天麻素在大鼠脑、肝、肾及脑不同区域组织匀浆中的代谢研究

目的 研究天麻素在大鼠脑、肝、肾和脑不同区域组织匀浆中的代谢。方法 采用体外匀浆孵育,高效液相法测定天麻素代谢物。结果 在脑、肝、肾匀浆中,天麻素代谢物苷元(对羟基苯甲醇)的生成反应速度常数分别为0.030 5,0.012 1,0.140 9 μg·mL^-1·min^-1,天麻素在大鼠脑、肝和肾匀浆中的清除率分别为(29.7 ± 2.1),(10.4 ± 0.8)和(299.5 ± 22.7)μL·min^-1·g^-1。天麻素在脑、肝匀浆中代谢较慢,在肾匀浆中能被迅速代谢。在脑组织不同区域中,天麻素被代谢生成苷元的反应速度常数以小脑、脑桥与延脑、丘脑3个区比较高,皮层、纹状体、海马3个区比较低,前者为后者的约1.5倍。天麻素在大鼠小脑、丘脑、皮层中的清除率分别为(45.9 ± 7.4),(39.6 ± 5.6)和(24.4 ± 3.0)μL·min^-1·g^-1。结论 天麻素在非酶体系中稳定,在肝、肾、脑组织匀浆中天麻素可被代谢为天麻苷元。在组织中的代谢,以肾最快,脑次之,肝最小;在脑组织中,天麻素在小脑、丘脑、脑桥与延脑区域代谢速度快于皮层、纹状体和海马区。     

水黄皮素在大鼠肝微粒体中的代谢研究

目的 研究水黄皮素在大鼠肝微粒体中的代谢稳定性,确定水黄皮素的代谢酶表型.方法 将水黄皮素与大鼠肝微粒体于37℃孵育,应用UPLC-MS/MS法检测孵育液中水黄皮素的含量,考察水黄皮素的代谢稳定性.将水黄皮素与各细胞色素P450(CYP)酶中的各同工酶CYP2E1、2C19、1A2、2D6、2C9和3A4的特异性抑制剂共孵育,确定其代谢酶表型.结果 在大鼠肝微粒体中,水黄皮素的t1/2=1.97 h、Cl =0.70 mL·h-1 ·mg-1,CYP1 A2是其主要代谢酶.结论 水黄皮素在大鼠肝微粒体中是由多个CYP同工酶介导代谢的,其中,CYP1 A2酶的介导作用最强.     

银莲花素A对结肠癌HCT116细胞增殖和凋亡的影响

目的 探究银莲花素A(RA)对结肠癌HCT116细胞增殖和凋亡及β-连环蛋白(β-catenin)/c-Myc通路的影响。方法 体外培养人结肠癌HCT116细胞,将细胞分为对照组和低、中、高剂量实验组。低、中、高剂量实验组分别用5、10和20μmol·L^-1 RA处理细胞。用细胞计数试剂盒(CCK-8)检测RA对结肠癌HCT116细胞增殖的抑制作用;用荧光显微镜观察细胞核的形态学改变;用流式细胞术检测细胞凋亡率;用蛋白质印迹法检测细胞β-catenin/c-Myc信号通路相关蛋白的表达情况。结果 对照组和低、中、高剂量实验组的细胞抑制率分别为0、(19.15±0.65)%、(35.11±0.40)%和(49.93±1.13)%,细胞凋亡率分别为(0.16±0.18)%、(9.26±0.42)%、(17.87±2.54)%和(38.10±2.70)%,β-catenin蛋白相对表达水平分别为0.74±0.03、0.69±0.01、0.33±0.02和0.16±0.04,c-Myc蛋白相对表达水平分别为0.89±0.01、0.54±0.03、0.29±0.03和0.1...     

米氮平在鼠肝微粒体中的体外代谢研究

目的:通过不同诱导剂预处理鼠肝,研究米氮平在肝微粒体中的代谢主要受何种酶影响,同时研究米氮平对介导其自身代谢的P450酶亚型是否有影响,为米氮平的临床合理应用提供科学依据。方法:将米氮平与不同诱导剂诱导的鼠肝微粒体进行体外孵育代谢,以乙腈中止反应,样品用25%氨水碱化后以环己烷提取。用RPHPLC测定剩余的米氮平含量,流动相为甲醇水(含10mmol·L-1NH4AC,5mmol·L-1SDS,pH3.5)6238(VV),检测波长为307nm。结果:本文测定方法回收率高,日内和日间精密度均良好,符合生物样本检测要求。苯巴比妥诱导的鼠肝微粒体对米氮平的代谢具有明显的催化作用,利福平也有一定的催化能力,米氮平诱导的鼠肝微粒体与对照组对米氮平的代谢无明显差异。结论:由苯巴比妥诱导的P450酶亚型(主要为细胞色素P4503A4)和利福平诱导的P450酶亚型(主要为细胞色素P4502C92C19,同时也对P4503A4有一定的诱导作用)在米氮平的体外代谢中起着重要作用;而米氮平诱导组对于米氮平代谢无明显影响,预示米氮平对介导其自身代谢的P450酶亚型无明显的诱导或抑制作用。     

应用HPLC-ED同时测定脑匀浆8种生物胺及其代谢产物含量

高效液相色谱-电化学检测器(HPLC-ED)是测定儿茶酚胺和吲哚胺等生物胺和相关化合物公认的方法,具有简便性、多功能性、精确性和特异性[1].本文报道同时测定脑组织中8种生物胺及其相关化合物含量的方法.     

右旋黄皮酰胺在大鼠肝微粒体中的代谢转化

目的：研究黄皮酰胺的主要代谢途径,为进一步研究黄皮酰胺代谢的立体选择性打下基础。方法：用大鼠肝微粒体体外温孵法对右旋黄皮酰胺((+)-clausenamide)进行温孵,用硅胶柱色谱、制备TLC分离纯化代谢产物并通过光谱分析鉴定其结构。结果：分离得到5个代谢产物CM1,CM3,CM4,CM5及CM6,其结构分别鉴定为6-羟基,4-羟基,4,6-二羟基,4-苯环邻位羟基,4,7-苯环间位-二羟基黄皮酰胺。结论：黄皮酰胺的代谢主要发生羟化或双羟化,CM3是其主要代谢产物,量较少的CM4,CM6为其进一步代谢产生的双羟基代谢产物;另2个代谢产物CM1,CM5产生的量也较少;CM2未分离得到,但通过HPLC分析知其为右旋黄皮酰胺的微量代谢产物。     

采用UPLC-MS/MS法研究树豆酮酸A在不同种属肝微粒体中的代谢差异

建立测定肝微粒体孵育体系中树豆酮酸A(CAA)质量浓度的方法,并比较其在不同种属肝微粒体中的代谢特征。方法:分别将CAA溶解于由还原型烟酰胺腺嘌呤二核苷酸磷酸(NADPH)启动的大鼠、比格犬、人肝微粒体孵育体系中,置于37℃水浴中进行孵育,分别于孵育的0、5、10、15、30、45、60 min时用乙腈终止反应,以染料木素为内标,采用超高效液相色谱-串联质谱法(UPLC-MS/MS)检测各孵育体系中CAA的质量浓度。色谱柱为Waters BEH C_(18),流动相为水(含0.1%甲酸)-乙腈(含0.1%甲酸)(45∶55,V/V),流速为0.25 mL/min,柱温为30℃,进样量为2μL;采用电喷雾离子源,以选择反应监测模式进行负离子扫描,用于定量分析的离子对分别为m/z 353.14→309.11(CAA)、m/z 269.86→224.11(内标)。以孵育0 min时CAA的质量浓度为参照,计算其在不同孵育体系中的剩余百分比和酶动力学参数。结果:CAA检测质量浓度的线性范围为0.05～20μg/mL,定量下限为0.05μg/mL,最低检测限为0.01μg/mL;日内、日间RSD均小于10%,相对误差为-4.83%～8.94%,提取方法和基质效应均不影响待测物的测定。孵育60 min时,CAA在大鼠、比格犬、人肝微粒体中的剩余百分比分别为(62.79±9.99)%、(64.07±11.59)%、(96.66±5.71)%;在大鼠、比格犬肝微粒体中的半衰期(72.19、68.61 min)均显著短于人肝微粒体(364.74 min),清除率[0.019 2、0.020 2 mL/(min·mg)]均显著高于人肝微粒体[0.003 8 mL/(min·mg)](P<0.05)。结论:本研究建立的UPLC-MS/MS法简便、快速、专属性强、灵敏度高,可用于肝微粒体孵育体系中CAA质量浓度的测定及体外代谢稳定性的研究。CAA在大鼠、比格犬肝微粒体中的代谢稳定性均差于人肝微粒体。     

黄芩苷与黄芩素在离体大鼠肝、肾、小肠及膀胱中代谢的相互转化

黄芩(Scutellaria baicalensis Georgi)是一种常用的中药, 在传统的中药方剂中被广泛用于治疗发炎、 发热、 咳嗽、 痢疾、 黄疸、 肝炎及高血压等症.黄芩苷(baicalin,BG)与黄芩素(baicalein,B)(图1)是黄芩中两种主要的有效黄酮类成分,具有抗菌、抗病毒、抗炎、清除氧自由基、调节免疫、保护大鼠脑损伤等多种作用[1～3].     

异莲心碱对大鼠肝匀浆脂质过氧化的影响

目的:研究异莲心碱(isoliensinine,IL)对大鼠肝匀浆脂质过氧化的影响.方法:用硫代巴比妥酸(TBA)法测定异莲心碱对大鼠肝匀浆自氧化及Vit C-Fe2 系统诱导引起的脂质过氧化产物丙二醛的含量.结果:异莲心碱能显著抑制大鼠肝匀浆自氧化及Vit C-Fe2 系统诱导所产生MDA的含量,且呈现出一定的量效关系,达到50%抑制率所需药物浓度IC50分别为0.67 g·L-1和1.05 g·L-1.结论:异莲心碱具有显著的抗脂质过氧化作用.     

抗肿瘤药LS-177在大鼠和人肝微粒体中的代谢产物研究

目的：推测LS-177在大鼠和人肝微粒体中代谢产物的结构及其可能的体外代谢途径。方法：体外孵育大鼠和人肝微粒体代谢模型,采用超高效液相质谱联用（LC-MSⁿ）法,推测LS-177的体外代谢产物的结构。结果：通过质谱数据、保留时间和碎片离子,在肝微粒体中共检测到5个代谢产物,初步推测LS-1177在肝微粒体中可能的代谢途径。结论：建立LC-MSⁿ方法,初步推测LS-177在大鼠和人肝微粒体中代谢产物的结构,为其体内外代谢的进一步研究以及化学结构类似物的体外代谢研究提供一定的参考依据。     

Generation of phase II in vitro metabolites using homogenized horse liver

The successful use of homogenized horse liver for the generation of phase I in vitro metabolites has been previously reported by the authors’ laboratory. Prior to the use of homogenized liver, the authors’ laboratory had been using mainly horse liver microsomes for carrying out equine in vitro metabolism studies. Homogenized horse liver has shown significant advantages over liver microsomes for in vitro metabolism studies as the procedures are much quicker and have higher capability for generating more in vitro metabolites. In this study, the use of homogenized liver has been extended to the generation of phase II in vitro metabolites (glucuronide and/or sulfate conjugates) using 17β‐estradiol, morphine, and boldenone undecylenate as model substrates. It was observed that phase II metabolites could also be generated even without the addition of cofactors. To the authors’ knowledge, this is the first report of the successful use of homogenized horse liver for the generation of phase II metabolites. It also demonstrates the ease with which both phase I and phase II metabolites can now be generated in vitro simply by using homogenized liver without the need for ultracentrifuges or tedious preparation steps. Copyright © 2015 John Wiley & Sons, Ltd.     

竹节香附素A抗肿瘤作用机制的研究进展

竹节香附素A是两头尖中主要含有的三萜皂苷,具有较强的抗肿瘤活性。竹节香附素A可抑制肿瘤细胞增殖,诱导其凋亡和自噬;诱导肿瘤细胞周期阻滞;抑制侵袭和转移;增强肿瘤细胞对化疗药物的敏感性。总结了竹节香附素A的抗肿瘤作用机制,以期为竹节香附素A的开发利用和临床应用提供依据。     

In vitro metabolic studies using homogenized horse liver in place of horse liver microsomes

The study of the metabolism of drugs, in particular steroids, by both in vitro and in vivo methods has been carried out in the authors' laboratory for many years. For in vitro metabolic studies, the microsomal fraction isolated from horse liver is often used. However, the process of isolating liver microsomes is cumbersome and tedious. In addition, centrifugation at high speeds (over 100 000 g) may lead to loss of enzymes involved in phase I metabolism, which may account for the difference often observed between in vivo and in vitro results. We have therefore investigated the feasibility of using homogenized horse liver instead of liver microsomes with the aim of saving preparation time and improving the correlation between in vitro and in vivo results. Indeed, the preparation of the homogenized horse liver was very simple, needing only to homogenize the required amount of liver. Even though no further purification steps were performed before the homogenized liver was used, the cleanliness of the extracts obtained, based on gas chromatography‐mass spectrometry (GC‐MS) analysis, was similar to that for liver microsomes. Herein, the results of the in vitro experiments carried out using homogenized horse liver for five anabolic steroids—turinabol, methenolone acetate, androst‐4‐ene‐3,6,17‐trione, testosterone, and epitestosterone—are discussed. In addition to the previously reported in vitro metabolites, some additional known in vivo metabolites in the equine could also be detected. As far as we know, this is the first report of the successful use of homogenized liver in the horse for carrying out in vitro metabolism experiments. Copyright © 2011 John Wiley & Sons, Ltd.     

Two sulfonate metabolites of physalin A in rats

1.?Physalin A is a bioactive withanolide isolated from the natural plant Physalis alkekengi var. franchetii (Solanaceae), a common traditional Chinese herbal medicine. This study aims to investigate the metabolites of physalin A in vivo.

2.?Two metabolites (M1 and M2) were characterized as sulfonate metabolites in the feces obtained from rats treated with physalin A orally at a dose of 15?mg/kg/day for 3 days, by application of a UPLC-Q/TOF-MS method. Furthermore, formation of the two sulfonate metabolites was verified by chemical synthesis and NMR, including ¹H NMR, ¹³C NMR and two-dimensional NMR. The structures of M1 and M2 were identified to be 3α-sulfo-2,25β,27-trihydrophysalin A and 3α,27-disulfo-2,25α-dihydrophysalin A, respectively.

3.?In summary, this study indicated that physalin A could be biotransformed to sulfonate metabolites with strong polarity, which contributed to the elimination of physalin A. A rare metabolic pathway has been revealed in this study.     

Measurements of macromolecule-bound and ultra-filtrable polyamines in rat liver homogenized without buffer

Ultra-filtrable and macromolecule-bound polyamines in rat liver homogenates, made without buffer, were determined, using Potter-Elvehjem homogenizer and commercially available, pressure-aided ultrafiltration device with a membrane pore size that allows passage of particles of molecular weight no larger than 5000. About 90% of polyamines in the liver were shown to be equilibrated with externally added 15N-labeled polyamines, based on the difference in the ratio of the natural to 15N-labeled polyamine in the liver homogenate and the ultrafiltrate. The entire amount of ultrafiltrate in the homogenized liver, required for calculation of the amounts of ultra-filtrable and macromolecule-bound polyamines, was estimated to be about 0.25 g in one gram of the homogenate, using a limited dilution curve of spermine in the ultrafiltrate with phosphate buffered saline and distilled water. With this value, ultra-filtrable polyamines in normal rat liver homogenate were calculated as about 25%, 8%, and 2% of the total amount of putrescine, spermidine, and spermine, respectively. The method was then used to measure ultra-filtrable and macromolecule-bound polyamines in regenerating rat liver homogenates, to examine possible changes of polyamines during cell growth. The method was also applied to measure other ultra-filtrable compounds such as amino acids and inorganic ions in rat liver homogenate.     

Characterization of in vitro metabolites of cudratricusxanthone A in human liver microsomes

Cudratricusxanthone A (CTXA), isolated from the roots of Cudrania tricuspidata, exhibits several biological activities; however, metabolic biotransformation was not investigated. Therefore, metabolites of CTXA were investigated and the major metabolic enzymes engaged in human liver microsomes (HLMs) were characterized using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). CTXA was incubated with HLMs or human recombinant CYPs and UGTs, and analysed by an LC‐MS/MS equipped electrospray ionization (ESI) to qualify and quantify its metabolites. In total, eight metabolites were identified: M1–M4 were identified as mono‐hydroxylated metabolites during Phase I, and M5–M8 were identified as O‐glucuronidated metabolites during Phase II in HLMs. Moreover, these metabolite structures and a metabolic pathway were identified by elucidation of MSⁿ fragments and formation by human recombinant enzymes. M1 was formed by CYP2D6, and M2–M4 were generated by CYP1A2 and CYP3A4. M5–M8 were mainly formed by UGT1A1, respectively. While investigating the biotransformation of CTXA, eight metabolites of CTXA were identified by CYPs and UGTs; these data will be valuable for understanding the in vivo metabolism of CTXA. Copyright © 2015 John Wiley & Sons, Ltd.     

葡磷酰胺在大鼠体内的代谢研究

目的初步阐明葡磷酰胺在大鼠体内的代谢情况。方法大鼠静脉给予葡磷酰胺50 mg·kg^-1，采用液相色谱-质谱联用法对大鼠尿中的代谢产物进行分析。分别在正、负离子两种检测方式采用一级全扫描、产物离子扫描、中性丢失扫描、母离子扫描等多种扫描方式下对代谢物进行检测。结果在正离子检测方式下，除原形外共检测到两种代谢物，即异磷酰胺氮芥和异磷酰胺氮芥脱卤素后生成的单胺丙啶基衍生物；在负离子检测方式下，由于异磷酰胺氮芥等化合物无质谱响应而只检测到葡磷酰胺原形。稳定性实验证明在大鼠尿中所检测到的两种化合物为代谢产物而非降解产物。结论葡磷酰胺在大鼠尿样中主要以原形的形式存在，另外还检测到异磷酰胺氮芥和异磷酰胺氮芥的单胺丙啶基衍生物两种代谢产物。     

Urinary metabolites of 2,6-diisopropylnaphthalene in rats

Metabolism of 2,6-diisopropylnaphthalene (2,6-DIPN) in rats was found to proceed exclusively through oxidation of the isopropyl chain of the molecule. Five unconjugated metabolites were isolated from the urine and identified: 2,6-naphthalenedi(2-propan)-2-ol, 2-[6-(1-hydroxy-1-methyl)ethylnaphthalen-2-yl]-2-propionic acid, 2,6-naphthalenedi-2-propionic acid, 2-[6-(1-hydroxy-1-methyl)ethylnaphthalen-2-yl]-2-hydroxypropionic acid, and 2-[6-(1-hydroxy-1-methyl)ethylnaphthalen-2-yl]-1,2-propanediol, together with a small amount of the unchanged compound. The identification of these metabolites was made by means of mass, infrared, and nuclear magnetic resonance spectrometry. The presence of glucuronides of five metabolites described above was also suggested by thin-layer and gas-liquid chromatography of the extract that was obtained after hydrolysis by beta-glucuronidase. In addition, the quantitative determination of metabolites indicated that these five were the major urinary metabolites of 2,6-DIPN, and that the total urinary excretion of these metabolites in 24 hr after administration was about 23% of the dose.