Cytochrome P450 (CYP) is a critical drug-metabolizing enzyme superfamily. Modulation of CYP enzyme activities has the potential to cause drug–drug/herb interactions. Drug–drug/herb interactions can lead to serious adverse drug reactions (ADRs) or drug failures. Therefore, there is a need to examine the modulatory effects of new drug entities or herbal preparations on a wide range of CYP isoforms. The classic method of quantifying CYP enzyme activities is based on high-performance liquid chromatography (HPLC), which is time- and reagent-consuming. In the past two decades, high-throughput screening methods including fluorescence-based, luminescence-based, and mass-spectrometry-based assays have been developed and widely applied to estimate CYP enzyme activities. In general, these methods are faster and use lower volume of reagents than HPLC. However, each high-throughput method has its own limitations. Investigators may make a selection of these methods based on the available equipment in the laboratory, budget, and enzyme sources supplied. Furthermore, the current high-throughput systems should look into developing a reliable automation mechanism to accomplish ultra-high-throughput screening in the near future.

Cathinone is the psychostimulatory major active ingredient of khat (Catha edulis Forsk) and are often co-abused with alcohols and polydrugs. With the increased consumption of khat and cathinones on a global scale, efforts should be channelled into understanding and minimising the excruciating effects of possible khat-drug interactions. This study aimed to determine the in vitro inhibitory effects of cathinone on CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2 and CYP3A5 and the in silico identification of their type of interactions and residues involved. The activities of CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C19, CYP2E1, CYP2J2 and CYP3A5 were examined by fluorescence based assays using recombinant cDNA-expressed human CYPs in Vivid® P450 screening kits. Cathinone reversibly inhibited CYP1A2, CYP2A6 and CYP3A5 via competitive, uncompetitive and noncompetitive modes with inhibition constant (K_i) values of 57.12, 13.75 and 23.57 µM respectively. Cathinone showed negligible inhibitory effects on CYP2B6, CYP2C8, CYP2C19, CYP2E1 and CYP2J2. Cathinone showed negligible time dependent inhibition on all 8 CYPs. Docking studies was performed on cathinone with CYP1A2, CYP2A6 and CYP3A5 following their inhibition in vitro. Cathinone is bound to a few key amino acid residues in the active sites while π-π interactions are formed in aromatic clusters of CYP1A2 and CYP3A5. These findings offer valuable reference for the use of cathinones and khat when combined with therapeutic drugs that are metabolised by CYP enzymes especially patients on medications metabolised by CYP1A2, CYP2A6 and CYP3A5.

Background: In recent years, the significance of cytochrome P450 enzymes (CYPs) has expanded beyond their role in the liver. Factors such as genetics, environmental toxins, drug biotransformation and underlying diseases mediate the expression of these enzymes. Among the CYP enzymes, CYP2E1, a well-recognized monooxygenase enzyme involved in the metabolism of various endogenous and exogenous substances, plays a crucial role in the brain concerning the development of Parkinson’s disease. The expression of CYP2E1 varies in different brain regions making certain regions more vulnerable than others. CYP2E1 expression is inducible which generates tissuedamaging radicals leading to oxidative stress, mitochondrial dysfunction and ultimately neurodegeneration. Objective: Less is understood about the role of CYP2E1 in the central nervous system, therefore the purpose of the study was to investigate the relationship between the expression and activity of CYP2E1 enzyme relevant to Parkinson’s disease and to identify whether an increase in the expression of CYP2E1 is associated with neurodegeneration. Methods: The objectives of the study were achieved by implicating an unsystematic integrative literature review approach in which the literature was qualitatively analysed, critically evaluated and a new theory with an overall view of the mechanism was presented. Results: The contribution of CYP2E1 in the development of Parkinson’s disease was found to be significant as the negative effects of CYP2E1 overshadowed its protective detoxifying role. Conclusion: Overexpression of CYP2E1 seems detrimental to dopaminergic neurons, therefore, to overcome this, a synthetic biochemical is required, which paves the way for further research and development of valuable biomolecules.