Antioxidants in liver health

Liver diseases are a worldwide medical problem because the liver is the principal detoxifying organ and maintains metabolic homeostasis. The liver metabolizes various compounds that produce free radicals(FR).However, antioxidants scavenge FR and maintain the oxidative/antioxidative balance in the liver. When the liver oxidative/antioxidative balance is disrupted, the state is termed oxidative stress. Oxidative stress leadsto deleterious processes in the liver and produces liver diseases. Therefore, restoring antioxidants is essential to maintain homeostasis. One method of restoring antioxidants is to consume natural compounds with antioxidant capacity. The objective of this review is to provide information pertaining to various antioxidants found in food that have demonstrated utility in improving liver diseases.     

槲皮素恢复柔红霉素在白血病耐药细胞K562/ADM和HL-60/ADM中的分布

背景与目的：槲皮素是一种天然黄酮类中药成分,儿有多种生理活性,最近发现其有逆转白血病细胞耐药的作用,本研究旨在探讨槲皮素恢复柔红霉素在白血病耐药细胞的分布从而达到逆转耐药的机制：方法：通过MTT体外药敏法检测槲皮素对柔红霉素的增敏作用并确定逆转的浓度范围,作用于K562／ADM、HL-60／ADM细胞及相应敏感株K562和HL-60,借助激光共聚焦显微镜观察槲皮素怍用前后柔红霉素在亚细胞水平的分布变化：结果：20～40μmol／L槲皮素在体外能日月显提高柔红霉素对K562／ADM和HL-60／ADM的敏感性,恢复柔红霉素在亚细胞水平的分布,使其回归细胞核内,从而逆转多药耐药。结论：黄酬类中药槲皮素能够成为蒽环类药物治疗白血病中有效的化疗增敏剂。     

Effects of quercetin on α9α10 nicotinic acetylcholine receptor-mediated ion currents

Quercetin, one of the flavonoids, is a low molecular weight substance found in fruits and vegetables. Quercetin, like other flavonoids, has a wide range of neuropharmacological actions and antioxidant effects. The α9α10 nicotinic acetylcholine receptor is one of the numerous nicotinic acetylcholine receptors that exist as a heteropentameric form between efferent olivocochlear fibers and hair cells of the cochlea. In this study, we report the effects of quercetin on rat α9α10 nicotinic acetylcholine receptor-mediated ion currents using the two-electrode voltage-clamp technique. Treatment with acetylcholine evoked inward currents (I_ACh) in oocytes heterologously expressing the α9α10 nicotinic acetylcholine receptor. Quercetin blocked I_ACh in concentration-dependent and reversible manners, and the blocking effect on I_ACh was stronger with pre-application than co-application of quercetin. The half maximal inhibitory concentration (IC₅₀) of quercetin was 45.4 ± 10.1 μM. Quercetin-mediated I_ACh inhibition was not affected by acetylcholine concentration and was independent of membrane-holding potential. Although the inhibitory effect of quercetin was significantly attenuated in the absence of extracellular Ca²⁺, the action of quercetin was independent of extracellular Ca²⁺ concentration, indicating that the presence of extracellular Ca²⁺ might be needed for quercetin-related effects and might play an important role in quercetin-mediated regulation of the α9α10 nicotinic acetylcholine receptor. These results indicate that quercetin-mediated regulation of the α9α10 nicotinic acetylcholine receptor could provide a molecular basis for quercetin actions at the cellular level.     

Oral administration of quercetin inhibits bone loss in rat model of diabetic osteopenia

Diabetic osteopenia can result in an increased incidence of bone fracture and a delay in fracture healing. Quercetin, one of the most widely distributed flavonoids in plants, possesses antioxidant property and beneficial effect on osteoporosis in ovariectomized mice. All these properties make quercetin a potential candidate for controlling the development of diabetic osteopenia. Therefore, the present study was designed to investigate the putative beneficial effect of quercetin on diabetic osteopenia in rats. Diabetes mellitus was induced by streptozotocin. The diabetic rats received daily oral administration of quercetin (5 mg/kg, 30 mg/kg and 50 mg/kg) for 8 weeks, which was started at 4 weeks after streptozotocin injection. Quercetin at 5 mg/kg showed little effect on diabetic osteopenia, while quercetin at 30 mg/kg and 50 mg/kg could increase the decreased serum osteocalcin, serum alkaline phosphatase activity, and urinary deoxypyridinoline in diabetic rats. In addition, quercetin (30 mg/kg and 50 mg/kg) could partially reverse the decreased biomechanical quality and the impaired micro-architecture of the femurs in diabetic rats. Histomorphometric analysis showed that both decreased bone formation and resorption were observed in diabetic rats, which was partially restored by quercetin (30 mg/kg and 50 mg/kg). Further investigations showed that quercetin significantly lowered the oxidative DNA damage level, up-regulated the total serum antioxidant capability and the activity of serum antioxidants in diabetic rats. All those findings indicate the beneficial effect of quercetin on diabetic osteopenia in rats, and raise the possibility of developing quercetin as potential drugs or an ingredient in diet for controlling diabetic osteopenia.     

部份省区市售山楂饮片总黄酮含量分析

目的：比较不同产地山楂饮片的质量。方法：采用紫外分光光度法测定山楂中总黄酮含量。结果：各地样品中总黄酮的含量在0.187～0.707mg／g之间,槲皮素标准品的线性范围为O．00176—0．00800mg／ml,回归方程Y=66．0744X＋0．0171,相关系数r=0．9994,加样回收率为99．11％,RSD为1．23％。结论：该方法简便易行,为广山楂的质量控制提供了实验依据。     

槲皮素对结肠癌作用及其机制的研究进展

槲皮素广泛存在于蔬菜和水果中,属于黄酮类物质,研究发现其对多种肿瘤细胞具有抑制作用,包括乳腺癌、前列腺癌、肝癌、食管癌、卵巢癌等.目前在体内和体外研究均发现槲皮素对结肠癌具有抑制作用,其不仅抑制结肠癌细胞的增殖、诱导癌细胞的凋亡.同时可以减少结肠畸形腺隐窝的数目.槲皮素抑癌的具体作用机制目前还不明确,可能是通过调节多个...     

Life or death: Neuroprotective and anticancer effects of quercetin

Ethnopharmacological relevance

Quercetin is a ubiquitous flavonoid that is present in numerous plants that are utilized in many different cultures for their nervous system and anticancer effects. To better understand the neuroprotective and antiproliferative activities of quercetin, we present a comprehensive review of the divergent actions that contribute to the ethnopharmacological profile of these plants.

Results

The pharmacological activities of quercetin that modulate antioxidation/oxidation/kinase-signaling pathways might be differentially elicited in neurons compared with malignant cells, ultimately promoting cell survival or death in a cell type- and metabolism-specific manner. Whereas the broad antioxidation and anti-inflammatory activities of quercetin are important for neuronal survival, the oxidative, kinase- and cell cycle-inhibitory, apoptosis-inducing effects of quercetin are essential for its anticancer effects. The diverse mechanistic interactions and activities of quercetin that modulate the phosphorylation state of molecules as well as gene expression would alter the interconnected and concerted intracellular signaling equilibrium, either inhibiting or strengthening survival signals. These mechanisms, which have been mainly observed in in vitro studies, cannot be easily translated into an explanation of the divergent simultaneous neuroprotective and anticancer effects observed in vivo. This is in part due to low bioavailability in plasma and in the brain, as well as the nature of the actual active molecules.

Conclusions

Numerous studies have demonstrated the beneficial effects of chronic quercetin intake, which is ethnopharmacologically meaningful, as many plants that are chronically ingested by people contain quercetin. Although quercetin and quercetin-containing plants exhibit potential as therapeutic modalities in neuropathology and in cancer, the data collectively highlight the need to elucidate issues such as bioavailability as well as its correlation with effectiveness at biomarkers in vivo. There would be an increased potentential of these plants for chemoprevention and neuropathology prevention.     

槲皮素对脂多糖刺激巨噬细胞炎症因子释放的影响

目的 观察槲皮素对脂多糖(LPS)刺激巨噬细胞炎症因子释放的影响.方法 采用四甲基偶氮唑盐微量酶反应比色(MTT)法测定不同浓度槲皮素对RAW264.7细胞活性的影响.将细胞分为五组:A组(对照组)、B组(LPS干预组)、C组(LPS+槲皮素50 μmol/L)、D组(LPS+槲皮素150 μmol/L)和E组(LPS+槲皮素250μmol/L).real-time测定各组细胞Toll样受体4(TLR4)、髓样分化因子88(Myd88)、NF-κB (p65) mRNA的表达;酶联免疫吸附测定(ELISA)测定各组细胞上清液白细胞介素6(IL-6)、肿瘤坏死因子-α(TNF-α)分泌水平.结果 槲皮素在0～250 μmol/L浓度范围内对RAW264.7细胞活性没有影响.同对照组相比,槲皮素可有效降低LPS引起的TLR4、MyD88、NF-κB (p65)的mRNA表达和细胞上清液中IL-6、TNF-α分泌水平,并呈剂量依赖性(P＜0.01).结论 槲皮素可能通过抑制TLR-Myd88-NF-κB传导通路的活化,减少巨噬细胞炎症因子的分泌.     

脉安颗粒质量标准研究

目的建立脉安颗粒质量标准。方法采用薄层色谱(TLC)法对脉安颗粒中山楂进行定性鉴别,采用高效液相色谱法(HPLC)对制剂中山楂槲皮素进行定量分析。结果山查中熊果酸薄层色谱斑点清晰,阴性对照无干扰,重现性好;槲皮素含量在0.050 75μg～0.812μg范围内有良好的线性关系;峰面积相对标准偏差(RSD)为0.36%,仪器精密度良好;平均回收率为99.67%,RSD为0.94%,回收率高。结论本实验方法简单、可靠、实用,可用于脉安颗粒的质量控制。     

析因分析法研究槲皮素对芒果苷抗炎祛痰作用的影响

目的 研究芒果叶主要化学成分芒果苷和槲皮素在抗炎、祛痰作用上是否存在交互影响.方法采用二甲苯致小鼠 耳廓肿胀模型研究抗炎作用;采用小鼠气管排泌酚红模型研究祛痰作用;采用析因方差分析判断药物间是否存在交互影响.结果 与空白对照组比较,芒果苷组有抗炎和祛痰作用(P＜0.05),槲皮素组有抗炎作用(P＜0.01),但没有祛痰作用(P＞0.05).芒果苷+槲皮素组的抗炎作用强于芒果苷组(P＜0.01),两者之间没有交互作用(P＞0.05);芒果苷+槲皮素组的祛痰作用明显高于芒果苷组(P＜0.01),且两者有交互影响(P＜0.05).结论 芒果苷有抗炎和祛痰作用,槲皮素有抗炎作用但没有祛痰作用;槲皮素在抗炎中占主要地位,芒果苷在祛痰中占主要地位;芒果苷与槲皮素合用,在抗炎作用中两者之间不存在药物交互影响;但两药在祛痰试验中有明显的协同效应,槲皮素能明显提高芒果苷的祛痰药效.