Objective: To evaluate the in vitro and in vivo inhibitory effects of two commonly used herbs, Aframomum melengueta(A. melengueta) and Dennettia tripetala(D. tripetala) on CYP 3A enzymes. Methods: In vitro inhibition ...Objective: To evaluate the in vitro and in vivo inhibitory effects of two commonly used herbs, Aframomum melengueta(A. melengueta) and Dennettia tripetala(D. tripetala) on CYP 3A enzymes. Methods: In vitro inhibition of the enzymes were assessed with microsomes extracted from female albino rats using erythromycin-N-demethylation assay(EMND) method while their in vivo effects were measured by estimating simvastatin plasma concentrations in rats. Pharmacokinetic parameters were determined using non-compartmental anaysis as implemented in Win Nonlin pharmacokinetic program. Results: EMND assay with intestinal microsomes indicated that aqueous extracts of D. tripetala and A. melengueta significantly(P < 0.05) inhibited intestinal CYP 3A activity at both 50 μg and 100 μg concentrations. Petroleum ether extract of D. tripetala and ethanol extracts of A. melengueta inhibited intestinal CYP3 A activity at 100 μg but not at 50 μg concentrations. All the extracts showed an in vitrodose dependent CYP 3A inhibition with liver microsomes. In vivo analysis showed that pretreatment with the extracts enhanced systemic absorption of simvastatin with reductions in metabolizing enzymes activity as indicated in significant increases in maximal concentration, area under curve, area under moment curve and mean resident time of simvastatin(P < 0.05). Conclusions: Herbal preparations containing these plants' extracts should be used with caution especially in patients on CYP450 3A substrate medications.展开更多
Precision-cut liver slice has been successfully used to study the mechanism of drug-induced hepatotoxicity, the prediction of liver toxicity, the discovery of early hepatic toxicity biomarker and the metabolism of dru...Precision-cut liver slice has been successfully used to study the mechanism of drug-induced hepatotoxicity, the prediction of liver toxicity, the discovery of early hepatic toxicity biomarker and the metabolism of drug in liver. We detected the expression of CYP3A4, CYP2B1 + CYP2B2 and CYP2E1 in precision-cut liver slice after co-cultured with monocrotaline or Tussilago farfara alkaloids to investigate the hepatotoxicity mechanism of those drugs. After co-culturing with monocrotaline or Tussilago farfara alkaloids for 6 hours, the expression of CYP3A4 in the microsome of precision-cut liver slices was detected by Western blot, and the expressions of CYP2B1 + CYP2B2 and CYP2E1 were detected by immunofluorescence. The results showed that monocrotaline induced the expression of CYP3A4 and CYP2B1 + CYP2B2, and Tussilago farfara alkaloids obviously up-regulated the expression of CYP2E1 and CYP3A4. Thus, we conclude that the up-regulation of CYP3A4, CYP2B1 + CYP2B2 and CYP2E1 may be one of the toxic mechanisms of liver injury of those drugs.展开更多
Monoclonal antibody (MAb) to rat liver cyto-chrome P-450j isozyme, an activating enzyme specific to nitrosamine metabolism, was used coupled with immunoblotting, densitometer scanning of SDS-PAGE gels and immunohistoc...Monoclonal antibody (MAb) to rat liver cyto-chrome P-450j isozyme, an activating enzyme specific to nitrosamine metabolism, was used coupled with immunoblotting, densitometer scanning of SDS-PAGE gels and immunohistochemical technique. The trace P-450HSj isozyme (Mr. 51.5 Kd) was found in human gastric mucosa. It was similar to P-450j in molecular weight, catalytic and immunochemical properties. The concentrations of P-450HSj in mucosa of lesser curvature were higher than those in greater curvature. This might be one of the important reasons that lesser curvature is the commonest area for gastric carcinoma. But there was possibly less P-450HSj in gastric mucosa with cancer. Im-munohistochemically, P-450HSj was discovered in the cytoplasm of some glandular epithelial cells, especially in the glands with hyperplastic and intestinal metaplastic changes adjacent to carcinoma. It was also found in some normal glands and in tumor cells of high-differentiated adenocarcinoma, but not in those of low-differentiated ones. Following subjects are discussed: (1) the method of detecting trace P-450HSj, (2) the rule of distribution of P-450HSj, and (3) the relationship between the isozyme and the occurrence of gastric cancer caused by nitrosa-mines.展开更多
Cancer enzymology is a promising filiation of bio-medical sciences. In thepast decades, enzymes, such as GST(glutathione S-transferase) , PKC(protein kinase C) , Topo(DNAtopoisomerases), TK(tyrosine kinase), CD (bacte...Cancer enzymology is a promising filiation of bio-medical sciences. In thepast decades, enzymes, such as GST(glutathione S-transferase) , PKC(protein kinase C) , Topo(DNAtopoisomerases), TK(tyrosine kinase), CD (bacterial cytosine deaminase), CPG2(carboxypeptidase G2) ,and PNP (purine nucleoside phosphorylase), have been known to bear close relations to cancer. Theirspecific expression and influence on the process of tumor initiation, promotion and progressionattract scientists to apply them as a biochemical marker of certain malignant tumor, a predictor ofresponse in cancer chemotherapy; to apply them to drug design, tumor prevention and as adjuvant toradiotherapy or surgery.展开更多
Engineering the biosynthesis of plant-derived natural products in microbes presents several challenges, especially when the expression and activation of the plant cytochrome P450 enzyme is required. By recruiting two ...Engineering the biosynthesis of plant-derived natural products in microbes presents several challenges, especially when the expression and activation of the plant cytochrome P450 enzyme is required. By recruiting two enzymes—HpaB and HpaC—from several bacteria, we constructed functional 4- hydroxyphenylacetate 3-hydroxylase (4HPA3H) in Saccharomyces cerevisiae to take on a role similar to that of the plant-derived cytochrome P450 enzyme and produce caffeic acid. Along with a common tyrosine ammonia lyase (TAL), the different combinations of HpaB and HpaC presented varied capabilities in producing the target product, caffeic acid, from the substrate, L-tyrosine. The highest production of caffeic acid was obtained with the enzyme combination of HpaB from Pseudomonas aeruginosa and HpaC from Salmonella enterica, which yielded up to (289.4 ± 4.6) mg-L1 in shake-flask cultivation. The compatibility of heterologous enzymes within a yeast chassis was effectively improved, as the caffeic acid production was increased by 40 times from the initial yield. Six key amino acid residues around the flavin adenine dinucleotide (FAD) binding domain in HpaB from Pseudomonas aeruginosa were differentiate from those other HpaBs, and might play critical roles in affecting enzyme activity. We have thus established an effective approach to construct a highly efficient yeast system to synthesize non-native hydroxylated phenylpropanoids.展开更多
Tobacco smoking is a global public health threat causing several illnesses including cardiovascular disease(Myocardial infarction), cerebrovascular disease(Stroke), peripheral vascular disease(Claudication), chronic o...Tobacco smoking is a global public health threat causing several illnesses including cardiovascular disease(Myocardial infarction), cerebrovascular disease(Stroke), peripheral vascular disease(Claudication), chronic obstructive pulmonary disease, asthma, reduced female infertility, sexual dysfunction in men, different types of cancer and many other diseases. It has been estimated in 2015 that approximately 1.3 billion people smoke, around the globe. Use of medications among smokers is more common, nowadays. This review is aimed to identify the medications affected by smoking, involving Cytochrome P450(CYP)and uridine diphosphate-glucuronosyltransferases(UGTs) enzymes and Nicotine. Polycyclic aromatic hydrocarbons(PAHs) of tobacco smoke have been associated with the induction of CYP enzymes such as CYP1A1, CYP1A2 and possibly CYP2E1 and UGT enzymes. The drugs metabolized by CYP1A1,CYP1A2, CYP2E1 and UGT enzymes might be affected by tobacco smoking and the smokers taking medications metabolized by those enzymes, may need higher doses due to decreased plasma concentrations through enhanced induction by PAHs of tobacco smoke. The prescribers and the pharmacists are required to be aware of medications affected by tobacco smoking to prevent the toxicityassociated complications during smoking cessation.展开更多
目的观察二苯乙烯苷(TSG)对小鼠肝微粒体细胞色素P450(CYP)的影响。方法将昆明种雄性小鼠分为空白组、TSG低剂量组和TSG高剂量组,TSG灌胃3、5、7d后分别麻醉处死小鼠,取肝脏通过荧光实时逆转录聚合酶链反应(real time RT-PCR)检测小鼠...目的观察二苯乙烯苷(TSG)对小鼠肝微粒体细胞色素P450(CYP)的影响。方法将昆明种雄性小鼠分为空白组、TSG低剂量组和TSG高剂量组,TSG灌胃3、5、7d后分别麻醉处死小鼠,取肝脏通过荧光实时逆转录聚合酶链反应(real time RT-PCR)检测小鼠肝脏组织CYP相关基因mRNA的表达。结果 TSG作用第3、5、7天时均能够抑制CYP1A2和CYP3A4mRNA表达;TSG呈时间依赖性的增加CYP2E1mRNA表达;TSG作用7d能够显著抑制CYP4A14mRNA表达。此外,TSG对CYP2B10、3A11和3A25mRNA表达无显著性影响。结论 TSG对CYP1A2、CYP2E1、CYP3A4和CYP4A14有显著影响,对CYP2B10、3A11和3A25无明显作用。展开更多
文摘Objective: To evaluate the in vitro and in vivo inhibitory effects of two commonly used herbs, Aframomum melengueta(A. melengueta) and Dennettia tripetala(D. tripetala) on CYP 3A enzymes. Methods: In vitro inhibition of the enzymes were assessed with microsomes extracted from female albino rats using erythromycin-N-demethylation assay(EMND) method while their in vivo effects were measured by estimating simvastatin plasma concentrations in rats. Pharmacokinetic parameters were determined using non-compartmental anaysis as implemented in Win Nonlin pharmacokinetic program. Results: EMND assay with intestinal microsomes indicated that aqueous extracts of D. tripetala and A. melengueta significantly(P < 0.05) inhibited intestinal CYP 3A activity at both 50 μg and 100 μg concentrations. Petroleum ether extract of D. tripetala and ethanol extracts of A. melengueta inhibited intestinal CYP3 A activity at 100 μg but not at 50 μg concentrations. All the extracts showed an in vitrodose dependent CYP 3A inhibition with liver microsomes. In vivo analysis showed that pretreatment with the extracts enhanced systemic absorption of simvastatin with reductions in metabolizing enzymes activity as indicated in significant increases in maximal concentration, area under curve, area under moment curve and mean resident time of simvastatin(P < 0.05). Conclusions: Herbal preparations containing these plants' extracts should be used with caution especially in patients on CYP450 3A substrate medications.
文摘Precision-cut liver slice has been successfully used to study the mechanism of drug-induced hepatotoxicity, the prediction of liver toxicity, the discovery of early hepatic toxicity biomarker and the metabolism of drug in liver. We detected the expression of CYP3A4, CYP2B1 + CYP2B2 and CYP2E1 in precision-cut liver slice after co-cultured with monocrotaline or Tussilago farfara alkaloids to investigate the hepatotoxicity mechanism of those drugs. After co-culturing with monocrotaline or Tussilago farfara alkaloids for 6 hours, the expression of CYP3A4 in the microsome of precision-cut liver slices was detected by Western blot, and the expressions of CYP2B1 + CYP2B2 and CYP2E1 were detected by immunofluorescence. The results showed that monocrotaline induced the expression of CYP3A4 and CYP2B1 + CYP2B2, and Tussilago farfara alkaloids obviously up-regulated the expression of CYP2E1 and CYP3A4. Thus, we conclude that the up-regulation of CYP3A4, CYP2B1 + CYP2B2 and CYP2E1 may be one of the toxic mechanisms of liver injury of those drugs.
文摘Monoclonal antibody (MAb) to rat liver cyto-chrome P-450j isozyme, an activating enzyme specific to nitrosamine metabolism, was used coupled with immunoblotting, densitometer scanning of SDS-PAGE gels and immunohistochemical technique. The trace P-450HSj isozyme (Mr. 51.5 Kd) was found in human gastric mucosa. It was similar to P-450j in molecular weight, catalytic and immunochemical properties. The concentrations of P-450HSj in mucosa of lesser curvature were higher than those in greater curvature. This might be one of the important reasons that lesser curvature is the commonest area for gastric carcinoma. But there was possibly less P-450HSj in gastric mucosa with cancer. Im-munohistochemically, P-450HSj was discovered in the cytoplasm of some glandular epithelial cells, especially in the glands with hyperplastic and intestinal metaplastic changes adjacent to carcinoma. It was also found in some normal glands and in tumor cells of high-differentiated adenocarcinoma, but not in those of low-differentiated ones. Following subjects are discussed: (1) the method of detecting trace P-450HSj, (2) the rule of distribution of P-450HSj, and (3) the relationship between the isozyme and the occurrence of gastric cancer caused by nitrosa-mines.
文摘Cancer enzymology is a promising filiation of bio-medical sciences. In thepast decades, enzymes, such as GST(glutathione S-transferase) , PKC(protein kinase C) , Topo(DNAtopoisomerases), TK(tyrosine kinase), CD (bacterial cytosine deaminase), CPG2(carboxypeptidase G2) ,and PNP (purine nucleoside phosphorylase), have been known to bear close relations to cancer. Theirspecific expression and influence on the process of tumor initiation, promotion and progressionattract scientists to apply them as a biochemical marker of certain malignant tumor, a predictor ofresponse in cancer chemotherapy; to apply them to drug design, tumor prevention and as adjuvant toradiotherapy or surgery.
基金the Ministry of Science and Technology of China (2014CB745100)the National Natural Science Foundation of China (21390203 and 21706186).
文摘Engineering the biosynthesis of plant-derived natural products in microbes presents several challenges, especially when the expression and activation of the plant cytochrome P450 enzyme is required. By recruiting two enzymes—HpaB and HpaC—from several bacteria, we constructed functional 4- hydroxyphenylacetate 3-hydroxylase (4HPA3H) in Saccharomyces cerevisiae to take on a role similar to that of the plant-derived cytochrome P450 enzyme and produce caffeic acid. Along with a common tyrosine ammonia lyase (TAL), the different combinations of HpaB and HpaC presented varied capabilities in producing the target product, caffeic acid, from the substrate, L-tyrosine. The highest production of caffeic acid was obtained with the enzyme combination of HpaB from Pseudomonas aeruginosa and HpaC from Salmonella enterica, which yielded up to (289.4 ± 4.6) mg-L1 in shake-flask cultivation. The compatibility of heterologous enzymes within a yeast chassis was effectively improved, as the caffeic acid production was increased by 40 times from the initial yield. Six key amino acid residues around the flavin adenine dinucleotide (FAD) binding domain in HpaB from Pseudomonas aeruginosa were differentiate from those other HpaBs, and might play critical roles in affecting enzyme activity. We have thus established an effective approach to construct a highly efficient yeast system to synthesize non-native hydroxylated phenylpropanoids.
文摘Tobacco smoking is a global public health threat causing several illnesses including cardiovascular disease(Myocardial infarction), cerebrovascular disease(Stroke), peripheral vascular disease(Claudication), chronic obstructive pulmonary disease, asthma, reduced female infertility, sexual dysfunction in men, different types of cancer and many other diseases. It has been estimated in 2015 that approximately 1.3 billion people smoke, around the globe. Use of medications among smokers is more common, nowadays. This review is aimed to identify the medications affected by smoking, involving Cytochrome P450(CYP)and uridine diphosphate-glucuronosyltransferases(UGTs) enzymes and Nicotine. Polycyclic aromatic hydrocarbons(PAHs) of tobacco smoke have been associated with the induction of CYP enzymes such as CYP1A1, CYP1A2 and possibly CYP2E1 and UGT enzymes. The drugs metabolized by CYP1A1,CYP1A2, CYP2E1 and UGT enzymes might be affected by tobacco smoking and the smokers taking medications metabolized by those enzymes, may need higher doses due to decreased plasma concentrations through enhanced induction by PAHs of tobacco smoke. The prescribers and the pharmacists are required to be aware of medications affected by tobacco smoking to prevent the toxicityassociated complications during smoking cessation.
文摘目的观察二苯乙烯苷(TSG)对小鼠肝微粒体细胞色素P450(CYP)的影响。方法将昆明种雄性小鼠分为空白组、TSG低剂量组和TSG高剂量组,TSG灌胃3、5、7d后分别麻醉处死小鼠,取肝脏通过荧光实时逆转录聚合酶链反应(real time RT-PCR)检测小鼠肝脏组织CYP相关基因mRNA的表达。结果 TSG作用第3、5、7天时均能够抑制CYP1A2和CYP3A4mRNA表达;TSG呈时间依赖性的增加CYP2E1mRNA表达;TSG作用7d能够显著抑制CYP4A14mRNA表达。此外,TSG对CYP2B10、3A11和3A25mRNA表达无显著性影响。结论 TSG对CYP1A2、CYP2E1、CYP3A4和CYP4A14有显著影响,对CYP2B10、3A11和3A25无明显作用。
