Search results for "Myricetin"
showing 10 items of 13 documents
Isolation and determination of phenolic compounds from freshwater Cladophora glomerata
2020
Abstract Marine algae biomass has gained widespread interest in the world of science and many industries. The growing number of publications proves that these algae are an interesting and essential natural resource. This interest is due to the presence of a variety of biologically active compounds that give algae extracts a broad spectrum of biological and functional properties. However, there is little data on the chemical composition of algae obtained from freshwater. This work focuses on the isolation and determination of phenolic compounds from freshwater algae of the species Cladophora glomerata. Different types of extraction and extractants were used to isolate these bioactive compoun…
Inhibition of human monoamine oxidase A and B by flavonoids isolated from two Algerian medicinal plants
2017
Abstract Background Monoamine oxidases (MAOs) are outer mitochondrial membrane flavoenzymes. They catalyze the oxidative deamination of a variety of neurotransmitters. MAO-A and MAO-B may be considered as targets for inhibitors to treat neurodegenerative diseases and depression and for managing symptoms associated with Parkinson's and Alzheimer's diseases. Purpose The objective was to evaluate the inhibitory effect of Hypericum afrum and Cytisus villosus against MAO-A and B and to isolate the compounds responsible for the MAO-inhibitory activity. Methods The inhibitory effect of extracts and purified constituents of H. afrum and C. villosus were investigated in vitro using recombinant human…
Flavonoid determination in onion, chili and leek by hard cap espresso extraction and liquid chromatography with diode array detection
2018
Abstract A low cost extraction procedure, based on the use of a hard cap espresso machine, has been developed for the extraction of myricetin, quercetin, luteolin and kaempferol from vegetables by using 50 mL of ethanol in water (80% v/v) in
Effect of polyphenols on enniatins-induced cytotoxic effects in mammalian cells
2012
Enniatins (ENs) are fungal secondary metabolites produced by genus Fusarium. The ENs exert antimicrobial and insecticidal effect, and has also been demonstrated cytotoxic effects on several mammalian cell lines. On the other hands, it has been proved that natural polyphenols have antioxidant effect. In this study, cell effects at low levels of exposure of four ENs (A, A(1), B and B(1)) and five polyphenols (quercetin, quercetin-3-β-D-glucoside, rutin, myricetin and t-pterostilbene) present in wine; and the cytoprotective effect of these polyphenols exposed simultaneously with ENs in Chinese Hamster Ovary (CHO-K1) cells, were studied. Cell effects were determined by the MTT test after 24 h o…
Extraction of polyphenols in Himanthalia elongata and determination by high performance liquid chromatography with diode array detector prior to its …
2016
Abstract Several studies have demonstrated the antioxidant capacity of seaweeds, which can be used for the development of biopharmaceuticals with extensive medical application. Antioxidant therapies appear to attenuate the organic deterioration originated by an excessive oxidative stress, which could prevent the harmful effects of various injuries such as ischemia-reperfusion (I/R) among others. Marine brown seaweeds play a significant role, as they are the only organisms on earth producing phlorotannins, which are polyphenols that exhibit important biological activity. To ensure obtaining an extract with the greatest antioxidant activity, some variables that affect the extraction of polyph…
A blend of polyphenolic compounds explains the stimulatory effect of red wine on human endothelial NO synthase
2005
A high intake of polyphenolic compounds is likely to have beneficial effects on the cardiovascular system. Especially red wine is a rich source of polyphenols, and we have previously shown that French red wine upregulates eNOS, a protective enzyme in the cardiovascular system. The current study tested (poly)phenolic constituents of red wine for their ability to enhance eNOS expression (and the activity of a 3.5-kb human eNOS promoter) in human EA.hy 926 endothelial cells. Of the compounds tested, we found 3,4',5-trihydroxy-trans-stilbene (trans-resveratrol) to be the most efficacious stimulator of eNOS expression (and eNOS transcription), but this compound alone could not explain the total …
Characterisation of phenolic compounds in Algerian honeys by RP-HPLC coupled to electrospray time-of-flight mass spectrometry
2017
Abstract A total of 35 honey samples from different regions of Algeria were studied to determine their phenolic profiles. Phenolic compounds, products of the secondary metabolism of plants, were extracted with amberlite XAD-4 and analysed by liquid chromatography, with diode array detection and electrospray ionisation mass spectrometry in negative ion polarity. By using colorometric assays, Erica honeys showed the highest content of phenolic compounds and flavonoids (245 ± 54 mg GAE/100 g and 29 ± 6 mg QE/100 g, respectively). More than 30 compounds were identified in the honey samples studied including 14 phenolic acids and 16 flavonoids. In general, honey samples showed different chromato…
Distinct signalling mechanisms are involved in the dissimilar myocardial and coronary effects elicited by quercetin and myricetin, two red wine flavo…
2011
Abstract Background and Aims: Moderate red wine consumption associates with lower incidence of cardiovascular diseases. Attention to the source of this cardioprotection was focused on flavonoids, the non-alcoholic component of the red wine, whose intake inversely correlates with adverse cardiovascular events. We analysed whether two red wine flavonoids, quercetin and myricetin, affect mammalian basal myocardial and coronary function. Methods and results: Quercetin and myricetin effects were evaluated on isolated and Langendorff perfused rat hearts under both basal conditions and a- and b-adrenergic stimulation. The intracellular signalling involved in the effects of these flavonoids was ana…
Flavonoids as noncompetitive inhibitors of Dengue virus NS2B-NS3 protease: Inhibition kinetics and docking studies
2014
NS2B-NS3 is a serine protease of the Dengue virus considered a key target in the search for new antiviral drugs. In this study flavonoids were found to be inhibitors of NS2B-NS3 proteases of the Dengue virus serotypes 2 and 3 with IC50 values ranging from 15 to 44 μM. Agathisflavone (1) and myricetin (4) turned out to be noncompetitive inhibitors of dengue virus serotype 2 NS2B-NS3 protease with Ki values of 11 and 4.7 μM, respectively. Docking studies propose a binding mode of the flavonoids in a specific allosteric binding site of the enzyme. Analysis of biomolecular interactions of quercetin (5) with NT647-NHS-labeled Dengue virus serotype 3 NS2B-NS3 protease by microscale thermophoresis…
Effects of Kaempferol and Myricetin on Inducible Nitric Oxide Synthase Expression and Nitric Oxide Production in Rats
2010
Abstract: When administered as drugs or consumed as food components, polyphenolic compounds synthesized in plants interfere with intracellular signal transduction pathways, including pathways of nitric oxide synthase expression. However, effects of these compounds in vivo do not always correlate with nitric oxide synthase-inhibiting activities revealed in experiments with cultured cells. The initial goal of this work was to compare effects of flavonoids kaempferol and myricetin on inducible nitric oxide synthase mRNA and protein expression monitored by real-time RT-PCR and immunohistochemistry and to evaluate the impact of these effects on nitric oxide production in rat organs measured by …