Modulation of drug resistance in staphylococcus aureus by a kaempferol glycoside from herissantia tiubae (malvaceae)

In an ongoing project to evaluate natural compounds isolated from plants from the Brazilian biodiversity as modulators of antibiotic resistance, kaempferol‐3‐O‐β‐d‐(6″‐E‐p‐coumaroyl) glucopyranoside (tiliroside), isolated from Herissantia tiubae (Malvaceae) was investigated using the strain SA‐1199B of Staphylococcus aureus, which overexpresses the norA gene encoding the NorA efflux protein which extrudes hydrophilic fluorquinolones and some biocides, such as benzalkonium chloride, cetrimide, acriflavine and ethidium bromide. The minimum inhibitory concentrations (MICs) of the antibiotics and biocides were determined by the microdilution assay in the absence and in the presence of sub‐inhibitory concentration of tiliroside. Although tiliroside did not display relevant antibacterial activity (MIC = 256 µg/mL), it modulated the activity of antibiotics, i.e. in combination with antibiotics a reduction in the MIC was observed for norfloxacin (16‐fold), ciprofloxacin (16‐fold), lomefloxacin (four‐fold) and ofloxacin (two‐fold), and an impressive reduction in the MICs for the biocides (up to 128‐fold). The results presented here represent the first report of a kaempferol glycoside as a putative efflux pump inhibitor in bacteria. The present finding indicates that H. tiubae (and broadly Malvaceae) could serve as a source of plant‐derived natural products that modulate bacterial resistance, i.e. a source of potential adjuvants of antibiotics. Copyright © 2009 John Wiley & Sons, Ltd.     

檵木中银椴苷的提取及测定

目的 研究檵木中银椴苷的提取分离及对银椴苷进行质量控制。方法 采用乙醇回流法提取药材,然后经过大孔树脂、减压硅胶柱色谱、洗脱,得到银椴苷单体,采用Cosmosil C₁₈柱（250 mm×4.6 mm,5 μm）,流动相为甲醇-0.1%磷酸水溶液（55∶45）,检测波长为320 nm,体积流量1.0 mL/min。结果 银椴苷能够很好地分离出来,质量分数为98%,银椴苷在0.041～0.513 μg呈良好的线性关系（r＝0.999 7）;平均回收率为100.05%,RSD为1.50%。结论 运用此方法能将银椴苷较好地提取分离,同时测定方法不仅操作简单、准确,且重复性好,可用于檵木中银椴苷的测定。     

HPLC测定仙鹤草中山奈酚-3-O-(6-p-香豆酰基)-β-D-吡喃葡萄糖苷含量

目的:建立高效液相色谱法测定仙鹤草药材中山奈酚-3-O-(6-p-香豆酰基)-β-D-吡喃葡萄糖苷含量的方法。方法:采用依利特ODS C18色谱柱(4.6 mm×250 mm,5μm);流动相为乙腈-0.05%磷酸(30∶70),流速为1.0 mL·min-1,柱温为30℃;检测波长315 nm。结果:山奈酚-3-O-(6-p-香豆酰基)-β-D-吡喃葡萄糖苷的线性范围为1.272⁸.904μg·mL-1(r=0.9999);加样回收率为100.5%,RSD为1.94%。结论:该方法简便易行、准确、重复性好,为仙鹤草药材的质量控制提供了依据。     

地桃花的本草考证、生药学研究及其有效成分定量测定

目的 对地桃花Urenalobata进行本草考证、生药学分析及有效成分测定。方法 通过查阅文献厘清地桃花的历史使用沿革及植物分布情况,野外实地调研地桃花的植物基原,采集并制作腊叶标本,通过原植物形态、药材性状、显微特征等方法进行生药学研究;采用Waters e2695型液相色谱仪,CAPCELL PAK MGⅡC18色谱柱（250 mm×4.6 mm,5μm）,乙腈-0.1%甲酸溶液为流动相,体积流量1.0 mL/min,梯度洗脱,柱温30℃,PDA检测器,检测波长315 nm,建立地桃花药材中N-反式-阿魏酰酪胺和银锻苷的HPLC测定方法。结果 对地桃花药材的性状及显微特征进行了归纳,建立的测定方法稳定性和重复性良好,N-反式-阿魏酰酪胺和银锻苷线性范围0.999～79.890、1.068～85.420μg/mL,R2>0.999,平均回收率95.3%、97.1%。10批样品N-反式-阿魏酰酪胺、银锻苷质量分数为0.003%～0.045%、0.016%～0.046%。结论 建立的方法能够有效鉴别地桃花药材,为完善地桃花药材质量标准和地桃花药材收购提供依据。     

RP-HPLC测定芫花中山柰酚-3-O-β-D-(6"-p-香豆酰)-吡喃葡萄糖苷的含量

目的:对芫花中山柰酚-3-O-β-D(6"-p-香豆酰)吡喃葡萄糖苷(tiliroside)的含量进行测定.方法:采用反相高效液相色谱,ZORBAX XDB C_(18)色谱柱(4.6mm×250 mm,5 μm);流动相为乙腈(A)-0.1%醋酸水溶液(B),梯度洗脱,0～18 min A:B26:74,18～33 mim A:B 80:20;流速1.0 mL·min~(-1),检测波长310 nm,柱温25℃.结果:山柰酚-3-O-β-D(6"-p-香豆酰)-吡喃葡萄糖苷在进样量0.1～5.0 μg与峰面积呈良好的线性关系,r=0.999 9(n=6).山柰酚-3-O-β-D(6"-P-香豆酰)-吡喃葡萄糖苷的平均回收率101:50%,RSD 0.90%(n=6).结论:该方法可准确地测定芫花中山柰酚-3-O-β-D(6"-p-香豆酰)-吡喃葡萄糖苷,方法精密度高、简便、快速.     

覆盆子中有效成分椴树苷的波谱学研究

目的确证覆盆子中有效成分椴树苷的波谱归属。方法采用硅胶柱色谱和凝胶柱色谱Sephadex LH-20进行分离纯化,通过理化方法和波谱数据进行结构鉴定。结果利用一维、二维核磁共振,解析椴树苷的结构。结论确定了椴树苷的1H-NMR、13C-NMR的归属。     

Flavonoids from the leaves of Litsea japonica and their anti-complement activity

Four flavonoids, epicatechin (1), afzelin (2), quercitrin (3), and tiliroside (4), were isolated from the leaves of Litsea japonica (Thunb.) Jussieu (Lauraceae). The structures of compounds were identified by comparing their chemical and spectral data with those previously reported. The flavonoids (1-4) were tested for their anti-complement activity against classical pathway of complement system. Compounds 2-4 showed inhibitory activity against complement system with IC50 values of 258, 440, and 101 microm, respectively, whereas 1 was inactive. For the evaluation of the structure-activity relationship of 5,7-dihydroxyflavones, myricitrin (5) from Juglans mandshurica also tested for it's anti-complement activity and is inactive in this assay system. Furthermore, compounds 2, 3, and 5 were hydrolyzed with naringinase to give kaempferol (2a), quercetin (3a), and myricetin (5a), and these were also tested for their activity. Of the three aglycones, 2a exhibited anti-complement activity with an IC50 value of 730 microM, while 3a and 5a were inactive. The inhibitory potencies of 2, 2a, 3, 3a, 5, and 5a against complement activity increased in inverse proportion to number of free hydroxyls on B-ring of 5,7-dihydroxyflavone. Of the compounds tested, 4 showed the most potent inhibitory activity against the complement system.     

益母草化学成分的分离与鉴定Ⅱ

目的 分离和鉴定益母草Leonurus japonicus Houtt.的水提物和醇提物化学成分。方法 利用大孔树脂、硅胶柱色谱和HPLC进行分离纯化，根据理化性质和光谱数据进行结构鉴定。结果 得到4个化合物，分别鉴定为丁香酸(syringic acid,1)、megastigrnane(2)、tiliroside(3)、益母草碱(1eonurine，4)。结论 化合物1和2为首次从该属植物中分离得到。     

基于网络药理学和分子对接的黄蜀葵花干预糖尿病肾病的作用机制研究

目的 运用网络药理学和分子对接的方法研究黄蜀葵花干预糖尿病肾病的多成分、多靶点、多通路作用机制,旨在为其基础研究及临床应用提供依据.方法 通过ETCM、HERB数据库结合文献报道,筛选黄蜀葵花活性成分,并通过PharmMapper数据库预测其潜在靶点,建立靶点数据库.通过Genecards、OMIM、Drugbank、...     

基于UHPLC-Q-Orbitrap HRMS分析覆盆子不同部位的化学成分及其9种成分含量的快速测定

目的 采用UHPLC-Q-Exactive Orbitrap HRMS法对覆盆子Rubus chingii不同部位（小核果和花托）化学成分进行分析鉴定,并建立快速测定覆盆子中9种成分含量的方法。方法 采用Acquity UPLC HSS T3(100 mm×2.1 mm,1.8μm)色谱柱,以0.1%甲酸水与乙腈为流动相,梯度洗脱;覆盆子化学成分鉴定时采用正负离子Full MS/dd-MS2模式,通过化合物的一级、二级质谱信息,结合对照品比对确认,进行覆盆子不同部位主要化学成分的快速、精准识别。采用ACQUITY BEH C18(50 mm×2.1 mm,1.7μm)色谱柱在负离子Full MS/SIM模式,建立快速测定覆盆子不同部位中9种成分（没食子酸、芦丁、鞣花酸、金丝桃苷、山柰酚-3-O-芸香糖苷、紫云英苷、椴树苷、槲皮素和山柰酚）含量的UHPLC-Q-Exactive OrbitrapHRMS方法,并测定其含量。结果 从覆盆子小核果和花托中共鉴定122种化学成分,包括黄酮类66种、有机酸类28种、萜类24种、其他类4种。成功建立一种6 min完成覆盆子中9种成分含量测定的方法,...