人参、藜芦合用对大鼠肝P450酶活性及mRNA表达的调控作用

目的 :研究中药十八反中人参与藜芦合用对P450同工酶在酶活性及mRNA水平的调控作用。方法 :采用紫外分光光度法测定大鼠肝微粒体细胞色素P450与细胞色素b₅含量及氨基比林N 脱甲基酶 (APND)、对硝基苯酚羟化酶 (pNPH)活性。采用RT-PCR技术检测大鼠肝中 5种P450同工酶CYP1A1,CYP2B1/ 2 ,CYP2C11,CYP2E1及CYP3A1mRNA的表达。结果 :人参与藜芦合用可明显降低P450蛋白含量 ,可降低细胞色素b₅的含量 ,单药及其与藜芦配伍都能使APND活性下降。在mRNA水平上 ,藜芦可诱导CYP2C11的基因表达 ,与人参合用后却使得CYP2C11的表达下降。藜芦与人参配伍诱导了CYP1A1的表达。人参可抑制CYP2B1/ 2的基因表达 ,与藜芦合用后却明显诱导了CYP2B1/ 2的表达 ,人参与藜芦合用后也明显诱导了CYP3A1的表达。结论 :人参与藜芦配伍前后对一些CYP亚型调控作用发生明显变化 ,可能存在基于药物代谢酶机理的相反作用 ,需进一步结合代谢研究加以综合分析 ,阐明相反作用的机理。     

黄药子与甘草配伍对大鼠肝CYP450酶活性及mRNA表达的影响

目的:研究甘草减轻黄药子肝损伤对CYP450酶活性及基因表达的影响。方法:采用紫外分光光度法测定大鼠肝微粒体细胞色素P450、细胞色素b5含量及氨基比林N-脱甲基酶、红霉素N-脱甲基酶活性,采用RT-PCR技术检测大鼠肝脏CYP2E1、CYP3A4的mRNA的表达。结果:黄药子甘草1∶2配伍组能显著减轻黄药子致大鼠肝损害,与黄药子甘草1∶2配伍组(27 g/kg)比较,黄药子组(9 g/kg)肝微粒体蛋白浓度、P450含量、b5含量均明显下降;氨基比林N-脱甲基酶活性、红霉素N-脱甲基酶活性亦明显下降。在mRNA水平上,黄药子组9 g/kg显著诱导CYP2E1、CYP3A4基因的表达,与甘草1∶2配伍后(27 g/kg)表达显著降低。结论:甘草可能通过提高CYP450酶活性,抑制CYP2E1、CYP3A4的mRNA表达,对黄药子致肝损伤具有一定的保护作用。     

枳椇子醋酸乙酯提取物对大鼠肝P450同工酶的影响

目的：观察枳椇子醋酸乙酯提取物对大鼠肝P450同工酶的影响。方法：大鼠分别灌胃给予枳椇子醋酸乙酯提取物相当于生药量0.14,0.17,0.2 g·kg^-1,连续10 d,采用紫外分光光度法测定细胞色素P450与NADPH-细胞色素C(P-450)还原酶含量及苯胺羟化酶(ANH)、氨基比林N-脱甲基酶(ADM)、红霉素N-脱甲基酶(ERD)的活性。采用RT-PCR技术检测大鼠肝脏CYP1A1,CYP2C11,CYP2E1,CYP3A1基因的水平。结果：枳椇子醋酸乙酯提取物对细胞色素P450及NADPH-细胞色素C(P-450)还原酶含量无显著影响；可抑制苯胺羟化酶(ANH)活性,抑制率可达31.5%；可增加氨基比林N-脱甲基酶(ADM)活性,可达42.4%；而对红霉素N-脱甲基酶(ERD)的活性没有明显变化。在mRNA水平上,CYP2E1基因的表达水平没有变化；CYP1A1,CYP2C11和CYP3A1基因表达水平则明显增加。结论：枳椇子醋酸乙酯提取物对大鼠肝P450同工酶的影响表现出特异性,对不同的P450同工酶作用不同。     

四物汤及其配伍对大鼠肝脏P450酶活性及mRNA表达的影响

研究四物汤复方及其配伍对大鼠肝脏P450酶活性及其mRNA表达水平的影响。大鼠口服灌胃四物汤及其配伍水煎液2周后,处死,用生理盐水灌流肝脏,制备肝微粒体,采用混合探针与肝微粒体体外孵育法考察四物汤对大鼠肝脏细胞色素P450酶的影响。利用实时定量聚合酶链式反应(Q-PCR)检测四物汤对大鼠肝脏细胞色素P450 mRNA表达的影响。四物汤复方组CYP1A2酶活性与对照组相比升高(P<0.05),熟地白芍、当归白芍、当归川芎以及白芍川芎组的CYP1A2和CYP2C19的酶活性与对照组相比降低(P<0.05),复方组、单药组、2味药配伍组的CYP2B6的酶活性与对照组相比降低(P<0.05)。复方组对CYP1A2的mRNA表达具有上调作用(P<0.05),4味单药对CYP2B1 mRNA表达具有下调作用的(P<0.05)。四物汤复方对大鼠肝脏CYP1A2的酶活性具有诱导作用,熟地和当归组与对照组相比酶活性相当,但与白芍合用后显著下调了CYP1A2的酶活性。复方及其配伍对CYP2B6的酶活性具有抑制作用,其中当归对酶活性下调作用较强。复方对CYP1A2以及4味单药对CYP2B1的mRNA表达的影响与酶活性水平相平行。     

基于肝脏药物代谢酶研究附子配伍干地黄的减毒机制

测定大鼠肝微粒体中CYP1A2和CYP3A4酶活性,并从蛋白和转录水平上阐明附子配伍干地黄对CYP450酶蛋白和基因表达的影响,探索附子配伍干地黄对其减毒的分子机制。采用"Cocktail"探针药物法进行CYP450酶活性测定;采用CO还原差示法测定肝微粒体中CYP450酶含量并采用RT-PCR测定大鼠肝脏CYP1A2和CYP3A4 mRNA表达量。结果显示,与空白组比较,附子干地黄组CYP1A2和CYP3A4酶活性及mRNA表达显著升高(P0.05);附子组CYP450含量显著降低(P0.01);干地黄组、附子干地黄组CYP450含量显著升高(P0.05)。因此,附子配伍干地黄能够诱导CYP1A2和CYP3A4酶活性,增加CYP450酶含量,加快附子毒性成分的代谢,达到附子减毒作用。     

酸枣仁、远志和桔梗水提液对大鼠肝CYP450酶活性 及mRNA表达的调控作用

目的:研究中药酸枣仁、远志和桔梗水提液对P450同工酶在酶活性及mRNA水平的调控作用。方法:大鼠ig给予酸枣仁、远志和桔梗水提液7 d后取肝脏称重并制备肝微粒体,采用紫外分光光度法测定大鼠肝微粒体细胞色素b5(Cytb5),P450的含量及红霉素N-脱甲基酶(ERD)的活性,高效液相色谱法测定非那西汀O-脱乙基酶(PHD)的活性和对硝基苯酚羟化酶(pNPH),采用RT-PCR技术检测大鼠肝中5种P450同工酶CYP1A1,CYP1A2,CYP2E1,CYP3A1及CYP3A2mRNA的表达。结果:与对照组比较,各给药组大鼠肝指数无显著变化;酸枣仁组显著降低Cytb5含量和ERD活性,增加pNPH活性,远志组显著升高pNPH,极显著降低ERD活性,桔梗组显著降低CYP450含量,并明显升高PHD和pNPH活性;在mRNA水平上,各组的CYP1A1基因均未能检出;酸枣仁组诱导CYP2E1,CYP3A1和CYP3A2基因表达,远志组抑制CYP3A1,诱导CYP3A2的mRNA表达,桔梗组诱导CYP1A2,CYP2E1,CYP3A2的mRNA表达;酸枣仁的CYP2E1、桔梗的CYP1A2和CYP2E1mRNA水平基本与酶活性水平相平行。结论:酸枣仁、远志水提液诱导CYP2E1的活性;桔梗水提液诱导CYP1A2,CYP2E1的活性,酶活性变化可能主要通过影响基因转录来实现。提示若酸枣仁和远志与经CYP2E1和CYP3A代谢的药物同用,桔梗若与经CYP1A2,CYP2E1,CYP3A代谢的药物同服,有可能会影响这些药物的临床疗效,临床用药时应慎重考虑。     

四种抗癌中药提取物对大鼠肝CYP3A酶活性及mRNA表达的影响

目的研究4种抗癌中药提取物对大鼠肝脏细胞色素P450 3A(CYP3A)酶在酶活性及mRNA水平的调节作用.方法采用紫外分光光度法测定大鼠肝微粒体CYP450含量及CYP3A同工酶--红霉素N-脱甲基酶(ERD)的活性;采用反转录PCR(RT-PCR)技术检测CYP3A1、CYP3A2 mRNA的表达.结果莪术、苍术、白术的提取物均可明显增加CYP450蛋白含量及CYP3A酶活性,而茯苓提取物无明显作用.在mRNA水平上,莪术、苍术、白术的提取物均能明显诱导CYP3A1的基因表达,茯苓提取物无明显作用;对于CYP3A2的基因表达,莪术和苍术的提取物均有明显的诱导作用,而白术和茯苓的提取物则有显著的抑制作用.结论莪术、苍术、白术的提取物对CYP3A酶的调控均发生在酶活性水平和转录水平,而茯苓提取物对CYP3A酶仅存在转录水平的调控.4种抗癌中药提取物对CYP3A酶的诱导或抑制可能会影响其他药物的体内代谢.     

基于CYP450酶的四逆汤复方配伍减毒机制研究

目的探讨CYP450酶的四逆汤复方配伍减毒机制。方法采用"Cocktail"探针药物法测定CYP1A2和CYP3A4酶活性,使用高效液相色谱仪检测血浆中咖啡因和咪达唑仑两种特异性探针药物的浓度。应用CO示差还原法测定大鼠肝微粒体中CYP450酶含量,通过反转录聚合酶链式反应来检测CYP1A2和CYP3A4 mRNA的表达。结果附子对CYP1A2和CYP3A4酶活性及CYP450酶含量无影响;甘草、附子配伍甘草和四逆汤对CYP1A2和CYP3A4酶活性有诱导作用并且显著增加CYP450酶含量;与对照组比较,甘草组、附子配伍甘草组和四逆汤全方组对CYP3A4 mRNA的表达有不同程度诱导作用。甘草组和四逆汤全方组对CYP1A2 mRNA表达有显著诱导作用,附子配伍甘草组对CYP1A2 mRNA表达无显著影响。结论实验研究表明甘草、附子配伍甘草、四逆汤全方能够诱导CYP1A2和CYP3A4酶活性,显著增加CYP450酶含量;附子配伍甘草对两种酶活性的影响可能由甘草对酶基因表达影响引发,使酶活性增强,从而加快附子毒性成分在体内代谢,从肝药代谢酶角度阐明甘草在四逆汤中对附子起主要减毒作用。     

心脏药代酶的附子-甘草配伍减毒机制

目的:基于心脏细胞色素P450(cytochrome P450,CYP450)系统考察附子与甘草配伍后对正常大鼠心脏的减毒机制研究。方法:雄性SD大鼠,随机分为空白组、诱导剂苯巴比妥组(0.08 g·kg^-1·d^-1),附子组(0.5 g·kg^-1·d^-1),甘草组(0.5 g·kg^-1·d^-1)和附子-甘草组(0.5 g·kg^-1·d^-1)。检测大鼠心肌酶天冬氨酸氨基转移酶(aspartate transaminase,AST),肌酸激酶(creatine kinase,CK)和乳酸脱氢酶(lactate dehydrogenase,LDH)含量变化,同时观察大鼠心脏组织的病理学改变,并观察各组对药物代谢酶CYP2B1,CYP2C11,CYP2E1,CYP2J3,CYP4A1,CYP4A3,CYP4F1,CYP4F5,CYP4F6 mRNA表达水平的变化。结果:与空白组比较,附子组中大鼠血清AST,CK和LDH含量升高(P<0.05),配伍后AST,CK和LDH心肌酶的含量较附子组降低,但未出现统计学差异;同时病理学结果显示附子组大鼠出现心脏损伤,配伍后甘草可减轻由附子产生的心脏损伤作用;在基因转录水平,甘草组能不同程度地上调CYP2C11和CYP2J3 mRNA表达(P<0.05),甘草与附子配伍后能上调CYP2B1,CYP2C11和CYP2J3家族mRNA表达(P<0.05),推测配伍可促进花生四烯酸(arachidonic acid,AA)代谢生成环氧二十碳三烯酸(expxyeicosatrienoic acid,EETs),附子能上调CYP4家族中CYP4A1,CYP4A3,CYP4F1,CYP4F5和CYP4F6 mRNA表达(P<0.05),其能促进20-羟-二十烷四烯酸(20-hydroxyeicosatetraenoicacid,20-HETE)的生成,附子-甘草配伍后能削弱附子下调CYP4A3,CYP4F1,CYP4F5和CYP4F6家族mRNA表达的能力(P<0.05),抑制20-HETE的生成,减轻由附子产生的心脏毒性。结论:附子-甘草配伍后可调控心脏CYP450酶的表达,使EETs生成量增加,20-HETE含量减少,起到减毒的作用。     

热毒宁注射液对大鼠肝脏CYP450酶的影响

研究热毒宁注射液对大鼠肝脏CYP450酶酶活性及其mRNA表达水平的影响。将SD大鼠腹腔注射7 d后,处死,制备大鼠的肝微粒体,与探针药物共孵育,利用LC/MS法测定各同工酶特异性底物在大鼠肝微粒的代谢产物的生成量,间接反映各同工酶的活性。应用荧光定量PCR技术考察热毒宁注射液对大鼠肝脏CYP450酶mRNA表达水平的影响。结果显示,酶活性方面,热毒宁注射液与空白组比较可抑制CYP2B1,2C12,2C13,2D2的酶活性,诱导CYP3A1的酶活性,对CYP1A2酶活性无明显影响。mRNA表达方面,热毒宁注射液对CYP2B1,3A1,1A2,2C11,2D1,2E1 mRNA的表达具有诱导作用。通过对上述结果分析,可以看出热毒宁注射液在酶活性和mRNA水平均对CYP3A1具有显著的诱导作用,与大环内酯类抗生素合用时可能会出现不良反应;对CYP2B1,2C12,2C13,2D2的酶活性均具有抑制作用,与其他药物联合用药时要充分考虑可能出现的药物相互作用或潜在风险。     

天王补心丸中生地黄、玄参、天冬和麦冬水提液对大鼠肝CYP450酶含量及其亚型CYP3A, CYP2E1和CYP1A2活性的影响

目的:研究天王补心丸中滋阴类药味生地黄、玄参、天冬和麦冬水提物对大鼠肝肝药酶(CYP450)含量及对亚型CYP3A,CYP2E1,CYP1A2活性的影响,探讨CYP450在天王补心丸代谢中的作用.方法:大鼠灌胃给予生地黄、玄参、天冬和麦冬水提物7d后取肝脏称重并制备肝微粒体,紫外分光光度法测定肝微粒体细胞色素b5(Cytb5),P450的含量及CYP3A的活性,高效液相法测定CYP2E1和CYP1A2的活性.结果:与空白对照组比较,各给药组大鼠肝指数无显著变化;生地黄组CYP450含量极显著减少(P＜0.01),CYP3A活性极显著增加(P＜0.01),CYP1A2活性显著增加(P＜0.05);玄参组CYP450含量减少(P＜0.05),CYP3A和CYP1A2活性均极显著增加(P＜0.01);天冬组Cytb5含量增加(P＜0.05),CYP2E1活性增加(P＜0.05),CYP1A2活性极显著增加(P＜0.01);麦冬组cytb5,CYP450含量无统计学差异,CYP3A活性增加(P＜0.05),CYP2E1活性增加(P＜0.05),CYP1A2活性极显著增加(P＜0.01).结论:天王补心丸中生地黄、玄参降低大鼠肝脏CYP450酶含量并均诱导CYP3A和CYP1A2活性,天冬诱导CYP2E1和CYP1A2活性,麦冬诱导CYP3A,CYP2E1和CYP1A2活性.由于抑制CYP450活性,减少对其他药代谢,滋阴药组在天王补心丸全方配伍中可增强其他各功能组比如补血养血、宁心安神类药味的作用,为探讨天王补心丸的配伍机制提供了理论基础.     

Cytochrome P450 inhibitory potential and RP-HPLC standardization of trikatu—A Rasayana from Indian Ayurveda

Ethnopharmacological relevance

Trikatu is a very well known ‘Rasayana’ in Ayurveda and widely used as a polyherbal ayurvedic formulation in India. It consists of three well known plants, viz., Piper longum (PL), Piper nigrum (PN) and Zingiber officinale (ZO) in equal ratio. Trikatu has been prescribed for cough, cold, fever, asthma, respiratory problems and improvement of digestive disorders. The aim of the present study was to investigate the effect of individual ingredients of trikatu namely PL, PN, and ZO and formulations [Marketed formulation (MF) and laboratory formulation (LF)] on drug metabolizing enzymes (CYP3A4 and CYP2D6), to assess its herb–drug interaction potential through cytochrome P450 inhibition assays. Further this work was aimed to develop an RP-HPLC method for the identification and quantification of piperine and 6-gingerol in the crude drug trikatu.

Materials and methods

Enzyme inhibition effect of LF, MF, PL, PN and ZO was explored through CYP450–CO complex assay using rat liver microsomes (RLM) and a fluorescence screening method using individual isoenzymes (CYP3A4 and CYP2D6). The RP-HPLC method was developed for the identification and quantification of piperine and 6-gingerol in LF, MF and individual plant materials at the concentration of 1 mg/mL.

Results

RP-HPLC analysis confirmed the presence of piperine and 6-gingerol in LF and MF [Piperine: 7.89±2.12% (w/w) (MF), 6.70±2.13% (w/w) (LF)]; [6-gingerol: 5.3±1.21% (w/w) (MF), 4.95±2.34% (w/w) (LF)]. Inhibitory potential of MF and LF in CYP450–CO complex assay was found to be 37.54±3.12% (MF) and 35.12±2.31% (LF) and against CYP2D6 and CYP3A4 was estimated to be IC₅₀ 251.30±3.98 and 245.23±1.92 μg/mL and IC₅₀ 225.50±1.02 and 223.254±0.92 μg/mL respectively.

Conclusions

Different concentrations of the trikatu formulation and its individual components showed significantly (p<0.001) less inhibitory activity on individual isoenzymes as compared to the positive control. The crude drug exhibited inhibitory potential against the CYP450 enzymes in a concentration dependent manner. Outcome of the present study demonstrated that trikatu has less interaction potential with drug metabolizing enzymes.     

Marsdenia tenacissima extract inhibits gefitinib metabolism in vitro by interfering with human hepatic CYP3A4 and CYP2D6 enzymes

Ethnopharmacological relevance

The stem of Marsdenia tenacissima (Roxb.) Wight et Arn. is mainly produced in Yunnan China and has long been used as a medicine to treat cancer in China. Xiao-Ai-Ping injection, the water-soluble part of the stem of Marsdenia tenacissima, is administrated as an anti-cancer agent in clinics for decades. Our previous study showed that Marsdenia tenacissima extract (MTE) restored gefitinib sensitivity in gefitinib-resistant non-small cell lung cancer (NSCLC) cells, but the mechanism involved is unknown. Gefitinib undergoes hepatic metabolism predominantly through human cytochrome P450 (CYP) 3A4 and CYP2D6 enzymes. This study aims to evaluate whether MTE interferes with gefitinib metabolism via human hepatic P450 enzymes.

Material and methods

A cocktail-substrate assay was used to test the effect of MTE on major CYP enzyme activities by incubation of pooled human liver microsomes with specific substrate probes of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 in the absence and presence of MTE. Recombinant human CYP450 enzymes were used to predict in vitro gefitinib metabolic clearance in the absence and presence of MTE. The metabolites of the substrate probes and gefitinib were detected by high-performance liquid chromatographic tandem mass spectrometry (HPLC-MS/MS). Human hepatoma HepG2 cells were used to investigate the effect of gefitinib alone or in combination with MTE on CYP3A4 and CYP2D6 mRNA and protein expression.

Results

The cocktail-substrate assay showed that MTE inhibited CYP450 activities in human liver microsomes with the inhibition rate of 3A4>2C9>2C19>1A2>2D6. The co-administration of MTE with gefitinib significantly decreased the in vitro intrinsic clearance (Cl_int) of gefitinib by 2.6 and 4.0-fold for CYP2D6 and CYP3A4, respectively, but did not affect other CYP450s. CYP2D6 and CYP3A4 mRNA and protein expression in human hepatoma HepG2 cells were greatly reduced in the combined gefitinib and MTE treatment.

Conclusion

We demonstrate that MTE inhibits gefitinib metabolism by interfering with CYP3A4 and CYP2D6. Meanwhile, MTE combined with gefitinib down-regulates the mRNA and protein expression of CYP3A4 and CYP2D6 in the HepG2 cells. Thus, these data suggest that MTE is a promising herbal medicine to enhance gefitinib efficacy through improving its metabolic stability.     

银杏内酯对大鼠肝细胞色素P450基因表达的影响

目的:观察银杏内酯对大鼠肝细胞色素P-450基因表达的影响。方法:银杏内酯100mg·kg^-1,大鼠灌胃给药,1日1次,连续4d,取肝组织,用竞争法反转录-聚合酶链式反应(competitiveRT-PCR)检测给药后细胞色素P-450基因表达的变化。结果:反转录反应体系不含目的RNA时,用参考模板竞争RNA反转录后用CYP和看家基因Cyclophilin引物进行PCR,CYP1A1,CYP1A2,CYP281/B2,CYP2C11,CYP2E1,CYP3A1,CYP4A1,Cyclophilin均出现了其预期的特异性片段,无其他非特异性带出现,表明参考模板竞争RNA对CYP和看家基因Cyclophilin引物具有特异性竞争能力。给银杏内酯后,对照组和给药组大鼠肝组织的CYP1A1mRNA均检测不到。CYP2C11和CYP2E1的基因表达水平没有变化;CYP1A2和CYP2B1/B2的基因表达水平下降;CYP3A1和CYP4A1的基因表达水平则明显增加。结论:银杏内酯对大鼠肝组织的细胞色素P-450基因表达水平的影响表现出特异性,对不同的细胞色素P-450成员的作用不同。     

三七对大鼠肝组织内CYP和GST基因表达的影响

目的:研究三七对大鼠肝组织内细胞色素P450(cytochrome P450,CYP)和谷胱甘肽转移酶(glutathione s-transferase,GST)基因表达的影响.方法:雄性SD大鼠,三七2,4 g·kg~(-1),每日1次连续灌胃14 d,用逆转录-实时定量PCR法检测肝组织内的CYP1A1,CYP1A2,CYP2B1,CYP2E1,CYP3A1,CYP4A1基因和GST-ml,GST-pi基因的表达情况.结果:三七不影响肝组织内CYP1A1,CYP1A2,CYP2E1,CYP3A1,GSTml和GST-pi基因的表达,2,4 g·kg~(-1)的三七可明显抑制CYP2B1基因(0.48倍,P<0.05和0.61倍,P<0.05)和CYP4A1基因(0.69倍和0.51倍)的表达.结论:三七可选择性地抑制大鼠肝组织内CYP2B1和CYP4A1的基因表达,这可能是三七的作用机制之一.三七对CYP1A1,CYP1A2,CYP2E1和CYP3A1的基因表达没有影响,提示三七与以上主要药物代谢酶代谢的药物合用时在肝内不会产生代谢性药物相互作用.