Degradation of pesticides by the ligninolytic enzyme Laccase : optimisation of in vitro conditions, immobilisation and screening for natural mediators

Pesticides are widely used in many industries but the majority reaches non-target organisms or locations through point or diffuse sources. Understanding conditions for their degradation is therefore important. The degradation of glyphosate, its metabolite AMPA and isoproturon using the ligninolytic enzyme laccase was studied. Optimisation of in vitro conditions were tested with findings indicating that factors such as altering pH and the concentrations of both manganese and redox mediators can impact degradation giving insight into optimal conditions. A method of encapsulation was used showing it is possible to immobilise laccase suggesting a possibility of its suitability as a co-formulation agent in pesticide applications. The immobilised laccase was applied in a laboratory scale experiment to investigate degradation of glyphosate and AMPA in soil and sand. The findings showed an apparent ability of the encapsulated laccase to be liberated and have an effect on glyphosate degradation, although much work still remains in this area. In the final part of this project ligninolytic substrates were screened for natural and easily extractable mediators. Extracts were used to check enzymatic activity and degradation potential. Candidates that showed promising results included extracts from hemp and wheat

Preliminary characterization of a Moroccan honey with a predominance of Bupleurum spinosum pollen

Honey with Bupleurum spinosum (zandaz) as a main pollen source has not been the subject of previous detailed study. Therefore, twelve Moroccan samples of this honey were subjected to melissopalynological, physicochemical and microbiological quality characterization, as well as antioxidant activity assessment. From a quality point of view, almost all samples were within the limits established by Codex Alimentarius, and/or the European legislation. All samples presented predominance of B. spinosum pollen (more than 48%). Relatively high levels of trehalose (1.3-4.0 g/100 g) and melezitose (1.5-2.8 g/100 g) were detected. Those sugars, not common in monofloral honeys, could be used as an important factor to discriminate zandaz honey. Flavonoid content correlated positively with the honey color, melanoidin and polyphenol content, and negatively with the IC50 values of scavenging ABTS (2,2' - azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) free radicals, while proline amount correlated negatively with IC50 values of nitric oxide scavenging activity and chelating power. This correlation supports the use of anti-oxidant activities as important variables for PCA (principal component analysis). Both components explained 70% from the given data, and showed certain homogeneity upon analyzed samples independent of the region, suggesting the importance of B. spinosum nectar in the resulting honey characteristics.Fundacao para a Ciencia e Tecnologia for Research Center [UID/BIM/04773/2013 CBMR 1334, UID/AGR/00239/2013, UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569)]; ERDF through the COMPETE - Programa Operacional Competitividade e Internacionalizacao (POCI

Optical beam guidance in monolithic polymer chips for miniaturized colorimetric assays

For the first time, we present a simple and robust optical concept to enable precise and sensitive read-out of colorimetric assays in flat lab-on-a-chip devices. The optical guidance of the probe beam through an incorporated measurement chamber to the detector is based on the total internal reflection at V-grooves in the polymer chip. This way, the optical path length through the flat measurement chamber and thus the performance of the measurements are massively enhanced compared to direct (perpendicular) beam incidence. This is demonstrated by a chip-based, colorimetric glucose-assay on serum. Outstanding features are an excellent reproducibility (CV= 1.91 %), a competitive lower limit of detection (cmin = 124 μM), and a high degree of linearity (R2 = 0.998) within a working range extending over nearly three orders of magnitude

Chemical Composition and in Vitro Evaluation of the Antioxidant and Antimicrobial Activities of Eucalyptus gillii Essential Oil and Extracts

In this study, essential oil and various extracts (hexane, petroleum ether, acetone, ethanol, methanol and water) of Eucalyptus gilii were screened for their chemical composition, antimicrobial and antioxidant activities. The essential oil chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID), respectively. Thirty four compounds were identified, corresponding to 99.5% of the total essential oil. Tannins [104.9-251.3 g catechin equivalent (CE)/Kg dry mass], flavonoids [3.3-34.3 g quercetin equivalent (QE)/Kg dry mass], phenolics [4.7-216.6 g gallic acid equivalent (GAE)/Kg dry mass] and anthocyannins [1.2-45.3 mg cyanidin-3-glucoside equivalent (C3GE)/Kg dry mass] of various extracts were investigated. Free radical scavenging capacity of all samples was determinedt. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, the IC50 of essential oil was 163.5 ± 10.7 mg/L and in the 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonate (ABTS) assay, it was 94.7 ± 7.1 mg/L. Among the various extracts, the water extract showed the best result (IC50 = 11.4 ± 0.6 mg/L) in the DPPH assay which was comparable to vitamin C (IC50 = 4.4 ± 0.2 mg/L). The antimicrobial activities were evaluated against different bacterial and fungal strains. Gram positive bacteria were found to be more sensitive to the essential oil and extracts than Gram negative ones. Anthocyanins seem to have a major effect on the growth of Bacillus subtilis (R2 = 0.79). A significant antifungal activity was observed against the yeast and fungi. Correlations between chemical composition and antioxidant activities were studied and R2 values were about 0.96 for the effect of phenolics on the DPPH assay

Antioxidant Capacity and Antimicrobial Activity of Commercial Samples of Guava Leaves (\u3cem\u3ePsidium guajava\u3c/em\u3e)

Psidium guajava is a small tree native to South and Central America. Guava leaves have traditionally been used for treating different illnesses. These benefits can be attributed to phenolics and flavonoids produced by guava. The chemical composition of guava leaf extracts was correlated with biological activity. Total phenolics, total flavonoids, ABTS/DPPH, TZM-bl, plaque reduction, XTT, spectrophotometric and Kirby-Bauer assays were used to test phenols, flavonoids, antioxidant properties, antiviral activity, cytotoxicity, and antibacterial activity, respectively. The median cytotoxicity concentration and half-maximal effective concentration values were obtained in order to determine antiviral selectivity against human immunodeficiency virus type 1 and herpes simplex virus type 1. Antibacterial activity against Escherichia coli and Bacillus subtilis were evaluated using a spectrophotometric assay and Kirby-Bauer test. The guava leaf extracts had a high phenol (0.8 to 2.1 GAE mg/mL) and flavonoid (62.7 to 182.1 Rutin Eq mg/g DW) content that correlated with high antioxidant capacity and selective antiviral activity (therapeutic index values above 10). Results of antibacterial tests indicated that the extracts have activity against gram-negative and gram-positive bacteria

A study of the antioxidant capacity of oak wood used in wine ageing and the correlation with polyphenol composition

The antioxidant capacity of oak wood used in the ageing of wine was studied by four different methods: measurement of scavenging capacity against a given radical (ABTS, DPPH), oxygen radical absorbance capacity (ORAC) and the ferric reducing antioxidant power (FRAP). Although, the four methods tested gave comparable results for the antioxidant capacity measured in oak wood extracts, the ORAC method gave results with some differences from the other methods. Non-toasted oak wood samples displayed more antioxidant power than toasted ones due to differences in the polyphenol compositon. A correlation analysis revealed that ellagitannins were the compounds mainly responsible for the antioxidant capacity of oak wood. Some phenolic acids, mainly gallic acid, also showed a significant correlation with antioxidant capacity

Phenolic content of Hypodaphnis Zenkeri and its antioxidant effects against fenton reactions’ mediated oxidative injuries on liver homogenate

Under oxidative stress conditions, endogenous antioxidant defenses are unable to completely inactivate the free radicals generated by an excessive production of reactive oxygen species (ROS). This state causes serious cell damage leading to a variety of human diseases. Natural antioxidants can protect cells against oxidative stress. Hypaodaphnis zenkeri (H. zenkiri) is a plant consumed as a spice in the Cameroonian diet, and its bark has been used in traditional medicine for the treatment of several diseases. The present study aims at investigating the antioxidant activity, which includes free radical scavenging and protective properties of an extract from H. Zenkiri against oxidative damage on a liver homogenate. The free radical assays determined the scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl (OH), nitrite oxide (NO) and 2,2-azinobis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radicals and the enzymes, whose protection was to be considered in the liver homogenate, including superoxide dismutase, catalase, and peroxidase. The antioxidative activities were studied using the ferric reducing antioxidant power (FRAP), reductive activity, and phosphomolybdenum antioxidant power (PAP) methods. In addition, the phenolic contents of the extracts were examined. The results showed that these extracts demonstrated significant scavenging properties and antioxidant activities, with the hydro-ethanolic extract of the bark of H. zenkeri (EEH) being the most potent. This extract had the highest total polyphenol (21.77 ± 0.05 mg caffeic acid (CAE)/g dried extract (DE)) and flavonoids (3.34 ± 0.13 mg quercetin (QE)/g dried extract) content. The same extract had significantly greater protective effects on enzyme activities compared to other extracts. The high performance liquied chromatography (HPLC) profile showed higher levels of caffeic acid, OH-tyrosol acid, and rutin in the leaves compared to the bark of H. zenkeri. In conclusion, the ethanolic and hydro-ethanolic extracts of the bark and leaves from H. zenkeri showed an antioxidant and protective potential against oxidative damage

In-vitro antioxidant and anti-inflamatory activities of Pituranthos chloranthus and Artemisia vulgaris from Tunisia

Pituranthos chloranthus and Artemisia vulgaris L. are two of the most important aromatic and medicinal species from the Apiaceae and Asteraceae families, respectively. They are traditionally used in certain pathologies in which inflammatory processes are involved. The present study investigates the potential of aqueous extracts of Tunisian P. chloranthus and A. vulgaris as a natural alternative source of antioxidant and anti-inflammatory activities using in-vitro techniques. The antioxidant activities of aqueous extracts were evaluated through several assays: capacity for scavenging free radicals (ABTS, DPPH, hydroxyl, superoxide, nitric oxide); and total antioxidant capacity by ferric reducing power activity and inhibition of lipid peroxidation by thiobarbituric acid reactive species (TBARS) method. The anti-inflammatory activity was evaluated through the lipoxygenase (LOX) inhibitory activity. P. chloranthos aqueous extract presented higher concentration of total phenols than A. vulgaris extract, nevertheless higher capacity for scavenging ABTS, superoxide, hydroxyl. and NO free radicals. In the presence of liver homogenate, both extracts had poorer antioxidant activity than in the remaining lipid substrates. P. chloranthos extract had a higher ability for inhibiting lipoxygenase twice higher than A. vulgaris, while it had lower capacity for reducing Fe3+ than P. chloranthos extract. Our results suggest that there are differences of antioxidant activity between both samples, but also the strength for inhibiting the oxidation is highly dependent on the method used.info:eu-repo/semantics/publishedVersio

Acidity and Antioxidant Activity of Cold Brew Coffee.

The acidity and antioxidant activity of cold brew coffee were investigated using light roast coffees from Brazil, two regions of Ethiopia, Columbia, Myanmar, and Mexico. The concentrations of three caffeoylquinic acid (CQA) isomers were also determined. Cold brew coffee chemistry was compared to that of hot brew coffee prepared with the same grind-to-coffee ratio. The pH values of the cold and hot brew samples were found to be comparable, ranging from 4.85 to 5.13. The hot brew coffees were found to have higher concentrations of total titratable acids, as well as higher antioxidant activity, than that of their cold brew counterparts. It was also noted that both the concentration of total titratable acids and antioxidant activity correlated poorly with total CQA concentration in hot brew coffee. This work suggests that the hot brew method tends to extract more non-deprotonated acids than the cold brew method. These acids may be responsible for the higher antioxidant activities observed in the hot brew coffee samples

Unlocking the in vitroanti- inflammatory and antidiabetic potential of Polygonum maritimum

Context: Several Polygonum species (Polygonaceae) are used in traditional medicine in Asia, Europe and Africa to treat inflammation and diabetes. Objective: Evaluate the in vitro antioxidant, anti-inflammatory and antidiabetic potential of methanol and dichloromethane extracts of leaves and roots of the halophyte Polygonum maritimum L. Material and methods: Antioxidant activity was determined (up to 1mg/mL) as radical-scavenging activity (RSA) of 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), copper (CCA) and iron (ICA) chelating activities and iron reducing power (FRAP). NO production was measured in lipopolysaccharide (LPS)-stimulated macrophages for 24 h at concentrations up to 100 mu g/mL and antidiabetic potential was assessed by alpha-amylase and alpha-glucosidase inhibition (up to 10 g/mL) assays. The phytochemical composition of the extracts was determined by gas chromatography-mass spectrometry (GC-MS). Results: The methanol leaf extract had the highest activity against DPPH center dot (IC50 = 26 mu g/mL) and ABTS1(+)center dot (IC50 = 140 mu g FRAP (IC50 = 48 mu g/mL) and CCA (IC50 = 770 mu g/mL). Only the dichloromethane leaf extract (LDCM) showed anti-inflammatory activity (IC50 = 48 mu g/mL). The methanol root (IC50 = 19 mu g/mL) and leaf (IC50 = 29 mu g/mL) extracts strongly inhibited baker's yeast alpha-glucosidase, but LDCM had higher rat's alpha-glucosidase inhibition (IC50 = 2527 mu g/mL) than acarbose (IC50 = 4638 mu g/mL). GC-MS analysis identified beta-sitosterol, stigmasterol, 1-octacosanol and linolenic acid as possible molecules responsible for the observed bioactivities. Conclusions: Our findings suggest P. maritimum as a source of high-value health promoting commodities for alleviating symptoms associated with oxidative and inflammatory diseases, including diabetes.XtremeBio project - Foundation for Science and Technology (FCT) [PTDC/MAR-EST/4346/2012]; Portuguese National Budget; FCT [CCMAR/Multi/04326/ 2013, IF/00049/2012, SFRH/BPD/86071/2012, UID/Multi/00612/2013