CYP450酶与中药代谢相互作用及酶活性测定的研究进展

药物对于人体属于外源性化合物,进入人体后将被许多酶所代谢。CYP450酶作为主要的代谢酶,且是重要的药物I相代谢酶,人体约75%的药物代谢是通过CYP450酶进行,而且CYP450酶是引起中药-中药(药对)、中药-西药等联合用药时药物相互作用产生的关键因素。为明确代谢酶与中药代谢的相互作用关系,普遍以酶活性作为评价指标,即以CYP450酶活性的增强和降低来推断中药有效成分及提取物等对酶的诱导或抑制作用。目前,代谢酶活性测定的常用方法是Cocktail探针药物法,其中探针底物的选择是关键。这对研究药物在机体内的吸收、分布、代谢及排泄(ADME)过程有着重大意义。该文就中药、中药有效成分、中药提取物及Cocktail探针底物等与CYP450酶的相互作用进行了综述,以期对将来的相关研究有借鉴和指导意义。     

Inhibitory potential of three Yin-tonification herbal formulas on the activities of human major cytochrome P450 and UDP-glucuronosyltransferases isozymes in vitro

OBJECTIVE:To investigate the influence of Yin-tonification herbal formulas Jaeumganghwa-tang(Ziyin Jianghuo Tang,JEGHT),Ssanghwa-tang(Shuanghe Tang,SHT) and Yukmijihwang-tang(Liuwei Di huang Tang,YMJHT) on the activities of human major cytochrome P450(CYP450 s) and UDP-glucuronosyltransferases isozymes(UGTs) in vitro.METHODS:The activities of CYP450 s(CYP1 A2,CYP3 A4,CYP2 B6,CYP2 C9,CYP2 C19,CYP2 D6 and CYP2 E1) and UGTs(UGT1 A1,UGT1 A4 and UGT2 B7)were assessed using in vitro fluorescence-and luminescence-based enzyme assays,respectively.The effects of herbal formulas on the activities of CYP450 s and UGTs were presented as IC50 values.RESULTS:JEGHT showed the potent inhibition of the CYP2 D6 activity,with weak inhibition on the activities of CYP1 A2,CYP2 B6,CYP2 C9,CYP2 C19,CYP2 E1,CYP3 A4,UGT1 A1,UGT1 A4 and UGT2 B7.SHT inhibited the activities of CYP1 A2 and CYP2 E1,whereas the negligible inhibition of the activities of CYP2 B6,CYP2 C9,CYP2 C19,CYP2 D6,CYP3 A4,UGT1 A1,UGT1 A4 and UGT2 B7 through SHT was observed.YMJHT inhibited CYP2 E1 activity,with a negligible inhibition on the activities of CYP1 A2,CYP2 B6,CYP2 C9,CYP2 C19,CYP2 D6,CYP3 A4,UGT1 A1,UGT1 A4 and UGT2 B7.CONCLUSION:These findings provide information about the potential interactions between three Yin-tonification herbal formulas and conventional drugs.     

Inhibition of human P450 enzymes by natural extracts used in traditional medicine

Different medicinal plants are widely used in Cuba and Mexico to treat several disorders. This paper reports in vitro inhibitory effects on the P450 system of herbal products commonly used by people in Cuba and Mexico in traditional medicine for decades. Experiments were conducted in human liver microsomes. The catalytic activities of CYP1A1/2, 2D6, and 3A4 were measured using specific probe substrates. The Heliopsis longipes extract exhibited a concentration-dependent inhibition of the three enzymes, and similar effects were produced by affinin (an alkamide isolated from the H. longipes extract) and two catalytically reduced alkamides. Mangifera indica L. and Thalassia testudinum extracts, two natural polyphenol-rich extracts, diminished CYP1A1/2 and 3A4 activities, but not the CYP2D6 activity. These results suggest that these herbs inhibit the major human P450 enzymes involved in drug metabolism and could induce potential herbal-drug interactions.     

中草药及化学成分对细胞色素CYP3A4影响的研究概况

目的 介绍中草药化学成分对细胞色素P3A4亚型影响.方法 查阅国内外近年来关于中草药化学成分对细胞色素CYP3A4亚型影响的有关文献并进行综述.结果 多种中草药及成分能够抑制或诱导细胞色素CYP3A4亚型,从而影响合用药物的代谢,导致药物相互作用的发生甚至不良反应的发生.结论 应重视一些中草药配伍其它药物对细胞色素CYP3A4亚型的影响及所引起的药物相互作用和形成机制的研究,促进临床合理用药,提高中草药的有效性和安全性.     

基于支持向量回归和分子对接技术的中药CYP450 2E1抑制剂筛选

细胞色素P450酶(CYP450)的抑制是药物相互作用最常见的原因,对CYPs抑制剂早期预测的研究有助于减少药物相互作用导致的不良反应。CYP450 2E1(CYP2E1)是CYP450酶系中参与药物体内代谢的主要酶,具有广泛的药物代谢底物谱。该研究以CYP2E1为研究对象,基于32个CYP2E1抑制剂,建立支持向量回归模型(support vector regression,SVR),并用测试集数据对CYP2E1定量模型进行验证,获得CYP2E1抑制剂最优预测模型。该研究同时利用CDOCKER分析阳性化合物与活性口袋相互作用模式及氨基酸,建立CYP2E1抑制剂最优筛选模型。综合利用支持向量回归模型和分子对接预测模型筛选中药化学成分数据库(traditional Chinese medicine database,TCMD),提高了计算效率和结果的准确性。SVR预测模型初步得到6 376个中药化合物,通过分子对接进一步验证,最终获得247个对CYP2E1具有潜在抑制活性的中药化合物,其中部分已有实验证实其的确对CYP2E1具有抑制作用。该研究对CYP2E1酶抑制剂的研究可为CYP450抑制剂的虚拟筛选及其介导的药物不良反应预测提供指导,对临床合理用药提供一定的参考。     

Effects of unprocessed versus vinegar-processed Schisandra chinensis on the activity and mRNA expression of CYP1A2, CYP2E1 and CYP3A4 enzymes in rats

Ethnopharmacological relevance

Schisandra chinensis (SC) is a well-known traditional Chinese herbal medicine that has been used in clinical practices for thousands of years. However, the differences between the effects of unprocessed and vinegar-processed Schisandra chinensis (VSC) on cytochrome P450 (CYP450) activities are poorly understood.

Aim of the study

To evaluate the differences between processed and unprocessed SC on the metabolism of CYP1A2, CYP2E1 and CYP3A4 substrates in rats using a cocktail method based on a developed and validated HPLC method. We also investigate the influence of processing on the levels of CYP mRNA.

Materials and methods

Three probe substrates (theophylline, dapsone and chlorzoxazone) were delivered simultaneously into rats treated with single or multiple doses of processed or unprocessed SC extract. The plasma concentrations of the three probes were profiled by HPLC, and their corresponding pharmacokinetic parameters were calculated. Real-time RT-PCR was performed to determine the effects of processed and unprocessed SC on the mRNA expression of CYP1A2, CYP2E1 and CYP3A4 in the liver.

Results

Treatment with single or multiple doses of either extract of SC induced CYP3A4 enzyme activity and inhibited CYP1A2 enzyme activity in rats. Furthermore, the inhibitory effect of SC was more potent after vinegar processing than without vinegar processing. CYP2E1 enzyme activity was induced after treatment with a single dose but was inhibited after multiple doses. The mRNA expression results were in accordance with the pharmacokinetic results.

Conclusions

These results provide useful scientific data for the safe clinical application of either extract of SC in combination with other drugs, which should lack the side effects induced by other herb–drug interactions.     

Effect of the water extract and ethanol extract from traditional Chinese medicines Angelica sinensis (Oliv.) Diels, Ligusticum chuanxiong Hort. and Rheum palmatum L. on rat liver cytochrome P450 activity

Angelica sinensis (Oliv.) Diels (DG), Ligusticum chuanxiong Hort. (CX) and Rheum palmatum L. (DH), three well known traditional Chinese medicines (TCM), have been used widely for the treatment of various types of disorders in China. Herb-drug interactions, especially cytochrome P450 (CYP)-mediated interactions, cause an enhancement or attenuation in the efficacy of co-administered drugs. In this study, to assess the possible interactions between TCM and drugs, the effect of water and ethanol extracts of DG, CX and DH on cytochrome P450 were studied in rats. The activities of various CYP enzymes were determined by HPLC method. Treatment of rats with water extracts or ethanol extracts of DG, CX and DH at daily dosages equivalent to 3 g (dry herbal material)/kg all increased the microsome protein contents and decreased the total CYP levels. The water extract of DG strongly increased the activities of CYP2D6 and 3A and the water extract of DH significantly increased the activity of 2D6. The other water extracts all showed inhibition against CYP isoforms. Only the ethanol extract of DG and DH increased the CYP2D6 and 3A activities, respectively, and the other ethanol extracts all decreased the level of CYP isoforms. All extract treatments had significant effects on CYP isoforms activities, whether induction or inhibition, compared with the blank control. Thus, caution should be paid to possible drug interactions of DG, CX, DH and CYP substrates.     

清开灵注射液及其主要成分黄芩苷和栀子苷对人肝微粒体CYP450酶6种亚型的体外抑制作用研究

 目的 研究清开灵注射液及其主要成分黄芩苷和栀子苷对人肝微粒体CYP1A2、CYP2C8、CYP2C9、CYP2C19、CYP2D6和CYP3A4的体外抑制作用。方法 采用液相色谱-串联质谱法（LC-MS/MS）同时测定对乙酰氨基酚、6α-羟基紫杉醇、4-羟基双氯芬酸、4-羟基美芬妥英、右啡烷、1-羟基咪达唑仑和6β-羟基睾酮,分别代表CYP1A2、CYP2C8、CYP2C9、CYP2C19、CYP2D6和CYP3A4的活性;清开灵注射液、黄芩苷、栀子苷和7种混合探针底物在人肝微粒体中共同孵育,并计算其IC₅₀值表示对CYP450酶的抑制程度。结果 在人肝微粒体体外孵育体系中,清开灵注射液对CYP1A2的IC₅₀值为0.6%,对其他亚型的IC₅₀值从1.1%到6.0%;黄芩苷和栀子苷对CYP450酶6种亚型的IC₅₀值均大于100 μmol·L-1。结论 在正常剂量下,清开灵注射液对人肝微粒体CYP1A2可能有抑制作用,对人肝微粒体CYP2C8、CYP2C9、CYP2C19、CYP2D6和CYP3A4无明显抑制作用;黄芩苷和栀子苷对CYP450酶6种亚型均无抑制作用。     

Effects of herbal medicinal products and food supplements on induction of CYP1A2, CYP3A4 and MDR1 in the human colon carcinoma cell line LS180

A selection of popular herbal medicinal products and food supplements were analysed for their potential to modulate the expression of the cytochrome P450 enzymes CYP1A2 and CYP3A4 and the transporter protein MDR1. A total of 31 products were analysed. Nine of the products have been approved by the Medical Products Agency (MPA) in Sweden and are marketed as herbal medicinal products. Twenty-two of the products have not been assessed by the MPA and are marketed as food supplements. LS180 cells were exposed to extracts from the different herbal products and real-time quantitative polymerase chain reaction, RT-QPCR, was subsequently used to analyse the relative mRNA levels of CYP1A2, CYP3A4 or MDR1 in treated and non-treated cells. Our results show that 17 of 31 products tested induced a two-fold expression or more for at least one of the genes analysed. Four products, of which a ginger-supplement was the most potent, induced all three genes.     

基于药物代谢酶的中药十八反研究

“十八反”是中药药性理论的重要组成部分,是古今临床医家用药配伍禁忌的核心内容,几千年来指导和影响着中医临床安全用药。随着人类社会的进步和对医疗健康的需求不断提高,中药安全性问题日益受到社会广泛关注,而“十八反”则是目前中药安全性研究亟待解决的关键科学问题。“十八反”中药反与不反的客观界定及其科学本质的阐明,对完善中药配伍禁忌理论,丰富和发展中药配伍理论体系具有重大意义。细胞色素P450 酶作为人体重要的玉相药物代谢酶系统,对药物代谢和药物之间的相互作用有着重要影响。中药以合并用药为主且其中许多成分或许为P450 酶的底物、诱导剂或抑制剂,因此有可能存在基于P450 酶的中药相互作用。本课题组将现代药理学中药物相互作用的分子基础P450 酶引入中药相互作用的研究,对十八反中各组药物与药物代谢酶的关系进行了较系统的研究,为揭示一类基于药物代谢酶的中药相互作用模式,阐明中药配伍产生相反作用的分子机制和中药十八反配伍禁忌的科学内涵提供了实验依据。     

In vitro inhibition of CYP3A4 by herbal remedies frequently used by cancer patients

The herbal remedies Natto K2, Agaricus, mistletoe, noni juice, green tea and garlic, frequently used by cancer patients, were investigated for their in vitro inhibition potential of cytochrome P‐450 3A4 (CYP3A4) metabolism. To our knowledge, only garlic and green tea had available data on the possible inhibition of CYP3A4 metabolism. Metabolic studies were performed with human c‐DNA baculovirus expressed CYP3A4. Testosterone was used as a substrate and ketoconazole as a positive quantitative inhibition control. The formation of 6‐β‐OH‐testosterone was quantified by a validated HPLC methodology. Green tea was the most potent inhibitor of CYP3A4 metabolism (IC₅₀: 73 µg/mL), followed by Agaricus, mistletoe and noni juice (1324, 3594, >10 000 µg/mL, respectively). All IC₅₀ values were high compared with those determined for crude extracts of other herbal remedies. The IC₅₀/IC₂₅ ratios for the inhibiting herbal remedies ranged from 2.15 to 2.67, indicating similar inhibition profiles of the herbal inhibitors of CYP3A4. Garlic and Natto K2 were classified as non‐inhibitors. Although Agaricus, noni juice, mistletoe and green tea inhibited CYP3A4 metabolism in vitro, clinically relevant systemic or intestinal interactions with CYP3A4 were considered unlikely, except for a probable inhibition of intestinal CYP3A4 by the green tea product. Copyright © 2009 John Wiley & Sons, Ltd.     

Cytochrome P3A4 inhibitors and other constituents of Fibraurea tinctoria

Four new furanoditerpenoids, fibrauretin A ( 1), fibrauretinoside A ( 2), epi-fibrauretinoside A ( 3), and epi-12-palmatoside G ( 4), and a new ecdysteroid glucoside, fibraurecdyside A ( 5), together with seven known compounds including two furanoditerpenoids ( 6 and 7), an ecdysteroid ( 8), and four quaternary protoberberine alkaloids ( 9- 12) were isolated from the stems of Fibraurea tinctoria. The structures of 1- 5 were established on the basis of spectroscopic evidence. Among these compounds, palmatine ( 9) and jatrorrhizine ( 10) showed inhibitory effects against cytochrome P450 3A4 (CYP3A4) with IC 50 values of 0.9 and 2.1 microM, respectively.     

In vitro Inhibition of Human CYP1A2, CYP2D6, and CYP3A4 by Six Herbs Commonly Used in Pregnancy

Black elderberry, cranberry, fennel, ginger, horsetail, and raspberry leaf, herbs frequently used in pregnancy, were investigated for their in vitro CYP1A2, 2D6, and 3A4 inhibitory potential. Aqueous or ethanolic extracts were made from commercially available herbal products, and incubations were performed with recombinant cDNA‐expressed human CYP enzymes in the presence of positive inhibitory controls. Metabolite formation was determined by validated LCMS/MS or HPLC methodologies. IC₅₀ inhibition constants were estimated from CYP activity inhibition plots using non‐linear regression. The most potent inhibition was shown for fennel towards CYP2D6 and 3A4 with respective IC₅₀ constants of 23 ± 2 and 40 ± 4 µg/ml, horsetail towards CYP1A2 with an IC₅₀ constant of 27 ± 1 µg/ml, and raspberry leaf towards CYP1A2, 2D6, and 3A4 with IC₅₀ constants of 44 ± 2, 47 ± 8, and 81 ± 11 µg/ml, respectively. Based on the recommended dosing of the different commercial herbal products, clinically relevant systemic CYP inhibitions could be possible for fennel, horsetail, and raspberry leaf. In addition, fennel and raspberry leaf might cause a clinically relevant inhibition of intestinal CYP3A4. The in vivo inhibitory potential of these herbs towards specific CYP enzymes should be further investigated. Copyright © 2013 John Wiley & Sons, Ltd.     

S(+)盐酸氯胺酮对大鼠肝微粒体细胞色素P450同工酶的影响

 目的研究S(+)盐酸氯胺酮对大鼠肝微粒体细胞色素P450(CYP450)6种主要同工酶的诱导或抑制作用。方法应用HPLC-UV测定CYP450 6种主要同工酶的特异性探针底物右美沙芬(CYP2D)、双氯酚酸钠(CYP2C6)、奥美拉唑(CYP2C)、氨苯砜(CYP3A)、非那西丁(CYP1A2)和氯唑沙宗(CYP2E1)的代谢速率。大鼠iv给予S(+)盐酸氯胺酮25 mg·kg^-1·d^-1,连续给药7 d,评价药物对大鼠肝微粒体CYP450主要同工酶的诱导或抑制作用。结果S(+)盐酸氯胺酮50μmol·L^-1时可明显抑制大鼠肝脏CYP2C,2C6和3A,分别为对照组的61.4%,45.8%和31.3%,其中以对CYP2C的抑制作用最为明显。S(+)盐酸氯胺酮1和10μmol·L^-1对CYP450同工酶无明显影响,仅10μmol·L^-1 S(+)盐酸氯胺酮对CYP2C有轻度抑制作用。S(+)盐酸氯胺酮iv给药7 d后,对大鼠肝微粒体CYP1A2和CYP2C有不同程度的诱导作用,分别诱导137.5%和117.6%,对CYP2E1,3A,2D,2C6无明显影响。结论S(+)盐酸氯胺酮50μmol·L^-1时可明显抑制肝脏CYP2C,2C6和3A,连续给药7 d后可诱导CYP1A2和CYP2C,提示S(+)盐酸氯胺酮与经上述同工酶代谢的药物联合应用时,应注意药物-药物相互作用的可能性。     

Fennel and Raspberry Leaf as Possible Inhibitors of Acetaminophen Oxidation

In addition to CYP2E1, several CYP isoenzymes, notably CYP1A2, 2D6, and 3A4, are suggested to contribute in acetaminophen oxidation and formation of the hepatotoxic metabolite N‐acetyl‐p‐benzoquinone imine (NAPQI). The in vitro CYP2E1 inhibitory potentials of fennel and raspberry leaf, herbs previously found to inhibit CYP1A2, 2D6, and 3A4 activities in vitro, were investigated. Extracts from commercially available herbal products were incubated with recombinant cDNA‐expressed human CYP2E1. A validated LC/MS/MS methodology was applied for determination of 6‐hydroxychlorzoxazone formation with disulfiram used as a positive inhibitory control. CYP2E1 IC₅₀ inhibition constants were found to be 23 ± 4 and 27 ± 5 µg/ml for fennel and raspberry leaf, respectively, constants significantly lower than those presented in the literature for other herbal extracts. Together with previous findings, the presented in vitro data for CYP2E1 inhibition suggest that fennel and raspberry leaf have a significant potential of inhibiting all the major metabolic pathways for acetaminophen oxidation and NAPQI formation. Both herbs should be further investigated for their in vivo ability of inhibiting acetaminophen oxidation and NAPQI formation. Copyright © 2014 John Wiley & Sons, Ltd.     

中药降脂方对肝细胞色素P450同工酶3A4的抑制作用

目的:分析中药复方降脂方对人体主要药物代谢酶——肝细胞色素P450(Cytchrome P450,CYP)同工酶(3A4)的抑制作用。方法:选择不同浓度的中药健脾泄浊降脂方,与人肝微粒体预孵育15 min后,加入CYP 3A4的底物睾酮及还原型辅酶烟酰胺腺嘌呤二核苷酸(NADPH),于37℃共同孵育30 min,之后加入0.5 ml预冷的甲醇终止反应。以紫外247 nm为基础的HPLC的方法检测探针底物睾酮的代谢产物6-β-羟基睾酮以判断CYP3A4的活性,确立中药降脂方对CYP 3A4的抑制作用。结果:降脂方全方及其拆方1(健脾化浊、活血化瘀)和拆方2(平补肝肾、活血通络)与人肝微粒体共同孵育后对CYP 3A4均有抑制作用,其中拆方1与拆方2的作用更明显,三方的IC50分别为0.024 64、0.008 96和0.007 69;而且随着中药复方浓度的升高,酶活性逐渐下降。结论:中药复方降脂方及其拆方对CYP 3A4酶均有抑制作用,且存在浓度效应关系,其中拆方作用较复方更明显。     

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.     

基于Cocktail探针法的玉屏风散复方配伍研究

目的:以Cocktail探针约物法评价玉屏风散对肝微粒体CYP450主要亚型活性的影响,探讨复方配伍规律.方法:按拆方设计,设计7个组方,采用大鼠肝微粒体孵育体系,测定其对CYP主要亚型的半数抑制浓度(IC50).结果:玉屏风散及拆方对肝药酶CYPs的IC50均大于生药1.0g·L-1,对CYP1 A2,CYP2C19,CYP3A4 而言,玉屏风散及拆方配伍后的IC50较方中主要影响因子的IC50有增大的趋势(对酶活性的影响减小);对CYPs而言,配伍后的实测IC50较线性预测值有减小的趋势.结论:从药物对代谢酶活性影响的角度而言,玉屏风散配伍应用具有一定优势和合理性.     

黄连黄芩及配伍诱导对大鼠肝微粒体5种CYP450亚酶活性的影响

探讨黄连和黄芩配伍代谢性相互作用的机制.大鼠连续ig黄连、黄芩及药对提取物7d诱导肝药酶后,采用cocktail探针底物与肝微粒体体外温孵法,通过HPLC同时检测肝微粒体中5种探针底物代谢消除率,评价各给药组对大鼠肝微粒体CYP450酶活性的影响.与空白组相比,黄连对CYP2D6,CYP1A2呈显著抑制作用;黄芩对CYP1 A2,CYP2E1,CYP2C9具有显著抑制作用.黄连、黄芩按1∶1配伍后仅对CYP1 A2显示抑制作用,对CYP2D6,CYP3A4则呈显著的激活作用;而黄连、黄芩按2∶1配伍后对代谢酶的激活作用消失,表现为对CYP1A2,CYP2C9的显著抑制.结果表明黄连与黄芩对P450酶主要表现为抑制作用,二者按一定比例配伍后作用特点发生改变,呈现出激活和抑制的双重性,且与配伍比例相关.推测黄连与黄芩配伍对代谢酶的抑制和诱导作用是其发挥减毒增效作用的原因之一.