槲皮素对小鼠淋巴细胞发光的影响

本文研究了槲皮素对小鼠淋巴细胞化学发光的影响，槲皮素５０ｍｇ／ｋｇ，１００ｍｇ／ｋｇ给小鼠腹腔注射，每天１次，连给６天后，测定小鼠脾淋巴细胞化学发光，结果表明，给药组小鼠淋巴细胞发光值显著高于对照组（Ｐ〈０．０１）。提示槲皮素具有提高淋巴细胞活性，增强其免疫功能的作用。     

槲皮素对人肺癌细胞和小鼠Lewis肺癌移植瘤细胞增殖的抑制作用及机制探讨

目的：研究槲皮素对人肺腺癌细胞株A549和小鼠Lewis肺癌移植瘤细胞增殖的抑制作用，并探讨其可能的机制。方法：①以不同剂量的槲皮素作用于人肺腺癌细胞株A549，用噻唑蓝(MTT)试验观察槲皮素对人肺癌细胞株增殖的影响。②将移植有Lewis肺癌的ICR小鼠随机分为模型对照组、槲皮素组及顺铂组，均采取腹腔内注射方式给药。给药结束后，测定各组小鼠的瘤重，计算抑瘤率；用免疫组化方法测定肿瘤的增殖细胞核抗原(PCNA)表达水平。结果：①槲皮素对3．549细胞增殖有明显的抑制作用，对细胞增殖的抑制率呈剂量效应关系。②槲皮素对小鼠Lewis肺癌移植瘤生长有明显的抑制作用，并显著下调小鼠Lewis肺癌移植瘤的PCNA表达水平。结论：槲皮素对人肺腺癌细胞A549和小鼠Lewis肺癌移植瘤细胞增殖有明显的抑制作用，其机制可能与抑制PCNA蛋白的表达有关。     

槲皮素抑制体外培养的人眼晶状体上皮细胞生长的研究

目的研究槲皮素对体外培养的人眼上皮细胞的抑制作用。方法时先天性白内障患者术中环行撕前囊膜，进行原代培养并传代，取第二代细胞用于实验，MTT法观察不同浓度的槲皮素（10μmol／ml、20μmol／ml、40μmol／ml、80μmol／ml、160μmol／m1）对晶状体上皮细胞的粘附的抑制作用；对基本融合的细胞进行划线，160μmol／ml的槲皮素进行干预，细胞计数法观察裸露区内细胞的移行数量；MTT法测定槲皮素对晶状体上皮细胞增殖的抑制效应。结果不同浓度的槲皮素（40μmol／ml、80μmol／ml、160μmol／m1）对晶状体上皮细胞的粘附和增殖具有抑制作用。160μmol／ml槲皮素明显抑制其移行。结论槲皮素对体外培养的人眼晶状体上皮细胞具有抑制作用，安全有效。     

黄酮类化合物逆转HeLa细胞株多药耐药性

目的　探讨黄酮类化合物对人类子宫颈癌 He L a细胞多药耐药 (MDR)的逆转作用。　方法　采用WST- 1法鉴定多药耐药亚系 Hvr1 0 0 - 6细胞对抗癌药物长春碱、阿霉素、柔红霉素及 5 -氟尿嘧啶 (5 - Fu)的耐药性 ,观察槲皮素等黄酮类化合物对其耐药的逆转作用 ;采用 RT- PCR法检测联用黄酮类化合物前后 Hvr1 0 0 - 6细胞mdr1 m RNA表达水平。　结果　 Hvr1 0 0 - 6细胞与亲本株 He L a细胞相比 ,对长春碱、阿霉素、柔红霉素均表现出显著耐药性 (P<0 .0 0 1 ) ,耐药倍数分别为 4 96 ,5 2和 1 98倍。加入槲皮素 (1 0μmol/ L )的长春碱、柔红霉素、5 - Fu组与相应浓度单用药物组比较 ,其细胞抑制率差异均有显著性 (P<0 .0 5 ) ,但细胞 m dr1 m RNA表达量在使用槲皮素前后没有变化。　结论　槲皮素对长春碱、柔红霉素、5 - Fu的细胞毒性有增敏作用 ,可逆转 He L a细胞耐药株对部分化疗药物的多药耐药     

槲皮素诱导Cloudman S91细胞凋亡的机制

目的：探讨槲皮素诱导小鼠黑色素瘤Cloudman S91细胞系凋亡的作用和机制。方法：采用噻唑蓝(MTT)比色法、吖啶橙／溴乙锭荧光染色、流式细胞仪及western blot分析技术对槲皮素诱导Cloudman S91细胞凋亡的作用及机制进行分析。结果：槲皮素对Cloudman S91细胞增殖有明显的抑制作用，其细胞存活率呈时间-剂量依赖性降低；用40～120μmol／L的槲皮素作用Cloudman S91细胞72h，可见明显的细胞凋亡形态学变化；流式细胞仪检测有亚G1峰出现，细胞被阻滞于G0／G1期；western blot分析提示槲皮素可抑制p53、bcl-2基因的表达，且呈显著的剂量依赖性。结论：槲皮素诱导Cloudman S91细胞的凋亡，其机制可能是通过阻滞细胞于G0／G1期、抑制p53、bcl-2基因的表达。     

Switchable-hydrophilicity solvent liquid-liquid microextraction for sample cleanup prior to dispersive magnetic solid-phase microextraction for spectrophotometric determination of quercetin in food samples

Switchable-hydrophilicity solvent-liquid-liquid microextraction (SHS-LLME), as an efficient sample cleanup method, was combined with dispersive solid-phase microextraction (DSPME) for preconcentration of quercetin prior to its spectrophotometric determination. Optimum SHS-LLME were found as 1000 μL of N,N-dimethylcyclohexylamine as the extraction solvent and 750 μL of 10.0 M sodium hydroxide as the phase separation trigger. Optimum DSPME were sample pH at 6.0, 1000 μL of acetone as the eluent, 30.0 mL of sample, 12.5 mg of Fe₃O₄@XAD-16 as the adsorbent, 4.0 and 1.5 min as the adsorption and elution times, respectively. Calibration graphs with coefficient of determination (R²) higher than 0.9956, limits of detection (LOD) of 9.0–11.9 ng mL^?1 and limits of quantitation (LOQ) of 29.9–39.6 ng mL^?1 were obtained. Repeatability, expressed as percentage relative standard deviation (%RSD), was better than 3.2 and 8.9% for intra- and inter-day precision, respectively. The proposed SHS-LLME-DSPME-UV/Vis method was applied for the determination of quercetin in four food samples (i.e., apple, pepper, red and white onion) with percentage recoveries in the range of 92.1–107.4%. The proposed method is superior to others in terms of greenness, rapidness, simplicity, good repeatability and low capital cost.     

Quercetin Induces Cell Cycle Arrest and Apoptosis in YD10B and YD38 Oral Squamous Cell Carcinoma Cells

Objective: Oral squamous cell carcinoma (OSCC) exhibits the highest lethality among head and neck cancers. Treatment for OSCC is limited due to diverse side effects. Quercetin is a natural flavonoid compound found in many kinds of plants and foods. Quercetin has been reported to be a modulator of proliferation and survival in various types of cancers due to its cytotoxic effects. We aimed to investigating chemopreventative roles of quercetin in YD10B and YD38 OSCC cells. Methods: For our study, two different types of OSCC cells were used. YD10B cells are tongue SCC cells with the p53 mutation and YD38 cells are lower gingiva SCC cells without the p53 mutation, respectively. The anticancer effects of quercetin were examined by cell viability, cell cycle, annexin-PI staining, and western blot. Result: Our results showed that quercetin decreased cell viability and induced G1 cell cycle arrest in YD10B and YD38 OSCC cells. Moreover, quercetin remarkably decreased the expression of cell cycle upregulating proteins and increased the expression of a CDK inhibitor. Quercetin also significantly increased the number of annexin-V-positive cells in a dose-dependent manner in both types of OSCC cells. This apoptotic potential of quercetin triggered cleavage of PARP followed by activation of p38 MAPK signaling pathway. Conclusion: In conclusion, this study demonstrates that quercetin shows different anti-cancer responses in OSCC with and without p53 mutation, respectively. Despite different p53 status in OSCC cells, quercetin led to apoptotic signals in both cells. Quercetin repressed cell proliferation with G1 cell cycle arrest and apoptosis by activating the p38 signaling pathway in two OSCC cells with different p53 status. These findings might provide new strategy for OSCC therapy by quercetin.     

Short-term consumption of a resveratrol-containing nutraceutical mixture mimics gene expression of long-term caloric restriction in mouse heart

An active area of aging research is focused on identifying compounds having the ability to mimic the effects of caloric restriction (CR). From 2 to 5 months of age, we fed male B6C3F₁ mice either a 40% CR diet, a control diet supplemented with a commercially available nutraceutical mixture (NCM) containing resveratrol, quercetin and inositol hexaphosphate, or a diet supplemented with an equivalent dose of chemical-grade resveratrol (RES; 1.25 mg resveratrol kg⁻¹ day⁻¹) from 2 to 5 months of age. Cardiac gene expression profiles were generated for the three groups of treated mice and compared to age-matched control (CO) mice. All three treatments were associated with changes in several cytoskeletal maintenance pathways, suggesting that RES and NCM are able to mimic short-term CR. CR uniquely affected several immune function pathways while RES uniquely affected multiple stress response pathways. Pathway analysis revealed that NCM (but not CR or RES) regulated multiple metabolic pathways that were also changed by long-term CR, including glucose and lipid metabolism, oxidative phosphorylation and chromatin assembly. Examination of key genes and pathways affected by NCM suggests that Foxo1 is a critical upstream mediator of its actions.     

Quercetin protects jejunal mucosa from experimental intestinal ischemia reperfusion injury by activation of CD68 positive cells

The aim of our study was to analyse the possible protective effect of quercetin application during the jejunal ischemia-reperfusion injury (IRI) in rats. Quercetin was administered intraperitoneally 30 min before 1 h ischemia of superior mesenteric artery with following 24 h lasting reperfusion period. The male specific pathogen-free (SPF) Charles River Wistar rats were used. In the group with applied quercetin, the significantly increased (p < 0.001) levels of anti-inflammatory cytokine IL10 were observed both in the blood serum and jejunal tissue. The improvement of the mucosal tissue morphology and proliferating and DNA repairing cell number measured by PCNA activity were recorded by more than 30% higher in the quercetin group. Simultaneously, significant elongation of the intestinal glands (p < 0.001) and increase in the number of CD68-positive cells in the lamina propria mucosae (p < 0.001) in comparison with control group were found. Based on our results, the preventive application of quercetin before induction of jejunal IRI stimulates faster jejunal mucosa restoration and it seems to have immunomodulatory and anti-inflammatory effects as well. CD68-positive macrophages could have crucial role in this process since they work as both growth factor and cytokine producers.     

槲皮素通过抑制c-Jun的表达水平增强5-氟尿嘧啶对胃癌细胞凋亡的诱导活性

目的:探讨槲皮素是否能增强5-氟尿嘧啶对胃癌细胞凋亡的诱导活性并研究其机制。方法:MTT法检测5-氟尿嘧啶在槲皮素辅助治疗下对胃癌细胞系BGC-823的杀伤活性和半抑制浓度(IC50)。免疫共沉淀和Western blot实验检测5-氟尿嘧啶和槲皮素对BGC-823细胞c-Jun和Bcl-x L的表达水平、c-Jun磷酸化水平、caspase-9和caspase-3活化水平以及细胞色素C释放的影响。流式细胞术检测5-氟尿嘧啶在槲皮素辅助下对BGC-823细胞凋亡的影响。结果:槲皮素能明显提高5-氟尿嘧啶对BGC-823细胞的杀伤活性,降低5-氟尿嘧啶对BGC-823细胞的IC50。槲皮素处理明显抑制BGC-823细胞c-Jun的表达,并抑制BGC-823细胞中5-氟尿嘧啶诱导的c-Jun磷酸化及其与ATF2蛋白的相互作用,进而抑制5-氟尿嘧啶诱导的Bcl-x L蛋白上调。转染c-Jun过表达质粒后,槲皮素联合5-氟尿嘧啶对BGC-823细胞的杀伤活性受到显著抑制。同时,槲皮素能显著增强BGC-823细胞中5-氟尿嘧啶诱导的细胞色素C从线粒体中释放和caspase依赖的凋亡。结论:槲皮素可通过c-Jun/ATF2/Bcl-x L途径增强5-氟尿嘧啶对胃癌细胞线粒体途径凋亡的诱导活性。