Simultaneous determination of kaempferol and quercetin in Heteropogon Contortus (L.) Beauv. by validated high-performance thin layer chromatography

Presently, the fingerprint analysis of kaempferol and quercetin has been developed simultaneously via High-Performance Thin Layer Chromatography (HPTLC) from leaves, stem, and inflorescence of Heteropogon contortus. The HPTLC method for kaempferol and quercetin was optimized with the elution of toluene: ethyl acetate: formic acid (7:3:0.5 v/v) as a mobile phase. The fingerprint analysis of kaempferol and quercetin was developed at R_f values of 0.39 and 0.24, respectively, and densitometric evaluation was done at 254 nm. The linear regression data for the calibration curve of both the compounds show a good linear relationship in the concentration range of 2–12 nanogram spot^?1. The suggested method has been validated in terms of limit of detection (LOD) and limit of quantification (LOQ), precision, specificity, sensitivity, and accuracy. Present results show that maximum amount of kaempferol and quercetin is found in leaf extracts (35.80 and 17.01 milligram/gram of dry weight, respectively) of H. contortus.     

月月红中槲皮素·山奈酚的定性与定量研究

[目的]通过对月月红中槲皮素、山奈酚的定性定量研究,拟建立其HPLC分析方法,为进一步研究民族民间药物月月红的药效学奠定基础。[方法]采用化学定性法确定月月红不同部位中的主要化学组分;色谱条件：Hypersil DJZ C18色谱柱（4.6 mm×200.0 mm,5μm）;流动相：甲醇-0.4%磷酸（60∶40,V/V）;检测波长：368 nm;流速：1.000 ml/min;柱温：30℃;理论塔板数按山奈酚和槲皮素峰计算不低于3 000,外标法计算。[结果]槲皮素在0.081 6~0.489 6μg线性关系良好（R2=0.999 6）,平均回收率为101.6%,RSD为0.87%;山奈酚在0.069 6~0.417 6μg线性关系良好（R2=0.999 6）,平均回收率为96.8%,RSD为1.01%。月月红叶中槲皮素为0.038 2%,茎为0.005 2%,全株为0.010 5%;月月红叶中山奈酚含量为0.027 6%,茎为0.002 1%,全株为0.009 6%。[结论]HPLC分析方法稳定、重复性较好;月月红不同部位均含有槲皮素、山奈酚,且叶含量高于全株和茎。     

固相萃取—高效液相色谱法测定兔血浆中山奈素的含量

兔的血浆样品经过β-葡萄糖醛酸酶和硫酸酯酶酶解、提取、C18固相萃取小柱富集净化后,在Agilent SB-C18柱(250mm×4.6 mm,5μm)上,以甲醇-0.4%磷酸(55∶45)为流动相,流速为1.0 mL.min-1,检测波长为360 nm,对山奈素进行测定的结果表明,血浆样品的最佳酶解条件为:β-葡萄糖醛酸酶和硫酸酯酶的终用量分别为400和20 U.mL-1,酶解时间为2h;血浆中山奈素含量的线性范围为0.019-0.608μg.mL-1,方法回收率为80.23%-84.27%,日内和日间精密度的RSD分别≤7.32%、10.17%.可见,本试验建立的高效液相色谱测定方法可以准确、灵敏地测定兔血浆中山奈素的含量,适用于山奈素血药含量检测和药代动力学研究.     

大麦籽粒中4种主要黄酮类化合物的HPLC测定方法研究

为给大麦主要黄酮类化合物含量的快速测定及开发利用提供依据,对利用高效液相色谱技术(HPLC)分离和同时测定大麦中黄酮类化合物儿茶素、杨梅素、槲皮素、山奈酚含量的方法进行了研究.结果表明,采用HPLC同时测定4种大麦黄酮类化合物的优化色谱条件为:YMC-Pack ODS AM-303 (5 μm, 250 mm_4.6 mm i.d.)色谱柱;流动相A-0.1%冰乙酸水溶液,B-乙睛,梯度洗脱;流速0.8 mL/min,进样量10 μL.儿茶素、杨梅素、槲皮素、山奈酚分别在0.063～2.000 μg (R2=0.9999)、0.034～1.100 μg (R2=0.9998)、0.025～0.800 μg (R2=0.9993)、0.018～0.560 μg (R2=0.9995)成良好的线性关系,加样回收率分别为96.88%(RSD=1.30%)、98.30%(RSD=0.57%)、96.29%(RSD=1.20%)、101.59%(RSD=0.73%). 测定方法简便、快捷,结果准确、重复性好,可用于大麦4种主要黄酮类化合物的同时测定.     

大麦花后四种主要黄酮物质含量的动态变化

为了解开花后大麦不同器官黄酮类物质的变化,以富含黄酮的大麦品系94-19-1为材料,在开花后10、25和40d时,分析测定了其根、茎、叶和穗中儿茶素、杨梅素、槲皮素和山奈酚四种主要黄酮类物质的含量。结果表明,在开花10~40d,四种黄酮类物质的含量在根、茎、叶和穗部均随着时间的变化而变化,且趋势不同,其总含量在根和叶中以花后25d最高,在茎和穗部中呈增加趋势。不同器官中四种黄酮物质含量在同一时期均存在差异,且其总含量都以穗部最高。     

Flavonoids from Acalypha indica

Four known kaempferol glycosides, mauritianin, clitorin, nicotiflorin and biorobin, have been isolated from the flowers and leaves of Acalypha indica. Some formerly published NMR data were corrected.     

HPLC测定不同树龄杜仲叶中黄酮类成分的含量

[目的]建立高效液相色谱同时测定不同树龄杜仲叶中绿原酸、芦丁、槲皮素和山萘酚含量的方法。[方法]采用Shim—packVP—ODS（4．6×150mm,5μm）色谱柱,以甲醇-0．4％磷酸水溶液为流动相进行梯度洗脱,流量1．0ml/min,用二极管阵列检测器扫描检测,以保留时间结合待测物质的紫外吸收光谱进行定性分析。采用外标法进行定量分析,检测波长为360nm,柱箱温度为40℃。[结果]绿原酸的线性范围为4．63～92．65μg,r=0．9998,回收率为98％～101．5％;芦丁的线性范围为0．714～14．285μg／ml,r=0．9999,回收率为96％-98．4％;槲皮素的线性范围为0．101～2．066μg／ml,r=0．9970,回收率为94％～101％;山萘酚的线性范围为0．043～0．886μg／ml,r=0．9980,回收率92％～96％。[结论]对不同树龄杜仲叶中4种有效成分含量用方差分析进行多重比较,从绿原酸含量方面考虑．三年树龄杜仲叶采收最佳。     

高效液相色谱法测定消浊通淋颗粒中槲皮素和山奈素的含量

[目的]建立消浊通淋颗粒中槲皮素和山奈素含量的测定方法。[方法]采用高效液相色谱法,色谱柱为岛津VP-ODS c（250.0mm×4.6 mm5,μm）,流动相为甲醇-0.4%磷酸水溶液（48∶52）,流速为1.1 ml/min,检测波长为360 nm。[结果]槲皮素在0.075 2～0.270 5μg范围内呈现良好线性关系,加样回收率为99.5%,RSD为0.30%（n=6）;山奈素在0.113 0～0.406 8μg范围内呈现良好线性关系,加样回收率为99.7%,RSD为0.34%（n=6）。[结论]高效液相色谱法测定消浊通淋颗粒中槲皮素和山奈素的含量操作简单、准确、重复性好、精密度高,可以作为消浊通淋颗粒的质量控制方法。     

Inhibition of glucose intestinal absorption by kaempferol 3-O-α-rhamnoside purified from Bauhinia megalandra leaves

Glucose intestinal absorption (GIA) is one of the factors that increase glycemia. Its reduction could be an important factor in decreasing hyperglycemia in diabetic patients. It has been shown that the aqueous extract of Bauhinia megalandra leaves inhibits GIA. In the present study we identified a compound present in the extract of B. megalandra responsible for the biological effect. The methanol extract of B. megalandra leaves was fractionated using different solvents, and high-speed counter-current chromatography yielding two pure compounds identified by ¹H NMR and ¹³C NMR as kaempferol 3-O-α-rhamnoside and quercetin 3-O-α-rhamnoside. The first one increased the K_M without changes in the V_MAX of GIA. In addition it exerted an additive inhibitory effect, on GIA, when combined with phlorizin. We suggest that kaempferol 3-O-α-rhamnoside is a competitive inhibitor of intestinal SGLT1 cotransporter.     

Comparative pharmacokinetics and bioavailability studies of quercetin, kaempferol and isorhamnetin after oral administration of Ginkgo biloba extracts, Ginkgo biloba extract phospholipid complexes and Ginkgo biloba extract solid dispersions in rats

The aim of this study was to improve the oral bioavailability of Ginkgo biloba extract (GBE) through preparing G. biloba extract phospholipid complexes (GBP) and G. biloba extract solid dispersions (GBS). Firstly we prepared the GBP and GBS and studied their physicochemical properties by differential scanning calorimetry (DSC), powder X-ray diffraction (XRD) and dissolution. Then we studied the pharmacokinetic characteristics and bioavailability in rats. The results showed that the bioavailability of quercetin, kaempferol and isorhamnetin in rats was increased remarkably after oral administration of GBP and GBS comparing with GBE. The bioavailabilities of GBP increased more than that of GBS.