Search results for "Quercetin"

A synergic nanoantioxidant based on covalently modified halloysite–trolox nanotubes with intra-lumen loaded quercetin

2016

We describe the preparation and properties of the first example of a synergic nanoantioxidant, obtained by different functionalizations of the external surface and the inner lumen of halloysite nanotubes (HNTs). Trolox, a mimic of natural α-tocopherol, was selectively grafted on the HNT external surface; while quercetin, a natural polyphenolic antioxidant, was loaded into the inner lumen to afford a bi-functional nanoantioxidant, HNT–Trolox/Que, which was investigated for its reactivity with transient peroxyl radicals and a persistent 1,1-diphenyl-2-picrylhydrazyl (DPPH˙) radical in comparison with the corresponding mono-functional analogues HNT–Trolox and HNT/Que. Both HNT–Trolox and HNT/Q…

HPLC Determination of Polyphenols from Calendula officinalis L. Flowers

2017

Abstract Romanian spontaneous flora provides a lot of resources for the determination of different chemical compounds. This study uses flower samples from Calendula officinalis L. extracted through maceration. The chemical compounds determined were: (+)-catechin, caffeic acid, chlorogenic acid, cinnamic acid, ferulic acid, gallic acid, rutin, resveratrol and quercetin. They were analyzed by using an optimized HPLC method. (+)-Catechin, caffeic acid, chlorogenic acid and quercetin could not be identified in the analyzed samples. The greatest amount of phenolic compound found was rutin and the smallest quantity was determined for ferulic acid. The quantified compounds have proven to have bene…

Anti-Inflammatory Activity of Flavonol Glycosides fromErythrospermum monticolumDepending on Single or Repeated Local TPA Administration

1995

Two anti-inflammatory principles were isolated from the methanol extract of the leaves of Erythrospermum monticolum (Flacourtiaceae). The isolation was based on a guided bioassay of the inhibitory activity on TPA-induced ear edema in mice. These compounds were identified as quercetin 3-O-xylosyl(1-->2) rhamnoside and quercetin 3-O-rhamnoside. In addition, their effects on a chronic topic inflammation model were evaluated.

Wine, Diet, and Arterial Hypertension

2007

Hypertension is one of the leading causes of death in developed countries, and the number of prehypertensive patients is increasing. The beneficial effects of moderate wine consumption on cardiovascular diseases have been demonstrated, along with the healthy influence of a Mediterranean dietary pattern. The association of these 2 factors on hypertension and its complications is considered here. As wine polyphenols exert a vasorelaxing action, they might positively influence the hemodynamic situation of these patients. These effects could be enhanced by dietary constituents, such as garlic, onions, and olive oil, which are widely employed in Mediterranean cooking. By evaluating many studies…

Chemical composition and microencapsulation suitability of sumac (Rhus coriaria L.) fruit extract

2021

Sumac (Rhus coriaria L.), a spice obtained by grinding whole sumac berries, is a complex natural product with a plethora of biological activities that can be favorably explored in nutraceutical and pharmaceutical fields. Sicilian sumac is herein chemically investigated by means of a combined NMR/HR MS-based profiling. A hydroalcoholic extract was prepared and its complexity unraveled following fractionation in an alcoholic and an aqueous fraction. The 1H-NMR spectrum of this latter fraction was dominated by the signals of gallic acid and its derivatives, whereas HR MS and HR MS/MS analyses highlighted the diversity in malic acid derivatives. Gallotannins and galloyl flavonol glycosides with…

Influence of quercetin and luteolin on the activity of the catalase: study ex vivo about erythrocytes in smokers and non-smokers

2015

Flavonoids are a group of polyphenolic compounds with different chemical structure and properties. These compounds may scavenge free radical species and other oxidants. In previous studies, we have observed that some polyphenols are able to cross the erythrocyte’smembrane and this process is influenced by the plasmatic albumin; in fact quercetin intracellular concentrations is albumin dose depending. The influence of flavonoids on catalase activity has been reported in some papers but the results are contradictory. Some authors have found an increase of catalase activity in cell in the presence of flavonoids. Others have observed any effect or even a decrease of catalase activity.The presen…

SMART NANOSPONGE-BASED SYSTEMS FOR ADVANCED APPLICATIONS

2023

Evaluation of the spectral characteristics, purity and antioxidant activity of C-phycocyanin from the cyanobacteria collected in Kaunas Lagoon (Lithu…

2022

The physicochemical characteristics of phycocyanin extracted from cyanobacteria collected in Kaunas Lagoon were studied (spectrum characteristics, C-PC content in the dry mass and chemical purity). It was determined that the tested concentrations of C-PC in purified water should be in the range of 0.02–0.16% for measuring C-PC content in the dry mass and its spectrum characteristics. The two clear absorption maxima were detected in the spectrum of C-PC at the wavelengths of 277 and 619 nm. The content of C-PC in the dry powder form was in the range of 7.25% to 9.30% depending on its concentration in the solution and type of spectrophotometer. Furthermore, a purity factor of 1.5 was calculat…

Compared Binding Properties between Resveratrol and Other Polyphenols to Plasmatic Albumin: Consequences for the Health Protecting Effect of Dietary …

2014

International audience; Phytophenols are considered to have beneficial effects towards human physiology. They are food microcomponents with potent chemopreventive properties towards the most three frequent contemporary human diseases, e.g., cardiovascular alterations, cancer and neurodegenerative pathologies. Related to this, the plasmatic form and plasmatic level of plant polyphenols in the body circulation are crucial for their efficiency. Thus, determinations of the binding process of resveratrol and of common flavonoids produced by major edible plants, berries and fruits to plasma proteins are essential. The interactions between resveratrol and albumin, a major plasma protein, were comp…