Interactions between polyphenolic antioxidants quercetin and naringenin dictate the distinctive redox-related chemical and biological behaviour of their mixtures

Food synergy concept is suggested to explain observations that isolated antioxidants are less bioactive than real foods containing them. However, mechanisms behind this discrepancy were hardly studied. Here, we demonstrate the profound impact of interactions between two common food flavonoids (individual: aglycones quercetin—Q and naringenin—N− or their glycosides rutin—R and naringin—N+ vs. mixed: QN− and RN+) on their electrochemical properties and redox-related bioactivities. N− and N+ seemed weak antioxidants individually, yet in both chemical and cellular tests (DPPH and CAA, respectively), they increased reducing activity of mixtures synergistically. In-depth measurements (differential pulse voltammetry) pointed to kinetics of oxidation reaction as decisive factor for antioxidant power. In cellular (HT29 cells) tests, the mixtures exhibited properties of a new substance rather than those of components. Pure flavonoids did not influence proliferation; mixtures stimulated cell growth. Individual flavonoids tended to decrease global DNA methylation with growing concentration; this effect was more pronounced for mixtures, but not concentration-dependent. In nutrigenomic studies, expression of gene set affected by QN− differed entirely from common genes modulated by individual components. These results question the current approach of predicting bioactivity of mixtures based on research with isolated antioxidants.

Effects of Eight Weeks of Resistance Exercises on Expression of Neurotrophins and Trk Receptors in Alzheimer Model Male Wistar Rats

This study aims to evaluate the effects of eight weeks of resistance exercises on expression of neurotrophins and Trk receptors in Alzheimer model male Wistar rats. For this purpose, 32 mature male Wistar rats with mean weights of 230 to 280 g were chosen and divided into Alzheimer and Sham groups. Rats in the Sham group received normal saline while rats in the Alzheimer group received STZ via intraventricular injection. These rats were then divided into the following four subgroups: 1. Resting Sham, 2. Exercising Sham, 3. Resting Alzheimer, and 4. Exercising Alzheimer. The two exercising rat subgroups, exercised three times a week for a period of eight weeks. A weight was attached to their tails and they had to carry this weight on a 26-step ladder in each cycle. Resting groups were handled every day to minimize the effects of stress level. At the end of the 8th week and 24 hours after the last exercise session (to avoid the effects of the last exercise session), the rats were put under deep anesthesia and scarified by head separation. Hippocampus tissues were precisely extracted and samples were sent to laboratory for molecular and cellular tests. In order to investigate gene expression, Quantitative RT-PCR was used. Results of the tests for comparing the means of BDNF, NT3, NGF, TrkA, and TrkB in two rat groups showed that with error levels of less than 5% and confidence of over 95%, there is a significant difference in the amounts of BDNF, NT3, NGF, TrkA, and TrkB between exercising rats and resting rats. These amounts were much higher in exercising Alzheimer rats group. Eight weeks of resistance exercises increased the expression of BDNF, NT3, and NGF genes as well as TrkA and TrkB receptors in Alzheimer model Wistar rats.

Qualitative Indicators of Experimental Brucellosis Antigen Preparations Designed for Cellular Tests in vitro

In order to develop the most diagnostically informative methods for carrying out antigen-stimulated cellular tests in vitro a careful selection of stimulating agent (antigen) is required, possessing an adequate activating potential and providing specificity of the reaction.Objective of the study was to identify the qualitative indicators of experimental batches of brucellosis antigen preparations designed for cellular tests in vitro.Materials and methods. Initially we produced antigen complexes of brucellosis microbe on the basis of the vaccine strains of three epidemically significant Brucella species (B. abortus, B. melitensis, B. suis). Quantitative determination of WsAg and PPBC proteins of experimental preparation series was performed applying capillary electrophoresis. Qualitative composition was assessed through ion exchange liquid chromatography with refractometric detection.Results and discussion. We have specified physical-chemical features, investigated chromatographic profiles and composition of protein fractions, as well as tried the produced experimental batches of brucellosis antigen preparations. After analyzing the defined protein and polysaccharide composition of the obtained WsAg samples, one can conclude that WsAg preparation cannot be used for cellular tests as the probability of non-specific lymphocyte reaction manifestation in vitro was experimentally proven. By contrast, complex brucellosis antigen preparation PPBC has an expressed specific activity and specificity under in vitro conditions and the prospects to be used when developing methodological approaches for laboratory diagnosis of brucellosis and assessment of de facto immunity rate in risk contingents after vaccination. The obtained parameters will allow for proper quality provision when manufacturing the developed experimental PPBC preparation designed for cellular tests in vitro, taking into account modern validation and standardization regulations.

Phytochemical Profile and Biological Activities of Tendrils and Leaves Extracts from a Variety of Vitis vinifera L.

Winery industry by-products have a great reuse potential in the pharmaceutical and cosmetic fields due to their bioactive compounds. This study investigates the phytochemical profile and the bioactivity of Vitis vinifera variety Fetească neagră tendrils extract (TE) and leaves extract (LE), intended to be used in oral hygiene products recommended in periodontal disease. The evaluation of the phenolic content was performed by colorimetric analysis. Liquid chromatography coupled with mass spectrometry was used to determine the chemical profile of the two extracts obtained from V. vinifera. Moreover, the antioxidant activity of the extracts was determined by spectrophotometric methods, as well as on human gingival fibroblasts (HGF) cell line. The cytocompatibility and cytoprotective effect against nicotine-induced cytotoxicity were tested, as well as the anti-inflammatory and antimicrobial effects. The TE showed higher total polyphenolic content, rich in rutin, compared to the leaves extract that displayed important amounts of isoquercitrin. The antioxidant effect was confirmed by both non-cellular and cellular tests. The cytocompatibility of the extracts was confirmed at a wide range of concentrations. The cytoprotective effect was demonstrated in HGF exposed to cytotoxic doses of nicotine; 300 µg/mL of both tested extracts decreased nicotine toxicity by approximately 20%. When challenged with E. coli polysaccharides, in HGF cells co-exposed to TE and LE, a reduction in the release of proinflammatory cytokines (IL-8, IL-6 and IL-1β) was observed. The extracts were both able to reduce the levels of reactive oxygen species and inflammatory cytokines, and had notable antimicrobial effects on pathogenic bacteria associated with periodontitis.

Applicability and Limitations in the Characterization of Poly-Dispersed Engineered Nanomaterials in Cell Media by Dynamic Light Scattering (DLS)

The dispersion protocol used to administer nanomaterials (NMs) in in vitro cellular tests might affect their toxicity. For this reason, several dispersion procedures have been proposed to harmonize the toxicological methods, allowing for the comparison of the data that were obtained by different laboratories. At the same time, several techniques and methods are available to monitor the identity of the NMs in the cell media. However, while the characterization of suspensions of engineered NMs having narrow size distribution may be easily performed, the description of aggregated NMs forming polydispersions is still challenging. In the present study, sub-micrometric/nanometric TiO2, SiO2, and CeO2 were dispersed in cell media by using two different dispersion protocols, with and without albumin (0.5%) and with different sonication procedures. Dynamic Light Scattering (DLS) was used to characterize NMs in stock solutions and culture media. Pitfalls that affect DLS measurements were identified and, guidance on a critical analysis of the results provided. The NMs were then tested for their cytotoxicity (LDH leakage) toward murine macrophages (RAW 264.7) and PMA-activated human monocytes (THP-1). As markers of pro-inflammatory response, nitric oxide (NO) and cytokine IL-1β production were measured on RAW 264.7 and THP-1 cells, respectively. The pre-treatment with albumin added to a strong sonication treatment increases the stability and homogeneity of the suspensions of nanometric samples, but not of the submicrometric-samples. Nevertheless, while TiO2 and CeO2 were non-cytotoxic in any conditions, differences in cytotoxicity, NO, and IL-1β releases were found for the SiO2, depending upon the protocol. Overall, the results suggest that there is no one-fits-all method valid for all NMs, since each class of NMs respond differently. The definition of validated procedures and parameters for the selection of the most appropriate method of dispersion for each class of NM appears to be a more efficacious strategy for the harmonization of the dispersion protocols.

Isoquinoline-Based Biaryls as a Robust Scaffold for Microtubule Inhibitors

<div> <div> <div> <div> <p>We here report the discovery of isoquinoline-based biaryls as a new scaffold for colchicine domain tubulin inhibitors. Colchicine domain inhibitors comprise a structurally diverse class of compounds offering highly desirable cytotoxic and vascular disrupting bioactivities. Current research on colchicine domain inhibitors is focused on improving in vivo robustness and tolerability: properties that are inextricably linked to the scaffold structure employed. The isoquinoline-based biaryl scaffold we now report offers high-potency tubulin inhibition with excellent robustness and druglikeness, allowing solubility, in vivo tolerability and facile late-stage structural diversification through a tolerant synthetic route. We have confirmed the tubulin-binding properties and mechanism of these isoquinoline-based biaryls through a series of cellular tests and established safe in vivo dosing parameters in mice. By addressing several problems facing the current families of inhibitors, we thus expect that this new scaffold will find a range of powerful in vivo applications towards translational use in cancer therapy. </p> </div> </div> </div> </div>

Isoquinoline-Based Biaryls as a Robust Scaffold for Microtubule Inhibitors

<div> <div> <div> <div> <p>We here report the discovery of isoquinoline-based biaryls as a new scaffold for colchicine domain tubulin inhibitors. Colchicine domain inhibitors comprise a structurally diverse class of compounds offering highly desirable cytotoxic and vascular disrupting bioactivities. Current research on colchicine domain inhibitors is focused on improving in vivo robustness and tolerability: properties that are inextricably linked to the scaffold structure employed. The isoquinoline-based biaryl scaffold we now report offers high-potency tubulin inhibition with excellent robustness and druglikeness, allowing solubility, in vivo tolerability and facile late-stage structural diversification through a tolerant synthetic route. We have confirmed the tubulin-binding properties and mechanism of these isoquinoline-based biaryls through a series of cellular tests and established safe in vivo dosing parameters in mice. By addressing several problems facing the current families of inhibitors, we thus expect that this new scaffold will find a range of powerful in vivo applications towards translational use in cancer therapy. </p> </div> </div> </div> </div>

Determination of antioxidantactivity of phytochemicals in cellular models by fluorescence/luminescence methods

As soon as the role of Reactive Oxygen Species (ROS) in so-called civilization diseases, which include non-infectious chronic diseases such as cancer, diabetes or high blood pressure has been discovered, and the possibility of employing antioxidants as a remedy for these diseases have been proposed, scientists developed a broad spectrum of methods to determine antioxidant activity of pure chemicals and plant extracts, as well as dietary supplements. Most of these methods are based on simple redox reactions between antioxidant and ROS (for example ABTS, DPPH, or FRAP tests). However, chemical methods of assessing antioxidant activity are rarely biologically relevant. They do not mirror the real effect of antioxidants in living organisms, because they are used in non-physiological conditions of temperature and pH; neither they take metabolism nor intracellular transport under consideration. The perfect model for assessment of antioxidant activity in living organisms would be human or animal model, but such determinations are very complicated and often ambiguous. The current best alternative to chemical and human tests are assays employing cell culture models being less expensive than human tests, yet still reflecting biological systems more convincingly than chemical assays. Cellular antioxidant assays are performed under physiological pH and temperature, but most importantly, they take metabolism and intracellular transport under consideration. In this review, we present cellular tests used to determine antioxidant activity that are based on luminescence and fluorescence methods.