Protective effects of quercetin on uterine receptivity markers and blastocyst implantation rate in diabetic pregnant mice

ObjectiveDiabetic women have different reproductive problems. In pregnant diabetic women, high rates of perinatal mortality, spontaneous abortion and congenital anomalies are observed. We hypothesized that quercetin, as an antidiabetic and phytoestrogen, might have protective effects on the embryo implantation in pregnant diabetic mice. We investigated the ameliorative effects of quercetin on the levels of serum estrogen and progesterone, rate of blastocyst implantation, and uterine receptivity markers in diabetic mice.Materials and methodsDiabetic and healthy female mice were treated with quercetin (30 mg/kg/day) four weeks before pregnancy. Plasma sex-steroid levels were determined on day 4 of pregnancy. Also, uteri were harvested for investigation of protein and mRNA expression changes. In another set of our study, implantation rate was determined on day 5 of pregnancy.ResultsOur results indicated that quercetin was significantly reduced blood glucose levels in diabetic mice. The number of implantation sites as well as serum estradiol level was reduced in diabetic mice, and then treatment with quercetin significantly increased both. On the other hand, insulin like growth factor1, integrin αvβ3, and cyclooxygenase2 mRNA expression in the uterus of diabetic mice were significantly reduced, and quercetin treatment augmented the expression level of these genes. Besides, the level of inactive β-catenin protein level in the uterus of diabetic mice was higher than normal group; treatment with quercetin reduced the level of inactive β-catenin protein as compared to diabetic mice.ConclusionWe conclude that administration of quercetin before pregnancy can probably alleviate reproductive problems in diabetic women likely via its estrogenic and antihyperglycemic effects.     

Quercetin abrogates bisphenol A induced altered neurobehavioral response and oxidative stress in zebrafish by modulating brain antioxidant defence system

Bisphenol A (BPA), a well-recognized anthropogenic xenoestrogen, has been identified as a causative agent responsible for inducing carcinogenicity, cognitive impairment, neurotoxicity, oxidative stress, etc. However, BPA-induced neurotoxicity and its possible amelioration through natural compound intervention remain elusive. The current study was performed to elucidate the neurotoxic potential of BPA in zebrafish (Danio rerio) by waterborne exposure and its possible amelioration by quercetin co-supplementation. Protective effect of quercetin against BPA-induced altered neurobehavioral response, oxidative stress and neuromorphological changes were evaluated in zebrafish brain. The present findings reveal that BPA-induced altered neurobehavioral response was ameliorated by quercetin. Biochemical studies advocate the potential therapeutic efficacy of quercetin against BPA-induced oxidative stress in zebrafish brain. Quercetin also shows neuroprotection against BPA-induced augmented neuronal pyknosis in periventricular grey zone (PGZ) of zebrafish brain. These basic findings indicate that quercetin may act as an effective intervention against BPA-induced neurotoxicity in zebrafish through down-regulation of oxidative stress.     

Quercetin derivatives regulate melanosome transportation via EPI64 inhibition and elongate the cell shape of B16 melanoma cells

4′-O-β-d-glucopyranosyl-quercetin-3-O-β-d-glucopyranosyl-(1→4)-β-d-glucopyranoside (3C4′GQ), first isolated from Helminthostachys zeylanica root extract, was synthesized as a compound that stimulates intracellular melanogenesis. 3-O-methylquercetin (3MQ) and 3,4′,7-O-trimethylquercetin (34′7TMQ) were synthesized as compounds that enhance extracellular melanin formation. The formation of dendrites and the expression of EBP50-PDZ interactor of 64 kDa (EPI64) relating to melanin transportation were investigated using B16 melanoma cells treated with 3C4′GQ, 3MQ, or 34′7TMQ in order to understand the mechanism underlying the observed activities. The influence of 3C4′GQ on the increase of intracellular melanin contents enhanced the expression of EPI64, exhibited no dendrite elongation activity, and inhibited melanin transportation. On the other hand, the increase of extracellular melanin content by 3MQ and 34′7TMQ inhibited the expression of EPI64 and formed elongated cells to stimulate melanin transportation.     

Effects of water-soluble cigarette smoke extracts upon the release of β-hexosaminidase from RBL-2H3 basophilic leukaemia cells in response to substance P,compound 48/80, concanavalin A and antigen stimulation

Objective and design: To determine whether water-soluble constituents of cigarette smoke affect mast cell function using an in vitro model, RBL-2H3 basophilic leukaemia cells. Materials and methods: RBL-2H3 cells were induced to degranulate in response to compound 48/80 and substance P, as assessed by monitoring the release of the granular enzyme -hexosaminidase, by treatment for 7 days with 20 M quercetin. Responses to concanavalin A and antigen were determined by measuring the -hexosaminidase release from cells cultured on fibronectin-coated plates. Results: The -hexosaminidase release response to compound 48/80 induced by quercetin treatment was accompanied by a release of lactate dehydrogenase, suggesting that degranulation is not the only process triggered by compound 48/80 under these conditions. Quercetin treatment reduced the -hexosaminidase release response to concanavalin A. Precoating of the culture wells with rat fibronectin enhanced the -hexosaminidase response to calcimycin, but not to concanavalin A. Under these conditions, concanavalin A did not induce a release of lactate dehydrogenase. The responses to c48/80, substance P, calcimycin, concanavalin A and antigen (after IgE pretreatment) were reduced by treatment with cigarette smoke solution obtained from standard and low-tar cigarettes (IR3 and IR5F). The effect of cigarette smoke solution from IR5F cigarettes upon the -hexosaminidase release elicited by compound 48/80 (in quercetin-treated cells) and by concanavalin A (in cells cultured on fibronectin-coated wells) could be prevented by N-acetyl-L-cysteine, but not with either hemoglobin, -tocopherol, catalase or palmitoylethanolamide. N-acetyl-L-cysteine also reduced the effect of cigarette smoke solution upon the degranulation response to antigen. Conclusion: Under the conditions used, oxidants present in cigarette smoke solution from IR5F cigarettes reduce the ability of RBL-2H3 cells to degranulate in response to both immunological and non-immunological stimuli.Received 6 December 2002; returned for revision 1 April 2003; accepted by I. Ahnfelt-RøJune 2003     

Quercetin调节肝癌HepG2细胞Fas表达诱导细胞凋亡

目的： 探讨三磷酸肌醇( IP3) 和Fas基因表达变化在quercetin诱导肝癌细胞凋亡中的作用。方法: 以肝癌HepG2 细胞培养72 h为对照, 20、40、60、80 μmol/ L quercetin作用于 HepG2 细胞72 h和60 μmol/L quercetin 作用于HepG2 细胞6 h、12 h、24 h、48 h、72 h,应用同位素试剂盒IP3 - ［3H］ Birtrak检测细胞IP3 含量，RT-PCR分析Fas mRNA表达，Western blotting 分析细胞Fas蛋白表达，流式细胞仪检测细胞凋亡率。结果: 各浓度的quercetin作用于肝癌HepG2 细胞72 h，IP3 含量显著低于对照组［（17.9±1.5 ）pmol/106cells、（15.5±1.1）pmol/106cells、（5.7±0.9）pmol/106cells、（5.5±0.8）pmol/106cells vs （29.4±0.5）pmol/106cells］，Fas mRNA表达显著高于对照组［RI 0.26±0.01、0.30±0.01、0.30±0.02、0.37±0.02 vs 0.19±0.02］，Fas蛋白表达显著高于对照组［RI（灰度与面积之积的相对强度）1.10±0.08、 0.91±0.02、0.78±0.07、0.73±0.05 vs 0.15±0.01］，细胞凋亡率显著高于对照组［（11.2±1.1）%、（15.5±1.1）%、（26.8±2.5）%、（27.1±1.5）% vs （2.6±0.1）%］； 60 μmol/L quercetin 作用于肝癌HepG2 细胞6 h、12 h、24 h、48 h、72 h ，各时相IP3 含量显著低于对照组［（23.3±1.4）pmol/ 106cells、 (12.0±1.4) pmol/ 106cells、(7.5 ±0.8) pmol/ 106cells、(5.6 ±0.5) pmol/ 106cells、(4.3 ±0.6) pmol/ 106cells vs (29.2 ±0.6) pmol/106cells,P<0.01］；12 h后Fas mRNA表达显著高于对照组［RI 0.26±0.02、0.28±0.02、0.26±0.01、0.24±0.01 vs 0.20±0.01］，Fas蛋白表达显著高于对照组［RI 0.65±0.17、 1.20±0.07、1.51±0.06、1.50±0.06、0.97±0.17 vs 0.18±0.01］，24 h后各时相细胞凋亡率显著高于对照组［(7.4 ±0.5)%、(20.5 ±2.0)%、(30.7 ±1.6)% vs (2.6 ±0.1)%，P< 0.01］。结论: Quercetin能减少IP3 生成，上调Fas基因表达，诱导肝癌细胞凋亡。     

槲皮素对LPS延迟中性粒细胞自发性凋亡效应的抑制作用

目的：研究槲皮素对接受细菌脂多糖(LPS)刺激的中性粒细胞(PMN)自发性凋亡的影响，探讨槲皮素的抗炎作用机制。方法：以人外周血PMN为研究对象，选择光镜和流式细胞术检测细胞凋亡情况，对裂解的片段化DNA进行定量(二苯胺测定法)和定性(琼脂糖凝胶电泳)分析。结果：槲皮素(1～100μmol／L)对PMN的自发性凋亡率并无影响，但却能部分恢复由LFS所延迟的PMN自发性凋亡进程。当槲皮素的浓度为40μmol／L时，其恢复作用达到最大。结论：槲皮素对LPS延迟PMN自发性凋亡的效应产生了抑制作用，减轻了因预激因子活化PMN而加重的炎症反应，部分揭示了槲皮素的抗炎作用机制。     

槲皮素对内分泌耐药乳腺癌三苯氧胺治疗增敏作用的体内研究

目的:探讨槲皮素(QUE)对内分泌耐药乳腺癌三苯氧胺(TAM)治疗的增敏作用。方法:用大剂量TAM冲击法构建TAM耐药乳腺癌细胞株MCF-7/TAM-R并移植裸鼠后,将荷瘤鼠随机分为4组,分别给予溶媒(对照组)、QUE 50 mg/kg 1次/2 d(QUE组)、TAM 5 mg/kg 1次/d(TAM组)、QUE 50 mg/kg 1次/2 d+TAM 5 mg/kg 1次/d(QUE+TAM组)处理,动态观测各组荷瘤鼠的一般情况与瘤体体积的变化,于给药21 d后,处死各组荷瘤鼠,检测瘤体质量及瘤组织ERα、HER-2、pMAPK、MAPK、pAkt、Akt蛋白的表达。结果:给药过程中,QUE+TAM组和QUE组裸鼠摄食减少、体质量减轻,对照组与TAM组裸鼠无明显异常;至第12天开始,QUE+TAM组瘤体生长呈下降趋势,且第21天明显下降(P0.05),其余各组瘤体均呈持续增长。与对照组比较,QUE+TAM组瘤体质量明显减轻(P0.05),而其余两组均无统计学差异(均P0.05);QUE+TAM组和QUE组瘤组织中ERα蛋白高表达,HER-2、pMAPK、pAkt蛋白低表达,而TAM组上述蛋白表达均无明显差异,各组非磷酸化的MAPK、Akt蛋白表达均无明显差异。结论:QUE能恢复内分泌耐药乳腺癌对TAM的敏感性,可能与其下调HER-2及其下游信号pMAPK、pAkt的表达,并上调ERα的表达有关;QUE有潜在的毒副作用,其安全范围及有效剂量有待进一步探讨。     

槲皮素对胃癌相关p53/AMPK/mTOR信号通路的影响

目的　探讨槲皮素（QE）对胃癌相关p53/AMPK/mTOR信号通路的影响。方法　将胃癌细胞分为QE组和溶剂组,QE组以DMSO为溶剂按配制QE浓度分别为0.02、0.04、0.06及0.08 mmol/L,对细胞进行干预,分别为QEA、QEB、QEC、QED组,溶剂组加入等量不含QE的溶剂。MTT实验检测槲皮素对胃癌细胞增殖的影响;MDC染色法检测槲皮素对胃癌细胞自噬的影响;双染法检测槲皮素对胃癌细胞凋亡的影响;实时荧光定量聚合酶链反应检测细胞内p53、AMPK及mTOR的mRNA相对表达水平;Western blot检测细胞内LC3Ⅱ/LC3Ⅰ、P53、AMPK、mTOR蛋白表达差异。结果　与溶剂组相比,QE各剂量组胃癌细胞的自噬程度和凋亡率均显著增加,细胞中LC3Ⅱ/Ⅰ蛋白表达量上调,p53、AMPK mRNA和蛋白水平均上调,mTOR的mRNA和蛋白表达量均下调（P＜0.05）,且呈剂量依赖性。结论　QE可以抑制胃癌细胞增殖,诱导其发生自噬、促进其凋亡,其作用机制可能与p53/AMPK/mTOR信号通路有关。     

Protective effects of quercetin on nicotine induced oxidative stress in ‘HepG2 cells’

Nicotine is a natural component of tobacco plants and is responsible for the addictive properties of tobacco. Nicotine has been recognized to result in oxidative stress by inducing the generation of reactive oxygen species (ROS). The purpose of this work was to estimate the hepatotoxicity effect of nicotine on viability and on antioxidant defense system in cultures of HepG2 cell line and the other hand, ameliorative effect of quercetin (Q) as an antioxidant was analyzed. Nicotine induced concentration dependent loss in HepG2 cell line viability. The results indicated that nicotine decreased activity of superoxide dismutase (SOD) and glutathione reductase (GR) and increased activities of catalase (CAT) and glutathione peroxidase (GPx) and glutathione (GSH) content in the HepG2 cells. Q significantly increased activity of SOD, GR and GSH content and decreased activity of GPX in nicotine?+?Q groups. Our data demonstrate that Q plays a protective role against the imbalance elicited by nicotine between the production of free radicals and antioxidant defense systems, and suggest that administration of this antioxidant may find clinical application where cellular damage is a consequence of ROS.