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.     

In vitro Inhibition of CYP3A4 by the Multiherbal Commercial Product Sambucus Force and its Main Constituents Echinacea purpurea and Sambucus nigra

The multiherbal product Sambucus Force contains Echinacea purpurea and Sambucus nigra as its main constituents. The aims of this study were to evaluate Sambucus Force's inhibition potential and inhibition mechanisms towards CYP3A4, and to evaluate the inhibitory co‐contribution of E. purpurea and S. nigra. Metabolic studies were performed with recombinant human CYP3A4, with testosterone as substrate. Sambucus Force inhibited CYP3A4 activity with a mean (95% confidence interval) half maximal inhibitory concentration (IC₅₀) value of 1192 (1091–1302) µg/mL. The inhibitory potency seems exclusively to be exerted by E. purpurea, implicating an insignificant inhibition by S. nigra. The inhibition by E. purpurea as a single herb was in agreement with mechanism‐based inhibition with heterotropic positive cooperative effects. Echinacea purpurea acted differently in the multiherbal product, which showed a dual inhibition profile with both an uncompetitive (substrate‐dependent) inhibition and a time‐dependent (substrate‐independent) inhibitory mechanism. These mechanistic differences are suggested to be caused by herb–herb interactions in the multiherbal product. The CYP3A4 inhibition of Sambucus Force in vitro is considered relatively weak, but recommended high herbal dosages might enhance the potential for clinical interactions. Copyright © 2012 John Wiley & Sons, Ltd.     

齐墩果酸对健康人体CYP1A2,CYP2E1及CYP3A4抑制作用的研究

 目的在人体内研究齐墩果酸对CYP1A2,CYP2E1及CYP3A4酶活性的影响,以预测齐墩果酸与常用临床药物的相互作用。方法分别以咖啡因、氯唑沙宗和咪哒唑仑作为CYP1A2,CYP2E1及CYP3A4的探药,采用随机、开放、双周期交叉设计,12名健康男性受试者在服用7d齐墩果酸前后均服用100mg咖啡因、400mg氯唑沙宗和7.5mg咪哒唑仑,服探药后采血测定探药及相应代谢产物的浓度,并计算相关参数。探药和代谢物的浓度分别用RP-HPLC和HPLC-MS测定。结果服用齐墩果酸7d后,咖啡因的代谢受到显著的抑制,其达峰时间、消除半衰期及药-时曲线下面积显著增加;氯唑沙宗的代谢受到轻微抑制,达峰浓度、达峰时间、消除半衰期及药-时曲线下面积均有升高趋势,但无显著性差异;咪哒唑仑的代谢未受影响。结论服用7d齐墩果酸对CYP1A2体内活性有显著抑制作用,对CYP2E1体内活性有轻微抑制作用,而对CYP3A4酶活性无影响。     

3种中药成分对大鼠CYP3A4酶代谢的影响

目的:探讨3种中药成分(延胡索乙素、甲基莲心碱、三七总皂苷)对CYP3A4酶代谢活性的影响,以了解中药与CYP3A4酶底物联合用药时可能产生的相互作用.方法:采用超高速离心法制备大鼠肝脏微粒体,建立体外肝脏微粒体混合酶代谢体系.以睾丸酮作为底物探针,用HPLC建立检测CYP3A4酶代谢活性的方法,分别考察体外代谢体系的最适宜底物浓度、代谢时间、pH、孵育温度以及磷酸盐浓度.在确定的条件下,将3种中药成分稀释成不同浓度,分别与睾丸酮共同孵育于肝微粒体代谢体系中,测定在有或无中药成分存在下代谢产物6β-羟基睾丸酮的产生量,以评估中药成分对CYP3A4酶代谢的影响.结果:在肝微粒体孵育体系中,睾丸酮代谢为6β-羟基睾丸酮最适宜的体外代谢条件为底物浓度200μmol·L~(-1),代谢时间3.5 h,pH 7.0,孵育温度37℃,磷酸盐终浓度0.1 mol·L~(-1).延胡索乙素和三七总皂苷均对CYP3A4酶的抑制作用较弱,IC_(50)>100μmol·L~(-1),甲基莲心碱有一定的抑制作用,IC_(50)为(47.5±2.3)μmol·L~(-1).结论:延胡索乙素和三七总皂苷对CYP3A4酶代谢无明显影响,提示这2种中药成分与CYP3A4酶底物之间的相互作用较低,甲基莲心碱有可能会产生微弱的药物相互作用.     

The in vitro inhibition of human CYP1A2, CYP2D6 and CYP3A4 by tetrahydropalmatine, neferine and berberine

The purpose of this study was to investigate the in vitro inhibition potential of the three purified herbal constituents tetrahydropalmatine (Tet), neferine (Nef) and berberine (Ber) towards recombinant human CYP1A2, CYP2D6 and CYP3A4 metabolic activities. In vitro incubations were performed with phenacetin, dextromethorphan and testosterone, respectively, as CYP substrates and their metabolites were determined by validated HPLC methods. Positive control inhibitors were run for each CYP in all incubation series. Inhibition was expressed by IC₅₀ values. All herbal constituents demonstrated some, but variable, inhibition potencies towards the investigated CYP enzymes. CYP2D6 was the most sensitive for inhibition and then mainly by Tet and Ber with IC₅₀ values of 3.04 ± 0.26 µm and 7.40 ± 0.36 µm , respectively. CYP3A4 and especially CYP1A2 were inhibited to a much smaller extent by all constituents. Neferine showed the lowest overall interaction potential towards the CYP enzymes investigated. The CYP inhibition potential for the purified constituents could be related to their chemical structures. No clinical significant metabolic interaction seems likely to occur between the CYP enzymes and herbal constituents tested, with a possible exception for the CYP2D6 inhibition by Tet and Ber. Copyright © 2011 John Wiley & Sons, Ltd.     

Effects of Panax notoginseng saponins on the activities of CYP1A2, CYP2C9, CYP2D6 and CYP3A4 in rats in vivo

The aim of this study was to assess the influence of the Panax notoginseng saponins (PNS) on the activities of the drug‐metabolizing enzymes cytochrome P450 (CYP450) 1A2, 2 C9, 2D6 and 3A4 in rats. The activities of CYP1A2, 2 C9, 2D6 and 3A4 were measured using specific probe drugs. After pretreatment for 1 week with PNS or physiological saline (control group), probe drugs caffeine (10 mg/kg; CYP1A2 activity), tolbutamide (15 mg/kg; CYP2C9 activity), metoprolol (20 mg/kg; CYP2D6 activity) and dapsone (10 mg/kg; CYP3A4 activity) were administered to rats by intraperitoneal injection. The blood was then collected at different times for ultra performance liquid chromatography/tandem mass spectrometry (UPLC‐MS/MS) analysis. The data showed that PNS exhibited an induction effect on CYP1A2 by decreasing caffeine C_max (36.3%, p < 0.01) and AUC_0‐∞ (22.77%, p < 0.05) and increasing CL/F (27.03%, p < 0.05) compared with those of the control group. Western blot analysis was used to detect the effect of PNS on the protein level of CYP1A2, and the results showed that PNS could upregulate the protein expression of CYP1A2. However, no significant changes in CYP2C9, 2D6 or 3A4 activities were observed. In conclusion, the results indicate that PNS could induce CYP1A2, which may affect the disposition of medicines primarily dependent on the CYP1A2 pathway. Our work may be the basis of related herb–drug interactions in the clinic. Copyright © 2011 John Wiley & Sons, Ltd.     

Exploring the possible metabolism mediated interaction of Glycyrrhiza glabra extract with CYP3A4 and CYP2D6

The rhizome of Glycyrrhiza glabra L. (licorice) is used very widely in Indian and Chinese traditional medicine, and it is a popular flavor ingredient of drinks, sweets and candies. Its medicinal uses include treating bronchitis, dry cough, respiratory infections, liver disorders and diabetes. Glycyrrhizin is normally considered to be its biologically active marker, so a rapid RP‐HPLC method was developed for the quantitative estimation of glycyrrhizin in the extract. The effect of the standardized extract and its marker on drug metabolizing enzymes was evaluated through CYP3A4 and CYP2D6 inhibition assays to evaluate the safety through its drug interaction potential. The inhibition of CYP3A4 and CYP2D6 isozymes was analysed by the fluorescent product formation method. In the CYP450‐CO assay, the interaction potential of the standardized extract and pooled microsomes (percentage inhibition 23.23 ± 1.84%), was found to be less than the standard inhibitor. In the fluorimetric assay, G. glabra extracts showed higher IC₅₀ values than their positive inhibitors, ketoconazole and quinidine for CYP3A4 and CYP2D6, respectively. Furthermore, the interaction potential of the plant extract was greater than the pure compound. The results demonstrate that G. glabra and its principle bioactive compound, glycyrrhizin, when co‐administered with conventional medicines showed only a weak interaction potential with drug metabolizing enzymes. Copyright © 2011 John Wiley & Sons, Ltd.     

健康志愿者多剂量服用六味地黄丸对CYP3A4活性的影响

 目的 在健康志愿者体内研究多剂量口服六味地黄丸对细胞色素P450（CYP）3A4活性的影响作用。方法 采用随机开放两周期试验设计, 8例健康志愿者口服六味地黄丸14 d（每天3次,每次8粒）的前后单剂量口服咪达唑仑15 mg, HPLC测定给药后咪达唑仑10 h内的不同时间点的血浆浓度。结果 口服六味地黄丸前与口服六味地黄丸14 d后的咪达唑仑ρ_max,AUC_0-10, CL/F和t_1/2比值的90%可信区间分别为(44.5, 78.5) ng·mL-1, (58.9, 85.8) ng·h·mL-1, (116.4, 170.7) L·h-1和(88.1,124.9) h,口服六味地黄丸前后咪达唑仑t_max无明显差异。结论 口服六味地黄丸14 d对肠道CYP3A4有诱导作用。     

体内代谢法研究糖类药物对大鼠CYP3A4的影响

 目的研究不同结构的糖类药物对肝药酶的影响,从而对这些新药进行安全性评价,并预测它们与其他药物合用的不良相互作用。方法通过研究肝药酶的专属探针药物的体内代谢过程的变化,进而判断不同结构糖类药物对这些酶有无诱导或抑制作用。结果SPMG对雌雄大鼠均有显著的抑制作用,但AOSC对CYP3A4无影响。结论结构不同的药物对CYP3A4的影响存在明显的差异,药物与各种与CYP3A4酶代谢有关的药物合用时,应充分考虑其对肝药酶的不同影响,以避免潜在的毒性或不良反应。     

归脾汤对雷公藤醇提物致肝损伤大鼠肝微粒体CYP3A4酶活性的影响

目的:建立一个快速、准确的测定大鼠肝微粒体中CYP3A4酶活性的HPLC,研究雷公藤醇提物对肝损伤大鼠肝微粒体CYP3A4酶活性的影响,进而探讨归脾汤对其保护机制。方法:50只大鼠随机分为正常组、模型组、归脾汤组、P450诱导组、P450抑制组。正常组、模型组灌服生理盐水,归脾汤组灌服归脾汤(9g·kg-1),P450诱导组、P450抑制组分别腹腔注射地塞米松(100mg·kg-1)和酮康唑(80mg·kg-1),连续ig 4d后,再以雷公藤醇提物(3.25mg·kg-1)ig 3d造模。选用HPLC以咪达唑仑为探针药物,检测各组大鼠肝微粒体中CYP3A4酶活性。结果:在所建立的HPLC条件下,咪达唑仑的出峰时间在8.960min,能够完全分离,且无其他生物基质峰干扰;线性范围是0.25~20μmol·L-1(r=0.9999),符合检测要求,方法可靠。结果显示,与正常组比较,模型组大鼠CYP3A4活性明显降低,差异有统计学意义(P<0.05);与模型组比较,归脾汤组、CYP450诱导组大鼠CYP3A4活性亦明显升高,差异有统计学意义(P<0.05);归脾汤组与CYP450诱导组之间比较,大鼠CYP3A4活性差异不明显,无统计学意义。结论:本方法能够对CYP3A4活性进行准确评价,雷公藤对大鼠肝微粒体CYP3A4酶活性有一定的抑制作用,归脾汤可能通过诱导CYP3A4活性而降低雷公藤的毒性从而发挥对肝脏的保护作用。