Quercetin glucuronides but not glucosidesare present in human plasma after consumption of quercetin-3-glucosideor quercetin-4-glucoside. Effect of quercetin on the pharmacokinetics oforal cyclosporine. Prostacyclin-deficient mice develop ischemic renal disorders, including nephrosclerosis and renal infarction. Scientifically reviewed by: Dr. Gary Gonzalez, MD, in January 2021. Quercetin from shallots(Allium cepa L. var. Quercetin glycosides with sugar moieties other than glucose (e.g., rutinosides) are absorbed in lower parts of the intestinal tract after deglycosylation. Duarte J, et al. Biochem Pharmacol 1992 Mar 17;43(6):1167-79. For the first time, a bioavailable form of quercetin has been added to formulas already used by Life Extension members. Ratings based on results of the 2022 ConsumerLab.com Survey of Supplement Users. Laboratory experiments suggest that a flavonoid called quercetin has the remarkable ability to prevent thrombus formation and to disperse thrombi that have already formed in blood vessels. The researchers note that quercetin has been found to arrest the cell cycle in cancer cells, and observe that it appears to do the same in vascular smooth muscle cells, locking them into a quiescent state.7, In another study, Japanese researchers found that quercetin inhibited the vascular smooth muscle cell hypertrophy seen during the development of coronary artery disease. Cermak R, Landgraf S, Wolffram S. The bioavailability of quercetinin pigs depends on the glycoside moiety and on dietary factors. Flavonoids of St. Johns Wort reduceHPA axis function in the rat. A clinical studied published late last year1 demonstrated that SunActive IsoQ converts into free quercetin in the body. Sesink AL, OLeary KA, Hollman PC. Dajas F, Rivera-Megret F, Blasina F, et al. Ischemia and reperfusion, discussed earlier in relation to cardiovascular disease, also damages the kidneys. He currently serves as director of scientific affairs at Integrative Therapeutics. Appleton left his private practice in 1998 to work in the natural products industry. Quercetin metabolism in the lens: role in inhibition of hydrogen peroxide induced cataract. Murota K, Terao J. Antioxidative flavonoid quercetin: implication of its intestinalabsorption and metabolism. They found that quercetin best protected cells against hydrogen peroxide-induced oxidative stress and calcium dysregulation. Caloric restriction, which is known to extend life span, has been found to reduce NF-kB activity in the kidneys of rats. Intestinaltransport of quercetin glycosides in rats involves both deglycosylation andinteraction with the hexose transport pathway. Relative bioavailabilityof the antioxidant flavonoid quercetin from various foods in man. It is not, however, the dominant form appearing in nature, and its bioavailability is poor. Quercetin became a popular dietary supplement based on evidence indicating it guards against a wide range of common disorders. Glycation is a pathologic mechanism that occurs when a glucose molecule inappropriately binds to a protein molecule. Not surprisingly, hydrogen peroxide levels are very high in the aqueous humor of cataract patients. Endothelial oxidation, inflammation, and capillary fragility can set the stage for thrombosis and venous insufficiency. Quercetin protects the kidneys during ischemia and reperfusion by preserving higher levels of the enzyme xanthine dehydrogenase relative to the injurious enzyme xanthine oxidase. Quercetin, the predominant flavonoid in the human diet, has been unobtainable as a practical dietary supplement due to poor absorption. In a study of cyclosporine's effects on rat kidneys, a 20% to 30% reduction in glomerular filtration rate (the rate at which the kidneys filter wastes from the blood) and up to 40% reduction in renal blood flow were found. Many studies have shown quercetin to inhibit mast cell secretion of inflammatory factors such as histamine, leukotrienes and prostaglandin D2.12. Quercetin 3-methyl ether, a methanolic extract of quercetin, was a more potent neuroprotectant than any of the other flavonoids tested. Quercetin and rutin inhibit the generation of inflammatory mediators (leukotriene LTB4 and prostaglandin E2) in human neutrophils. In humans, about 93% of quercetin is metabolized in the gut. The problem has been that the oral bioavailability of quercetin supplements (quercetin dihydrate) is poor. Erlund I, Kosonen T, Alfthan G, et al. Written by: Life Extension Editorial Staff. This ingredient, called SunActive IsoQ, may be up to 25 times more bioavailable than free quercetin. Manach C, Morand C, Demign C, Texier O, Rgrat F, Rmsy C. Bioavailabilityof rutin and quercetin in rats. We have already seen that quercetin reduces platelet aggregation and adhesion by reducing hydrogen peroxide production. When the blood flowing over a piece of rabbit aorta contained a low concentration of quercetin, platelet thrombi dissolved. Morikawa K, Nonaka M, Narahara M, et al. van der Hoeven JC, Bruggeman IM, Debets FM. Human metabolism of dietary flavonoids:identification of plasma metabolites of quercetin. Difference in absorption of the two structurally similar flavonoid glycosides, hyperoside and isoquercitrin, in rats. Deglycosylation by small intestinalepithelial cell beta-glucosidases is a critical step in the absorption and metabolismof dietary flavonoid glycosides in humans. Kim HY, Moon BH, Lee HJ, Choi DH. Activity of the plant flavanol quercetin in themouse lymphoma L5178Y TK+/- mutation, DNA single-strand break, andBalb/c 3T3 chemical transformation assays. It remains controversial whether or not the food matrix confers advantages in terms of bioavailability of quercetin and its glycosides. Takizawa S, Fukuyama N, Hirabayashi H, et al. Inhibitory effect of quercetin on carrageenan-induced inflammation in rats. Takahama U, Hirota S. Deglucosidation of quercetin glucosides to theaglycone and formation of antifungal agents by peroxidase-dependentoxidation of quercetin on browning of onion scales. SunActive IsoQ is derived from rutin extracted from the flower buds of the Japanese Pagoda tree (Styphnolobium japonicum Schott). They found that quercetin is methylated by an enzyme present in the lens, and that both quercetin and this methylated quercetin metabolite protected the lens from opacification and oxidative damage. Antihypertensive effects of the flavonoid quercetin in spontaneously hypertensive rats. Pharmacokinetics and bioavailability ofquercetin glycosides in humans. Disposition and metabolism of [2-14C]quercetin-4-glucoside in rats. Free Rad Biol Med 2002;32(10):991-1005. Circulation 2002 Oct 29;106(18):2397-403. Taiyo (Minneapolis) has introduced a patented new ingredient that is said to be much more bioavailable than free quercetin. Many flavonoids, such as rutin, pass unchanged into the large intestine, where they are hydrolyzed by microbially produced glycosidases, yielding quercetin aglycone and its sugar. Spanish researchers evaluated the antihypertensive effects of quercetin in an animal model of essential hypertension.9 They discovered that 10 mg/kg of quercetin given orally to spontaneously hypertensive rats for five weeks reduced systolic blood pressure by18%, diastolic blood pressure by 23%, and mean arterial blood pressure by 21%. Jeremy Appleton, ND, is a licensed naturopathic physician. Isoquercetin demonstrated slightly better anti-inflammatory efficacy than quercetin on the expression of COX-2 mRNA and inflammatory cell exudation, though overall effects of the two were roughly comparable in this in vitro study. 2003;980(1):156-160. Quercetin glucosides, however, have better bioavailability, resulting in potentially increased efficacy compared to the aglycone form. In numerous experimental studies on both animals and humans, quercetin has been found to protect kidney tissues against age-related insult. They hypothesize that quercetin works by inhibiting the activation of a key MAP kinase called JNK by the angiotensin II enzyme. Walle T, Browning AM, Steed LL, et al. 2022 MJH Life Sciences and Nutritional Outlook. Caridi D, Trenerry C, Rochfort S, Duong S, Laugher D, Jones R. Profiling andquantifying quercetin glucosides in onion (Allium cepa L.) varieties usingcapillary zone electrophoresis and high performance liquid chromatography. Bouriche H, Miles FA, Selloum L, Calder PC. Genotoxicity of quercetin incultured mammalian cells. Vitor RF, Mota-Filipe H, Teixeira G et al. Inhibition of smooth muscle cell proliferation and migration, During the formation of atherosclerotic lesions, the smooth muscle cells that line the coronary arteries multiply in number and begin to migrate into the interior of those vessels. All rights reserved. Most of these flavonoids are in the form of glycosides with high molecular weight. As mentioned, quercetin does not principally occur in the form in which it is available as a dietary supplement (an aglycone). It has been deemed Generally Recognized as Safe by a panel of independent experts. Neuroprotective effects of antioxidative flavonoids,quercetin, (+)-dihydroquercetin and quercetin 3-methyl ether, isolated from Opuntia ficus-indica var. Rutin and quercetin (aglycone), the most commonly used flavonol compounds in nutritional supplements, have poor bioavailability, which may lessen efficacy. Water-soluble quercetin delivers the benefits of quercetin-the predominant flavonoid in the human diet-at a lower dosage through improved absorption. Not only can a thrombus prevent blood and oxygen from reaching tissues and vital organs, but it can also break off and travel through the blood stream to the heart, brain, lung or a distant blood vessel. Regrettably, the poor absorption rate means that people taking conventional quercetin supplements can't translate the impressive roster of research findings into reality. Dietary flavonoids, antioxidant vitamins, and incidence of stroke: the Zutphen study. The effects of plant flavonoids on mammalian cells: implications for inflammation, heart disease, and cancer . Protective effects of flavonoidscontained in the red vine leaf on venular endothelium against the attack of activated blood components in vitro. In the Zutphen Elderly Study, for example, researchers evaluated the diets of 805 Danish men between the ages of 65 and 84. This enabled the mitochondria-the tiny cellular "engines" that metabolize carbohydrates and fats into energy using oxygen-to regenerate ATP (cellular energy) following ischemia-reperfusion injury.10, The dosage of quercetin used in this study corresponds (after adjusting for body weight) to the amount that would be consumed by the average adult male who drinks one to two glasses of red wine daily. Quercetin supplements, including isoquercetin, should also be avoided by people taking cyclosporine, estradiol, nifedipine, or felodipine. Its anti-thrombotic action helps prevent the proclotting state that sets the stage for cardiovascular disease and major cardiovascular events. Quercetin's antioxidant effects and its enhancement of mitochondrial function-including improved intracellular/extracellular calcium balance -likely explain these protective effects. Thus it is anticipated that a lower does of isoquercetin would be required for comparable efficacy. Review of 93 intervention studies. Sanhueza J, et al. Portfolio of Integrative Healthcare Media + Events. Inhibition of dihydropyridine metabolism in rat and human liver microsomes by flavonoidsfound in grapefruit juice. Although quercetin protects against age-related diseases, it is poorly absorbed into the bloodstream. This allows for a 100-mg dose of SunActive IsoQ to deliver the equivalent of 275 mg of bioavailable quercetin, providing significant formulation benefits, the companys press release states. Effects of luteolin, quercetin and baicalein on immunoglobulin E-mediated mediator release from human cultured mast cells. All rights reserved. A recent study evaluated the effects of quercetin and catechin on collagen-induced platelet aggregation. Discover the Basics of Popular Health Topics, Stay informed with Life Extension Magazine, From basic health panels to genetic testing. This new innovative delivery form for quercetin will be sought-after by brands because of its ease of formulation in powders, capsules, gummies, soft chews, and beverage applications, added Alan Yengoyan, CEO of NutriScience Innovations, in the press release. NF-kB activity in the kidneys increases with age and leads to increased oxidative stress. Instead, quercetin occurs principally as glucuronated, sulfated, and methylated quercetin conjugates. 2022 MJH Life Sciences and Nutritional Outlook. The brain is particularly susceptible to oxidative damage because of its high utilization of oxygen, its high levels of unsaturated lipids and transition metals like iron, and its relatively inefficient antioxidant defenses. This has been demonstrated in humans as well as in animals. Loke WM, Hodgson JM, Proudfoot JM, McKinley AJ, Puddey IB, Croft KD.Pure dietary flavonoids quercetin and (-)-epicatechin augment nitric oxide products and reduce endothelin-1 acutely in healthy men. Wiczkowski W, Romaszko J, Bucinski A, et al. For example, a thrombus in the large blood vessels of the leg, called deep venous thrombosis, will often break off to form an embolus that drifts through the bloodstream and cuts off circulation downstream from the spot where it eventually lodges. Rutin has the lowest relative bioavailability and is not significantly absorbed before 2 hours, showing peak plasma concentrations at 6 hours after intake. (If calcium concentrations rise too high, blood vessels become constricted. Early identification of therapeutic activity of isoquercetin came from studies in which the flavonol was extracted from. Flavonoids are a group of polyphenolic compounds, which are widely distributed throughout the plant kingdom. Taiyos new ingredient is a water-soluble form of isoquercitrin, a quercetin precursor. Teratogenic potential of quercetin in the rat. Cyclosporine is a potent immune suppressant, the first-line therapy for solid organ transplant patients and autoimmune disease patients. This leads some nutritionally oriented doctors to shun isolated nutrients in favor of obtaining the nutrients from foods. Satyanarayana PSV, et al. In the text Markers in Cardiology, the authors review current evidence that statins and aspirin reduce heart attack risk due to their anti-inflammatory effects on NF-kB and other inflammatory mediators. The presence of the glucoside moiety, whether in the 3 or 4 position, appears to be responsible for the increased bioavailability of isoquercetin and other quercetin glucosides, as compared with quercetin aglycone. Paulke A, Schubert-Zsilavecz M, Wurglics M. Determination of St. Johnswort flavonoid-metabolites in rat brain through high performance liquidchromatography coupled with fluorescence detection. Bioavailabilities of quercetin-3-glucoside and quercetin-4-glucoside do not differ in humans. Quercetin is soluble in alcohol, which helps explain the health-promoting effects of red wine. Researchers demonstrated that a low concentration of quercetin suppressed thrombus deposits on collagen bathed in a stream of blood. Butterweck V, Hegger M, Winterhoff H . Neuroprotection by flavonoids. Katske F, Shoskes DA, Sender M, et al. Ader P, Wessmann A, Wolffram S. Bioavailability and metabolism of theflavonol quercetin in the pig. Shoskes DA, Zeitlin SI, Shahed A, Rajfer J.Quercetin in men with categoryIII chronic prostatitis: a preliminary prospective, double-blind, placebo-controlled trial. Flavonoid glycosides are hydrolyzedand thus activated in the oral cavity in humans. Choi JS, Choi BC, Choi KE. Dietary flavonoid and isoflavone glycosidesare hydrolysed by the lactase site of lactase phlorizin hydrolase. In the case of quercetin derivatives, onions are a major source of quercetin glucosides. NutriScience will work with brands to maximize the benefits while minimizing the formulation challenges., AlgaeCal introduces plant-based calcium supplements made from algae, Upcycling: Important opportunities for food development, Gelita opens biotech hub to sustainably develop proteins for nutrition, cosmetics, and more, Bioavailability of dietary isoquercitrin--cyclodextrin molecular inclusion complex in Sprague-Dawley rats and healthy humans. Chang Q, Zuo Z, Chow MS, Ho WK. Effects of flavonoids on immune and inflammatory cell functions. Aeschbacher HU, Meier H, Ruch E. Nonmutagenicity in vivo of the foodflavonol quercetin. He is the author of several books and hundreds of articles on natural medicine. Hertog MGL, et al, Dietary antioxidant flavonoids and risk of coronary heart disease: the Zutphen Elderly study. Induction of sister-chromatid exchanges (SCE), polyploidy,and micronuclei by plant flavonoids in human lymphocyte cultures. In fruits and vegetables, quercetin is bound to sugars that make it absorbable. aggregatum) is more bioavailable than its glucosides. They found that quercetin potently inhibited NF-kB activation in PTC. Many plants store chemicals in the form of inactive glycosides, which can be activated by enzyme hydrolysis. Surgery 2002;131:198-204. The researchers found that quercetin preserved mitochondrial function in heart cells, and that mitochondrial function correlated with cardiac function. Flavonols have also demonstrated neuroprotective,cardioprotective, chemopreventive, antioxidant, anti-inflammatory, and anti-allergic activity in numerous preclinical studies. Dietary flavonoid and isoflavone glycosidesare hydrolysed by the lactase site of lactase phlorizin hydrolase. Mitochondrial function in response to cardiac ischemia-reperfusion after oral treatment with quercetin. PNAS 2000 Aug 1;97(16):9052-7. The researchers analyzed the chemical structural characteristics that confer these protective effects, and concluded that the quercetin molecule displays precisely the desired characteristics.17. The rutin used in dietary supplements is typically derived from, The flavonols rutin, quercetin, and isoquercetin are found not only in foods such as apple and onion, but in many medicinal plants, likely contributing to the medicinal qualities of a large number of botanical medicines.
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