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    Antioxidant Capacities and Total Polyphenol Contents of Hydro‐ethanolic Extract of Phytococktail from Trans‐Himalaya
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    Abstract:
    The aim of this study was to evaluate the in vitro antioxidant potential of hydro-ethanolic extract of a novel phytococktail comprising of sea buckthorn, apricot, and Rhodiola (SAR) from trans-Himalaya. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) activity of the extract increased in a dose-dependent manner (upto 0.1 mg/mL), and was found to be about 38% of that of ascorbic acid at 0.1 mg/mL. The hydro-ethanolic extract of SAR also scavenged the ABTS(.+) radical generated by ABTS/potassium persulfate (PPS) system and was found to be about 62% of that of ascorbic acid at 0.1 mg/ mL. The total antioxidant power of the extract was determined by ferric reducing antioxidant power (FRAP) assay. Total phenolic content was found to be 1.28016 × 10(-3) mol gallic acid equivalent (GAE)/g extract. Total flavonoid and flavonol contents were estimated to be 2.5970 × 10(-4) mol and 4.87 × 10(-4) mol quercetin equivalent/g extract, respectively. The hydro-ethanolic extract of this phytococktail indicated presence of essential phytoconstituents of polyphenols, flavonoids, flavonols, and ascorbic acid, which contributed significantly to its antioxidant capacity. The combination of the 3 plants may well support their use in traditional medicine to combat oxidative stress and high-altitude sickness.
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    ABTS
    Flavonols
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    Animal studies
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    Flavonols
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    Flavonoids are proved to be prominent plant-derived compounds generally found in fruit- and vegetable- rich diets with free radicals quenching ability. Quercetin, a member of flavonoids subclass – flavonols, has gained major attention due to its overwhelming potential. Quercetin was demonstrated to preserve diverse degenerative diseases by inhibiting lipid peroxidation. In the present paper, we deal with two polyphenolic compounds’ – quercetin and dihydroquercetin – influence on functional parameters of mitochondria. Thus, the fore mentioned flavonols showed the mitochondrial permeability transition pore (mPTP) inhibition and ATP-sensitive potassium channel activation capacities as well as strong antioxidаnt/antiradiсal activity. Improving functional parameters of mitochondria by both quercetin and dihydroquercetin formed a basic idea of the hypothesis that the studied flavonols may provide antihypoxic defense.
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    Quercetin is rapidly and avidly taken up by human red blood cells (RBC) via a passive diffusion mechanism, driven by flavonoid binding to haemoglobin and resulting in an almost quantitative accumulation of the flavonoid. Heamoglobin-free resealed ghosts accumulated quercetin exclusively in the membrane fraction. Cell-associated quercetin was biological active and could be quantitatively utilised to support the reduction of extracellular oxidants mediated by a transplasma-membrane oxido-reductase. Additional experimental evidence revealed that quercetin uptake declined in the presence of albumin and that, under these conditions, the amount of cell-associated quercetin is enhanced by increasing the RBC number. Quercetin release from flavonoid-preloaded RBC was observed only in the presence of albumin (or in human plasma) and this response was progressively inhibited upon incubation in solutions containing albumin previously exposed to increasing concentrations of quercetin and cleared of the unbound fraction of the flavonoid. Furthermore, exposure to quercetin pre-saturated albumin promoted accumulation of the flavonoid in fresh RBC and this response was a direct function of the extent of albumin saturation. These results, indicating a flow of quercetin from albumin to haemoglobin, and vice versa, are therefore consistent with the possibility that human RBC play a pivotal role in the distribution and bioavailability of circulating flavonoids.
    Serum Albumin
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    Flavonols
    Aglycone
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