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Plant-Based Adjunct Therapy for Tuberculosis
Published in Namrita Lall, Medicinal Plants for Cosmetics, Health and Diseases, 2022
Lydia Gibango, Anna-Mari Reid, Jonathan L. Seaman, Namrita Lall
Inhibition of cytochrome P450 enzymes results in a decreased rate of metabolism and excretion of drugs metabolized by these enzymes. This may concurrently result in the accumulation of the drug in the body, and toxicity may occur within 2–3 days, depending on the level of inhibition and the drug used. The clinical significance of enzyme inhibition interactions is dependent on the extent to which serum levels rise (Harris and Swart, 2005). Inhibitors inactivate specific CYP enzymes irreversibly. Metabolism will resume back to normality once the inhibitor has been cleared and new enzymes have been produced (Scripture et al., 2006).
Drug Design, Synthesis, and Development
Published in Nathan Keighley, Miraculous Medicines and the Chemistry of Drug Design, 2020
Metabolism by Cytochrome p450 enzymes is also affected by other chemicals. For example, other drugs and even certain foods can influence these processes. For certain drugs, brussel sprouts and cigarette smoke can enhance activity, whereas grapefruit juice suppresses it. Because a person’s diet can influence how a drug is metabolised, recommendations are usually given regarding what foodstuff should be eaten while taking the medication. For example, the immunosuppressant drug cyclosporine has improved activity if taken with grape fruit juice; being less speedily metabolised, but if the antihistamine terfenadine, which is a pro-drug, is taken with grapefruit juice, inhibition of metabolism that produces the active compound means that terfenadine persists in the body and can have cardiovascular side effects; hence, the active ingredient is now administered directly and is marketed as Allegra.
Information on level of drugs into breastmilk
Published in Wendy Jones, Breastfeeding and Medication, 2018
The glitazones are the most recently developed oral anti-diabetic agents designed to increase the body’s sensitivity to insulin. They are associated with weight gain in patients, particularly around the central line. They are metabolised by cytochrome P450 and therefore subject to drug interactions. They may be given as monotherapy or added into metformin or sulphonylureas where glucose control has not been achieved. When combined with insulin pioglitazone increases the incidence of heart failure. There are no data on transfer into human milk of pioglitazone. It is present in milk in animal studies (BNF).
Open hepatic artery flow with portal vein clamping protects against bile duct injury compared to pringles maneuver
Published in Scandinavian Journal of Gastroenterology, 2023
Siliang Zhang, Pingli Cao, Pinduan Bi, Fu Yang, Ming Wu, Ding Luo, Bin Yang
Finally, we performed next-generation transcriptome sequencing to explore the mechanism underlying bile duct injury due to various forms of hepatic blood inflow occlusion. A large number of differential expressed genes were identified and most of them significantly enriched in metabolism pathways, such as Tryptophan metabolism, Pyruvate metabolism, Arginine and proline metabolism, Ascorbate and aldarate metabolism, et al. Retinol metabolism [32] and Tryptophan Metabolism [14] has been reported to be associated with Cholestasis, may be induced or aggravated the bile duct injury. Several studies showed biliary obstruction and subsequent internal biliary bile change may affect cytochrome P450 isozymes [33,34]. Consistently, our study also identified the changes in the Drug metabolism-cytochrome P450 pathway.
DEC1 negatively regulates CYP2B6 expression by binding to the CYP2B6 promoter region ascribed to IL-6-induced downregulation of CYP2B6 expression in HeLa cells
Published in Xenobiotica, 2021
Xiaofei Luan, Yi Zhao, Na Bu, Yue Chen, Nan Chen
Currently, treatment methods for malignant tumours include chemotherapy drug control, radiotherapy, and immunotherapy, among which drug therapy plays an irreplaceable role (Chemoradiotherapy for Cervical Cancer Meta-analysis 2010). Chemotherapy drugs that induce tumour cell death or inhibit tumour cell survival are the main principles of cancer treatment. However, due to the side effects of chemotherapy drugs, drug resistance, and individual differences in drug response, only 30%-40% of chemotherapy patients can obtain good curative effect (Wang et al. 2018). Therefore, from a drug metabolism perspective, exploring the efficacy of drugs, side effects, and selecting appropriate drugs for individualised chemotherapy has become a rational choice to improve efficacy and reduce ineffective treatment. Cytochrome P450 – is involved in approximately 90% of drug metabolism. It is a key enzyme in the metabolism of exogenous chemicals in organisms. (Wei et al. 2001; Jin et al. 2018) and is related to the metabolism of various precancerous substances and the mechanism of action of chemotherapeutic drugs (Kim et al. 2004). Cytochrome P450 enzyme activity can be induced or inhibited by a variety of drugs to enhance or inhibit enzyme activity. The effects of most tumour chemotherapeutic agents are mediated by Cytochrome P450 enzyme metabolism (Thelen and Dressman 2009; Dutheil et al. 2010).
Metabolic activation of deferiprone mediated by CYP2A6
Published in Xenobiotica, 2021
Xiaojiao Zheng, Xu Wang, Zifang Ding, Wei Li, Ying Peng, Jiang Zheng
Metabolic activation is one of the mechanisms of drug-induced liver injury (Chi et al. 2016). Those drugs execute toxicities after metabolic transformation. A number of drug metabolizing enzymes have been found to participate in the bioactivation and toxicities of the drugs (Yao et al. 2016). Cytochrome P450 enzymes are involved in such undesired toxic effects (Venkatakrishnan et al. 2001; Lee et al. 2003). Specifically, the enzymes can catalyse the oxidation via addition of oxygen and dehydrogenation. Oxidative N-, O-, and S-dealkylations are the metabolic pathways catalysed mainly by P450 enzymes. Structurally, DFP has a frame of pyridinone, along with a methyl group attached on the nitrogen. We speculated that N-demethylation catalysed by P450 enzymes would take place with DFP, which may produce a quinone-like reactive metabolite. Quinones are highly reactive electrophiles that can react with nucleophilic group occurring in biomolecules, i.e., DNA and protein (Graham et al. 1978; Bolton et al. 2000). The present study aimed to characterize metabolite(s) of DFP in vitro and in vivo, determine metabolic activation pathway(s) of DFP, and identify cytochromes P450 enzymes participating in the production of reactive metabolite(s) of DFP.