RP-HPLC法同时测定侧柏叶炭中槲皮素和山柰素的含量

目的:建立以反相高效液相色谱法同时测定侧柏叶炭中槲皮素和山柰素含量的方法。方法:色谱柱为Lichrospher C_(18)(250 mm×4.6 mm,5μm),流动相为甲醇-0.2%磷酸溶液(55:45),柱温为25℃,流速为1.0 mL·min~(-1),检测波长为368 nm。结果:槲皮素和山柰素的进样量分别在0.24～1.68μg(r=0.9999)和0.052～0.624μg(r=0.9998)范围内与各自峰面积积分值呈良好的线性关系;二者平均回收率分别为100.91%和99.59%,RSD分别为0.80%(n=6)和1.07%(n=6)。结论:本方法简便、准确、重现性好,可用于侧柏叶炭的质量控制。     

HPLC法测定木贼中槲皮素和山柰素的含量

目的建立高效液相色谱法测定木贼中槲皮素和山柰素的含量.方法采用Kromasil C18柱(4.6 mm×250mm,5μm);流动相:甲醇-0.4%磷酸溶液(60∶40);检测波长:360 nm,柱温:30℃.结果槲皮素和山柰素的回收率分别为100.2%、100.1%;线性范围分别为0.025 8～0.774μg、0.316～3.16μg.结论该法结果准确,重复性好,可用于该产品的质量控制.     

槲皮素对过氧化氢诱导A375细胞氧化损伤的保护机制研究

目的探讨槲皮素对人A375黑素瘤细胞的氧化损伤是否具有保护作用。方法体外培养人A375黑素瘤细胞,随机分为空白对照组、H2O2损伤组、不同浓度槲皮素预处理组(槲皮素终浓度为5、10、25、50μmol/L)。四甲基偶氮唑蓝(MTT)显色法测定细胞增殖,NaOH法测定黑素含量,流式细胞仪(Annexin V/PI法)测定细胞早期凋亡百分率。结果与H2O2损伤组相比,25μmol/L槲皮素组对细胞增殖有促进作用,其余槲皮素各组与H2O2损伤组相比差异无统计学意义(P0.05);与H2O2损伤组相比,各浓度的槲皮素均对细胞的黑素合成有促进作用(P0.05)。各槲皮素预处理组细胞早期凋亡百分率均低于H2O2损伤组(P0.05)。结论槲皮素可以减轻H2O2对人黑素瘤细胞造成的氧化损伤和早期凋亡。     

Neuroprotective effect of bioflavonoid quercetin in 6-hydroxydopamine-induced oxidative stress biomarkers in the rat striatum

An increasing large body of research on Parkinson's disease (PD) has focused on the understanding of the mechanisms behind the potential neuro protection offered by antioxidants and iron chelating agents. In this study, the protective effect of the bioflavonoid quercetin on 6-hydroxydopamine (6-OHDA)-induced model of PD was investigated. PD was induced by a single intracisternal injection of 6-hydroxydopamine (300 μg) to male Sprague-Dawley rats. Quercetin treatment (30 mg/kg body weight) over 14 consecutive days markedly increased the striatal dopamine and antioxidant enzyme levels compared with similar measurements in the group treated with 6-OHDA alone. There was a significant decrease in protein carbonyl content in the striatum compared with that of rats that did not receive quercetin. A significant increase in neuronal survivability was also found with quercetin treatment in rats administered 6-OHDA. In conclusion, treatment with quercetin defended against the oxidative stress in the striatum and reduced the dopaminergic neuronal loss in the rat model of PD.     

酶解-溶剂联合提取洋葱中槲皮素的研究

目的:研究酶解与溶剂联合提取洋葱中槲皮素的最佳工艺条件。方法:以槲皮素得率为考察指标,通过单因素试验及正交实验确定最佳提取工艺。结果:酶解-溶剂联合提取槲皮素的最佳工艺条件是:酶解pH为5.5,酶解浓度为0.5mg.ml-1,酶解温度为45℃,酶解时间为2 h,液固比为20∶1,提取温度为65℃,提取时间为1.5 h,乙醇浓度为60%,槲皮素平均得率为0.046%。结论:采用酶解-溶剂联合提取槲皮素,工艺方法简单,可大大提高原料利用率。     

Ins and outs of dietary phytochemicals in cancer chemoprevention

A voluminous number of evidence suggests that an increased consumption of fruit and vegetables is a relatively easy and practical strategy to reduce significantly the incidence of chronic diseases, such as cancer, cardiovascular diseases and other aging-related pathologies. This review will critically discuss the applications of chemical and dietary chemoprevention, intending the protecting effects against cancer of chemically synthesized molecules, or phytochemicals present in the regular diet. The length of chemopreventive treatments requires the administration of low doses of chemopreventive agents, to avoid toxic side effects. This poses the question, here discussed, of the bioavailability of these compounds, usually very modest. Another key issue is whether purified phytochemicals have the same protective effects, as do the whole food or mixture of foods in which these compounds are present. These aspects will be analysed at the light of the "antioxidant hypothesis" in cancer prevention and the "combination chemoprevention", both referring to the pleiotropic and synergistic effects of compounds present in the diet. Single molecules may evolve in perfect chemopreventive agents, as in the case of tamoxifen, or generate ambiguity. Resveratrol and quercetin represent two paradoxes, discussed here.     

The polyphenol quercetin strongly increases homocysteine production in a human hepatoma (Hep G2) cell line

OBJECTIVE: The metabolism of homocysteine is influenced by several dietary factors, including folate, cobalamin and possibly also the intake of polyhydroxylated phenolic compounds (polyphenols), which were shown to increase plasma homocysteine (tHcy) concentration. In order to reveal the cause of the increased plasma tHcy, we have therefore investigated the effects of a polyphenol in cell cultures from human cell lines. DESIGN AND METHODS: We have studied the influence of the polyphenol quercetin (Quer) on intra- and extracellular homocysteine concentrations in HeLa and hepatoma cell cultures. RESULTS: The main finding is an increased concentration of extracellular homocysteine in the presence of Quer in hepatoma cell cultures, whereas there were no significant changes of homocysteine concentration in HeLa cell cultures. There was no effect on cellular growth, as judged by cell protein. The presence of adenosyl-dialdehyde, an inhibitor of adenosyl-homocysteine hydrolase, abolished the increased extracellular concentration of homocysteine observed in hepatoma cell cultures in the presence of Quer. CONCLUSION: The antioxidative agent Quer strongly increased the extracellular concentration of homocysteine in hepatoma cell cultures probably due to increased cellular methylation. In the human body, the same phenomenon might lead to increased plasma tHcy. Since elevated plasma tHcy is associated with premature vascular disease, high long-lasting dietary intake of polyphenols might be harmful. The interaction between Quer and homocysteine turnover may therefore warrant a re-evaluation of polyphenols as relatively harmless antioxidative food supplements or therapeutic antioxidative agents.     

基于网络药理学与分子对接探究宁心通郁滋肾方治疗早发性卵巢功能不全的作用机制

[目的]基于四级杆-静电轨道阱（Q exactive orbitrap,Q-Orbitrap）高分辨液质联用系统分析结果,利用网络药理学结合分子对接的方法探究宁心通郁滋肾方治疗早发性卵巢功能不全（premature ovarian insufficiency,POI）的作用机制。[方法]采用Q-Orbitrap高分辨液质联用系统分析宁心通郁滋肾方中的活性成分,再通过Swiss Target Prediction数据库获取方中活性成分的靶点。利用基因组注释数据平台（Genome Annotation Database Platform,GeneCard）和在线人类孟德尔遗传（Online Mendelian Inheritance in Man,OMIM）数据库获取POI的疾病靶点。在String平台构建交集靶点的蛋白互作（protein-protein interaction,PPI）网络后,通过Cytoscape 3.8.2软件筛选关键靶点,并构建“关键靶点-关键活性成分”网络,筛选主要关键活性成分。通过生物学信息注释数据库（the Database for Annotation,V...     

槲皮素对白血病细胞中PML基因及蛋白表达的影响和定位的研究

目的 探讨PML基因及蛋白在白血病细胞中的表达和细胞内分布定位。方法 经全反式维甲酸（ATRA）、槲皮素处理后的NB4、HL-60、K562细胞为研究对象，细胞形态学观察采用Wright染色法及荧光染色法；PML蛋白细胞分内分布定位采用免疫荧光技术；PML mRNA表达的检测采用RT-PCR法。结果 （1）ATRA处理后，NB4和HL-60细胞形态学上出现分化表现，K562细胞无变化；经槲皮素处理后，各组细胞形态学上均出现凋亡特征性改变。（2）ATRA处理后，NB4细胞内融合蛋白降解，PML蛋白恢复定位，HL-60、K562细胞内PML蛋白定位分布无变化；槲皮素处理后NB4细胞内融合蛋白降解，PML蛋白聚积于POD结构，随后降解，在HL-60及K562细胞，PML蛋白发生相似改变。（3）ATRA、槲皮素对各组细胞PMLmRNA表达均无显著影响。结论 在不同诱导剂刺激下，PML在蛋白水平参与细胞终末分化及诱导白血病细胞凋亡机制；PML蛋白在POD中发挥诱导凋亡、控制细胞生长的作用。     

槲皮素对重症急性胰腺炎相关性肺损伤肺泡中性粒细胞TLR4/NF-κB通路的影响

目的探讨槲皮素(Quercetin)对大鼠重症急性胰腺炎相关性肺损伤(SAP-LI)肺泡中性粒细胞(PMN)TLR4/NF-κB信号通路的影响。方法 48只成年SD大鼠随机分为4组,每组12只,假手术(Sham)组、重症急性胰腺炎(SAP)组、槲皮素低剂量组(50 mg/kg)及槲皮素高剂量组(100 mg/kg)。逆行性胰胆管注射5%牛磺酸钠建立SAP大鼠模型。槲皮素组在胰腺炎模型基础上予槲皮素干预,Sham组、SAP组给予等量生理盐水。计算肺湿/干重比(W/D)和肺通透指数(LPI),经支气管肺泡灌洗分离收集PMN,ELISA检测PMN培养上清液中TNF-α含量,RT-PCR检测PMN TLR4 m RNA表达,Western blotting检测PMN TLR4和NF-κB p65的表达。结果与Sham组比较,其余三组W/D、LPI及TNF-α含量明显升高,TLR4 m RNA及其蛋白和NF-κB p65蛋白表达上调;与SAP组比较,槲皮素处理组W/D、LPI及TNF-α含量降低,TLR4 m RNA及其蛋白和NF-κB p65蛋白表达下调。结论槲皮素减轻SAP引起的肺损伤可能与其抑制PMN TLR4/NF-κB信号通路活化有关。