Browsing by Subject "Flavonoids"

Now showing 1 - 6 of 6
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    Bioactive Compounds Enhance the Biocompatibility and the Physical Properties of a Glass Ionomer Cement
    (MDPI, 2024-11-07) de Castilho, Aline Rogéria Freire; Rosalen, Pedro Luiz; Oliveira, Marina Yasbeck; Burga-Sánchez, Jonny; Duarte, Simone; Murata, Ramiro Mendonça; Puppin Rontani, Regina Maria; Pediatric Dentistry, School of Dentistry
    In order to characterize a novel restorative material, knowledge about the toxicological effect on human cells and the physical behavior of a glass ionomer cement (GIC) containing flavonoids was established. The flavonoids apigenin, naringenin, quercetin, and liquiritigenin were manually incorporated into a GIC. In the control group, no incorporation was performed. Two cell culture assays evaluated the toxicity of GICs: SRB and MTT. For both assays, the keratinocyte cell line (HaCaT) was exposed to GIC (n = 3/group) for 24 h. The physical properties of the GICs were evaluated by compressive strength (n = 10), surface roughness (n = 10), and hardness (n = 10) tests. Cell viability by SRB ranged from 103% to 97%. The control revealed a significant decrease in the metabolism of cells (61%) by MTT, while the GIC+apigenin slightly increased the succinic dehydrogenase activity (105%; p > 0.05), also confirmed microscopically. The compressive strength and roughness values were similar among groups, but the hardness increased after the incorporation of naringenin and quercetin into GIC (p < 0.05). The incorporation of flavonoids positively altered the biological and physical properties of the GICs.
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    Effects of Various Flavonoids on the -Synuclein Fibrillation Process
    (Hindawi, 2010-01-28) Meng, Xiaoyun; Munishkina, Larissa A.; Fink, Anthony L.; Uversky, Vladimir N.
    α-Synuclein aggregation and fibrillation are closely associated with the formation of Lewy bodies in neurons and are implicated in the causative pathogenesis of Parkinson's disease and other synucleinopathies. Currently, there is no approved therapeutic agent directed toward preventing the protein aggregation, which has been recently shown to have a key role in the cytotoxic nature of amyloidogenic proteins. Flavonoids, known as plant pigments, belong to a broad family of polyphenolic compounds. Over 4,000 flavonoids have been identified from various plants and foodstuffs derived from plants and have been demonstrated as potential neuroprotective agents. In this study 48 flavonoids belonging to several classes with structures differing in the position of double bonds and ring substituents were tested for their ability to inhibit the fibrillation of α-synuclein in vitro. A variety of flavonoids inhibited α-synuclein fibrillation, and most of the strong inhibitory flavonoids were also found to disaggregate preformed fibrils.
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    Preventing Oral Dual Biofilm Development with Innovative Bioactive Varnishes
    (MDPI, 2025-02-18) Costa, Tainá de Lima; Puppin-Rontani, Regina Maria; de Castilho, Aline Rogéria Freire; Pediatric Dentistry, School of Dentistry
    This study introduces innovative varnishes incorporating natural bioactive compounds to inhibit the formation of oral dual biofilms, a critical contributor to dental caries and other oral diseases. The purpose of this study was to evaluate the effectiveness of bioactive varnishes containing tt-farnesol, quercetin, and theobromine in inhibiting the formation of mixed Streptococcus mutans and Candida albicans biofilms. Mixed biofilms of Streptococcus mutans UA159 and Candida albicans SC5314 were grown in 96-well plates containing a specialized culture medium. Approximately 0.2 mL of experimental varnishes with A-1.5% or B-4.5% concentrations of tt-farnesol, quercetin, and theobromine were separately added to the wells using a disposable applicator, with a vehicle varnish (lacking bioactives) serving as the control. Biofilms were incubated at 37 °C with 5% CO2 for 24 h. Microbial viability was determined in terms of colony-forming units per milliliter (CFU/mL), and biofilm morphology was evaluated qualitatively via scanning electron microscopy (SEM). Statistical analyses were performed using ANOVA/Tukey tests at a 5% significance level. Varnishes A and B achieved significant reductions in microbial populations within the biofilms (p < 0.05) compared to the vehicle control (C). SEM imaging revealed marked structural disruptions in the biofilms, validating the quantitative results. Higher bioactive concentrations demonstrated enhanced inhibitory effects. Bioactive varnishes enriched with theobromine, quercetin, and tt-farnesol represent a novel and effective strategy for inhibiting oral dual biofilm development, offering a promising advancement in preventive dentistry.
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    Protective effects of quercetin, polydatin, and folic acid and their mixtures in a zebrafish (Danio rerio) fetal alcohol spectrum disorder model
    (Elsevier, 2020) Cadena, Pabyton Gonçalves; Cadena, Marilia Ribeiro Sales; Sarmah, Swapnalee; Marrs, James A.; Biology, School of Science
    Protective effects of quercetin (QUE), polydatin (POL), and folic acid (FA) and their mixtures were tested using zebrafish to model fetal alcohol spectrum disorder in this study. Zebrafish embryos were exposed to 150 mM ethanol for 6 or 22 h and co-treated with QUE, POL, FA, and their mixtures (37.5 – 100.0 μM). Epiboly progression, teratogenic effects, and behavior were evaluated. Ethanol exposure reduced epiboly, and FA and QUE protected against these ethanol-induced defects. POL did not reduce epiboly defects. The mixture QUE+FA showed a possible antagonistic effect. The observed teratogenic effects were similar in all ethanol exposed groups. QUE, FA and QUE+POL reduced the percentage of affected animals, but treatments did not eliminate teratogenic effects. Behavioral measurements were divided into small (between 4 and 8 mm/s) and high swimming activity (> 8 mm/s). All experimental groups displayed a reduction in small swimming activity as compared to control and ethanol groups when exposed to bright light. Additionally, larvae exposed to ethanol were more inhibited than control, not showing a habituation period (after 60 min of experiment) in high swimming activity. Chemical treatments like QUE and POL reduced behavioral defects induced by ethanol exposure. In conclusion, this study presents new evidence that QUE, POL, FA and their mixtures partially protected epiboly, teratogenic, and behavioral defects induced by ethanol exposure. QUE, FA and QUE+POL were more effective in reducing these defects than the other studied compounds and mixtures.
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    Regulation of Cell Motility by Mitogen-activated Protein Kinase
    (Rockefeller University Press, 1997) Klemke, Richard L.; Cai, Shuang; Giannini, Ana L.; Gallagher, Patricia J.; de Lanerolle, Primal; Cheresh, David A.; Anatomy, Cell Biology and Physiology, School of Medicine
    Cell interaction with adhesive proteins or growth factors in the extracellular matrix initiates Ras/mitogen-activated protein (MAP) kinase signaling. Evidence is provided that MAP kinase (ERK1 and ERK2) influences the cells' motility machinery by phosphorylating and, thereby, enhancing myosin light chain kinase (MLCK) activity leading to phosphorylation of myosin light chains (MLC). Inhibition of MAP kinase activity causes decreased MLCK function, MLC phosphorylation, and cell migration on extracellular matrix proteins. In contrast, expression of mutationally active MAP kinase kinase causes activation of MAP kinase leading to phosphorylation of MLCK and MLC and enhanced cell migration. In vitro results support these findings since ERK-phosphorylated MLCK has an increased capacity to phosphorylate MLC and shows increased sensitivity to calmodulin. Thus, we define a signaling pathway directly downstream of MAP kinase, influencing cell migration on the extracellular matrix.
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    Structure Based Identification and Characterization of Flavonoids That Disrupt Human Papillomavirus-16 E6 Function
    (Public Library of Science, 2013-12-23) Cherry, Jonathan J.; Rietz, Anne; Malinkevich, Anna; Liu, Yuqi; Xie, Meng; Bartolowits, Matthew; Davisson, V. Jo; Baleja, James D.; Androphy, Elliot J.; Dermatology, School of Medicine
    Expression and function of the human papillomavirus (HPV) early protein 6 (E6) is necessary for viral replication and oncogenesis in cervical cancers. HPV E6 targets the tumor suppressor protein p53 for degradation. To achieve this, "high-risk" HPV E6 proteins bind to and modify the target specificity of the ubiquitin ligase E6AP (E6 associated protein). This E6-dependent loss of p53 enables the virus to bypass host cell defenses and facilitates virally induced activation of the cell cycle progression during viral replication. Disruption of the interaction between E6 and E6AP and stabilization of p53 should decrease viability and proliferation of HPV positive cells. A new in vitro high-throughput binding assay was developed to assay binding between HPV-16 E6 and E6AP and to identify compounds that inhibit this interaction. The compound luteolin emerged from the screen and a library of novel flavones based on its structure was synthesized and characterized using this in vitro binding assay. The compounds identified in this study disrupt the E6/E6AP interaction, increase the levels of p53 and p21(Cip1/Waf1), and decrease proliferation of HPV positive cell lines. The new class of flavonoid E6 inhibitors displays a high degree of specificity for HPV positive cells. Docking analyses suggest that these compounds bind in a hydrophobic pocket at the interface between E6 and E6AP and mimic the leucines in the conserved α-helical motif of E6AP. The activity and specificity of these compounds represent a promising new lead for development as an antiviral therapy in the treatment of HPV infection and cervical cancer.