1、饮片进行指纹图谱研究,为山茱萸饮片质量控制提供科学依据。1 仪器与试药Agilent型高效毛细管电泳仪(型号:G1600 AX ),包括惠普化学工作站,DAD 检测器,自动进样器;BUCHI 旋转蒸发仪(型号:Rotavapor R-3);AG 285电子天平;PHS-3C型pH计(上海康仪仪器有限公司);KQ-500E 型超声波清洗器(昆山市超声仪器有限公司)。莫诺苷对照品(江苏省药物研究所制备,纯度98%);马钱苷对照品(中国药品生物制品检定所,批号:111640-200503)。其他化学试剂均为分析纯,实验用水为超纯水。山茱萸饮片均经作者鉴定为山茱萸科植物山茱萸 Cornus offic
2、inalis Siebl. et Zucc. 的干燥成熟果肉,其中S1-S3由浙江中医药大学中药饮片厂按2005年版中国药典加工制得,S4-S5由亳州市中药饮片厂按2005年版中国药典加工制得,来源见表1。表1 样品来源编 号来 源批 号酒制品S1河南080625S2浙江080627S3陕西080626S4安徽081201S5山西S6南京国医堂提供S7S8南京百草堂提供S9S10传统中医门诊部提供生S11Y080626S12Y0806252 方法与结果2.1 电泳条件:未涂渍标准熔融石英毛细管75 64.5cm,有效长度56cm(Agilent科技有限公司);检测波长:压力进样:50 mbar
3、8 s;分离电压:10 kV;毛细管温度:运行缓冲液50 mmol/L 硼砂-40 mmol/L SDS-5%乙腈 (pH 9.5)。毛细管使用前以0.1 mmol/L 氢氧化钠溶液、超纯水和运行缓冲液依次通过压力冲洗5,10,5 min。2.2 供试品溶液的制备:取山茱萸粉末1 g(过50目筛),至100 mL具塞三角瓶中,加80甲醇50 mL,精密称定,浸渍1 h后,超声提取60 min,放冷,再精密称定,用80甲醇补足其重量,摇匀,滤过。取滤液30 mL,水浴蒸干,用80甲醇溶解并定容至5 mL,摇匀,以0.45 m微孔滤膜过滤,作为供试品溶液。2.3 方法学考察2.3.1 精密度试验:
4、取同一供试品溶液(S1-河南),连续进样5次,共有指纹峰的相对迁移时间RSD0.95%,共有峰相对峰面积RSD2.10%。2.3.2 重现性试验:取同一样品(S1-河南),按2.2 供试品溶液制备方法项下,平行制备山茱萸饮片供试液5份,在高效毛细管电泳仪上进样分析,共有峰相对迁移时间RSD1.80%,共有峰相对峰面积RSD2.40%。2.3.3 稳定性试验:取一新制备的供试品溶液(S1-河南)于0 h、2 h、4 h、8 h、12 h、24 h测定其峰面积,共有峰相对迁移时间RSD3.15%,共有峰相对峰面积RSD2.99%。2.4 指纹图谱的建立将供试品溶液(S1-S10)分别放入自动进样的
5、样品管中,按选定的测试条件进行检测。在上述实验条件下,测定所有供试品HPCE色谱图。根据不同批次供试品测定结果所给出的峰数、峰值(积分值)和峰位(相对迁移时间)等相关参数,进行分析、比较,制定优化的指纹图谱。(图1)图1 山茱萸饮片的HPCE指纹图谱1-莫诺苷 3-马钱苷2.5 指纹图谱分析2.5.1 共有指纹峰标定经对供试品HPCE色谱图的分析、比较,共标定9个共有峰,作为指纹图谱的特征峰,1、3号峰与对照品对照分别鉴定为莫诺苷、马钱苷。以3号峰马钱苷为参照峰,分别求出各共有峰与之相比的值(调整迁移时间之比)和各共有峰的相对峰面积(峰面积之比)。(表2)表2 山茱萸HPCE指纹图谱中共有峰的
6、相对迁移时间值和相对峰面积峰号相对峰面积10.871.321.200.970.821.361.801.870.760.801.6220.930.070.090.370.170.240.250.230.160.29341.060.210.610.740.260.380.540.480.360.3351.100.390.270.500.190.220.180.2061.190.310.410.1471.240.340.430.470.440.400.3581.280.2891.840.121.210.302.5.2 指纹图谱的聚类分析:选择山茱萸HPCE指纹图谱中9个比较明显的共有峰,根据表1中的
7、数据,用SPSS软件中的hierarchical cluster analysis对10个山茱萸样品进行聚类分析,所用聚类方法为average linkage (between groups),距离公式为square euclidean distance,得不同样品山茱萸的聚类分析图。(图2)图2 山茱萸饮片HPCE指纹图谱的聚类分析图结果显示,当距离标尺在1时,样品S8、S9,S6、S7分别归为一类,当距离标尺在3时,样品S6、S7与S10归为一类,当距离标尺在4时,样品S2、S3归为一类,当距离标尺在5时,样品S8、S9与S4归为一类,当距离标尺在9时,样品S8、S9、S4与S2、S3,样
8、品S6、S7、S10与S1各归为一类,当距离标尺在18时,S8、S9、S4、S2、S3与S6、S7、S10、S1归为一类,当距离标尺在25时,所有样品才归为一类。2.5.3 色谱峰的重叠率:以山茱萸标准谱图(R)为基准,按以下公式计算待测样品与标准样品共有的峰数2/(待测样品与标准样品峰数和)100,110号样品色谱峰的重叠率依次为:81.82%,75%,78.26%,72%,78.26%,81.82%,81.82%,75%,78.26%,75%。2.5.4 相似度评价:将测试数据导入国家药典委员会“中药指纹图谱相似度评价系统(2004A)”软件,经校正选峰,设定匹配模式,将色谱峰自动匹配,生
9、成对照图谱(图3),进行色谱峰差异性评价和整体相似性评价。各相似度值如下:S1-0.922,S2-0.873,S3-0.799,S4-0.646,S5-0.932,S6-0.807,S7-0.817,S8-0.911,S9-0.912,S10-0.918。 图3 山茱萸饮片HPCE指纹图谱共有模式2.5.5 山茱萸炮制前后HPCE谱比较对河南产山茱萸生品(S1)与相对应的酒制品(S12)的HPCE谱进行比较,发现山茱萸炮制前后均具有上述9个共有峰,但共有峰的相对峰面积具有一定差异,山茱萸(河南产)酒制品与生品的相似度为0.874。(图4)图4 山茱萸炮制前后HPCE谱比较S1-河南(制品),S
10、12-河南(生品) Fig.4 Comparison of the HPCE fingerprints betweenthe rude product and the processed S1.Henan(the processed) S12. Henan(the rude)实验结果表明,不同产地加工或商品山茱萸酒制品的HPCE指纹谱具有一定差异,河南、山西 、南京百草堂、南京百草堂、传统中医门诊部山茱萸饮片指纹谱相似度较好(0.911),其它来源的山茱萸饮片除陕西、安徽外,相似度均在0.8以上;山茱萸炮制前后共有峰相同,但相对峰面积有异,山茱萸(河南产)酒制品与生品的相似度为0.874,其炮
11、制过程中共有峰相对峰面积变化规律有待进一步探讨。3 讨论3.1 电泳条件优化毛细管电泳的分离选择性的分离效率主要取决于缓冲液的类型、酸度及浓度,缓冲液添加剂、电压、温度等也有一定影响。实验对山茱萸饮片中的獐牙菜苷、马钱苷进行了分离研究,重点考察了缓冲溶液浓度、表面活性剂浓度、有机溶剂、缓冲溶液pH、运行电压、运行温度等实验条件对分离的影响。3.1.1 缓冲液体系选择 本实验考察了硼砂、乙酸铵、硼砂-SDS及硼砂-SDS-乙腈4个体系的缓冲溶液,发现选用硼砂缓冲液或乙酸铵缓冲液时,獐牙菜苷和马钱苷分离度很差,基本不能分开,但当在硼砂缓冲液中加入SDS,分离有所改善,但獐牙菜苷和马钱苷的分离度达不
12、到Rf1.5的要求,故需要加入有机溶剂以增加样品溶液中非水物质的溶解度,同时也会影响胶束相和流动相的性质,进而改变溶质在水相和胶束相的分配比例,有利于提高分离效率,当加入乙腈后分离度变好,Rf1.5,故选择硼砂-SDS-乙腈缓冲体系。3.1.2 硼砂浓度的影响 缓冲液浓度是影响被测物迁移时间和分离度的一个重要因素,这是因为缓冲液的浓度决定了溶液的粘度系数、溶质的扩散系数以及毛细管内壁的电位。实验考察了850 mmolL-1的硼砂缓冲溶液,结果发现迁移时间和分离度随着缓冲液浓度的升高而增大。当缓冲液浓度到50 mmolL 1时对照品的峰形和分离度最佳。3.1.3 SDS浓度的影响 考察了10、1
13、5、20、25、30、35、40 mmol/L 7个SDS浓度下的分离情况,当SDS浓度为40mmol/L 时,山茱萸中成分的分离情况较理想,且被测物的峰形及迁移时间较好。3.1.4 乙腈浓度的影响 在胶束电泳(MECC)中,乙腈作为有机添加剂,有利于提高憎水溶质在水相中的溶解性,并且会影响胶束相和流动相的性质,进而改变了溶质在水相和胶束相的分配比例,有利于提高分离效率。实验考察了5%、10%、15%、20%(V/V) 乙腈浓度对山茱萸中成分分离的影响,发现乙腈浓度在5%时,峰形较好,且各组分的分离也达到Rf 1.5。3.1.5 缓冲溶液pH的影响 缓冲液的pH直接影响毛细管表面的电势,从而影
14、响电渗流的方向和速度,同时溶液的pH也决定样品中各组分分子的表面电荷数,从而影响组分的迁移时间和分离度,故本实验对缓冲液的pH进行了优化选择以获得较好的分离条件。考察了pH 8.89.5的缓冲液,发现随着pH值的增大,各组分的分离度增加而迁移时间延长,峰高亦增高,当PH为9.5时被测物可达到基线基本分离。3.1.6 运行电压的影响 实验考察了分离电压在1022kV的条件下对各组分迁移时间的影响,结果表明分离电压增高,组分迁移时间缩短,分离效果较差,当分离电压为10 kV时, 山茱萸中成分分离效果较好。3.1.7 运行温度的影响 毛细管电泳中,运行温度也影响电场的强度,从而影响电渗流速度和带电物
15、质的迁移速率,影响分析物的迁移时间。实验考察了运行温度1530 的条件下对各组分迁移时间的影响,实验结果表明运行温度越高,组分的迁移时间越短,当运行温为18 时样品的各组分分离效果好,且分析时间缩短。3.1.8 检测波长的选择 采用二极管阵列检测器对检测波长进行考察,记录并比较不同波长的色谱图,根据分析物的紫外吸收特征,发现在240 nm波长处,被测物质均有较好的吸收,故选择240nm为检测波长。3.2 共有峰面积与总峰面积比值的计算:对各样品的峰面积进行统计,计算各样品指纹图谱中的9个共有峰的总面积各占总峰面积的比值。结果显示所有样品的共有峰总面积占总峰面积的比值均大于90%,满足指纹图谱的
16、技术要求。本实验初步建立了山茱萸饮片的HPCE指纹图谱分析方法,为山茱萸饮片的品质评价提供了依据。Determination of amino acids in the traditional Chinese medicine formula Sheng-Mai-San by high performance capillary electrophoresisAbstract A method was developed for the quantitative analysis of amino acids in Sheng-Mai-San (SMS), using micellar ele
17、ctrokinetic chromatography (MEKC) in uncoated fused silica capillaries and UV detection. The influence of different parameters, such as the organic modifier and applied voltage on the MEKC separation of amino acids was investigated. A good compromise between resolution and migration time was obtaine
18、d by use of a 70mM SDS on borate buffer (pH 9.5, I=40mM) with 15% acetonitrile. That method was applied to determine amino acid in SMS and SMS market formulas samples. Keywords: Sheng-Mai-San;Free amino acids analysis; High performance capillary electrophoresis 1. IntroductionSheng-Mai-San (SMS), a
19、traditional Chinese formula, containing Radix Ginseng (Panax ginseng C.A. Mey., Araliaceae), Radix Ophiopogonis (Ophiopogon japonicus (Thunb.) Ker-Gawl., Liliaceae) and Fructus Schisandrae (Schisandrachinensis (Turcz.) Baill., Magnoliaceae), is officially recorded in Chinese Pharmacopoeia(Committee
20、of Pharmacopoeia of PR China 2005). It has long been used as a cardiotonic, antishock, antiarrhythmia (Yue et al. 2002). It is well known that saponins、flavonoids and polysaccharides are the major bioactive components in SMS. Recent research showed that the amino acids in SMS also present bioactivit
21、y (Yan et al. 2003). The amino acids are indispensable for the efficacy of the treatment of viral myocarditis with SMS (Wang et al. 2004). They are also responsible for the recovery of the patient from viral myocarditis treated with SMS. Amino acids can be analyzed by both liquid chromatography (Puc
22、ci et al. 1983; Lottspeic 1985; Bhushan and Rachna1998; Hayakawa et al.1999)and capillary electrophoresis. Some of the liquid chromatography methods, e.g. the standard method using the amino acid analyzer, have drawbacks such as the lengthy cleanup and preparation steps. CE, a relatively new method,
23、 has several advantages over HPLC due to its speed, high efficiency and low consumption of chemicals. It is found to be an alternative of HPLC and may be used as a complementary method in the routine analysis of pharmaceuticals, being especially useful for multicomponent sample analysis (Sun et al.
24、1993).The determination of amino acids is generally accomplished by a combination of derivatization and separation of amino acids using a pre- or postcolumn derivatization method. OPA has been commonly used as a precolumn derivatization agent for the separation of amino acids by CE. Some chiral thil
25、os, including N-isobutyryl-l-cysteine(AC), Boc-l-cysteine, N-isobutyryl-l-cysteine(IBC), 2,3,4,6-tetra-o-acetyl-l-thio-D-glucopyranose(TATG),were used in the derivatived reaction of amino acids with OPA and the derivatives formed with most of these chiral thiols are quite stable (Tanaka et al. 1992;
26、 Ueda et al, 1991; Ueda et al, 1992). This method has been applied to the analysis of amino acid standards but no validation of the method for these types of crude herb and market products.In this paper, a CE method was developed for the separation and determination of amino acids in SMS and SMS for
27、mulas. It may be used to distinguish the quality of the relative crude herbs and market formulas.2. Experimental2.1. Reagents and materialsThirteen kinds of amino acids were received from Huixing Biochemical Reagent CO., LTD, China. OPA and TATG were from Sigma. Boric acid, anhydrous sodium tetrabor
28、ate (borax) and sodium hudroxide were from Nanjing Chemical Reagent CO., LTD. SDS was purchased from Serva. Deionized water was from a Milli-Q system.2.2. Apparatus The analysis was carried out on a Beckman P/ACE MDQ CE system equipped with a photodiodearray detector,operated under Version 7.0 system software for control, data acquisition, and analysis(Beckman Co., USA). Separation was performed on a 6
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