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    Wyświetlanie 1-9 z 9
    Tytuł:
    Correlation between mammalian cell cytotoxicity of flavonoids and the redox potential of phenoxyl radical/phenol couple
    Autorzy:
    Marozienė, Audronė
    Nemeikaitė-Čėnienė, Aušra
    Vidžiūnaitė, Regina
    Čėnas, Narimantas
    Powiązania:
    https://bibliotekanauki.pl/articles/1039753.pdf
    Data publikacji:
    2012
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    cytotoxicity
    antioxidants
    flavonoids
    oxidative stress
    Opis:
    Flavonoids exhibit prooxidant cytotoxicity in mammalian cells due to the formation of free radicals and oxidation products possessing quinone or quinomethide structure. However, it is unclear how the cytotoxicity of flavonoids depends on the ease of their single-electron oxidation in aqueous medium, i.e., the redox potential of the phenoxyl radical/phenol couple. We verified the previously calculated redox potentials for several flavonoids according to their rates of reduction of cytochrome c and ferricyanide, and proposed experimentally-based values of redox potentials for myricetin, fisetin, morin, kaempferol, galangin, and naringenin. We found that the cytotoxicity of flavonoids (n=10) in bovine leukemia virus-transformed lamb kidney fibroblasts (line FLK) and murine hepatoma (line MH-22a) increases with a decrease in their redox potential of the phenoxyl radical/phenol couple and an increase in their lipophilicity. Their cytotoxicity was decreased by antioxidants and inhibitors of cytochromes P-450, α-naphthoflavone and isoniazide, and increased by an inhibitor of catechol-O-methyltransferase, 3,5-dinitrocatechol. It shows that although the prooxidant action of flavonoids may be the main factor in their cytotoxicity, the hydroxylation and oxidative demethylation by cytochromes P-450 and O-methylation by catechol-O-methyltransferase can significantly modulate the cytotoxicity of the parent compounds.
    Źródło:
    Acta Biochimica Polonica; 2012, 59, 2; 299-306
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Flavonoids as reductants of ferryl hemoglobin
    Autorzy:
    Gebicka, Lidia
    Banasiak, Ewa
    Powiązania:
    https://bibliotekanauki.pl/articles/1040549.pdf
    Data publikacji:
    2009
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    methemoglobin
    ferryl hemoglobin
    oxyhemoglobin
    flavonoids
    Opis:
    The ferryl derivatives of hemoglobin are products of the reactions of oxy- and methemoglobin with hydrogen peroxide. Ferryl hemoglobins, either with or without a radical site on the protein moiety, are oxidizing species. Plant polyphenols, flavonoids, have been shown to act as antioxidants in vivo and in vitro. Reactions of met- and oxyhemoglobin with hydrogen peroxide in the presence of catechin, quercetin and rutin were studied. These flavonoids accelerated reduction of ferryl hemoglobin to methemoglobin. The rate constants of the reactions of ferryl hemoglobin with catechin, quercetin and rutin were in the order of 102 M-1 s-1, i.e. similar to the rate constants of ferryl hemoglobin with intracellular reducing compounds like urate or ascorbate. The beneficial effect of flavonoids against oxidative damage of hemoglobin caused by hydroperoxides, reported in the literature, is probably, at least in part, connected with the ability of flavonoids to scavenge ferryl hemoglobin.
    Źródło:
    Acta Biochimica Polonica; 2009, 56, 3; 509-513
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Isolation and antioxidant activity of flavonoids from Holarrhena floribunda (G.don) leaves
    Autorzy:
    Badmus, Jelili
    Ekpo, Okobi
    Rautenbach, Fanie
    Marnewick, Jeanine
    Hussein, Ahmed
    Hiss, Donavon
    Powiązania:
    https://bibliotekanauki.pl/articles/1038826.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    polyphenolics
    plants
    Holarrhena floribunda
    antioxidant
    flavonoids
    Opis:
    Bioactive polyphenolics are ubiquitously present in plants and may play an important role in the prevention and management of certain human diseases. Three known flavonoids viz Kaemperol-3-O-rutinoside (1), quercetin-3-O-glucoside (2) and kaemperol-3-O-glucoside (3) and inseparable mixture (1:1) of quercetin-3-O-glucose/galactose (4) were isolated, and identified for the first time from Holarrhena floribunda. The antioxidant capacity using the ORAC, FRAP and TEAC assays and inhibition of lipid peroxidation were measured for isolated flavonoids. The result showed that compounds 2 and 4 showed significantly increased ORAC, TEAC, and FRAP activities with low pro-oxidant potential as well as improved lipid peroxidation inhibition levels when compared to compounds 1 and 3. The most active compounds were found to be flavonoids with a quercetin basic structure. These results imply that the isolated flavonoid glycosides are responsible for the antioxidant activity of the plant leaves and it forms the scientific basis for its traditional usage.
    Źródło:
    Acta Biochimica Polonica; 2016, 63, 2; 353-358
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis of kaempferide Mannich base derivatives and their antiproliferative activity on three human cancer cell lines
    Autorzy:
    Nguyen, Van-Son
    Shi, Ling
    Luan, Fang-Qian
    Wang, Qiu-An
    Powiązania:
    https://bibliotekanauki.pl/articles/1039003.pdf
    Data publikacji:
    2015
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    kaempferide
    flavonoids
    Mannich base derivatives
    synthesis
    antiproliferative activity
    Opis:
    Kaempferide (3,5,7-trihydroxy-4'-methoxyflavone, 1), a naturally occurring flavonoid with potent anticancer activity in a number of human tumour cell lines, was first semisynthesized from naringin. Based on Mannich reaction of kaempferide with various secondary amines and formaldehyde, nine novel kaempferide Mannich base derivatives 2-10 were synthesized. The aminomethylation occurred preferentially in the position at C-6 and C-8 of the A-ring of kaempferide. All the synthetic compounds were tested for antiproliferative activity against three human cancer cell lines (Hela, HCC1954, SK-OV-3) by the standard MTT method. The results showed that compounds 1, 2 and 5-10 were more potent against Hela cells with IC50 values of 12.47-28.24 μM than the positive control cis-platin (IC50 41.25 μM), compounds 5, 6, 8 and 10 were more potent against HCC1954 cells with IC50 values of 8.82-14.97 μM than the positive control cis-platin (IC50 29.68 μM), and compounds 2, 3, 5, 6 and 10 were more potent against SK-OV-3 cells with IC50 values of 7.67-18.50 μM than the positive control cis-platin (IC50 21.27 μM).
    Źródło:
    Acta Biochimica Polonica; 2015, 62, 3; 547-552
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis and biological evaluation of 4-O-acetyl-isoxanthohumol and its analogues as antioxidant and antiproliferative agents
    Autorzy:
    Stompor, Monika
    Świtalska, Marta
    Podgórski, Rafał
    Uram, Łukasz
    Aebisher, David
    Wietrzyk, Joanna
    Powiązania:
    https://bibliotekanauki.pl/articles/1038626.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    O-acylated flavanones
    antiproliferative effect
    isoxanthohumol
    hop flavonoids
    Opis:
    Isoxanthohumol (2) and its 4'-O-monoacylated (3) and 7,4'-O-diacetylated (4) derivatives were synthesized and evaluated in vitro for their cytotoxic activity against several cancer cell lines of various origins: MCF-7 (breast), A549 (lung), MESSA (uterine sarcoma), LoVo (colon), drug-resistant human cancer cells (MESSA/DX and LoVo/DX), glioblastoma (U-118 MG), and also towards the non-cancerous cell line MCF-10A (normal breast cells). An antiproliferative assay indicates that 7,4'-di-O-acylisoxanthohumol (4) has similar cytotoxicity to its precursor, isoxanthohumol (2), against selected cell lines (A549, MES-SA, MES-SA/5DX, and U-118 MG). Compound 4 was only slightly more cytotoxic to lung, colon, breast (cancerous and normal) and uterine sarcoma (drug sensitive and drug resistant) cell lines compared to its monoacylated derivative (3). Both acylated isoxanthohumols showed preferential activity against tumor cells (MCF-7) and low cytotoxicity to normal cells (MCF-10A), which suggests selectivity of the acylated isoxanthohumols towards cancer cells. Additionally, the activity of the acylated isoxanthohumols was higher than for 2. To the best of our knowledge this is the first report on bioactivity of monoacylated isoxanthohumol (3) and its ester derivatives as antiproliferative compounds in drug resistant cell cultures. Acylation of 2 decreased the antioxidant activity determined by the DPPH method in the order isoxanthohumol (2) >4'-O-acetylisoxanthohumol (3) >7,4'-di-O-acetylisoxanthohumol (4).
    Źródło:
    Acta Biochimica Polonica; 2017, 64, 3; 577-583
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Protective effects of quercetin on cadmium fluoride induced oxidative stress at different intervals of time in mouse liver
    Autorzy:
    Zargar, Seema
    Siddiqi, Nikhat
    Al Daihan, Sooad
    Wani, Tanveer
    Powiązania:
    https://bibliotekanauki.pl/articles/1039092.pdf
    Data publikacji:
    2015
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    cadmium fluoride
    quercetin
    oxidative stress
    flavonoids
    histology
    adverse effect
    Opis:
    Quercetin, a member of the flavonoid family is a major antioxidant acquired in humans by food consumption, while Cadmium fluoride (CdF2) is one of the naturally occurring chemicals having adverse effects. The protective effect of quercetin on time dependent oxidative damage induced in mice liver by CdF2 was studied in the following groups of mice consisting of six mice each: (i) control group; (ii) mice treated with single i.p injection of 2 mg/kg bw CdF2 for 24 h; (iii) mice treated with single i.p injection of 2 mg/kg bw CdF2 for 48 h; (iv) mice treated with single i.p injection of quercetin (100 mg/kg bw); (v) mice treated with i.p injection of 100 mg/kg bw of quercetin followed by i.p injection of CdF2 (2 mg/kg bw) for 24 h; and (vi) mice treated with i.p injection of 100mg/kg bw of quercetin followed by CdF2 (2 mg/kg bw) for 48 h. Administration of quercetin two hours before CdF2 significantly reduced the biochemical alterations in reduced glutathione, ascorbic acid, lipid peroxidation, super oxide dismutase, catalase and total protein (p<0.05). Histopathology also showed the protective effect of quercetin. The livers treated with CdF2 were atrophic, markedly nodular, inflamed and necrotic. However, this effect was reduced to a minimum in the mice pre-treated for two hours with quercetin.
    Źródło:
    Acta Biochimica Polonica; 2015, 62, 2; 207-213
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of glycosylated flavonoids extracted from sweet-cherry stems, as antibacterial agents against pathogenic Escherichia coli isolates
    Autorzy:
    Aires, Alfredo
    Dias, Carla
    Carvalho, Rosa
    Saavedra, Maria
    Powiązania:
    https://bibliotekanauki.pl/articles/1038644.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    flavonoids
    agro-food wastes
    enhanced extraction
    antimicrobial agents
    pathogenic bacteria
    Opis:
    The aim of this study was to evaluate the bioactivity of flavonoids extracted from sweet-cherry stems which are often used by a traditional system of medicine to treat gastro-intestinal and urinary tract infections but lacking any consistent scientific evidence; moreover the information about the class of phenolics, their content and the potential bioactivity of such material is very scarce. Thus, in this context, we have set a research study in which we evaluated the profile and content of phenolics extracted from sweet-cherry stems through a conventional (70ºC and 20 min) and ultrasound assisted extraction (40 kHz, room temperature and 20 min). The extracts were phytochemically characterized by using an HPLC-DAD-UV/VIS system and assayed by an in vitro minimum inhibitory concentration (MIC) bioassay against Escherichia coli isolates. Simultaneously, the total antioxidant activities were measured using the 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonate (ABTS•+) radical cation assay. Our results indicate that sweet-cherry stems have a high content of sakuranetin, ferulic acid, p-coumaric acid, p-coumaroylquinic acid, chlorogenic acid and its isomer neochlorogenic acid. Their average levels were highly affected by the extraction method used (p<0.001). The same trend was observed for total antioxidant activity and MIC values. The extracts produced with ultrasounds presented both, a higher total antioxidant activity and a lower minimum inhibitory concentration. Statistical analyses of our results showed a significant correlation (p<0.01) of total antioxidant activity and minimum inhibitory concentration with phenolics present in the extracts studied. Thus, we can conclude that cherry stems can be further exploited to purify compounds and produce coproducts with enhanced biologically added value for pharmaceutical industry.
    Źródło:
    Acta Biochimica Polonica; 2017, 64, 2; 265-271
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The flavonoids, quercetin and isorhamnetin 3-O-acylglucosides diminish neutrophil oxidative metabolism and lipid peroxidation.
    Autorzy:
    Zielińska, Małgorzata
    Kostrzewa, Artur
    Ignatowicz, Ewa
    Budzianowski, Jaromir
    Powiązania:
    https://bibliotekanauki.pl/articles/1044184.pdf
    Data publikacji:
    2001
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    flow cytometry
    respiratory burst
    polymorphonuclear neutrophils
    reactive oxygen species
    lipid peroxidation
    flavonoids
    Opis:
    Two natural flavonoids, quercetin and isorhamnetin 3-O-acylglucosides, were examined for their inhibitory influence on the in vitro production and release of reactive oxygen species in polymorphonuclear neutrophils (PMNs). The generation of superoxide radical, hydrogen peroxide and hypochlorous acid were measured by, respectively, cytochrome c reduction, dichlorofluorescin oxidation and taurine chlorination. Membrane lipid oxidation was studied by the thiobarbituric acid method in mouse spleen microsomes. The addition of flavonoids at the concentration range 1-100 μM inhibited PMNs oxidative metabolism and lipid peroxidation in a dose-dependent manner. The results suggest that these flavonoids suppress the oxidative burst of PMNs and protect membranes against lipid peroxidation.
    Źródło:
    Acta Biochimica Polonica; 2001, 48, 1; 183-189
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Interaction of phenothiazines, stilbenes and flavonoids with multidrug resistance-associated transporters, P-glycoprotein and MRP1
    Autorzy:
    Wesołowska, Olga
    Powiązania:
    https://bibliotekanauki.pl/articles/1039822.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    multidrug resistance-associated protein 1 (MRP1,ABCC1)
    P-glycoprotein (ABCB1)
    phenothiazines
    multidrug resistance reversal
    stilbenes
    flavonoids
    Opis:
    Multidrug resistance (MDR) of cancer cells poses a serious obstacle to successful chemotherapy. The overexpression of multispecific ATP-binding cassette transporters appears to be the main mechanism of MDR. A search for MDR-reversing agents able to sensitize resistant cells to chemotherapy is ongoing in the hope of their possible clinical use. Studies of MDR modulators, although they have not produced clinically beneficial effects yet, may greatly enrich our knowledge about MDR transporters, their specificity and mechanism of action, especially substrate and/or inhibitor recognition. In the present review, interactions of three groups of modulators: phenothiazines, flavonoids and stilbenes with both P-glycoprotein and MRP1 are discussed. Each group of compounds is likely to interact with the MDR transporters by a different mechanism. Phenothiazines probably interact with drug binding sites, but they also could indirectly affect the transporter's activity by perturbing lipid bilayers. Flavonoids mainly interact with ABC proteins within their nucleotide-binding domains, though the more hydrophobic flavonoids may bind to regions within transmembrane domains. The possible mechanism of MDR reversal by stilbenes may result from their direct interaction with the transporter (possibly within substrate recognition sites) but some indirect effects such as stilbene-induced changes in gene expression pattern and in apoptotic pathways should also be considered. Literature data as well as some of our recent results are discussed. Special emphasis is put on cases when the interactions of a given compound with both P-glycoprotein and MRP1 have been studied simultaneously.
    Źródło:
    Acta Biochimica Polonica; 2011, 58, 4; 433-448
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

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