Quercetin and your skin
Lipolysis, blood circulation support, skin irritation, cellulite
Quercetin is a flavonoid found in many herbs, vegetables and fruits and is well researched for its antioxidant action and circulation supporting benefits. It has also been found to be a PDE4 inhibitor and therefore acts as a lipolytic. Finally, quercetin is well-known for its anti-irritation / anti-histamine action.
Quercetin is of great importance as an active ingredient in anti-cellulite, leg wellness, contouring and under-eye creams [the Celluence® creams are the only leg wellness / cellulite creams in the world with high concentrations of 95%+ pure quercetin, encased in liposomes, plus 39x other natural anti-cellulite actives].
8+ ways Quercetin...
...helps fight skin irritation, inflammation, oxidative damage, water retention and cellulite
2/ Quercetin, alone or with green tea extract EGCG, fights fat tissue inflammation...
...caused by high fat diet, by reducing proinflammatory gene expression.
[Source: Quercetin and Green Tea Extract Supplementation Downregulates Genes Related to Tissue Inflammatory Responses to a 12-Week High Fat-Diet in Mice]
1/ Quercetin PREVENTS mitochondria-related health dysfunction...
...by protecting mitochondria from oxidative stress, by helping regulate mitochondrial metabolism and biogenesis, and by modulating cell apoptosis due to mitochondrial dysfunction [Source: Dietary Polyphenols and Mitochondrial Function: Role in Health and Disease]
Quercetin improves endothelial function in diabetic rats through inhibition of endoplasmic reticulum stress-mediated oxidative stress
Endoplasmic reticulum (ER) stress attributes a crucial role in diabetes-induced endothelial dysfunction. The present study investigated the effects of quercetin, a potent antioxidant on the attenuation of ER stress-modulated endothelial dysfunction in streptozotocin (STZ)-induced diabetic rats. Oral administration of quercetin for six weeks to diabetic rats dose-dependently reduced the blood glucose levels and improved insulin secretion. Histopathological examination of pancreatic tissues in diabetic rats showed pathological changes such as shrunken islets, reduction in islet area and distorted β-cells, which were found to be restored by quercetin treatment. In addition, quercetin reduced the pancreatic ER stress-induced endothelial dysfunction as assessed by immunohistochemical analysis of C/ERB homologous protein (CHOP) and endothelin-1 (ET-1). Moreover, quercetin administration progressively increased the expression of vascular endothelial growth factor (VEGF) and its receptor, VEGFR2 in diabetes rats. Quercetin-mediated decrease in the nitric oxide (NO∙) and cyclic 3',5'- guanosine monophosphate (cGMP) levels were also observed in the diabetic rats. Quercetin treatment reduced the lipid peroxidation in the diabetic rats, meanwhile increased the total antioxidant capacity in the pancreas from diabetic rats. Altogether, these results demonstrated the vasoprotective effect of quercetin against STZ-induced ER stress in the pancreas of diabetic rats.
Screening of potential anti-adipogenic effects of phenolic compounds showing different chemical structure in 3T3-L1 preadipocytes
This study was designed to analyze the anti-adipogenic effect of fifteen phenolic compounds from various chemical groups in 3T3-L1 pre-adipocytes. Cells were treated with 25 μM, 10 μM or 1 μM of apigenin, luteolin, catechin, epicatechin, epigallocatechin, genistein, daizein, naringenin, hesperidin, quercetin, kaempferol, resveratrol, vanillic acid, piceatannol and pterostilbene for 8 days. At 25 μM lipid accumulation was reduced by all the compounds, with the exception of catechin, epicatechin and epigallocatechin. At a dose of 10 μM apigenin, luteolin, naringenin, hesperidin, quercetin and kaempferol induced significant reductions, and at 1 μM only naringenin, hesperidin and quercetin were effective. The expression of c/ebpα was not. C/ebpβ was significantly reduced by genistein and kaempferol, pparγ by genistein and pterostilbene, srebp1c by luteolin, genistein, hesperidin, kaempferol, pterostilbene and vanillic acid, and lpl by kaempferol. In conclusion, the most effective phenolic compounds are naringenin, hesperidin and quercetin. Differences were found in terms of effects on the expression of genes involved in adipogenesis among the analyzed compounds.
Quercetin negates the effects of hypoxia in fat cells, fights cellulite
In this study quercetin has been found to not only counter the effects of hypoxia in fat cells, but but actually to overcompensate those effects and improve fat tissue oxygenation. Hypoxia is a key cause of cellulite and quercetin proves once again a valuable tool in the fight against cellulite, warranting it's use in anti-cellulite creams and also in nutritional supplements. In addition quercetin has been found to boost the levels of irisin and PAI-1, which fight adipogenesis and fibrosis, respectively
Paper: Quercetin Impacts Expression of Metabolism- and Obesity-Associated Genes in SGBS Adipocytes
Abstract: Obesity is characterized by the rapid expansion of visceral adipose tissue, resulting in a hypoxic environment in adipose tissue which leads to a profound change of gene expression in adipocytes. As a consequence, there is a dysregulation of metabolism and adipokine secretion in adipose tissue leading to the development of systemic inflammation and finally resulting in the onset of metabolic diseases. The flavonoid quercetin as well as other secondary plant metabolites also referred to as phytochemicals have anti-oxidant, anti-inflammatory, and anti-diabetic effects known to be protective in view of obesity-related-diseases. Nevertheless, its underlying molecular mechanism is still obscure and thus the focus of this study was to explore the influence of quercetin on human SGBS (Simpson Golabi Behmel Syndrome) adipocytes' gene expression. We revealed for the first time that quercetin significantly changed expression of adipokine (Angptl4, adipsin, irisin and PAI-1) and glycolysis-involved (ENO2, PFKP and PFKFB4) genes, and that this effect not only antagonized but in part even overcompensated the effect mediated by hypoxia in adipocytes. Thus, these results are explained by the recently proposed hypothesis that the protective effect of quercetin is not solely due to its free radical-scavenging activity but also to a direct effect on mitochondrial processes, and they demonstrate that quercetin might have the potential to counteract the development of obesity-associated complications.
Quercetin and vitamin D3 both found to improve keloid scars
Source: Response of keloid fibroblasts to Vitamin D3 and quercetin treatment - in vitro study
Summary: Keloid scars continue to pose a challenge to clinicians as the treatment armamentarium lacks a formidable agent to tackle them. We have undertaken an in vitro study based on the mechanism of action of Vitamin D3 and quercetin on isolated keloid fibroblasts. Dose-dependent action on the reduction of cellular proliferation, collagen synthesis and induction of apoptosis by Vitamin D3 and quercetin are analyzed and probable mechanism of action is elaborated. This study thus opens up newer avenues in tackling keloid scars effectively.
The citrus flavonoid quercetin inhibits glycation by 60%
Quercetin, one of the most versatile and healthful flavonoids, found in citrus fruits, onions and herbs like parsley, has been found in a study published this week to inhibit glycation and advanced glycation end-products (AGE). Glycation is a major cause of metabolic syndrome/diabetes, cardiovascular disease, skin ageing and overall body ageing and involves the damage of proteins by sugars. Glycation is caused by the ingestion of excess carbohydrates, especially sugars. Heavily roasting food increases the amounts of glycation, while boiling produces no glycation.
In this study, quercetin was compared to vitamin C, green tea extract, Padma Circosan (an ancient Tibetan multi-herbal formula) and, most especially, aminoguanidin (the standard with which anti-glycation agents are compared to). Quercetin was found to have the highest overall anti-glycation effect (60.5% reduction), higher than aminoguanidin itself, and to exert the highest high molecular weight AGE reduction (79.5% reduction)!
Padma Circosan was found to inhibit lower molecular weight AGE more (74.9% reduction), while vitamin C had the best antioxidant effect. This study shows that glycation can be inhibited by widely available foods, supplements and anti-ageing cream actives, with the aim to fight whole body and skin ageing and deterioration cause by lifestyle factors.
Source: Inhibitory actions of selected natural substances on formation of advanced glycation endproducts and advanced oxidation protein products.
Abstract: BACKGROUND: Advanced glycation endproducts (AGE) and advanced oxidation protein products (AOPP) arise as a result of excessive glycation and oxidation processes of proteins in hyperglycemia and oxidative stress conditions respectively, both in vivo and in vitro. In vivo these processes are especially intensified in patients with diabetes, and the adverse effects of AGE and AOPP are particularly unfavorable for the pathogenesis and aggravate the biochemical disturbances and clinical complications of diabetes. Total AGE and AOPP (T-AGE and T-AOPP) are heterogeneous groups of compounds, and they can be divided into two main fractions: high- and low-molecular-weight, i.e. HMW-AGE and HMW-AOPP as well as LMW-AGE and LMW-AOPP. Therefore it is important to find natural substances that will prevent formation of total AGE and AOPP and their high- and low-molecular-weight fractions and thereby reduce their adverse effects on tissues and organs. METHOD: Selected natural substances and dietary supplements such as vitamin C, aminoguanidine, quercetin and green tea as well as the multicompound formulations Padma Circosan and Padma 28 were tested in an in vitro model using bovine serum albumin (BSA). Fluorescence of T-, HMW- and LMW-AGE and concentration of T-, HMW- and LMW-AOPP were measured after incubation with these substances. RESULTS: In the examined concentrations quercetin showed the greatest degree of inhibition for T-AGE (60.5 %) as well as for HMW-AGE (79.5 %), while in the case of LMW-AGE the greatest degree of glycation inhibition was shown by Padma Circosan (74.9 %). T-AOPP and HMW-AOPP were best inhibited by vitamin C (87.3 and 89.1 % respectively). The results obtained for LMW-AOPP are atypical, but the lowest concentration was observed in a sample with Padma 28. CONCLUSION: The results show that all tested natural compounds have inhibitory activity towards the formation of total and low- and high-molecular-weight forms of AGE and AOPP in vitro. That suggest a possible role in the prevention of diabetic complications, especially the multi-herbal compound Padma preparations, which are especially effective in lowering the most dangerous, i.e. LMW fractions.
Quercetin fights inflammation and free radical damage
Quercetin is known for it's antioxidant, anti-inflammatory and immune modulating activity, and due to those properties it is a valuable anti-cellulite active
Source: Well-Known Antioxidants and Newcomers in Sport Nutrition: Quercetin
Abstract: Quercetin (3,4,5,7-pentahydroxylflavone) is a natural bioactive flavonoid found in a wide variety of natural foods, such as nuts, grapes, apples, berries, onions, broccoli and black tea (Boots et al. 2008, Kelly 2011). In vitro and animal studies indicate that quercetin has many biological effects such as antioxidant, antiinflammatory, anticarcinogenic, antiviral, psychostimulant, cardioprotective, neuroprotective, antipathogenic, immune regulatory and increasing mitochondrial biogenesis (Davis et al. 2009a). Antioxidant properties of quercetin are attributed to its chemical structure, particularly the presence and location of the hydroxyl (-OH) substitutions. The beneficial effects of quercetin largely depend on its bioavailability after oral administration. Although initial reports indicated that bioavailability of quercetin was limited, recent evidence suggests that quercetin can be detected in plasma within 15–30 min of ingestion of a 250 or 500 mg quercetin chew preparation, reaching a peak concentration at approximately 120–180 min, returning to baseline levels at 24 h in humans (Boots et al. 2008, Davis et al. 2009a). Quercetin also has been shown to reach and accumulate in various tissues such as the colon, kidney, liver, lung, muscle and brain, though the tissue distribution has not yet been studied in humans (de Boer et al. 2005, Harwood et al. 2007). Quercetin supplementation studies in athletes have focused on the potential effects of exercise-induced inflammation, oxidative stress, immune dysfunction and exercise performance (Nieman et al. 2012). The available evidence for a beneficial effect of quercetin on exercise performance, while encouraging, is limited by the lack of sophisticated clinical trials. The first human exercise study investigating quercetin supplementation was published in 2006 (MacRae and Mefferd 2006), with many more published in the past few years and continuing to be published. When athletes are studied, most of the researches have failed to find an ergogenic effect (Quindry et al. 2008, Utter et al. 2009), in contrast to that of a study of elite cyclists, who exhibited an improvement of their aerobic performance (MacRae and Mefferd 2006). MacRae and Mefferd (2006) indicated that administration of quercetin (1200 mg) for 6 weeks resulted in performance improvement in cyclists. Davis et al. (2010) examined the effects of 7 days of quercetin (1000 mg) supplementation on both VO2max and time to fatigue on a bicycle ergometer in healthy untrained men and women. Increases in both VO2max (3.9%) and time to fatigue (13.2%) were found. In a recently published meta-analysis (Pelletier et al. 2013), it has been demonstrated that quercetin supplementation improves endurance performance by 0.74 ± 1.04% compared with placebo. However, no relationship was found between quercetin duration and percentage changes in endurance performance between groups. In this meta-analysis, it was demonstrated that quercetin confers an increase in performance which is much less than this efficacy threshold, thereby indicating that it is unlikely to confer any ergogenic value, at least within the length of supplementation used and quercetin doses provided by the actual studies. The authors concluded that quercetin is unlikely to improve performance, independent of the training state. Athletes may hope to benefit from use of a sport nutrition supplement during out of doors, real-world exercise conditions, if it produces an effect under laboratory-controlled exercise conditions that is 1.3–1.6% (Hopkins et al. 1999, Hopkins and Hewson 2001) greater than the effect of the placebo. In a study by Dumke et al. (2009), no effect of quercetin supplementation (1000 mg·day–1) was observed on cycling time trial performance in elite cyclists. Quindry et al. (2008) reported that quercetin supplementation (1000 mg·day–1 for 3 weeks) had no effect on race performance at the Western States 100-mile race. A single, very high dose of quercetin (2 g) was also shown not to increase exercise performance in moderately fit military personnel during exercise in the heat (Cheuvront et al. 2009). Supplementation with quercetin and vitamin C for 8 weeks did not improve exercise performance but reduced muscle damage and body fat percent in athletes (Askari et al. 2012). Sharp et al. (2012) demonstrated that supplementation with quercetin (1000 mg·day–1 for 9 days) did not improve aerobic capacity, aerobic performance, steady state load carriage exercise and change the metabolic or perceptual responses to exercise. In a recent study, Casuso et al. (2013) suggested that quercetin supplementation showed no effect on VO2peak, speed at VO2peak or endurance time to exhaustion after 6 weeks of quercetin supplementation. Some studies (MacRae and Mefferd 2006, Davis et al. 2010, Nieman et al. 2010) reported an improvement in exercise performance in humans after ingestion of quercetin, whereas most others failed to find statistically significant benefits in exercise capacity (Cureton et al. 2009, Utter et al. 2009, Bigelman et al. 2010, Ganio et al. 2010, Sharp et al. 2012, Askari et al. 2013). The most important novel effect of quercetin related to a possible benefit on endurance performance comes from two recent in vitro and rodent studies (Rasbach and Schnellmann 2008, Davis et al. 2009b) that show a benefit on mitochondrial function. Davis et al. (2009b) found that quercetin feedings (12.5 and 25 mg·kg–1day–1) for 7 days improve running time to fatigue by stimulation of mitochondrial biogenesis, including peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and sirtuin 1 (SIRT1) gene expression, mitochondrial DNA (mtDNA) and cytochrome c enzyme concentration in both the brain and soleus muscle of rats. However, this effect has not yet been observed in humans. A study investigating markers of mitochondrial biogenesis in humans after quercetin administration (1000 mg·day–1 for 2 weeks) observed trends towards increased markers of mitochondrial biogenesis such as cytochrome c oxidase and muscle mtDNA but failed to reach statistical significance (Nieman et al. 2010). Possible reasons for the inconsistent findings among these studies may include the range of subject fitness levels, differences in plasma quercetin concentration obtained via the various supplementation protocol/supplement types and differences in research design. In accordance with anti-inflammatory properties, it has been shown that quercetin modulates intracellular signalling pathways, including the inflammatory signalling cascade, by inhibiting activation proinflammatory transcription factor and nuclear factor-kappa B (NF-κB) (Harwood et al. 2007). Strenuous exercise is capable of damaging muscle and initiating an inflammatory response. Nieman et al. (2007a,b,c) examined the effect of quercetin upon inflammation after three consecutive days of cycling and following an ultralong endurance run. Except for an attenuation of interleukin (IL)-8 and IL-10 mRNA in blood leukocytes following the cycling bouts, quercetin failed to attenuate any of the measured markers of muscle damage, inflammation, increases in plasma cytokines and alterations in muscle cytokine mRNA expression. Recently, Overman et al. (2011) reported that quercetin decreased expression of inflammatory cytokine TNF-α, interferon-γ, IL-6 and IL-1β transcripts in cultured human macrophages, which are known to be contributors to secondary muscle damage. O’Fallon et al. (2012), McAnulty et al. (2008) and Abbey and Rankin (2011) demonstrated no effect of quercetin supplementation on the markers of muscle damage and no effect of quercetin or eccentric exercise on biological markers of systemic inflammation (IL-6 and C-reactive protein) in untrained and trained individuals. Konrad et al. (2011) reported that ingestion of a quercetin-based supplement (1000 mg) 15 min before the 2 hours of treadmill run did not attenuate exercise-induced inflammation or immune changes or improve performance. In a study, quercetin feedings reduced self-reported symptoms of upper respiratory tract infection (URTI) following 3 days of exhaustive exercise (Nieman et al. 2007c). In this study, highly trained cyclists ingesting 1000 mg·day–1 of quercetin during a 3-week period experienced a significantly lower incidence of URTI during the 2-week period following the 3 days of intensified training. However, there was no beneficial effect of quercetin on any of the immune components measured, including natural killer (NK) cell lytic activity, polymorphonuclear respiratory burst or phytohaemagglutinin-stimulated lymphocyte proliferation, despite the reduced incidence of URTI symptoms that were observed after quercetin feedings. However, in a similar study, Henson et al. (2008) reported no benefit on illness rates following the Western States Endurance Run. Davis et al. (2008) reported that quercetin supplementation (12.5 mg·kg–1·day–1) for 7 days reduces susceptibility to influenza infection following stressful exercise in rats. No effects of quercetin were found on leukocyte subset counts, granulocyte respiratory burst activity and salivary immunoglobulin A following quercetin supplementation for 3 weeks before and 2 weeks after the Western States Endurance Run (Henson et al. 2008). Another interesting property of quercetin which may enhance mental and physical performance is its caffeine-like psychostimulant effect. Psychostimulants, like caffeine, can delay fatigue during endurance exercise, because of their ability to block adenosine receptors in the brain, which results in an increase in dopamine activity (Davis et al. 2003). A psychostimulant effect of quercetin has also been reported in vitro (Alexander 2006) in a manner similar to that of caffeine (Ferré 2008), but this effect was not found in human subjects (Cheuvront et al. 2009).