槲皮素抗小鼠P388白血病的作用

目的：研究槲皮素抗小鼠P388白血病的作用。方法：采用DBA／2小鼠腹腔注射P388细胞的方法建立白血病小鼠模型，80只小鼠随机分为空白对照组、溶剂对照组、高剂量槲皮素组、低剂量槲皮素组，每组20只。于第7天末次给药后每组小鼠随机抽取10只处死，收集腹水分别计数，观察腹水细胞荧光形态变化，分析细胞周期及细胞凋亡率，观察骨髓涂片及心、肝、脾、肾的组织病理学改变。观察记录其它小鼠一般情况及生存期。结果：给予槲皮素的两组小鼠平均生存期较两对照组显著延长（P〈0．05），且高剂量组小鼠平均生存期较低剂量组显著延长（P〈0．05）。在第7天处死小鼠后，高剂量组小鼠无肉眼可见腹水。低剂量组小鼠腹水细胞的密度显著减小，G0-G1期细胞比例减少，S期细胞比例增加，细胞凋亡率显著升高（P〈0．05）。各组小鼠骨髓涂片及心、肝、脾、肾组织病理切片未见明显异常。结论：槲皮素对P388白血病小鼠有延长生存期及抑制腹水细胞增殖和诱导腹水细胞凋亡的作用。     

槲皮素联合川芎嗪对小鼠Lewis 肺癌生长的抑制作用

 目的 探讨槲皮素联合川芎嗪对小鼠Lewis肺癌生长的抑制作用及其机制。方法 复制C57BL小鼠Lewis肺癌模型，将40只接种Lewis肺癌的C57BL小鼠随机分成4组：对照组（A组）、槲皮素组（B组）、川芎嗪组（C组）、槲皮素＋川芎嗪组（D组），每组10只。连续用药20日，观察移植瘤生长情况，于接种后第22天处死各组小鼠，采用免疫组化半定量检测肿瘤组织微血管密度（MVD）、血管内皮生长因子（VEGF）及增殖核抗原（PCNA）的表达水平，用原位凋亡TUNEL法检测肿瘤细胞凋亡指数（AI）。结果 （1）B、C、D组肿瘤的生长明显受到抑制，瘤重明显低于A组，其抑瘤率分剐为39．87％、35．45％、54．58％，D组抑瘤率明显高于B、C组，差异有显著性（P〈0．05）。（2）B、C、D组MVD、VEGF及PCNA表达水平明显低于A组（P〈0．05或0．01），尤其是D组表达最低。B、C、D组AI较A组增高（P〈0．05或0．01），D组最高。结论 槲皮素与川芎嗪联合用药可明显抑制Lewis肺癌移植瘤的生长，其作用机制与抑制微血管生成、抑制细胞增殖和促进细胞凋亡有关。     

西河柳中槲皮素与异鼠李素在植物体内分布及随季节变化

目的:建立西河柳中槲皮素与异鼠李素的HPLC测定方法;研究槲皮素与异鼠李素在西河柳不同部位的分布及随季节变化的规律。方法:以NUCLEODUR100-5C_(18)柱(150 mm×4.6 mm,5μm),甲醇-0.4%磷酸溶液(50:50)为流动相,流速为0.8ml·min~(-1),柱温为30℃,检测波长为360 nm。结果:槲皮素与异鼠李素线性范围分别为:0.17～1.01μg(r=0.999 7)和0.19～0.95μg(r=0.999 6),回收率分别为:102.3%,100.7%RSD4.0,3.1%;西河柳中槲皮素与异鼠李素含量随季节的变化而变化,且不同部位有不同的含量。结论:该方法可用于控制西河柳药材质量;西河柳中槲皮素与异鼠李素含量按春、夏、秋次序依次降低,在嫩技叶中含量最高。     

GSTM1 and GSTT1 polymorphism influences protection against induced oxidative DNA damage by quercetin and ascorbic acid in human lymphocytes in vitro

Antioxidants are of major importance in the protection against cellular oxidative damage caused by endogenous as well as exogenous free radicals. This study aims to establish the impact of genetic polymorphisms in GSTM1 and GSTT1, which encode for enzymatic antioxidative defence, on H₂O₂-induced oxidative DNA damage and on the effectiveness of quercetin and ascorbic acid in preventing this induced damage in human lymphocytes. Lymphocytes from 12 healthy volunteers were pre-incubated either with 10 μM of quercetin or with 10 μM of ascorbic acid, and exposed to 25 μM H₂O₂ for 1 h. The induction of oxidative DNA damage was quantified using the Comet assay. Genotyping of these 12 subjects showed that six individuals were GSTM1+ and six were GSTM1−; eight were GSTT1+ and four GSTT1−.

Results

Baseline levels of oxidative DNA damage did not differ between GSTM1 or GSTT1 variants and their respective wild types. Also with respect to ex vivo induced levels of oxidative DNA damage, no significant difference was seen between variants and wild types of both genotypes. The protection against H₂O₂-induced oxidative DNA damage by quercetin was significantly higher in GSTT1 wild types than in GSTT1 variants (57% and 9% decrease, respectively; p = 0.01); furthermore, GSTT1 wild types were protected against induced oxidative DNA damage by ascorbic acid pre-incubation while GSTT1 variants showed an increase of damage (16% decrease vs. 91% increase; p = 0.01). For GSTM1 variants and wild types, observed differences in protective effects of quercetin or ascorbic acid were not statistically significant. Overall, quercetin proves to be better in protecting human lymphocytes in vitro against oxidative DNA damage upon H₂O₂ challenge than ascorbic acid.     

糖尿病新型分子靶点葡萄糖-6-磷酸酶活性的检测及应用

目的:研究利用葡萄糖脱氢酶偶联反应测定葡萄糖-6-磷酸酶(G-6-Pase)的活性,并推荐其作为一种常用的实验室检测方法。方法:以胶原酶原位灌注消化的方法分离大鼠肝细胞,用含10?S的1640培养液进行原代培养。待细胞贴壁后分别换用新鲜的含葡萄糖和不同浓度栎精的培养液培养16 h,随后利用葡萄糖脱氢酶偶联反应测定酶的活性。结果:各组G-6-Pase的活性不全相同,其差别具有统计学意义(F=114.423,P<0.05);高糖组与对照组相比较,G-6-Pase的活性明显增加(P<0.05);不同浓度栎精组G-6-Pase的活性下降,均低于高糖组(P<0.05),但其组间差异无统计学意义(P>0.05),没有呈现出剂量依赖性变化。结论:利用葡萄糖脱氢酶偶联反应测定葡萄糖-6-磷酸酶活性,是目前值得推崇的一个检测速度较快、结果较稳定的方法。此外,栎精能够有效逆转高糖诱导的G-6-Pase活性增加,利用它对于G-6-Pase活性的干预作用可能改善糖尿患者的高血糖状态。     

槲皮素对2型糖尿病患者外周血单个核细胞DNA损伤体外修复的观察

目的观察2型糖尿病(DM)患者氧化/抗氧化状态、外周血单个核细胞(PBMCs)DNA损伤情况及槲皮素的体外修复作用。方法采用单细胞凝胶电泳技术检测39例2型DM合并血管并发症、29例2型DM无并发症患者PBMCsDNA损伤情况(用彗星率表示),与26例健康对照比较。检测受试者血浆总抗氧化能力(TAC)、丙二醛(MDA)及巯基(SH)含量。观察槲皮素对2型DM患者PBMCsDNA损伤的体外修复作用。结果2型DM无并发症组PBMCs彗星率及血浆MDA含量明显高于健康对照组(P均<0.01),血浆SH含量、TAC明显低于健康对照组(P均<0.01);2型DM血管并发症组彗星率及MDA含量高于无并发症组(分别为P<0.01和P<0.05),TAC低于无并发症组(P<0.05)。2型DM无并发症组及血管并发症组患者彗星率与MDA含量呈正相关(r分别为0.446和0.504,P<0.05和P<0.01),与TAC呈负相关(r分别为-0.418和-0.399;P均<0.05)。体外修复显示:10μmol/L槲皮素作用4h显著降低了2型DM患者PBMCs彗星率(P均<0.01)。结论2型DM患者体内存在氧化/抗氧化失衡、DNA氧化损伤,血管并发症组重于无并发症组。氧化应激可能参与了2型DM患者血管并发症的发生发展。     

Differential effects of dietary flavonoids on reactive oxygen and nitrogen species generation and changes in antioxidant enzyme expression induced by proinflammatory cytokines in Chang Liver cells.

This study was aimed to investigate the differential protective effect of dietary flavonoids against oxidative stress induced by proinflammatory stimuli in parenchymal liver cells. Chang Liver cells were incubated with a cytokine mixture (CM) supplemented with the flavonols quercetin and kaempferol, the flavanone taxifolin and the flavone apigenin (5-50 microM). Concentrations of oxidised and reduced glutathione, generation of different ROS/RNS, and expression of antioxidant enzymes were measured. Oxidised glutathione concentration and the oxidised/reduced glutathione ratio were increased by the CM. These effects were significantly prevented by quercetin, kaempferol and taxifolin at all tested concentrations. Effects of apigenin reached a lesser extent and were not significant at 25 microM. Treatment with quercetin and kaempferol prevented the production of peroxides, superoxide anion and nitric oxide induced by CM. Taxifolin 50 microM and apigenin 25-50 microM caused a significant increase in peroxides and nitric oxide generation. Protein concentration of the different antioxidant enzymes was generally reduced by kaempferol and quercetin in comparison to CM, although quercetin 25 and 50 microM increased Mn SOD protein concentration. GPx protein level was significantly increased by apigenin 25 and 50 microM. Changes in mRNA tended to be parallel to those in protein concentration. Our study reveals that important differences exist between flavonoids with different structural features in their capacity to abrogate the generation of different ROS/RNS, and suggests that the modulation of antioxidant enzymes by flavonoids may be also important in their antioxidant effects in liver cells.     

HPLC法测定复方银杏叶胶囊中总黄酮苷的含量

目的:建立以高效液相色谱法测定复方银杏叶胶囊中总黄酮苷含量的方法。方法:色谱柱为Shiseido MG C18(250mm×4.6mm,5μm),流动相为甲醇-0.4%磷酸(68∶32),检测波长为378nm,以外标法定量。结果:槲皮素、山柰酚、异鼠李素的检测浓度分别在6～120μg·mL-1(r=0.99997)、3～60μg·mL-1(r=0.99998)、1～20μg·mL-1(r=0.99996)范围内与各自峰面积积分值呈良好线性关系。3批样品中的总黄酮苷含量分别为10.14、10.01、10.07mg。结论:本法快速、准确、重现性好,可用于复方银杏叶胶囊的质量控制。     

Experimental and mesoscale computational dynamics studies of the relationship between solubility and release of quercetin from PEG solid dispersions

The flavonol quercetin is potentially clinically relevant for its antimicrobial, beneficial cardiovascular effects, cancer treatment amongst others. However, its successful therapeutic application is severely curtailed by its poor water solubility and poor absorption following oral administration. In this study, solid dispersions of quercetin in poly(ethylene glycol) (PEG) at various compositions demonstrated an increase in the solubility, however with time, dissolution profiles show a decrease in dissolved flavonol concentration. The mechanism by which this decrease in solubility occurs was studied experimentally as well as by computational mesocscale particle dynamics simulations. The results suggest that phase separation of the polymer and flavonol during release from the solid dispersion is responsible for the time-dependent decrease in dissolved quercetin. It is suggested that the increase in release of quercetin in a PEG solid dispersion would only be beneficial if it were administered at the site of absorption, e.g. rectal administration, to ensure absorption prior to phase separation. The solid dispersions presented here would greatly improve the pharmaceutical availability of the flavonol at the site of absorption. Computational mesoscopic modeling was successfully applied to study the solid dispersions and corroborate experimental findings.     

HPLC法测定槲皮素微乳的含量

目的:建立高效液相色谱法测定槲皮素微乳中槲皮素含量的方法.方法:色谱柱为Zorbax Eclipse XDB-C18(250 mm×4.6 mm,5 μm),流动相为甲醇-0.4%磷酸水溶液(50:50),流速1.0 ml·min-1,检测波长372 nm,柱温25℃.结果:槲皮素在11.8~118.0 μg·ml-1浓度范围内线性关系良好(r=0.999 7),平均回收率为97.6%,RSD为1.69%(n=9).结论:该方法准确、便捷、重复性好,可用于槲皮素微乳的含量测定.