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Flavonoids from italian multifloral honeys reduce the extracellular ferricyanide in human red blood cells
No full textMitochondria accumulate large amounts of quercetin: prevention of mitochondrial damage and release upon oxidation of the extramitochondrial fraction of the flavonoid
Quercetin is a naturally occurring flavonoid producing beneficial effects for the human health, via scavenging of reactive oxygen species/metal chelation and stimulation/inhibition of enzyme activities/signal transduction pathways. While the hierarchy and relevance of these effects is not yet fully appreciated, it appears obvious that its accumulation in specific subcellular compartments might dictate the specificity of the effects mediated by the flavonoid. Quercetin uptake in Jurkat cells is extremely rapid and associated with a remarkable accumulation of the flavonoid, dependent on its binding to intracellular components. Cell-associated quercetin is biologically active, quantitatively consumed to promote survival in the presence of reactive species, such as peroxynitrite (ONOO−), or reduction of extracellular oxidants via activation of plasma membrane oxidoreductases. In alternative, quercetin is very slowly released upon post-incubation in drug-free medium, an event significantly accelerated by extracellular albumin. Quercetin uptake is also observed in isolated mitochondria, resulting in an enormous accumulation of the flavonoid, consumed under conditions associated with prevention of lipid peroxidation induced by ONOO−. Interestingly, remarkable quercetin accumulation is also detected in the mitochondria isolated from quercetin-pre-loaded cells, and exposure to either ONOO− or extracellular oxidants caused the parallel loss of both the mitochondrial and cytosolic fractions of the flavonoid. In conclusion, Jurkat cells accumulate large amounts of quercetin and even larger amounts of the flavonoid further accumulate in their mitochondria. Intramitochondrial quercetin appears to be functional for prevention of mitochondrial damage as well as for redistribution to the cytosol, when the fraction of the flavonoid therein retained is progressively consumed either by cell-permeant oxidants or by activation of plasma membrane oxidoreductases, thereby implying that mitochondria represent a reservoir of biologically active quercetin
The cellular antioxidant activity in red blood cells (CAA-RBC): A new approach to bioavailability and synergy of phytochemicals and botanical extracts
No full text
Glucosinolate content and antioxidant activity of edible Brassicaceae sprouts.
No full textFirst European Food Congress (EFFO) 2008
Poster number 019
Chemical and cellular antioxidant activity of phytochemicals purified from olive oil waste waters
No full textIl miele come fonte di antiossidanti naturali
No full textConvegno: Sicurezza e qualità alimentare per la promozione della salut
Raw Millefiori honey is packed full of antioxidants
No full textRaw Millefiori honey is packed full of antioxidants
Abstract
Honey is the natural substance produced by honeybees, Apis mellifera, in almost every country of the world. Raw honeys are usually produced by small farms and left in their natural state without undergoing processing (e.g., filtration and heat treatment). Honey is essentially a concentrated aqueous solution of inverted sugar, but it also contains a very complex mixture of other saccharides, enzymes, amino and organic acids, polyphenols, carotenoid-like substances, Maillard reaction products, vitamins, and minerals. Among minor honey constituents, polyphenols such as flavonoids
and phenolic acids, may function as natural antioxidants in our diet. In recent years, considerable
interest has been focussed on dietary antioxidants in reference to their protective effect against oxidative damage.There are many studies about the polyphenol content and antioxidative effects of fruits, vegetables and beverages; in contrast, hardly any work has been reported with honey. Available literature indicates that no previous antioxidant power studies have been done on Italian honeys; thus, the objective of this work was to evaluate antioxidant activity of two representative Italian raw honeys, , i.e., Millefiori and Acacia, obtained from beekeepers belonging to the same geographical region (central Italy) as a function of their sensorial characteristics and content of total polyphenols and flavonoids. Total polyphenols, flavonoids and antioxidant power of samples from Millefiori and Acacia raw honey varieties were evaluated. Phenolic content, expressed as caffeic acid equivalents, ranged from 12.5 to 17.5 mg/100 g and from 3 to 11 mg/100 g in Millefiori and Acacia honeys, respectively. All Millefiori samples exhibited the highest flavonoid concentration being between 1.23 and 2.93 mg catechin equivalents (CE)/100 g honey. Total flavonoids in 100 g Acacia honeys were in the range of 0.45–1.01 mg CE. Acacia honeys had lower total antioxidant power, as assessed by ferric reducing/antioxidant power assay, than Millefiori. The relationship between phenolic content and antioxidant power was discussed. These results demonstrated a strong correlation between honey colour and antioxidant power, with darker and more crystallized honeys having stronger antioxidant activity than lighter and transparent honeys.. Comparative experimental analysis was performed with an artificial honey and processed honeys. Raw Millefiori honey is rich in both amount and variety of antioxidant substances, and its inclusion in the diet may be recommended to complement other polyphenol sources
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