Flavonoids are considered as health-protecting food constituents. The testing of their biological effects is however hampered by their low oral absorption and complex metabolism. In order to investigate the direct effect(s) of unmetabolized flavonoid, a preparation in a biologically friendly solvent for intravenous administration is needed. Isorhamnetin, a natural flavonoid and a human metabolite of the most frequently tested flavonoid quercetin, has very low water solubility (<3.5 μg/mL). The aim of this study was to improve its solubility to enable intravenous administration and to test its pharmacokinetics in an animal model. By using polyvinylpyrrolidone (PVP10) and benzalkonium chloride, we were able to improve the solubility approximately 600 times to 2.1 mg/mL. This solution was then administered intravenously at a dose of 0.5 mg/kg of isorhamnetin to rats and its pharmacokinetics was analyzed. The pharmacokinetics of isorhamnetin corresponded to two compartmental model with a rapid initial distribution phase (t1/2α: 5.7 ± 4.3 min) and a slower elimination phase (t1/2β: 61 ± 47.5 min). Two sulfate metabolites were also identified. PVP10 and benzalkonium did not modify the properties of isorhamnetin (iron chelation and reduction, and cell penetration) substantially. In conclusion, the novel preparation reported in this study is suitable for future testing of isorhamnetin effects under in vivo conditions.
- MeSH
- benzalkoniové sloučeniny farmakokinetika chemie MeSH
- intravenózní podání * MeSH
- krysa rodu rattus MeSH
- potkani Wistar MeSH
- povidon * chemie MeSH
- quercetin * farmakokinetika analogy a deriváty aplikace a dávkování chemie MeSH
- rozpustnost * MeSH
- voda * chemie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
This study aimed to examine the effect of dietary flavonoid isoquercitrin on ovarian granulosa cells using the immortalized human cell line HGL5. Cell viability, survival, apoptosis, release of steroid hormones 17beta-estradiol and progesterone, and human transforming growth factor-beta2 (TGF-beta2) and TGF-beta2 receptor as well as intracellular reactive oxygen species (ROS) generation were investigated after isoquercitrin treatment at the concentration range of 5-100 microg.ml-1. It did not cause any significant change (p>0.05) in cell viability as studied by AlamarBlue assay in comparison to control. No significant change was observed (p>0.05) in the proportion of live, dead and apoptotic cells as revealed by apoptotic assay using flow cytometry. Similarly, the release of 17beta-estradiol, progesterone, TGF-beta2 and its receptor were not affected significantly (p>0.05) by isoquercitrin as detected by ELISA, in comparison to control. Except for the highest concentration of 100 microg.ml-1, which led to oxidative stress, isoquercitrin exhibited antioxidative activity at lower concentration used in the study (5, 10, 25, and 50 microg.ml-1) by hampering the production of intracellular ROS, in comparison to control, as detected by chemiluminescence assay (p<0.05). Findings of the present study indicate an existence of the antioxidative pathway that involves inhibition of intracellular ROS generation by isoquercitrin in human ovarian granulosa cells.
Acute dilation brought about by the dietary flavonoid quercetin in coronary arterioles has been described earlier, but no information is available on its chronic effects. Male Wistar rats (body weight about 190 g) were divided to two groups: the quercetin-treated group (n=22) had quercetin supplementation of approximately 30 mg/kg/day, whereas the control group (n=20) had none. After eight weeks of treatment, intramural coronary arterioles with identical passive diameters (178+/-14 microm and 171+/-9 microm) were prepared and their biomechanics and pharmacological reactivities were tested using pressure arteriography ex vivo. The spontaneous tone of quercetin-treated arteries was higher (16.5+/-1.9 % vs. 12.9+/-0.9 %), which resulted in a reduced lumen size (144+/-9 microm vs. 167+/-12 microm), thicker vascular wall (22.6+/-1.8 microm vs. 17.4+/-1.6 microm) and decreased tangential wall stress (16.8+/-1.1 kPa vs. 20.5+/-1.6 kPa) in supplemented animals (in spontaneous tone at 50 mm Hg, p<0.01 in all these comparisons). Elevated basal NO release resulted in increased endothelial dilation in quercetin-treated animals, especially at higher intraluminal pressures (10.8+/-2.5 % vs. 5.7+/-1.3 % at 70 mm Hg, p<0.01). We found remodeling of the geometry of coronary arterioles to ensure higher dilatory reserve and nitrogen monoxide production, as well as lowered elastic stress of the vessel wall.
- MeSH
- koronární cévy účinky léků fyziologie MeSH
- krysa rodu rattus MeSH
- potkani Wistar MeSH
- quercetin aplikace a dávkování MeSH
- remodelace cév účinky léků fyziologie MeSH
- rozvrh dávkování léků MeSH
- vazodilatace účinky léků fyziologie MeSH
- vazodilatancia aplikace a dávkování MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Quercetin and phenylpropanoids are well known chemoprotective compounds identified in many plants. This study was aimed at determining their effects on activation of Nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant response element (Nrf2-ARE) signalling pathway and expression of its important downstream effector phase II detoxification enzyme glutathione-S-transferase P1 (GSTP1) in BJ foreskin fibroblasts and skin HaCaT keratinocytes. Cell lines and their corresponding Nrf2-ARE luciferase reporter cells were treated by ginger phenylpropanoids and quercetin for 10 h and the level of Nrf2 activity was subsequently determined. Both, ginger phenylpropanoids and quercetin, significantly increased the level of Nrf2 activity. Subsequent western blot analyses of proteins showed the increased expression level of glutathione-S-transferase P1 (GSTP1) in BJ cells but not in HaCaT cells. Such phenomenon of unresponsive downstream target expression in HaCaT cells was consistent with previous studies showing a constitutive expression of their GSTP1. Thus, while both ginger phenylpropanoids and quercetin have the property of increasing the level of Nrf2 both in HaCaT and in BJ cells, their effects on its downstream signalling were mediated only in BJ cells.
- MeSH
- antioxidancia aplikace a dávkování chemie MeSH
- buněčné linie MeSH
- faktor 2 související s NF-E2 biosyntéza genetika MeSH
- fibroblasty účinky léků metabolismus MeSH
- glutathion-S-transferasa fí biosyntéza genetika MeSH
- glutathiontransferasa MeSH
- keratinocyty účinky léků metabolismus MeSH
- lidé MeSH
- quercetin aplikace a dávkování MeSH
- regulace genové exprese účinky léků MeSH
- signální transdukce účinky léků MeSH
- zázvor lékařský chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Quercetin je přírodní flavonoid s protizánětlivými a antioxidační účinky. Studium působení quercetinu na normální a nádorově transformované buňky přináší v současnosti nové poznatky o možnostech využiti quercetinu v terapii onkologických onemocnění. Studium účinků quercetinu při aplikaci na nádorové buňky přineslo poznatky o tom, že jeho aplikace vede v nádorových buňkách s přítomným regulačním proteinem p53 k významnému zvýšení procesů spojených s apoptózou. Zvýšení produkce proteinu p53 je přitom spojeno s aktivací AMPK (AMP-aktivovaná proteinová kináza, AMP-activated protein kinase). Dále bylo jasně prokázáno, že typ superoxid dismutázy s manganem v aktivním místě a geny BCL2 jsou hlavními cíli v molekulárním mechanizmu, který aktivuje chemoterapii, jejíž součástí je také quercetin. Tento mechanizmus indukuje apoptózu přímou aktivací kaspázové kaskády v mitochondriích nádorových buněk. Aplikace quercetinu snižuje v buňkách koncentraci proteinu Her-2/neu spojovaného se špatnou prognózou pro nemocné s rakovinou prsu. Qercetin významně zvyšuje apoptózu, která je indukována TRAIL. To je spojeno se zvýšením exprese death receptoru 5 a inhibicí exprese survivinu a má mnoho dalších účinků, které uvádíme podle typu nádorových buněk, na kterých byly účinky quercetinu zkoumány. Přímé klinické využití mohou najít poznatky o tom, že quercetin zvyšuje účinnost terapie v kombinaci s doxorubicinem, tamoxifenem, vinkristinem, cisplatinou, 5-fluorouracilem a temozolomidem. V mnoha případech quercetin zvyšuje citlivost buněk k terapii nebo činí chemoterapii méně toxickou. Terapeutické aplikace quercetinu mohou být však limitovány z důvodu různorodosti a množství účinků v buňkách a potenciálně v celém organizmu.
This review deals with biological activity of quercetin with the use of newer data from PubMed database. Quercetin is a flavonoid of natural origin possessing antiinflamatory and antioxidative properties. Studies of quercetin effects on normal and tumor cells are resulting in a new information about posibilities of quercetin use in cancer therapy. These studies on quercetin cellular effects in cancer cells elucidated the fact that quercetin application leads in these cells to significant increase of apoptotic processes when these cells produce protein p53. Increased production of protein p53 is accompanied by an activation of AMPK (AMP-activated protein kinase). It was clearly demonstrated that a manganese-containing superoxid dismutase and BCL2 genes represent main targets in a molecular mechanism that activates quercetin-containing chemotherapy and which also induces apoptosis through a direct activation of caspase cascade in mitochondrias of cancer cells. Quercetin administration decreases cellular concentrations of Her-2/neu protein that indicates unfavorable prognosis for patients with breast cancer. Quercetin also significantly increases TRAIL-induced apoptosis. This is accompanied by an increase in death receptor 5 expression and by an inhibition of survivine expresion and also by numerous other effects that are discused according to the type of cancer cells, in which they were investigated. Data regarding the ability of quercetin to increas effectivity of therapies in combinations with doxorubicine, tamoxifen, vinkristin, cisplatin, 5-fluorouracil and temozolomide are of direct clinical relevance. In many cases, quercetin increases cell sensitivity to the therapy or makes chemotherapy less toxic. However, therapeutic use of quercetin may be limited because of its various other effects in cells and potentially in a whole organism.
- MeSH
- adjuvantní chemoterapie metody MeSH
- kolorektální nádory farmakoterapie MeSH
- lékařská onkologie * metody trendy MeSH
- lidé MeSH
- metaanalýza jako téma MeSH
- nádorový supresorový protein p53 diagnostické užití účinky léků MeSH
- nádory mozku farmakoterapie MeSH
- nádory plic farmakoterapie MeSH
- nádory prostaty farmakoterapie MeSH
- nádory prsu farmakoterapie MeSH
- nádory farmakoterapie terapie MeSH
- quercetin * aplikace a dávkování farmakologie chemie terapeutické užití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
- MeSH
- glutathion MeSH
- modely u zvířat MeSH
- myši MeSH
- oxidační stres MeSH
- peroxidace lipidů MeSH
- přetížení železem MeSH
- quercetin * aplikace a dávkování farmakologie MeSH
- silibinin * aplikace a dávkování farmakologie MeSH
- statistika jako téma MeSH
- železo analýza aplikace a dávkování farmakologie MeSH
- Check Tag
- myši MeSH
