代谢产物鉴定及汉黄芩素与汉黄芩素-7-O-葡萄糖醛酸苷的同时测定:小鼠肝脏的分布研究(英文)

汉黄芩素具有体内外抗肿瘤活性及良好的安全性。本文采用高效液相色谱串联质谱法研究了小鼠静脉注射汉黄芩素后肝脏中的代谢产物,鉴定了五个主要的代谢产物。建立了小鼠肝脏中汉黄芩素及其代谢产物汉黄芩素-7-O-葡萄糖醛酸苷的同时测定方法。肝匀浆经醋酸乙酯提取,在C₁₈色谱柱上,采用甲醇-10 mm醋酸铵（80:20,v/v）为流动相,质谱检测采用负离子选择反应监测模式。肝组织中汉黄芩素与汉黄芩素-7-O-葡萄糖醛酸苷在0.2-40μg/g范围内呈良好线性关系,方法学评价表明本法适用于动物静脉注射汉黄芩素后体内的组织分布研究。     

黄芩素在人及不同种属肝微粒体中的UDP-glucuronosyltransferase代谢差异（摘要）

目的：研究黄芩素在不同种属肝微粒体中的UDP-葡萄糖醛酸转移酶（UDP-glucuronosyltransferase, UDPGA）代谢差异特性。方法使用肝微粒体体外代谢孵育法、HPLC-UV分析方法,选用不同种属的肝微粒体进行黄芩素UDPGA体外代谢研究。结果黄芩素在人肝微粒体及不同种属的肝微粒中,加入UDPGA进行37℃恒温孵育,孵育结束后离心,取上清液,经HPLC-UV分离检测得到3个代谢产物,分别是：黄芩素-7-O-β-葡萄糖醛酸结合物、黄芩素-6-O-β-葡萄糖醛酸结合物和黄芩素-6-O-葡萄糖醛酸结合物-7-O-β-葡萄糖醛酸结合物;通过与标准品对照确定黄芩素的三个代谢产物都是葡萄糖醛酸化的代谢产物。同时,不同种属间UGT代谢物的活性表现出较大差异,黄芩素-7-O-β-葡萄糖醛酸结合物在人肝微粒体中的代谢活性最强,Km=1.61,Vmax=0.77（BG在人肝微粒体中的代谢活性是SD雌鼠的25.2倍）;黄芩素-6-O-β-葡萄糖醛酸结合物在比格犬肝微粒体中代谢活性最强,Km=3.05,Vmax=3.51（雄性比格犬肝微粒体的活性是雄性恒河猴肝微粒体的2.6倍）;黄芩素-6-O-葡萄糖醛酸-7-O-β-葡萄糖醛酸结合物在猪肝微粒体中代谢活性最强,Km=5.38, Vmax=0.17（猪肝微粒体的活性是人肝微粒体的13.6倍）,其他依次是犬、恒河猴、鼠和人。结论黄芩素在人及不同种属肝微粒体UGT代谢中均生成上述三种葡萄糖醛酸化代谢产物,但是不同种属间的代谢表现出酶动力学的差异。     

大鼠微粒体代谢酶对黄芩素葡萄糖醛酸化代谢物影响的实验研究

目的 观察大鼠微粒体代谢酶对黄芩素(治疗呼吸道感染中药)代谢作用的影响.方法 用体外微粒体药物代谢酶孵育法;用HPLC法测定黄芩素及其葡萄糖醛酸化代谢物的含量,在不同孵育时间和不同浓度下,观察大鼠肝肠不同微粒体对黄芩素葡萄糖醛酸化代谢产物生成速率的影响.结果 5种不同微粒体药物代谢酶对黄芩素均有代谢作用,且随孵育时间延长,代谢作用也相应增加,呈较好的时间和剂量依赖关系.在5种微粒体中,十二指肠微粒体代谢作用最强;而肝代谢作用最弱.结论 黄芩素主要代谢部位是肠道.     

高效液相色谱法测定黄芩素葡萄糖醛酸化产物的浓度

目的：建立黄芩素葡萄糖醛酸化代谢产物B-7G和B-6G的高效液相色谱方法。方法用Kromasil C18柱（4.6 mm ×150 mm,5μm）,柱温40℃,流动相为乙腈（A）和0.2％磷酸水溶液（B）,梯度洗脱,检测波长270 nm,流速1 mL· min-1,进样量20μL。结果黄芩素葡萄糖醛酸化产物B-7G和B-6G分别在0.1～1000.0,0.1～500.0μmol· L-1具有良好的线性关系,r 分别为0.9993和0.9995。日间、日内精密度（ RSD ）均小于10％,回收率和稳定性均符合要求。结论本研究方法简便、快速、准确,适用于大样本连续分析,可以为黄芩素的体外代谢研究提供平台。     

牡荆素在大鼠体内的代谢研究

目的 研究黄酮碳苷牡荆素在大鼠体内的代谢产物,并推测其代谢途径。方法 SD大鼠灌胃给予5 mg·kg^-1牡荆素,收集0~3 h,3~6 h,6~12 h的尿液,采用UPLC-Q-TOF检测尿样中代谢产物。结果 采用Metabolynx XS代谢物分析软件,根据质谱碎片信息对代谢物进行结构鉴定,最终得到3个代谢产物。结论 牡荆素在大鼠尿液中检测得到1个一相代谢产物,2个二相代谢产物,推测牡荆素在大鼠体内主要发生氧化、甲基化和葡萄糖醛酸结合反应,其中葡萄糖醛酸化反应是较强的代谢种类。     

采用UFLC-IT-TOF/MS鉴定大鼠口服黄芩提取物后胆汁、血浆和尿液中的主要成分(英文)

黄酮类化合物是中国传统中药黄芩的主要活性成分。大鼠口服黄芩提取物后, 采用超快速液相色谱-离子阱飞行时间质谱(UFLC-IT-TOF/MS)对胆汁、血浆和尿液进行分析, 鉴定入血成分和代谢产物。根据对这些成分质谱裂解规律的分析, 共鉴定了36种不同的黄酮类化合物, 其中包括13个新的代谢产物。本实验在体外对黄芩提取物进行分析,鉴定了其中16个黄酮类成分, 大鼠胆汁中鉴定了25个黄酮类化合物, 血浆中15个黄酮类化合物, 尿液中14个黄酮类化合物。结果表明, 黄芩提取物中的黄酮类化合物以葡萄糖醛酸化、硫酸化和甲基化的为主要代谢途径。本实验首次对黄芩提取物的代谢产物进行综合分析。     

芹菜素在大鼠体内代谢产物的鉴定与分析

目的:阐明芹菜素在大鼠体内的生物转化形式,推测其可能的代谢途径。方法:取大鼠分为空白组和给药组(灌胃给予芹菜素,200 mg/kg),每组6只。给药24 h内分别收集两组的尿液和粪便,进行相应处理后同时在正离子模式和负离子模式下采用高效液相串联离子阱飞行时间多级质谱法进行分析检测。结果:从给药组的大鼠尿液中鉴定出9个代谢产物,分别为芹菜素发生2,3位双键还原(U1、U7、U8、U9)、与葡萄糖醛酸结合(U2、U3、U4)、与硫酸酯结合(U5、U6、U7、U8、U9)、与葡萄糖结合的产物(U2);从给药组的大鼠粪便样品中鉴定出4个代谢产物,分别为芹菜素发生2,3位双键还原(代谢产物F3)、与葡萄糖醛酸结合(F2)、与葡萄糖结合的产物(F1)。结论:芹菜素在大鼠体内主要仍以原型药物存在,推测在肠道细菌的作用下可发生2,3位双键的还原,在肠道与体内排泄时均可形成葡萄糖醛酸或葡萄糖结合产物,而形成硫酸酯结合产物则仅在体内排泄时发生。     

止得咳颗粒在大鼠体内的代谢产物研究

目的 分析止得咳颗粒在大鼠体内的代谢产物并推测其代谢途径。方法 将雄性SD大鼠随机分为空白组、给药组（止得咳颗粒,9.45 g/kg）,每组灌胃超纯水或相应药液,每天2次,每次灌胃间隔6～8 h,连续3 d。收集各组大鼠血清、粪便、尿液样品,利用超高效液相色谱-四极杆-静电场轨道阱高分辨质谱（UPLC-Q-Exactive-MS）技术鉴定大鼠灌胃止得咳颗粒后上述生物样品中的代谢产物,并推测其代谢途径。结果 大鼠灌胃止得咳颗粒后,在其血清、尿液、粪便样品中共鉴定出16个原型成分（如野鸢尾黄素、黄芩素、绿原酸等）和11个代谢产物（如山柰酚或木犀草素水合产物、绿原酸甲基化产物、黄芩苷羟基化产物）。其中,血清样品中鉴定出8个原型成分和4个代谢产物;尿液样品中鉴定出10个原型成分和7个代谢产物;粪便样品中鉴定出8个原型成分和5个代谢产物。结论 止得咳颗粒在大鼠体内的代谢成分主要包括黄芩苷、野鸢尾黄素、绿原酸,主要涉及甲基化、羟基化、葡萄糖醛酸化等代谢途径。     

液相色谱-串联质谱法分析抗肿瘤新药乙烷硒啉在大鼠体内的代谢产物

本研究对抗肿瘤新药1,2-[二(1,2-苯并异硒唑-3(2H)-酮)]乙烷(乙烷硒啉,BBSKE)在大鼠体内的代谢产物进行鉴定。在灌胃给予大鼠单剂量乙烷硒啉200mg·kg-1后,采用液相色谱-串联质谱法(LC-MSn)对大鼠尿液、粪样、胆汁和血浆中的代谢产物进行检测,通过全扫描和选择离子扫描,以及根据多级质谱裂解规律对代谢物的结构进行分析。研究发现在大鼠尿样、粪样、胆汁和血浆中检测到3种Ⅰ相代谢产物和1种Ⅱ相代谢产物,其代谢途径分别为氧化、甲基化、硫甲基化和葡萄糖醛酸化反应,提示乙烷硒啉在大鼠体内的代谢方式可能是通过氧化、甲基化及葡萄糖醛酸化反应形成代谢产物。     

基于一测多评法定量的四季三黄片质量评价研究

目的 建立同时测定四季三黄片中黄芩苷、去甲汉黄芩素苷、千层纸素A-7-O-β-D葡萄糖醛酸苷、汉黄芩苷、黄芩素、汉黄芩素、千层纸素A等7种成分的一测多评法。方法 采用HPLC,岛津VP-ODS色谱柱(4.6 mm×250 mm,5μm),以乙腈-0.1%三氟乙酸溶液为流动相,梯度洗脱;流速1.0 mL·min^-1;柱温30℃;检测波长276 nm。以黄芩苷为内参物,建立去甲汉黄芩素苷、千层纸素A-7-O-β-D葡萄糖醛酸苷、汉黄芩苷、黄芩素、汉黄芩素和千层纸素A的相对校正因子,同时采用一测多评法和外标法测定四季三黄片中7个成分的含量,并将2种方法的测定结果进行比较。结果 7种成分在各自范围内线性关系良好(r>0.999 8),平均加样回收率97.0%～102.1%,RSD为1.2%～2.5%。共测定了4个企业29批四季三黄片中7种成分的含量,结果一测多评法与外标法测定结果无明显差异。不同企业样品间各成分含量存在明显差异。结论 建立的含量方法能够反映出投料用黄芩饮片的质量状况,进而全面有效地评价四季三黄片的质量,为其质量标准的提升奠定基础。     

Involvement of UDP-Glucuronosyltransferases in the Extensive Liver and Intestinal First-Pass Metabolism of Flavonoid Baicalein

Purpose The present study aims to investigate the involvement of UDP-glucuronosyltranferase (UGT) in the extensive liver and intestinal first-pass glucuronidation of baicalein (B) in both rats and humans and also to study sulfation and P450 mediated hydroxylation of B.Materials and Methods B was incubated with liver and intestine microsome, cytosol, S9 fractions from human, rat and various human recombinant UGT isozymes, respectively. The generated metabolites were identified by HPLC/MS/MS and quantified by HPLC/UV.Results Three metabolites of B namely baicalein 7-O-glucuronide (BG), the isomer of baicalein 7-O-glucuronide (BG’), and baicalein sulfate were found. BG, the predominant metabolite of B, was extensively generated in liver and jejunum microsomes in both humans and rats. Its formation was mainly catalyzed by UGT 1A9 and also mediated by UGT 1A1, 1A3, 1A8, 1A7 and 2B15 with different kinetic profiles. UGT 1A8 mediated formation of BG’ was mainly found in human intestine and rat liver microsomes. Sulfation and P450 mediated hydroxylation of B were much less significant than glucuronidation.Conclusions Extensive liver and intestinal first-pass glucuronidation of B were found in both humans and rats. Under the current experimental conditions, UGT 1A9 and UGT 1A8 demonstrated the fastest formation rate of BG in human liver preparations and BG’ in human intestine preparations, respectively.     

Identification of the metabolites of baicalein in human plasma

The metabolites of baicalein in human plasma were investigated after taking baicalein, which is one of the main bioactive flavones in Scutellaria baicalensis Georgi. Five metabolites (M1-M5) together with the parent drug baicalein (P) were detected and identified by the HPLC-diode-array detector (DAD) and LC-MS/MS methods. Among them, 7-methoxybaicalein 6-O-glucuronide (M5) is a new metabolite. Based on the results, the proposed metabolic pathway of baicalein in humans was inferred.     

Baicalin, the predominant flavone glucuronide of scutellariae radix, is absorbed from the rat gastrointestinal tract as the aglycone and restored to its original form

When baicalin was orally administered to conventional rats, it was detected in their plasma for 24 h after administration, but baicalein, the aglycone of baicalin, was not detected. However, when baicalin was given to germ-free rats, only a small amount of baicalin was detected in their plasma within 2 h after the administration, its AUC0-lim (the area under the concentration-time curve from 0 to last determination time) being 12.0% of that in conventional rats. Subsequently, a considerable amount (55.1 +/- 6.2%) of baicalin was recovered from the gastrointestinal tract even 4 h after administration. When baicalein was orally administered to conventional rats, however, baicalin appeared rapidly in their plasma at an AUC0-lim value similar to that obtained after oral administration of baicalin, despite the absence of baicalein in plasma. When intestinal absorption was evaluated by the rat jejunal loop method, baicalein was absorbed readily, but only traces of baicalin were absorbed. Moreover, in conventional rats a small amount (13.4 +/- 3.1%) of baicalin and an appreciable amount (21.9 +/- 3.4%) of baicalein were recovered from the gastrointestinal tract even 4 h after oral administration of baicalin, but only a small amount (3.93 +/- 1.43%) of baicalein was detected in the intestinal tract 1 h after administration of baicalein. Baicalin was transformed to baicalein readily by the rat gastric and caecal contents. When baicalin was administered orally to conventional rats, an appreciable amount of baicalein was recovered in their gastrointestinal tracts. Moreover, baicalein was efficiently conjugated to baicalin in rat intestinal and hepatic microsomes. These results indicate that baicalin itself is poorly absorbed from the rat gut, but is hydrolysed to baicalein by intestinal bacteria and then restored to its original form from the absorbed baicalein in the body.     

6,7-二乙酰黄芩素对四氯化碳和D-氨基半乳糖所致的急性肝损伤的保护作用

目的:研究6,7-二乙酰黄芩素对四氯化碳(CCl4)和D-氨基半乳糖(D-GalN)所致急性肝损伤的保护作用。方法:分别用CCl4和D-GalN诱导化学性急性肝损伤模型,测定血清中丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)水平;并用苏木素-伊红(HE)染色处理肝脏组织切片,光镜观察病理学改变;用试剂盒测定肝线粒体中AST,SOD和GSH-PX的活性及脂质过氧化产物MDA含量。结果:在CCl4和D-GalN诱导和的小鼠肝急性损伤模型中,6,7-二乙酰黄芩素给药(50,100 mg.kg-1,ig)明显降低血清ALT,AST水平;明显改善肝脏病理组织状况;6,7-二乙酰黄芩素给药(25,50,100 mg.kg-1,ig)明显降低CCl4诱导的肝急性损伤小鼠的肝线粒体中AST活性和MDA的含量,显著增加SOD和GSH-PX的活性。结论:6,7-二乙酰黄芩对CCl4和D-GalN诱导和的小鼠肝急性损伤均具有保护作用,该作用与其增加线粒体中抗氧化酶的酶的活性、降低脂质过氧化水平有关。     

Identification and quantification of baicalein, wogonin, oroxylin A and their major glucuronide conjugated metabolites in rat plasma after oral administration of Radix scutellariae product

The current study aims to identify and quantify three flavones (baicalein, wogonin and oroxylin A) and their major metabolites (baicalin, wogonoside and oroxylin A-7-O-glucuronide) in rat plasma after oral administration of Radix scutellariae product. A simple HPLC/UV method has been developed to simultaneously determine the three flavones and their major metabolites in rat plasma. The chromatographic separation of the six analytes was achieved by a Thermo C(18) column with linear gradient elution of a mobile phase containing acetonitrile and 20mM sodium dihydrogen phosphate buffer (pH 4.6). All the tested analytes were detected by PDA detector at a wavelength of 320nm. The intra-day and inter-day precision for the current assay of the six analytes was within the range of -2.23% to 15.13% and -10.83% to 6.42%, respectively. All the studied analytes could be efficiently extracted from the rat plasma using HLB cartridge with extraction recoveries above 70% and were stable under different storage conditions. The developed assay method was successfully applied to the pharmacokinetic study of baicalin, wogonoside after oral administration of a commercially available Radix scutellariae containing capsule at a dose of 3.2g/kg to Sprague-Dawley rats. In addition to wogonoside, a new metabolite of wogonin has been identified using LC/MS/MS for the first time.     

Effects of Baicalin on Oral Pharmacokinetics of Caffeine in Rats

Scutellaria baicalensis is one of the most widely used herbal medicines in East Asia. Because baicalein and baicalin are major components of this herb, it is important to understand the effects of these compounds on drug metabolizing enzymes, such as cytochrome P450 (CYP), for evaluating herb-drug interaction. The effects of baicalin and baicalein on activities of ethoxyresorufin O-deethylase (EROD), methoxyresorufin O-demethylase (MROD), benzyloxyresorufin O-debenzylase (BROD), p-nitrophenol hydroxylase and erythromycin N-demethylase were assessed in rat liver microsomes in the present study. In addition, the pharmacokinetics of caffeine and its three metabolites (i.e., paraxanthine, theobromine and theophylline) in baicalin-treated rats were compared with untreated control. As results, EROD, MROD and BROD activities were inhibited by both baicalin and baicalein. However, there were no significant differences in the pharmacokinetic parameters of oral caffeine and its three metabolites between control and baicalin-treated rats. When the plasma concentration of baicalin was determined, the maximum concentration of baicalin was below the estimated IC₅₀ values observed in vitro. In conclusion, baicalin had no effects on the pharmacokinetics of caffeine and its metabolites in vivo, following single oral administration in rats.     

大鼠血清中黄芩素代谢产物的鉴定(英文)

黄芩素是黄芩苷的苷元,是黄芩的主要活性黄酮类成分之一。大鼠灌胃给予黄芩素(200mg/kg)之后,利用HPLC-DAD和LC-MS/MS法从大鼠血清中检测并鉴定出5个代谢产物(M1-M5)以及原型药(M0)。在此结果上,推测了黄芩素在大鼠血清中可能的代谢途径。     

Inhibition of rat liver NAD(P)H:quinone acceptor oxidoreductase (DT-diaphorase) by flavonoids isolated from the Chinese herb scutellariae radix (Huang Qin).

The glucuronide conjugates of oroxylin A and two other flavones, baicalein, and wogonin, were isolated from the methanol extract of the herb scutellariae radix (Huang Qin) and were found to be inhibitors of rat liver NAD(P)H:quinone acceptor oxidoreductase (EC 1.6.99.2). Baicalin (baicalein 7-O-glucuronide) and oroxylin-A 7-O-glucuronide are approximately 50-fold more potent than wogonin 7-O-glucuronide. The enzyme kinetic analysis revealed that oroxylin-A 7-O-glucuronide is a competitive inhibitor with respect to NADH (the electron donor), with a Ki value of 63 nM. Considering the similarities of their structures and inhibition kinetics to those of dicoumarol, it is thought that oroxylin-A 7-O-glucuronide and the other two flavonoids bind to an identical site and inhibit this quinone reductase in the same fashion as dicoumarol. The results also suggest that the inhibition of NAD(P)H:quinone acceptor oxidoreductase or another vitamin K reductase by oroxylin-A 7-O-glucuronide and the related flavonoids may be one of the steps associated with the anticoagulation action of the herb. These compounds are potentially useful anticoagulant drugs.     

Comparison of genistein metabolism in rats and humans using liver microsomes and hepatocytes.

Species differences and metabolism are the most crucial factors in considering the effects of genistein. The aim of this study was to have a better knowledge of the metabolic fate of genistein in humans as compared with rats. For this purpose, radiolabeled genistein was incubated with human and rat liver microsomes and with cryopreserved hepatocytes from both species. Incubations were performed using a wide range of genistein concentrations to analyze the kinetics of formation of the metabolites. Metabolite profiling was obtained using an HPLC system connected to a radioactivity detector. Identification of the metabolites was based on their retention times as compared with those of authentic standards and on LC-MS (ESI-MS/MS) or NMR analyses. In both species, liver microsomes produced the same three hydroxylated metabolites (8-OH, 6-OH and 3'-OH-genistein) whereas cryopreserved hepatocytes produced the same glucurono- and sulfo-conjugates (genistein 4'-O-sulfate 7-O-glucuronide, genistein 7-O-glucuronide, genistein 4'-O-glucuronide, genistein 7-O-sulfate and genistein 4'-O-sulfate). The rate of metabolism varied with species. 3'-Hydroxygenistein was the predominant metabolite produced by rat liver microsomes, whereas in humans 3'-hydroxy and 8-hydroxygenistein were produced in the same range. In both human and rat hepatocyte incubations, genistein 7-O-glucuronide represented more than 50% of the incubated dose. Our results on hepatocytes confirmed the predominance of conjugation reaction compared to oxidative reaction observed in vivo.     

Baicalein loaded in tocol nanostructured lipid carriers (tocol NLCs) for enhanced stability and brain targeting

The objective of the present work was to investigate the specific brain targeting of baicalein by intravenous injection after incorporation into nanostructured lipid carriers (NLCs). The NLC system, composed of tripalmitin, Gelucires, vitamin E, phospholipids, and poloxamer 188 (referred to as tocol NLCs), was characterized in terms of its physicochemical properties, differential scanning calorimetry (DSC), stability, in vivo pharmacokinetics, and brain distribution. The lipid nanoparticles were spherical with an average size of ∼100 nm. The zeta potential of the nanoparticles was about −50 mV. DSC studies suggested that the majority of the inner cores of tocol NLCs had a slightly disordered crystal arrangement. The nanoparticulate dispersions demonstrated good physical stability during storage for 6 days. The incorporation of vitamin E in the formulations greatly reinforced baicalein's stability. The aqueous control and tocol NLCs were intravenously administered to rats. The plasma level of baicalein in NLCs was much higher and the half-life much longer than those in the free control. In the experiment on the brain distribution, NLCs respectively revealed 7.5- and 4.7-fold higher baicalein accumulations compared to the aqueous solution in the cerebral cortex and brain stem. Greater baicalein accumulations with NLCs were also detected in the hippocampus, striatum, thalamus, and olfactory tract. A 2-3-fold increase in baicalein amounts were achieved in these regions. Tocol NLCs improved baicalein's stability and the ability of baicalein to penetrate the brain; thus, this is a promising drug-targeting system for the treatment of central nervous system disorders.