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.     

Role of Bax in quercetin-induced apoptosis in human prostate cancer cells

The aim of this study was to investigate the effect of quercetin, a flavonoid, on the apoptotic pathway in a human prostate cell line (LNCaP). We observed that treatment of cells for 24h with quercetin-induced cell death in a dose-dependent manner. A sustained inhibition of the major survival signal, Akt, occurred in quercetin-treated cells. Treatment of LNCaP cells with an apoptosis inducing concentration of quercetin (100 microM) resulted in a rapid decrease in the inhibitory Ser473 phosphorylation of Akt leading to inhibition of its kinase activity. Quercetin treatment (100 microM) also caused a decrease in Ser136 phosphorylation of Bad, which is a downstream target of Akt. Protein interaction assay revealed that during treatment with quercetin, Bcl-xL dissociated from Bax and then associated with Bad. Our results also show that quercetin decreases the Bcl-xL:Bax ratio and increases translocation and multimerization of Bax to the mitochondrial membrane. The translocation is accompanied by cytochrome c release, and procaspases-3, -8 and -9 cleavage and increased poly(ADP-ribose) polymerase (PARP) cleavage. Similar results were observed in human colon cancer HCT116Bax+/+ cell line, but not HCT116Bax-/- cell line. Interestingly, at similar concentrations (100 microM), quercetin treatment did not affect the viability or rate of apoptosis in normal human prostate epithelial cell line (PrEC) and rat prostate epithelial cell line (YPEN-1). Our results indicate that the apoptotic processes caused by quercetin are mediated by the dissociation of Bax from Bcl-xL and the activation of caspase families in human prostate cancer cells.     

槲皮素对糖尿病视网膜病变小鼠氧化应激损伤和炎症反应的影响

目的：探讨槲皮素对糖尿病视网膜病变（DR）的保护作用及其抗氧化和抗炎机制。方法： 腹腔注射链脲佐菌素（STZ）建立小鼠糖尿病模型,随机分为正常对照组、造模组、槲皮素治疗组（n = 10）。治疗后定期监测小鼠精神状态、血糖、体重;检测小鼠视网膜结构变化、超氧化物歧化酶（SOD）活性、8-羟基脱氧鸟苷（8-OHdG）、丙二醛（MDA）、肿瘤坏死因子-α（TNF-α）、白介素-6（IL-6）、白介素-β（IL-β）的mRNA等水平。结果：与造模组相比,槲皮素降低小鼠血糖（P ＜ 0.05）,小鼠体重无明显差异（P ＞ 0.05）,视网膜细胞排列整齐,厚度增加;视网膜组织中8-OHdG、MDA、TNF-α mRNA、IL-6 mRNA、IL-β mRNA、Bax及p-p38 MAPK蛋白表达指数显著降低（P ＜ 0.05）,T-SOD活力和Bcl-2蛋白表达水平明显升高（P ＜ 0.05）,但各组p38 MAPK蛋白表达水平无明显差异（P ＞ 0.05）。结论： 槲皮素改善2型糖尿病小鼠视网膜组织氧化应激损伤和炎症反应,其机制可能与p38 MAPK信号通路有关。     

HPLC法测定姜黄素-槲皮素复方自微乳的载药量和包封率

摘 要 目的：建立HPLC法测定姜黄素 槲皮素复方自微乳（CUR-QUE-SMEDDS）的载药量和包封率。方法: 采用离心法分离游离药物,HPLC法测定药物含量。色谱柱：Purospher STAR LP C18 柱（250 mm×4.6 mm,5 μm）,流动相：乙腈 4%冰醋酸（50∶50）,流速：1.0 ml·min^-1,检测波长：370 nm,柱温：30℃,进样量：10 μl。结果: 姜黄素和槲皮素的线性范围分别为10.728~96.552 μg·mL^-1（r=0.999 8）和1.08~9.72 μg·mL^-1（r=0.999 9）,平均回收率分别为99.98%（RSD=1.46%,n=9）和100.34%（RSD=1.06%,n=9）。CUR QUE SMEDDS中姜黄素和槲皮素的包封率分别为（95.97±0.50）% 和（95.91±2.52）%,载药量分别为（25.82±0.15）mg·g^-1和（1.80±0.05）mg·g^-1。结论:该法准确可靠,快速简便,适用于测定CUR-QUE-SMEDDS的载药量和包封率。     

槲皮素对LPS诱导中性粒细胞活性化效应的抑制作用

目的研究槲皮素(Quercetin,Que)对细菌脂多糖(Lipopolysaccharide,LPS)诱导的中性粒细胞(Polymorphonuclear,PMN)活化效应的影响。方法运用免疫荧光法和流式细胞术,对接受1h LPS刺激的PMN表面黏附分子(CD62L,CD11b／CD18)的表达进行测定,同时应用MTT法对不同状态下的PMN活性进行测定。结果Que对LPS诱导的中性粒细胞活化效应有明显抑制作用,表现为抑制细胞表面黏附分子CD62L的表达和促进CD11b／CD18的表达,同时Que对LPS增加细胞活性的效应有抑制作用。结论槲皮素通过对抗LPS对PMN黏附分子CD62L,CD11b／CD18的表达的影响,抑制LPS诱导的中性粒细胞活化效应,从而阻止PMN对血管内皮细胞的黏附,减少炎症细胞向炎症局灶的浸润,这可能是槲皮素发挥抗炎作用的一个重要机制。     

槲皮素对K562细胞形态及VEGF表达的影响

目的探讨槲皮素对K562细胞的形态、血管内皮生长因子(VEGF)蛋白分泌和VEGF mRNA表达的影响.方法以K562细胞为研究对象,细胞形态学观察采用Wright's染色法;AnnecxinV标记检测细胞凋亡率;RT-PCR方法检测VEGF mRNA表达;ELISA法检测VEGF蛋白表达.结果1.经槲皮素处理后,细胞形态学上出现凋亡特征性改变;2.槲皮素处理后K562细胞凋亡率明显增加(P＜0.01);3.槲皮素能下调K562细胞VEGF mRNA的表达(P＜0.05);4.槲皮素处理后K562细胞显著降低VEGF蛋白的分泌(P＜0.05).结论槲皮素在体外能抑制白血病细胞K562生长并诱导其凋亡;槲皮素可抑制白血病细胞分泌VEGF.