Peptide cell-display for selection of inhibitors against human glutathione transferase P1-1 (hGSTP1-1) allozymes

We developed a combinatorial strategy aiming at designing peptide inhibitors against the hGSTP1-1 isoenzyme involved in MDR. We developed a combinatorial strategy aiming at designing peptide inhibitors against the hGSTP1-1 isoenzyme. We employed a combinatorial peptide library featuring engineered E. coli cells harboring a plasmid able to express a fusion protein containing random 12peptides. After five selection rounds, clones were screened for hGSTP1-1 binding (dot blot hybridization) and those with the strongest signal were selected and sequenced. Sequence alignments showed a core binding sequence which, along with selected peptide fragments, were synthesized using the solid phase methodology . The synthetic peptides were studied for their inhibition potency against three human GSTP1-1 allozymes, A, B and

Combinatorial design, selection and synthesis of peptide inhibitors against human glutathione transferase p1-1

Certain glutathione S-transferase (GST) isoenzymes detoxify the cell from xenobiotics, thus becoming inhibition targets when overexpressed in various tumours leading to MDR. We developed a combinatorial strategy aiming at designing peptide inhibitors against the hGSTP1-1 isoenzyme involved in MDR. We employed a combinatorial peptide library featuring engineered E. coli cells harboring a plasmid able to express a fusion protein containing random 12 peptides which were inserted into the active loop of thioredoxin, which itself was inserted into the dispensable region of the flagellin gene. After five selection rounds, clones were screened for hGSTP1-1 binding and those with the strongest signal were selected and sequenced. Sequence alignments showed a core binding sequence which, along with selected peptide fragments, were synthesized using the solid phase methodology and Fmoc/tBu chemistry on 2-chlorotrityl chloride solid support. The four peptides were studied for their inhibition potency against hGSTP1-1 allozymes A, B and C

Synthesis of glutathione analogues and screening as substrates & inhibitors for human glutathione transferase p1‐1

A major detoxification mechanism of the cell involves the glutathione transferase (GST)‐catalyzed formation of glutathione (GSH) conjugates with various xenobiotics Based on the same mechanism, GST overexpression may lead to multidrug resistant phenotypes Therefore, several compounds with inhibitory potency against GSTs have been developed as potential tools fortackling GST-­‐attributed MDR. Several individual compounds and prodrugs have been proposed as GST‐inhibiting substances. In addition, GSH analogues have been considered as specific GST inhibitors, with particular attention been directed towards the synthesis of GSH analogues stable against γ‐glutamyltranspeptidase (γGT) and peptidases, as GST inhibitors

Berry Leaves: An Alternative Source of Bioactive Natural Products of Nutritional and Medicinal Value

Berry fruits are recognized, worldwide, as “superfoods” due to the high content of bioactive natural products and the health benefits deriving from their consumption. Berry leaves are byproducts of berry cultivation; their traditional therapeutic use against several diseases, such as the common cold, inflammation, diabetes, and ocular dysfunction, has been almost forgotten nowadays. Nevertheless, the scientific interest regarding the leaf composition and beneficial properties grows, documenting that berry leaves may be considered an alternative source of bioactives. The main bioactive compounds in berry leaves are similar as in berry fruits, i.e., phenolic acids and esters, flavonols, anthocyanins, and procyanidins. The leaves are one of the richest sources of chlorogenic acid. In various studies, these secondary metabolites have demonstrated antioxidant, anti-inflammatory, cardioprotective, and neuroprotective properties. This review focuses on the phytochemical composition of the leaves of the commonest berry species, i.e., blackcurrant, blackberry, raspberry, bilberry, blueberry, cranberry, and lingonberry leaves, and presents their traditional medicinal uses and their biological activities in vitro and in vivo

Production of Antioxidants and High Value Biomass from <i>Nannochloropsis</i> <i>oculata</i>: Effects of pH, Temperature and Light Period in Batch Photobioreactors

Nannochloropsis oculata is a marine microalgal species with a great potential as food or feed due to its high pigment, protein and eicosapentaenoic acid contents. However, for such an application to be realized on a large scale, a biorefinery approach is necessary due to the high cost of microalgal biomass production. For example, techno economic analyses have suggested the co-production of food or feed with antioxidants, which can be extracted and supplied separately to the market. The aim of this study was to investigate the effect of cultivation conditions on the antioxidant capacity of Nannochlosopsis oculata extracts, derived with ultrasound-assisted extraction at room temperature, as well as the proximate composition and fatty acid profile of the biomass. A fractional factorial approach was applied to examine the effects of temperature (20–35 °C), pH (6.5–9.5) and light period (24:0, 12:12). At the end of each run, biomass was collected, washed with 0.5M ammonium bicarbonate and freeze-dried. Antioxidant capacity as gallic acid equivalents as well as pigment content were measured in the ethanolic extracts. Optimal conditions were different for productivity and biomass composition. Interesting results regarding the effect of light period (LP) and pH require further investigation, whereas the effect of moisture on the extraction process was confounded with biomass composition. Finally, further data is provided regarding the relation between chlorophyll content and apparent phenolic content using the Folin–Ciocalteu assay, in agreement with our previous work

Monitoring of Volatile Organic Compounds in Strawberry Genotypes over the Harvest Period

Volatile Organic Compounds (VOCs) over the harvest period have been assessed in twenty-five strawberry genotypes cultivated in western Greece. Using liquid–liquid extraction and gas chromatography–mass spectrometry (GC–-MS), twenty-eight volatiles were monitored at early (T1) and mid-harvest (T3) time points to investigate the effect of the genotype and harvest time on strawberry volatilome. A quantitative impact of both harvest date and genotype on VOCs associated with aroma was demonstrated, with the most significant VOCs being terpenes, esters, and acids, followed by lactones and furanones. Harvest date was crucial for terpenoid and phenylpropanoid content, and important for esters, short-chain acids, and lactones. Six out of the twenty-five genotypes (four commercial varieties, including ‘Rociera’, ‘Victory’, ‘Leyre’, and ‘Inspire’, and two advanced selection genotypes (G2 and G8) were evaluated at two additional time points, covering the entire harvest season. The volatile levels were higher in fruits harvested at early stages (T1–T2) for most of the genotypes examined. The G2 genotype turned out to have a less ample but more stable volatile profile throughout harvesting, while ‘Victory’, ‘Leyre’, and ‘Inspire’ exhibited less abrupt changes than ‘Rociera’. This study demonstrates that the determination of VOCs provides significant information regarding the differences in strawberry genotypes related to aroma and enables the selection of genotypes based on specific VOCs content and/or volatile stability over the harvest period. Furthermore, this study pinpoints that growers could opt for optimal harvest dates based on the genotypes and the VOC content

Polymeric Nanoparticles of Pistacia lentiscus var. chia Essential Oil for Cutaneous Applications

Polymeric nanoparticles (NPs) encapsulating Pistacia lentiscus L. var. chia essential oil (EO) were prepared by a solvent evaporation method, in order to obtain a novel carrier for administration on the skin. The specific EO exhibits antimicrobial and anti-inflammatory properties thus stimulating considerable interest as a novel agent for the treatment of minor skin inflammations. The incorporation into nanoparticles could overcome the administration limitations that inserts the nature of the EO. Nanoparticles were prepared, utilizing poly(lactic acid) (PLA) as shell material, due to its biocompatibility and biodegradability, while the influence of surfactant type on NPs properties was examined. Two surfactants were selected, namely poly(vinyl alcohol) (PVA) and lecithin (LEC) and NPs&rsquo; physicochemical characteristics i.e. size, polydispersity index (PdI) and &zeta;-potential were determined, not indicating significant differences (p &gt; 0.05) between PLA/PVA-NPs (239.9 nm, 0.081, -29.1 mV) and PLA/LEC-NPs (286.1 nm, 0.167, &minus;34.5 mV). However, encapsulation efficiency (%EE) measured by GC-MS, was clearly higher for PLA/PVA-NPs than PLA/LEC-NPs (37.45% vs. 9.15%, respectively). Moreover PLA/PVA-NPs remained stable over a period of 60 days. The in vitro release study indicated gradual release of the EO from PLA/PVA-NPs and more immediate from PLA/LEC-NPs. The above findings, in addition to the SEM images of the particles propose a potential structure of nanocapsules for PLA/PVA-NPs, where shell material is mainly consisted of PLA, enclosing the EO in the core. However, this does not seem to be the case for PLA/LEC-NPs, as the results indicated low EO content, rapid release and a considerable percentage of humidity detected by SEM. Furthermore, the Minimum Inhibitory Concentration (MIC) of the EO was determined against Escherichia coli and Bacillus subtilis, while NPs, however did not exhibit considerable activity in the concentration range applied. In conclusion, the surfactant selection may modify the release of EO incorporated in NPs for topical application allowing its action without interfering to the physiological skin microbiota

Evaluation of Essential Oils and Extracts of Rose Geranium and Rose Petals as Natural Preservatives in Terms of Toxicity, Antimicrobial, and Antiviral Activity

Essential oils (EOs) and extracts of rose geranium (Pelargonium graveolens) and petals of rose (Rosa damascena) have been fully characterized in terms of composition, safety, antimicrobial, and antiviral properties. They were analyzed against Escherichia coli, Salmonella enterica serovar Typhimurium, Staphylococcus aureus, Aspergillus niger, and Adenovirus 35. Their toxicity and life span were also determined. EO of P. graveolens (5%) did not retain any antibacterial activity (whereas at 100% it was greatly effective against E. coli), had antifungal activity against A. niger, and significant antiviral activity. Rose geranium extract (dilutions 25−90%) (v/v) had antifungal and antibacterial activity, especially against E. coli, and dose-dependent antiviral activity. Rose petals EO (5%) retains low inhibitory activity against S. aureus and S. Typhimurium growth (about 20−30%), antifungal activity, and antiviral activity for medium to low virus concentrations. Rose petals extract had significant antibacterial activity at dilutions of 25−90%, especially against E. coli and S. Typhimurium, antifungal, and the most potent antiviral activity. None of the EOs and extracts were toxic in dilutions of up to 5% and 90%, respectively. Finally, all materials had a life span of more than eight weeks. These results support the aspect that rose petals and rose geranium EOs, and extracts, have beneficial antimicrobial and antiviral properties and they can be used as natural preservatives

Ultrasound-Assisted Extraction of Nannochloropsis oculata with Ethanol and Betaine: 1,2-Propanediol Eutectic Solvent for Antioxidant Pigment-Rich Extracts Retaining Nutritious the Residual Biomass

The aim of this study was the development of an efficient &ldquo;green&rdquo; extraction method of Nannochloropsis oculata to produce antioxidant extracts and nutritious residual biomass. Twenty-one extraction methods were evaluated by measuring the reactivity with the Folin&ndash;Ciocalteu reagent: ultrasonication or maceration at different temperatures with different organic solvents, extraction at different pH values, enzyme-assisted extraction, encapsulation with &beta;-cyclodextrin, and the use of natural deep eutectic solvents. Ultrasound-assisted extraction with ethanol or betaine: 1,2-propanediol in a molar ratio of 2:5 (BP) had optimal extractive capacity. Both extracts were evaluated with antioxidant assays and the ethanol extract exhibited significantly higher (at least twofold) values. The determination of carotenoids by LC-MS and HPLC-DAD revealed the dominance of violaxanthin and antheraxanthin and their fourfold higher concentrations in the ethanol extract. The 1H-NMR characterization of the ethanol extract confirmed the results of the colorimetric and chromatographic assays. The microalgal biomass was characterized before and after the extraction in terms of humidity, ash, carbohydrates, proteins, chlorophyll-a, carotenoids, and lipids; the identity and content of the latter were determined with gas chromatography. BP caused a smaller depletion of the lipids from the biomass compared to ethanol, but proteins, carbohydrates, and ash were at a higher content in the biomass obtained after ethanol extraction, whereas the biomass was dry and easy to handle. Although further optimization may take place for the scale-up of those procedures, our study paves the way for a green strategy for the valorization of microalgae in cosmetics without generating waste, since the remaining biomass can be used for aquafeed