxia possess considerable antioxidant activity over Datura metel and therefore can be established as a potential source of natural antioxidant.

Spectrophotometric Determination of Phenolic Antioxidants in the Presence of Thiols and Proteins

Development of easy, practical, and low-cost spectrophotometric methods is required for the selective determination of phenolic antioxidants in the presence of other similar substances. As electron transfer (ET)-based total antioxidant capacity (TAC) assays generally measure the reducing ability of antioxidant compounds, thiols and phenols cannot be differentiated since they are both responsive to the probe reagent. In this study, three of the most common TAC determination methods, namely cupric ion reducing antioxidant capacity (CUPRAC), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt/trolox equivalent antioxidant capacity (ABTS/TEAC), and ferric reducing antioxidant power (FRAP), were tested for the assay of phenolics in the presence of selected thiol and protein compounds. Although the FRAP method is almost non-responsive to thiol compounds individually, surprising overoxidations with large positive deviations from additivity were observed when using this method for (phenols + thiols) mixtures. Among the tested TAC methods, CUPRAC gave the most additive results for all studied (phenol + thiol) and (phenol + protein) mixtures with minimal relative error. As ABTS/TEAC and FRAP methods gave small and large deviations, respectively, from additivity of absorbances arising from these components in mixtures, mercury(II) compounds were added to stabilize the thiol components in the form of Hg(II)-thiol complexes so as to enable selective spectrophotometric determination of phenolic components. This error compensation was most efficient for the FRAP method in testing (thiols + phenols) mixtures.

Design of Laccase-Metal Organic Framework-Based Bioelectrodes for Biocatalytic Oxygen Reduction Reaction

Laccase in combination with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as a mediator is a well-known bioelectrocatalyst for the 4-electron oxygen reduction reactions (ORR). The present work deals with the first exploitation of mesoporous iron(III) trimesate-based metal organic frameworks (MOF) MIL-100(Fe) (MIL stands for materials from Institut Lavoisier) as a new and efficient immobilization matrix of laccase for the building up of biocathodes for ORR. First, the immobilization of ABTS in the pores of the MOF was studied by combining micro-Raman spectroscopy, X-ray powder diffraction (XRPD), and N2 porosimetry. The ABTS-MIL-100(Fe)-based modified electrode presents excellent properties in terms of charge transfer kinetics and ionic conductivity as well as a very stable and reproducible electrochemical response, showing that MIL-100(Fe) provides a suitable and stabilizing microenvironment for electroactive ABTS molecules. In a second step, laccase was further immobilized on the MIL-100(Fe)-ABTS matrix. The Lac-ABTS-MIL-100(Fe)-CIE bioelectrode presents a high electrocatalytic current density of oxygen reduction and a reproducible electrochemical response characterized by a high stability over a long period of time (3 weeks). These results constitute a significant advance in the field of laccase-based bioelectrocatalysts for ORR. According to our work, it appears that the high catalytic efficiency of Lac-ABTS-MIL-100(Fe) for ORR may result from a synergy of chemical and catalytic properties of MIL-100(Fe) and laccase.

Influence of hydroxyl substitution on flavanone antioxidants properties

The aim of our study was to determine the effect of the position of the hydroxyl group on the antioxidant properties of flavonoid derivatives. For this purpose, we performed electrochemical analysis and quantum-mechanical calculations to describe the mechanisms of electrochemical oxidation, and we selected the two methods of ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) and DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate), which allowed us to determine the ability to scavenge free radicals. On the basis of the research, we found that the derivatives of flavonoids, which have a hydroxyl group substituted at the R-3 position on the C ring, have outstanding antioxidant activity. Flavone, which had an OH group substituted at the R-6 and R-7 position on the ring A, showed similar antioxidant activity to flavone without -OH groups in the structure and slightly higher activity than the di-substituted flavone on the ring A.

In vitro membrane stabilizing, thrombolytic and antioxidant potentials of Drynaria quercifolia L., a remedial plant of the Garo tribal people of Bangladesh

Background

Drynaria quercifolia L. (Family- Polypodiaceae) is a fern grows in Bangladesh used in traditional healing by the Garo tribe of Mymensingh district. In the current study, rhizomes and fertile foliage fronds of this plant have been investigated comprehensively to assess their in vitro membrane stabilizing, thrombolytic and antioxidant properties.

Methods

Rhizomes and fertile foliage fronds of D. quercifolia were collected, dried, powdered and extracted with methanol. Later on, crude methanol extracts of the plant parts were fractionated into petroleum ether, carbon tetrachloride, chloroform and aqueous soluble fractions. The extractives were then subjected to membrane stabilizing, thrombolytic and antioxidant assays.

Results

In membrane stabilizing assay, crude methanol extracts of rhizomes and fertile foliage fronds and their petroleum ether fractions were found to be very effective for stabilizing erythrocyte membrane in hypotonic solution. In case of thrombolytic study, crude methanol extract of rhizomes and its aqueous fraction exhibited noticeable clot lysis. However, in antioxidant assays, crude methanol extracts of the tested plant parts and their aqueous fractions exhibited potent 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydrogen peroxide and 2, 2’-azinobis (3-ethylbenzothiazoline sulphonic acid) (ABTS) radical scavenging activity. Besides, these extractives also displayed substantial ferric reducing potential in ferric reducing antioxidant power (FRAP) assay. Crude methanol extracts of the plant parts and their aqueous fractions were also found rich in phenolics.

Conclusion

This study demonstrates the medicinal potentials of D. quercifolia and justifies the local uses of it by the Garo tribal people of Bangladesh for multiple disease management.

Optimization of laccase production from Aspergillus flavus by design of experiment technique: Partial purification and characterization

The present study describes isolation of laccase producing fungal strain and optimization of the process parameters by design of experiment (DOE) technique to achieve the maximum production of extracellular laccases by Aspergillus flavus obtained from natural habitat. Bromophenol blue dye and ABTS (2,2'-azinobis 3-ethyl-benzothiazoline-6-sulfonate) were used as substrates for the screening of laccase activity. Design expert 8.0.7.1 software was used to optimize culture conditions such as carbon source, nitrogen source, temperature and pH. Subsequently, optimization for inoculums size was also carried out. The optimization studies revealed that the laccase yield was highest when operated at the following conditions: carbon source - cellulose (8%), nitrogen source - peptone (2%), temperature - 35 °C, pH - 7 and inoculum of size 1.5 cm.

HPLC profiling, antioxidant and in vivo anti-inflammatory activity of the ethanol extract of Syzygium jambos available in Bangladesh

BACKGROUND

Syzygium jambos has been used as a traditional medicine for the treatment of inflammatory diseases in Bangladesh. The study investigates the high performance liquid chromatography (HPLC) profiling of phenolic compounds, and evaluates the antioxidant and anti-inflammatory activities of ethanol extract of S. jambos available in Bangladesh.

METHODS

The extract was subjected to HPLC for the identification and quantification of the major bioactive polyphenols present in S. jambos. Antioxidant activity was determined using 2, 2'-azino bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging, reducing power assay, total antioxidant capacity, total phenolic and flavonoid content. Furthermore, the anti-inflammatory effect of the extract in rats for two different test models: carrageenan and histamine-induced paw edema was inspected.

RESULTS

High levels of catechin hydrate and rutin hydrate (99.00 and 79.20 mg/100 g extract, respectively) and moderate amounts of ellagic acid and quercetin (59.40 and 69.30 mg/100 g extract, respectively) were quantified in HPLC. Catechin hydrate from this plant extract was determined for the first time through HPLC. For ABTS scavenging assay, the median inhibition concentration (IC50) value of S. jambos was 57.80 µg/ml, which was significant to that of ascorbic acid (12.01 µg/ml). The maximum absorbance for reducing power assay was found to be 0.4934. The total antioxidant capacity, phenolic and flavonoid contents were calculated to be 628.50 mg/g of ascorbic acid, 230.82 mg/g of gallic acid and 11.84 mg/g of quercetin equivalent, respectively. At a dose of 400 mg/kg, a significant acute anti-inflammatory activity (P < 0.01) was observed in rats for both the test models with a reduction in the paw volume of 58.04 and 53.95 %, in comparison to those of indomethacin (62.94 and 65.79 %), respectively.

CONCLUSIONS

The results suggest that the phenolic and flavonoid compounds are responsible for acute anti-inflammatory and antioxidant activities of S. jambos.

Antiobesity, hypolipidemic, antioxidant and hepatoprotective effects of Achyranthes aspera seed saponins in high cholesterol fed albino rats

INTRODUCTION

Numerous herbal medicines have been recommended for the treatment of different diseases. Achyranthes aspera, Linn. (Family: Amaranthaceae), popularly known as Charchitta or Pitpapra, is commonly used by traditional healers for the treatment of fever, malaria, dysentery, asthma, arterial hypertension, pneumonia, and diabetes. The root extract is well reputed for its insect molting hormonal activity. This investigation was conducted to evaluate the effects of saponins from Achyranthes aspera seeds on the serum lipid profile of albino rats fed a high cholesterol diet.

MATERIAL AND METHODS

Hypolipidemic, antioxidant and hepatoprotective activities of these saponins were tested as described previously. To determine the mechanism underlying the observed effects, serum antioxidant status was assessed according to ABTS (2,2'-azino-bis-3-ethylbenzo-thiazoline-6-sulfonic acid), superoxide dismutase and ferric ion reducing antioxidant power (FRAP) assays in saponin-treated hyperlipidemic animals. Liver enzyme levels were determined to reveal any possible hepatotoxicity.

RESULTS

Four-week oral administration of A. aspera seed saponins produced a significant (p < 0.05) decrease of total cholesterol, total triglycerides and LDL-C and a significant increase of HDL-C level in hyperlipidemic rats. Treatment with A. aspera seed saponins also showed a significant (p < 0.01) improvement of serum antioxidant status in tested animals. No significant hepatotoxicity was produced by such treatment as the serum liver enzyme activity remained unaltered.

CONCLUSIONS

Saponins from A. aspera seeds possess antihyperlipidemic and antioxidant properties which might lead to improvement of serum lipid profile and blood antioxidant status. Our findings support the folkloric use of this indigenous plant in the treatment of hyperlipidemia. However, its exact mechanism of action remains to be elucidated.

Competitive kinetics as a tool to determine rate constants for reduction of ferrylmyoglobin by food components

Competitive kinetics were applied as a tool to determine apparent rate constants for the reduction of hypervalent haem pigment ferrylmyoglobin (MbFe(IV)O) by proteins and phenols in aqueous solution of pH 7.4 and I=1.0 at 25°C. Reduction of MbFe(IV)O by a myofibrillar protein isolate (MPI) from pork resulted in kMPI=2.2 ± 0.1 × 10(4)M(-1)s(-1). Blocking of the protein thiol groups on the MPI by N-ethylmaleimide (NEM) markedly reduced this rate constant to kMPI-NEM=1.3 ± 0.4 × 10(3)M(-1)s(-1) consistent with a key role for the Cys residues on MPI as targets for haem protein-mediated oxidation. This approach allows determination of apparent rate constants for the oxidation of proteins by haem proteins of relevance to food oxidation and should be applicable to other systems. A similar approach has provided approximate apparent rate constants for the reduction of MbFe(IV)O by catechin and green tea extracts, though possible confounding reactions need to be considered. These kinetic data suggest that small molar excesses of some plant extracts relative to the MPI thiol concentration should afford significant protection against MbFe(IV)O-mediated oxidation.

Enzymatic Glycosylation of Phenolic Antioxidants: Phosphorylase-Mediated Synthesis and Characterization

Although numerous biologically active molecules exist as glycosides in nature, information on the activity, stability, and solubility of glycosylated antioxidants is rather limited to date. In this work, a wide variety of antioxidants were glycosylated using different phosphorylase enzymes. The resulting antioxidant library, containing α/β-glucosides, different regioisomers, cellobiosides, and cellotriosides, was then characterized. Glycosylation was found to significantly increase the solubility and stability of all evaluated compounds. Despite decreased radical-scavenging abilities, most glycosides were identified to be potent antioxidants, outperforming the commonly used 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT). Moreover, the point of attachment, the anomeric configuration, and the glycosidic chain length were found to influence the properties of these phenolic glycosides.

Radical Scavenging by Acetone: A New Perspective to Understand Laccase/ABTS Inactivation and to Recover Redox Mediator

The biosynthetic utilization of laccase/mediator system is problematic because the use of organic cosolvent causes significant inhibition of laccase activity. This work explored how the organic cosolvent impacts on the laccase catalytic capacity towards 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) in aqueous solution. Effects of acetone on the kinetic constants of laccase were determined and the results showed K_m and V_max varied exponentially with increasing acetone content. Acetone as well as some other cosolvents could transform ABTS radicals into its reductive form. The content of acetone in media significantly affected the radical scavenging rates. Up to 95% of the oxidized ABTS was successfully recovered in 80% (v/v) acetone in 60 min. This allows ABTS to be recycled at least six times with 70%–75% of active radicals recovered after each cycle. This solvent-based recovery strategy may help improve the economic feasibility of laccase/ABTS system in biosynthesis.

Influence of water biscuit processing and kernel puffing on the phenolic acid content and the antioxidant activity of einkorn and bread wheat

The whole meal flour of wheat is rich in phenolic acids, which provide a relevant antioxidant activity to food products. Aim of this research was to assess the influence of processing on phenolic acid content and antioxidant activity of whole meal flour water biscuits and puffed kernels of einkorn and bread wheat. To this end, the evolution of syringaldehyde, ferulic, vanillic, syringic, p-coumaric, p-hydroxybenzoic, and caffeic acids was studied during manufacturing. Overall, from flour to water biscuit, the total soluble conjugated phenolic acids increased slightly in einkorn, while the insoluble bound phenolic acids decreased in all the accessions as a consequence of losses during the mixing step. In the puffed kernels, instead, the total soluble conjugated phenolic acids increased markedly, while the bound phenolics did not show any clear change, evidencing their high thermal stability. The antioxidant activity, measured by FRAP and ABTS, increased during processing and was highest under the most drastic puffing conditions.

Adaptation and Validation of QUick, Easy, New, CHEap, and Reproducible (QUENCHER) Antioxidant Capacity Assays in Model Products Obtained from Residual Wine Pomace

Evaluation of the total antioxidant capacity of solid matrices without extraction steps is a very interesting alternative for food researchers and also for food industries. These methodologies have been denominated QUENCHER from QUick, Easy, New, CHEap, and Reproducible assays. To demonstrate and highlight the validity of QUENCHER (Q) methods, values of Q-method validation were showed for the first time, and they were tested with products of well-known different chemical properties. Furthermore, new QUENCHER assays to measure scavenging capacity against superoxide, hydroxyl, and lipid peroxyl radicals were developed. Calibration models showed good linearity (R(2) > 0.995), proportionality and precision (CV < 6.5%), and acceptable detection limits (<20.4 nmol Trolox equiv). The presence of ethanol in the reaction medium gave antioxidant capacity values significantly different from those obtained with water. The dilution of samples with powdered cellulose was discouraged because possible interferences with some of the matrices analyzed may take place.

Phenolic, flavonoid contents, anticholinesterase and antioxidant evaluation of Iris germanica var; florentina

This study was designed to investigate antioxidant and anticholinesterase potential of Iris germanica var; florentina. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potential of plant samples were investigated by Ellman's assay. Antioxidant activity was performed using DPPH, H2O2 and ABTS free radical scavenging assays. Total phenolics and flavonoids contents were expressed in mg GAE/g dry weight and mg RTE/g, respectively. In AChE inhibition assay, Ig.Fl, Ig.Sp and Ig.Cf fractions exhibited highest activity with IC50 values of < 0.1, 5.64 and 19 μg/mL, respectively. In BChE inhibitory assay, Ig.Fl, Ig.Sp, Ig.Cf and Ig.Cr were most active with IC50 of < 0.1, < 0.1, 31 and 78 μg/mL, respectively. In DPPH assay, Ig.Fl and Ig.Cf exhibited highest inhibition of free radicals, 80.52% (IC50 = 9 μg/mL) and 78.30% (IC50 = 8 μg/mL), respectively. In ABTS assay Ig.Cr, Ig.Cf, Ig.Fl and Ig.Sp exhibited IC50 values of < 0.1, 2, 2 and 3 μg/mL, respectively.

Synthesis, Characterization and Biological Studies of Metal(II) Complexes of (3E)-3-[(2-{(E)-[1-(2,4-Dihydroxyphenyl) ethylidene]amino}ethyl)imino]-1-phenylbutan-1-one Schiff Base

Co(II), Ni(II), Zn(II) and Cu(II) complexes of (3E)-3-[(2-{(E)-[1-(2,4-dihydroxyphenyl)ethylidene]amino}ethyl)imino]-1-phenylbutan-1-one (DEPH2) derived from ethylenediamine, 2',4'-dihydroxyacetophenone and 1-phenylbutane-1,3-dione have been synthesized and characterized by elemental analysis, FTIR, UV-Visible spectroscopy, and screened to establish their potential as antibacterial agents, antioxidants and DPPH radical scavengers. The FTIR spectra showed that the ligand behaves as a dibasic tetradentate ligand with the dioxygen-dinitrogen donor atom system oriented towards the central metal ion. The analytical and spectroscopic data suggest a square planar geometry for Cu(II) and Ni(II) complexes and an octahedral geometry for the Co(II) complex. The ligand and their metal complexes were screened for antibacterial activity against Gram (+) and Gram (-) bacteria by the agar well diffusion method. In addition, the antioxidant activities of the complexes were also investigated through their scavenging effect on DPPH and ABTS radicals. The obtained IC50 value of the DPPH activity for the copper complex (2.08 ± 0.47 µM) and that of the ABTS activity for the copper complex (IC50 = 2.11 + 1.69 µM) were higher than the values obtained for the other compounds.

Traditional elderflower beverages: a rich source of phenolic compounds with high antioxidant activity

Traditional elderflower beverages are very popular due to their pleasing taste and pro-health properties. Phenolics were quantified in three elderflower extracts (methanolic extraction and two water extracts prepared as fresh drinks according to local recipes) with HPLC-MS. Chromatographic patterns of methanolic and water extracts were quite similar; however, content levels of individual compounds differed between the two extraction solvents. Two feruloylquinic acids and two p-coumaroyl-caffeoylquinic acids and different flavonol glycosides have been identified in elderflowers for the first time. Hydroxycinnamic acids and flavonol glycosides were the major phenolic constituents in elderflowers. Methanolic extract contained higher levels of all phenolic groups compared to water-extracted samples. The yield of elderflower extracts depended on extract solution and time of extraction. Elderflower beverages were characterized by high total phenolic content (91.09 to 746.63 mg GAE/L). The results confirmed that elderflower beverages (sabesa, syrup) should be recommended as a good source of phenolics in human diet.

Antioxidant capacity of hydrolyzed animal by-products and relation to amino acid composition and peptide size distribution

The antioxidative capacity of six different tissue hydrolysates (porcine colon, heart and neck and bovine lung, kidney and pancreas) were tested by three different assays monitoring iron chelation, ABTS radical scavenging and inhibition of lipid oxidation in emulsions, respectively. The hydrolysates were also investigated with respect to amino acid composition and peptide size distribution. The hydrolysates contained peptides ranging from 20 kDa to below 100 Da with a predominance of peptides with low molecular weight (53.8 to 89.0 % below 3 kDa). All hydrolysates exhibited antioxidant activity as assessed with all three methods; inhibition of lipid oxidation ranging from 72 to 88 % (at a final protein concentration of 7 mg/mL), iron chelation capacity from 23 to 63 % (at 1.1 mg/mL), and ABTS radical scavenging from 38 to 50 % (at 10 μg /mL). The antioxidant activity did not correlate with the proportion of low molecular weight peptides in the hydrolysed tissues, but with the content of specific amino acid residues. The ABTS radical scavenging capacity of the tissues was found to correlate with the content of Trp, Tyr, Met and Arg, whereas the ability to inhibit the oxidation of lineoleic acid correlated with the content of Glu and His. The chosen animal by-products thus represent a natural source of antioxidants with potential for food application.

Anti-oxidant, anti-inflammatory and antinociceptive properties of the acetone leaf extract of vernonia amygdalina in some laboratory animals

PURPOSE

Vernonia amygdalina is a medicinal plant of great importance that has its fresh leaves rich in vitamins and salt hence, it is valuable in human diet. The anti-oxidant, anti-inflammatory and analgesic activities of its acetone leaf extract were evaluated in this study to validate its folkloric use.

METHODS

The acetone extract is prepared by dissolving ground plant materials (200g) in 1 L of acetone for 48 h, filtered, and then dried using rotary evaporator before it is used for the pharmacological investigations. Standard phytochemical methods were used to test for the presence of phytoactive compounds in the plant. Acute toxicity was carried out in mice to determine safe doses for use. The anti-inflammatory activities were conducted using carrageenan and histamine to induce oedema in rats while analgesic activities were embarked upon using acetic acid- induced writhing test and formalin-induced paw lick test. The anti-oxidant activities were assessed in vitro using ABTS, DPPH, FRAP and total polyphenolics.

RESULTS

The results from this study showed that the 100 and 200 mg/kg doses of the acetone extract caused significant reduction in oedema induced by both carrageenan and histamine. Similar effect was observed in analgesic tests which were comparable to that of indomethacin, the reference drug used in the study.

CONCLUSION

The anti-oxidant effects were also good and the pharmacological activities may be due to the presence of polyphenols and other phytochemicals contained in the plant. The study may have thus validated the folkloric use of this plant as a medicinal and nutritional agent.

Evaluation of sour cherry (Prunus cerasus L.) fruits for their polyphenol content, antioxidant properties, and nutritional components

Nutritional compounds (phenolic compounds, L-ascorbic acid), antioxidant activities, and physicochemical characteristics (fruit weight, dry matter, soluble solids, pH, acidity, total and reducing sugars) of 33 different sour cherry cultivars were studied. Polyphenols were identified by LC-PDA-QTOF/MS and quantified by UPLC-PDA-FL. A total of 41 polyphenolic compounds found were identified and presented as 14 flavan-3-ols, 11 anthocyanins, 5 hydroxycinnamic acids, 10 flavonols, and 1 flavon. The content of total polyphenols (TPs) ranged from 2982.51 ('Wisok' cultivar) to 1539.43 mg/100 g dry weight ('Erdi Nagygyϋmϋscu'cultivar). Flavan-3-ols, the major class of sour cherry polyphenols, represented ∼ 40% of the TP compounds, whereas anthocyanins and hydroxycinnamic acids amounted for about 25% each. The content of l-ascorbic acid did not exceed 22.18 mg/100 g fresh matter. Some polish sour cherry cultivars (especially 'Agat', 'Ametyst', 'Wider', 'Winer', and 'Wisok') may be selected to promote the growth of cultivars with strong nutritional and phytochemical beneficial effects on human health.

Antioxidant compounds from ethanol extracts of bamboo (Neosinocalamus affinis) leaves

Activity-guided fractionation of Neosinocalamus affinis leaves led to obtain two new flavonoids, 4'-O-((7″R,8″S)-8″-guaiacylglyceryl)-pleioside B (9) and apigenin 6-C-β-d-fucopyranosyl-7-O-β-d-glucopyranoside (10) along with eight known compounds. Their structures were elucidated on the basis of spectroscopic data (UV, IR, NMR, and MS). Among these 10 compounds, farobin A (4) and isoorientin (7) showed significant antioxidant activity evaluated by 1,1-diphenyl-2-picrylhydrazyl, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), superoxide anion and nitric oxide (NO) radical-scavenging assays.

Antioxidant Generation during Coffee Roasting: A Comparison and Interpretation from Three Complementary Assays

Coffee is a major source of dietary antioxidants; some are present in the green bean, whereas others are generated during roasting. However, there is no single accepted analytical method for their routine determination. This paper describes the adaption of three complementary assays (Folin-Ciocalteu (FC), ABTS and ORAC) for the routine assessment of antioxidant capacity of beverages, their validation, and use for determining the antioxidant capacities of extracts from coffee beans at different stages in the roasting process. All assays showed a progressive increase in antioxidant capacity during roasting to a light roast state, consistent with the production of melanoidins having a higher antioxidant effect than the degradation of CGAs. However, the three assays gave different numbers for the total antioxidant capacity of green beans relative to gallic acid (GA), although the range of values was much smaller when chlorogenic acid (CGA) was used as reference. Therefore, although all three assays indicated that there was an increase in antioxidant activity during coffee roasting, and the large differences in responses to GA and CGA illustrate their different sensitivities to different types of antioxidant molecule.

Phenolic and flavonoid contents and anti-oxidative potential of epicarp and mesocarp of Lagenaria siceraria fruit: a comparative study

OBJECTIVE

To conduct a comparative analysis of the phenolic and flavonoid contents and anti-oxidative potential of epicarp and mesocarp of Lagenaria siceraria fruit.

METHODS

The dried methanolic extracts of mesocarp and epicarp of the fruit and their hexane, chloroform, ethyl acetate, n-butanolic and aqueous fractions were subjected to antioxidant assays including ferric reducing antioxidant potential, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid, reducing power capacity, 2,2-diphenyl-1-picrylhydrazyl, lipid peroxidation inhibitory and phosphomolybdate assays. Total phenolic and flavonoid contents were also determined.

RESULTS

Ethyl acetate fractions of epicarp and mesocarp had considerable amounts of phenolics (243.50 and 109.50 μg/mL of gallic acid equivalents, respectively). 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of ethyl acetate fractions of both the plant parts showed higher activity than vitamin C with IC50 (0.75 and 3.91 mg, respectively). In phosphormolybdate assay, the hexane fractions of both the parts showed highest activity [1.16 and 2.99 μg/mL of ascorbic acid equivalents (AAE) for epicarp and mesocarp, respectively], mesocarp being much potent than epicarp. The n-butanolic fraction of mesocarp also showed much higher activity (1.13 μg/mL AAE) than that of epicarp (0.74 μg/mL AAE), while the chloroform and ethyl acetate fractions of epicarp were also considerably potent. In ferric reducing antioxidant potential assay, the chloroform fractions of both the fruit parts were most active. The hexane fractions of both the parts showed highest activity in reducing power assay, epicarp being more potent than mesocarp. In 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid assay, the antioxidant activities of ethyl acetate and chloroform fractions of both the parts were comparable to gallic acid and vitamin C. In lipid peroxidation inhibitory assay, all the samples were moderate to good activity sustainable over the period of 72 h, indicating the presence of both slow and fast releasing antioxidants.

CONCLUSIONS

The findings of the study suggest that epicarp is a better source of antioxidants than the mesocarp, and the ethyl acetate fractions of both the parts contain higher contents of antioxidants.

Comparison of a novel extraction-based colorimetric (ABTS) method with membrane introduction mass spectrometry (MIMS): trichloramine dynamics in pool water

Trichloramine is a hazardous disinfection by-product, which is present in chlorinated swimming pools. Although it is primarily taken up by inhalation, the concentration in pool water is important to monitor pool water quality and to assess trichloramine mitigation strategies. To date, scarce data is available on trichloramine concentration in pool water due to the lack of a suitable and easily applicable analytical method. This study presents a novel low cost, colorimetric method which is easy to operate and suitable for on-site measurements of trichloramine concentrations ≥0.05 μM (≥0.01 mg L(-1) as Cl2). The analytical method (termed "extraction-based ABTS method") consists of, (i) trichloramine stripping from pool water samples, (ii) passing it through a solid phase filter, composed of silica gel impregnated with sulfamic acid to eliminate interferences and (iii) trichloramine reaction with the indicator 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) to produce the coloured ABTS(•-) radical, which is measured at λ = 405 nm to determine the trichloramine concentration in the pool water sample. A comparison of the extraction-based ABTS method with membrane introduction mass spectrometry (MIMS) for 28 pool samples revealed a good correlation of the two methods. The trichloramine concentration in pool samples is correlated to HOCl, which is the most important factor for its formation. Other parameters such as combined chlorine and pH play a minor role while no correlation between trichloramine and the urea or the TOC concentration was observed. On-site measurements with MIMS in a wading pool over 6 days with a time resolution of 1 h confirmed that trichloramine concentrations strongly responded to changes in free chlorine concentrations. A diurnal measurement of trichloramine with a time resolution of 20 min revealed that trichloramine concentrations reacted quickly and sensitively to the bather load and that urea is probably not the main precursor for its formation.

Antioxidant and Free Radical Scavenging Capacity of Seed and Shell Essential Oils Extracted from Abrus precatorius (L)

Essential oils from plants have been proven safe as natural antioxidants, and few are already marketed as digestive enhancers as well as in prevention of several degenerative diseases. This study evaluated the antioxidant capacity of seed and shell essential oils of Abrus precatorius (L), a herb used for ethno-medicinal practices in Nigeria. The essential oils were obtained by hydro-distillation. The ability of the oils to act as hydrogen/electrons donor or scavenger of radicals were determined by in-vitro antioxidant assays using 2,2-diphenyl-2-picryl-hydrazyl free radical (DPPH^.) scavenging; 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging; lipid peroxide and nitric oxide radicals scavenging assays. The IC₅₀ of the seed and shell oils (2.10 mg/mL and 1.20 mg/mL respectively) showed that antioxidant activity is higher than that for the standard drugs (3.20 mg/mL and 3.40 mg/mL) for the nitric oxide scavenging assay. The lipid peroxidation radical activity of the oils were similar to vitamin C, weak DPPH and ABTS radical scavenging activities were discovered in comparison to vitamin C and rutin. Generally, in the four antioxidant assays, a significant correlation existed between concentrations of the oils and percentage inhibition of free radicals and lipid peroxidation. The composition of A. precatorius essential oils reported earlier may account for their antioxidant capacity.

Phenolic and antioxidant profiles of rowan (Sorbus L.) fruits

Fruits of different Sorbus L. species have been traditionally used in food production and in the treatment of various ailments. Besides common antioxidant active phytochemicals such as ascorbic acid, tocopherols and carotenoids, fruits are rich in phenolic compounds that are of particular interest. In this study, profiles of separate antioxidant active compounds (reducing and radical-scavenging activities) were investigated using online assays with post-column reactions. Significant variations in phenolic acids and flavonoids contents and antioxidant activity values were observed in the fruits of Sorbus L. species studied. Neochlorogenic and chlorogenic acids were determined as markers of antioxidant activity. Characteristic patterns of antioxidant profiles obtained using HPLC post-column FRAP and ABTS assays significantly depend on specific Sorbus L. species and are suitable for equivalency research of Sorbus L. fruits.

Purification and characterization of an extracellular laccase from solid-state culture of Pleurotus ostreatus HP-1

A native isolate of Pleurotus ostreatus HP-1 (Genbank Accession No. EU420068) was found to have an excellent laccase producing ability. The extracellular laccase was purified to electrophoretic homogeneity from copper sulphate induced solid-state fermentation medium by ammonium sulphate precipitation and ion-exchange chromatography. The enzyme was determined to be monomeric protein with an apparent molecular mass of 68,420 kDa, and an isoelectric point (pI) of 3.5. The inductively coupled plasma spectroscopy showed a presence of iron, zinc and copper in the purified enzyme. The absorption spectrum in the range of 200-700 nm showed the maximum absorption at 610 nm characteristic of fungal laccase and corresponding to the presence of type I copper atom. The laccase was stable at different temperatures up to 70 °C and retained 61 % activity at 50 °C. The enzyme reaction was inhibited by cysteine; sodium azide and EDTA. The enzyme oxidized various known laccase substrates, its lowest K_m value being for ortho-dianisidine and highest K_cat and K_cat/K_m for ABTS. The purified laccase exhibited different pH optima for different substrates. The N-terminal sequence did not show any similarity with N-terminal sequence of other species of genera Pleurotus.

Decolorization and detoxification of sulfonated toxic diazo dye C.I. Direct Red 81 by Enterococcus faecalis YZ 66

Isolated Enterococcus faecalis YZ 66 strain shows ability to decolorize various industrial dyes among which, it showed complete decolorization and degradation of toxic, sulfonated recalcitrant diazo dye Direct Red 81 (50 mg/L) within 1.5 h of incubation under static anoxic condition. The optimum pH and temperature for decolorization was 7.0 and 40°C, respectively. Significant induction in the activity of intracellular oxidoreductive enzymes suggested its involvement in the decolorization of Direct Red 81. The biodegradation of Direct Red 81 was monitored by UV-Visible, FT-IR spectroscopy and HPLC. The final products were characterized by GC-MS and possible pathway of the degradation of the dye was proposed. The phytotoxicity assay (with respect to plants Sorghum vulgare and Phaseolus mungo) revealed that the degradation of Direct Red 81 produced nontoxic metabolites. Finally E. faecalis was employed to decolorize actual industrial effluent showing decolorization (in terms of ADMI value) with moderate COD and BOD reduction. Moreover the result increases the applicability of the strain for the treatment of industrial wastewaters containing dye pollutants.

Differential induction of antioxidant stilbenoids in hairy roots of Vitis rotundifolia treated with methyl jasmonate and hydrogen peroxide

Stilbenoids are polyphenolic phytoalexins that exhibit potential health applications in humans. Hairy root cultures of muscadine grape (Vitis rotundifolia Michx.) were used to study the biochemical and molecular regulation of stilbenoid biosynthesis upon treatment with 100 μM methyl jasmonate (MeJA) or 10 mM hydrogen peroxide (H2O2) over a 96-h period. Resveratrol, piceid, and ε-viniferin were identified in higher concentrations in the tissue whereas resveratrol was the most abundant stilbenoid in the medium under either treatment. An earlier increase in resveratrol accumulation was observed for the MeJA-treated group showing a maximum at 12 h in the tissue and 18 h in the medium. Furthermore, the antioxidant capacity of extracts from the tissue and medium was determined by the 2,2'-azinobis[3-ethylbenzthiazoline sulfonic acid] (ABTS) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays showing correlation with the stilbenoid content. Fourteen candidate reference genes for qPCR were tested under the described experimental conditions and resulted in the selection of 5 reference genes. Quantitative analyses of transcripts for phenylalanine ammonia-lyase (PAL), resveratrol synthase (RS), and two stilbene synthases (STS and STS2) showed the highest RNA level induction at 3 h for both treatments with a higher induction for the MeJA treatment. In contrast, the flavonoid-related chalcone synthase (CHS) transcripts showed induction and a decrease in expression for MeJA and H2O2 treatments, respectively. The observed responses could be related to an oxidative burst triggered by the exposure to abiotic stressor compounds with signaling function such as MeJA and H2O2 which have been previously related to the synthesis of secondary metabolites.

Synthesis, Characterization and Antioxidant Property of Quercetin-Tb(III) Complex

PURPOSE

Nearly all of flavonoids are good metal chelators and can chelate many metal ions to form different complexes. This article describes a synthesis of Quercetin-Tb(III) in methanol, characterized by using elemental analysis, UV-visible and evaluation of its antioxidant properties.

METHODS

The formation of complexes is realized from the UV-visible spectra which shows that the successive formation of Quercetin-Tb(III) occurs. To find out the antioxidant activity variation and the role of Tb(III) ion on the antioxidant activity of the complexes different radical scavenging methods such as: 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and 2,2'-azinobis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS) were used.

RESULTS

The results from DPPH, ABTS and FRAP methods showed that Quercetin and Quercetin-Tb(III) complex are capable of donating electron or hydrogen atom, and consequently could react with free radicals or terminate chain reactions in a time- and dose-dependent manner.

CONCLUSION

This study showed that the chelation of metal ions by Quercetin decrease the redox potential of Quercetin-metal complex.

Effect of reverse photoperiod on in vitro regeneration and piperine production in Piper nigrum L

In this study, a novel approach for in vitro regeneration of Piper nigrum L. has been applied in order to increase healthy biomass, phytochemicals and piperine production via reverse photoperiod (16hD/8hL). Leaf portions of the seed-derived plants were placed on an MS-medium fortified with different PGRs. Under 16hD/8hL, thidiazuron (TDZ; 4.0 mg L⁻¹) and BA (1.5 mg L⁻¹) was found to be the most effective (<90%) in callus induction. Two concentrations (1.5, 2.0 mg L⁻¹) of the IBA produced>80% shoots from callus cultures. Healthy shoots were transferred to rooting medium and higher percentage of rooting (<90%) was observed on IBA (1.5 mg L⁻¹). These in vitro tissues were subjected to amino acid analysis, spectrophotometry, and HPLC. ARG, SER, THR, and TYR were the most abundant components out of 17 amino acids. Higher amino acid production was observed under normal photoperiod (16hL/8hD) than under reverse photoperiod (16hD/8hL). The highest total phenolic content (TPC; 9.91 mg/g-DW) and flavonoid content (7.38 mg/g-DW) were observed in callus cultures incubated under 16hL/8hD than other tissues incubated under 16hD/8hL photoperiod. Higher DPPH and PoMo activities were observed in tissues incubated under 16hL/8hD photoperiod, while ABTS and Fe²⁺ chelating activities were found higher in tissues incubated under reverse photoperiod. Significant quantities of piperine content were observed in all tissues except callus cultures. These results suggest that reverse photoperiod is a promising approach for callus induction, phytochemicals and piperine production for commercial applications.

Antioxidant property and storage stability of quince juice phenolic compounds

The aim of this study was to characterise, in depth, 11 quince cultivars to provide data for their industrial processing into high-quality juices. Polyphenolic composition analyses (identification and quantification), soluble fraction of procyanidins, antioxidant capacity assays and cluster analysis were measured. A total of 19 kinds of polyphenolic compounds were the following in the juices: before and after 6 month of storage time at 4 and 30 °C. Large variations in polyphenolic compounds content were found as affected by quince cultivar. The total phenolics determined by UPLC ranged from 4045 mg to 721 mg/100 mL of juices, and was high correlated with antioxidant activity. During 6 months of storage a significant change was observed in the content of polyphenols, especially in procyanidins (37% and 55%, respectively). This result may be useful for the juice industry as a starting point for the development of tasty quince juices with high levels of bioactive compounds.

Spectroscopic studies on the antioxidant activity of p-coumaric acid

p-coumaric acid (4-hydroxycinnamic acid), a phenolic acid, is a hydroxyl derivative of cinnamic acid. It decreases low density lipoprotein (LDL) peroxidation and reduces the risk of stomach cancer. In vitro radical scavenging and antioxidant capacity of p-coumaric acid were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe(2+)) chelating activity and ferric ions (Fe(3+)) reducing ability. p-Coumaric acid inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45μg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and ascorbic acid displayed 66.8%, 69.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, p-coumaric acid had an effective DPPH scavenging, ABTS(+) scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe(3+)) reducing power and ferrous ions (Fe(2+)) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that p-coumaric acid can be used in the pharmacological and food industry because of these properties.

A study on four antioxidation effects of lycium barbarum polysaccharides in vitro

The objective of the study was to investigate the in vitro antioxidation activity of lycium barbarum polysaccharides (LBP). Ultraviolet spectrophotometry was adopted to determine the capability of LBP to clear superoxide anions, hydroxyl radicals, DPPH free radicals and ABTS free radicals. The result showed that the law for LBP to clear superoxide anions, hydroxyl radicals and DPPH free radicals was that the clearance rate increased gradually with the increase of the concentration, and when the concentration reached a certain value, the clearance rate leveled off, while the IC50 for clearing ABTS free radicals was 47.158 ± 6.231 µg/ml. The study concluded that LBP is a good in vitro antioxidant.

Abolishing activity against ascorbate in a cytosolic ascorbate peroxidase from switchgrass

Switchgrass (Panicum virgatum L.) is being developed as a bioenergy species. Recently an early version of its genome has been released permitting a route to the cloning and analysis of key proteins. Ascorbate peroxidases (APx) are an important part of the antioxidant defense system of plant cells and present a well studied model to understand structure-function relationships. Analysis of the genome indicates that switchgrass encodes several cytosolic ascorbate peroxidases with apparent varying levels of tissue expression. A major cytosolic ascorbate peroxidase was thus selected for further studies. This gene was cloned and expressed in Escherichia coli cells to obtain purified active protein. Full heme incorporation of the enzyme was achieved utilizing slow growth and supplementing the media with 5-aminolevulinic acid. The enzyme was observed to be monomeric in solution via size exclusion chromatography. Activity toward ascorbate was observed that was non-Michaelis-Menten in nature. A site-directed mutant, R172S, was made in an attempt to differentiate activity against ascorbate versus other substrates. The R172S protein exhibited negligible ascorbate peroxidase activity, but showed near wild type activity toward other aromatic substrates.

Evaluation of Antioxidant Activity of Picrorhiza kurroa (Leaves) Extracts

Picrorhiza kurroa is a well-known herb in Ayurvedic medicine. Although it shows antioxidant, antiinflammatory and immunomodulatory activities, it is most valued for its hepatoprotective effect. The rhizomes are widely used against indigestion problems since ancient times due to improper digestive secretions. Aim of this study was to explore antioxidant study of P. kurroa leaves for a new source of naturally occurring antioxidants. Two pure compounds, luteolin-5-O-glucopyranoside (1) and picein (2) were isolated from butanol extract through column chromatography. Different extracts of P. kurroa leaves (ethanol, ethyl acetate, butanol) were quantified for isolated compound (2) by high-performance liquid chromatography. All the extracts and isolated compounds were evaluated for its antioxidant activity using two assays, 2,2-diphenyl-1-picrylhydrazyl radical and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) assay. The linear detection range was 1.56-200 μg/ml for picein. The limit of detection and limit of quantification for picein were 2.34 and 7.81 μg/ml, respectively. Butanol and ethyl acetate extract showed greater antioxidant activity as compare to ethanol extract. Compound 1 and ascorbic acid showed nearly similar antioxidant activity where as 2 showed no activity at standard concentration. The IC₅₀ values for 2,2-diphenyl-1-picrylhydrazyl radical and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) assay for ascorbic acid, compound 1, ethanol extract and its different fractions (ethyl acetate and butanol) were found to be 0.81, 1.04, 67.48, 39.58, 37.12 and 2.59, 4.02, 48.36, 33.24, 29.48 μg, respectively.

Amplified colorimetric detection of mercuric ions through autonomous assembly of G-quadruplex DNAzyme nanowires

An amplified colorimetric detection of Hg(2+) is proposed by combining T-Hg(2+)-T base pairs and hybridization chain reaction (HCR). Two hairpins consisting of three-fourths and one-fourth of the horseradish peroxidase (HRP)-mimicking DNAzyme in inactive configuration are used as functional elements. In the presence of Hg(2+), one of the hairpins is opened by an assistant probe with the help of T-Hg(2+)-T base pairs and this triggers an autonomous cross-opening of the two hairpins using the strand displacement principle, resulting in the formation of DNA nanowires consisting of numerous reunited Q-quadruplex DNAzyme units. The resulting catalytically active hemin/G-quadruplex HRP-mimicking DNAzymes catalyze the oxidation of ABTS(2-) by H2O2 into a green-colored cationic radical ABTS(•+) for the colorimetric readout. This "turn-on" sensing system enables the high sensitive and selective detection of aqueous Hg(2+) with a detection limit of 9.7 pM.

Carbamoylation abrogates the antioxidant potential of hydrogen sulfide

Hydrogen sulfide (H2S) has been identified as the third gasotransmitter. Beside its role as signaling molecule in the cardiovascular and nervous system the antioxidant and cyto-protective properties of H2S have gained much attention. In the present study we show that cyanate, an uremic toxin which is found in abundant concentration in sera of patients suffering from chronic kidney disease (CKD), can abrogate the antioxidant and cytoprotective activity of H2S via S-carbamoylation reaction, a reaction that previously has only been shown to have a physiological effect on cysteine groups, but not on H2S. Carbamoylation strongly inhibited the free radical scavenging (ABTS(+·) and alkylperoxyl ROO(·)) properties of H2S. The extent of intracellular ROS formation induced by ROO(·) was diminished by H2S whereas carbamoylation counteracted the protective effect. Reagent HOCl was rapidly inactivated by H2S in contrast to the carbamoylated compound. Protein modification by HOCl was inhibited by H2S but carbamoylation significantly reduced the effect. Thus, S-carbamoylation of low molecular weight thiols by abrogating their antioxidant potential may contribute to the higher oxidative stress observed in CKD.

Extraction, chemical characterization and biological activity determination of broccoli health promoting compounds

Broccoli (Brassica oleracea L. var. Italica) contains substantial amount of health-promoting compounds such as vitamins, glucosinolates, phenolic compounds, and dietary essential minerals; thus, it benefits health beyond providing just basic nutrition, and consumption of broccoli has been increasing over the years. This review gives an overview on the extraction and separation techniques, as well as the biological activity of some of the above mentioned compounds which have been published in the period January 2008 to January 2013. The work has been distributed according to the different families of health promoting compounds discussing the extraction procedures and the analytical techniques employed for their characterization. Finally, information about the different biological activities of these compounds has been also provided.

Development of an ELISA for the quantification of the C-terminal decapeptide prothymosin α(100-109) in sera of mice infected with bacteria

Apoptosis is characterized by a series of discrete biochemical events, among which is the truncation of the nuclear polypeptide prothymosin alpha (proTα) by activated caspase-3. This early apoptotic event results in the generation of a carboxy-terminal fragment of proTα, the immunoactive decapeptide proTα(100-109). We hypothesized that the detection of increased levels of proTα(100-109) in serum can be directly correlated with the induction of massive cell apoptosis, resulting from a severe bacterial infection. Thus, using high-affinity-purified polyclonal antibodies (Abs), raised in rabbits and a prototype antibody-capture system, we developed a highly sensitive and specific competitive ELISA for proTα(100-109). The sensitivity of the ELISA (0.1ng/mL to 10μg/mL) is acceptable for the quantification of the decapeptide in serum samples. To assess our initial hypothesis, we determined the concentration of proTα(100-109) in the sera of mice infected with the bacterium Streptococcus pyogenes over the course of the infection. We show that serum concentration of proTα(100-109) was marginal to undetectable before infection, increased over time and peaked at 72h postinfection. In silico analysis suggests that the Abs generated are unlikely to cross-react with any other unrelated mouse or bacterial protein. Further validation of our ELISA using serum samples from humans, infected with bacteria, may provide a useful tool to differentiate the causative agent of a potentially lethal septic infection.

Antioxidants and ROS scavenging ability in ten Darjeeling tea clones may serve as markers for selection of potentially adapted clones against abiotic stress

Ten Darjeeling tea clones (BT15/263, RR17/144, B777, T253, B157, Sundaram, HV39, AV2, K1/1 and TTV1) were collected from the experimental garden of Darjeeling Tea Research and Development Centre, Kurseong. Total phenol, flavonoids and two antioxidating enzymes (peroxidase and superoxide dismutase) were estimated. The total phenol ranged between 241 and 28 GAE mg g(-1) of leaf dry weight. The highest amount obtained in four clones, B15/263 (241.47), RR17/144 (221.2), B777 (154.54) and B157 (140.23 mg g(-1)). Flavonoids were estimated as Catechin equivalent (CE) and ranged between 56.88 and 20.81 CE mg g(-1) leaf dry weight. Higher amounts occurred in BT15/263 (56.88 mg g(-1)), B777 (56.69) and RR17/144 (48.63). Antioxidant activities were measured following DPPH and ABTS free radicle scavenging procedures and the results were well according to total polyphenol content among the clones (in total phenols, ranges of correlation in DPPH assay were r (2)  = 0.990-0.989, p ≤ 0.05; in flavonoids r (2)  = 0.954, p ≤ 0.01-0.987, p ≤ 0.05). Similarly, ABTS percent scavenging results were quiet significant. The IC50 values were determined for both DPPH and ABTS assay. PAGE expressions of isoforms in two antioxidative enzymes and quantification of them also varied much among the investigated clones. The incidence of total phenols, flavonoids, PRX and SOD and ROS scavenging assay in in-situ condition, might be used as biochemical markers towards the superior adaptability against abiotic stress. In the present work, four clones (B15/263, B777, RR17/144 and B157) would be designated as comparatively better suited to the predicted abiotic stress.

Comparative immunochemical characteristics of botulinum neurotoxin type A and its associated proteins

Clostridium botulinum strains secrete their neurotoxins (BoNT) along with a group of neurotoxin-associated proteins (NAPs) that enhance the oral toxicity and provide protection to the neurotoxin against acidity, temperature and proteases in the G.I. tract. A major component of NAPs is Hn-33, a 33 kDa protein, which is also protease resistant and strongly protects BoNT. The complex form of BoNT/A is used as a commercial therapeutic formulation against many neuromuscular disorders and for cosmetic purposes. Immune response against this formulation could hinder its long-term use; therefore, it is important to characterize the immunological properties of the associated proteins. This study aims to understand the immunological reactivity of BoNT/A complex, BoNT, NAPs, and Hn-33 through a series of competitive enzyme-linked immunosorbent assays (ELISA). The results indicated that BoNT/A complex competed 6 times more with complex antibodies compared to the neurotoxin confirming that the higher immunogenicity of BoNT/A complex was indeed a result of the associated proteins with the neurotoxin complex. While the nearly identical immuno-reactivity of BoNT/A complex and Hn-33 with Hn-33 antibodies indicated that the reactivity was due to the higher immunogenicity not the abundance of Hn-33 in the complex. Both the ELISA and immuno-blot results implied that Hn-33 is primarily responsible for eliciting the antibody response in BoNT/A complex.

The potentiation of myeloperoxidase activity by the glycosaminoglycan-dependent binding of myeloperoxidase to proteins of the extracellular matrix

BACKGROUND

Myeloperoxidase (MPO) is an abundant hemoprotein expressed by neutrophil granulocytes that is recognized to play an important role in the development of vascular diseases. Upon degranulation from circulating neutrophil granulocytes, MPO binds to the surface of endothelial cells in an electrostatic-dependent manner and undergoes transcytotic migration to the underlying extracellular matrix (ECM). However, the mechanisms governing the binding of MPO to subendothelial ECM proteins, and whether this binding modulates its enzymatic functions are not well understood.

METHODS

We investigated MPO binding to ECM derived from aortic endothelial cells, aortic smooth muscle cells, and fibroblasts, and to purified ECM proteins, and the modulation of these associations by glycosaminoglycans. The oxidizing and chlorinating potential of MPO upon binding to ECM proteins was tested.

RESULTS

MPO binds to the ECM proteins collagen IV and fibronectin, and this association is enhanced by the pre-incubation of these proteins with glycosaminoglycans. Correspondingly, an excess of glycosaminoglycans in solution during incubation inhibits the binding of MPO to collagen IV and fibronectin. These observations were confirmed with cell-derived ECM. The oxidizing and chlorinating potential of MPO was preserved upon binding to collagen IV and fibronectin; even the potentiation of MPO activity in the presence of collagen IV and fibronectin was observed.

CONCLUSIONS

Collectively, the data reveal that MPO binds to ECM proteins on the basis of electrostatic interactions, and MPO chlorinating and oxidizing activity is potentiated upon association with these proteins.

GENERAL SIGNIFICANCE

Our findings provide new insights into the molecular mechanisms underlying the interaction of MPO with ECM proteins.

Enhancement of catalysis and functional expression of a bacterial laccase by single amino acid replacement

Structure-function relationships underlying laccases properties are very limited that makes these enzymes interesting for protein engineering approaches. Therefore in the current study, a thermostable laccase that was isolated from Bacillus sp. HR03 with the ability of bilirubin oxidation besides its laccase and tyrosinase activity is used. The extensive application of this enzyme is limited by its low expression level in Escherichia coli. Based on sequence alignments and structural studies, three single amino acid substitutions, D500G, D500E, D500S and a glycine insertion, are introduced using site-directed mutagenesis to evaluate the role of Asp(500) located in the C-terminal segment close to the T1 copper center. Substitution of aspartic acid with less sterically hindered, conserved residue such as glycine increase kcat (2.3 fold) and total activity (7.3 fold) which is accompanied by a significant increase in the expression level up to 3 fold. Biochemical characterization and structural studies using far-UV CD and fluorescence spectroscopy reveal the importance of C-terminal copper-binding loop in the laccase functional expression and catalytic efficiency. Kinetic characterization of the purified mutants toward 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), syringaldazine (SGZ) and bilirubin, shows that substrate specificity is left unchanged.

Targeting high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance analysis with high-resolution radical scavenging profiles-Bioactive secondary metabolites from the endophytic fungus Penicillium namyslowskii

The high-resolution radical scavenging profile of an extract of the endophytic fungus Penicillium namyslowskii was used to target analysis by high-performance liquid chromatography-high-resolution mass spectrometry-solid-phase extraction-nuclear magnetic resonance spectroscopy, i.e., HPLC-HRMS-SPE-NMR, for identification of anti-oxidative secondary metabolites. This revealed the two chromatographic peaks with the highest relative response in the radical scavenging profile to be griseophenone C and peniprequinolone. The HPLC-HRMS-SPE-NMR analysis was performed in the tube-transfer mode using a cryogenically cooled NMR probe designed for 1.7mm NMR tubes. To further explore the potential of the above HPLC-HRMS-SPE-NMR platform for analysis of endophytic extracts, six peaks displaying no radical scavenging activity were also analyzed. This allowed unambiguous identification of six metabolites, i.e., dechlorogriseofulvin, dechlorodehydrogriseofulvin, griseofulvin, dehydrogriseofulvin, mevastatin acid, and mevastatin. The high mass sensitivity of the 1.7mm cryogenically cooled NMR probe allowed for the first time acquisition of direct detected (13)C NMR spectra of fungal metabolites, i.e., dechlorogriseofulvin and griseofulvin, directly from crude extract via HPLC-HRMS-SPE-NMR. Dechlorodehydrogriseofulvin was reported for the first time from nature.

Relationship between Antioxidant Properties and Chemical Composition of Abutilon Indicum Linn

Aim of this paper is to find out the relationship between antioxidant activity of Abutilon indicum Linn and their phytochemical composition especially phenols and flavonols. Successive extractions were carried out for the Abutilon indicum plant with petroleum ether, chloroform, ethyl acetate, n-butanol, ethanol and water. All these extracts were evaluated for their antioxidant activities. Their antioxidant activities were correlated with their total phenol and flavonol content present in the plant. Ethyl acetate showed maximum free radical scavenging activity. IC₅₀ value for various antioxidant methods for all extract showed no significance with total antioxidant capacity except IC₅₀ value of LPO (r² = 0.7273). Correlation between total antioxidant capacity and total phenolic content was not significant with r² = 0.2554, P<0.3065. Total antioxidant capacity and total flavonol content showed similar correlation with r² = 0.2554, P<0.0962.