Search Results (24)

Theaflavins, benzotropolone compounds formed during black tea processing via catechin condensation, have drawn attention for their potential health benefits and diverse biological effects. This study evaluated the inhibitory effects of four theaflavin monomers—theaflavin-3′-gallate, theaflavin-3,3′-digallate, theaflavin-3-gallate, and theaflavin—on eight CYP450 enzymes using pooled human liver microsomes and specific probe substrates, and seven UGT enzymes using human recombinant UGT enzymes and specific probe substrates. Theaflavin-3′-gallate moderately inhibited CYP1A2-catalyzed phenacetin metabolism and CYP2C8-mediated amodiaquine metabolism, with IC₅₀ values of 8.67 μM and 10–20 μM, respectively. Theaflavin-3,3′-digallate exhibited similar effects. Both compounds showed negligible inhibition with other CYP enzymes. In UGT assays, theaflavin-3′-gallate and theaflavin-3,3′-digallate moderately inhibited UGT1A1- and UGT1A3-mediated beta-estradiol glucuronidation (IC₅₀: 1.40–5.22 μM), with weak or no effects on other UGT enzymes. Molecular docking revealed that CYP1A2-theaflavin-3′-gallate and CYP2C8-theaflavin-3,3′-digallate interactions were non-competitive, primarily mediated by hydrogen bonding and π-interactions. UGT1A1-theaflavin interactions suggested non-competitive inhibition, while UGT1A3-theaflavin interactions indicated competitive inhibition. Other enzyme-theaflavin interactions exhibited minimal binding energy differences, implying mixed-type inhibition. These findings highlight the selective inhibitory effects of theaflavins on specific hepatic enzymes, with potential implications for nutrient interactions, particularly for nutrients metabolized by CYP1A2, CYP2C8, UGT1A1, and UGT1A3. Further research is needed to explore the in vivo relevance and assess the dietary implications of theaflavin-rich black tea in nutrition and metabolism. Full article

Acetaminophen (C₈H₉NO₂, also called paracetamol) is an active metabolite of phenacetin with antipyretic and analgesic effects and has been extensively used as a painkiller. Currently, the problem of pharmaceuticals in water and sewage is common, especially in highly urbanized countries. Laboratory-scale experiments were carried out using an adsorbent—granulated activated carbon (WD-extra)—to remove acetaminophen (ACT) from water. The initial concentration of acetaminophen was 20 mg ACT/dm³. The adsorption kinetics, influence of the pH on adsorption and dose of the used adsorbent were determined under batch conditions. The adsorption of ACT on activated carbon was more efficient when the water solution was acidic (at pH 2, it was the most effective). The highest percentage of removal (99%) was obtained for the WD-extra dose of 10.0 g/dm³. The time taken to establish the dynamic equilibrium of the system was 60 min. The effectiveness of adsorption was determined based on the Freundlich and Langmuir adsorption isotherms. It was found that WD-extra activated carbon effectively removed ACT from water solutions. Full article

Lekethromycin (LKMS) is a synthetic macrolide compound derivative intended for use as a veterinary medicine. Since there have been no in vitro studies evaluating its potential for drug–drug interactions related to cytochrome P450 (CYP450) enzymes, the effect of the inhibitory mechanisms of LKMS on CYP450 enzymes is still unclear. Thus, this study aimed to evaluate the inhibitory effects of LKMS on dog CYP450 enzymes. A cocktail approach using ultra-performance liquid chromatography–tandem mass spectrometry was conducted to investigate the inhibitory effect of LKMS on canine CYP450 enzymes. Typical probe substrates of phenacetin, coumarin, bupropion, tolbutamide, dextromethorphan, chlorzoxazone, and testosterone were used for CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2D6, CYP2E1, and CYP3A4, respectively. This study showed that LKMS might not be a time-dependent inhibitor. LKMS inhibited CYP2A6, CYP2B6, and CYP2D6 via mixed inhibition. LKMS exhibited mixed-type inhibition against the activity of CYP2A6 with an inhibition constant (K_i) value of 135.6 μΜ. LKMS inhibited CYP2B6 in a mixed way, with K_i values of 59.44 μM. A phenotyping study based on an inhibition assay indicated that CYP2D6 contributes to the biotransformation of LKMS. A mixed inhibition of CYP2D6 with K_i values of 64.87 μM was also observed. Given that this study was performed in vitro, further in vivo studies should be conducted to identify the interaction between LKMS and canine CYP450 enzymes to provide data support for the clinical application of LKMS and the avoidance of adverse interactions between other drugs. Full article

In this work, we present a comprehensive study of the thermodynamic properties of 3-and 4-ethoxyacetanilides. The heat capacities in crystalline, liquid, and supercooled liquid states from 80 to 475 K were obtained using adiabatic, differential scanning (DSC), and fast scanning (FSC) calorimetries. The fusion enthalpies at T_m were combined from DSC measurement results and the literature data. The fusion enthalpies at 298.15 K were evaluated in two independent ways: adjusted according to Kirchhoff’s law of thermochemistry, and using Hess’ law. For the latter approach, the enthalpies of the solution in DMF in crystalline and supercooled liquid states were derived. The values obtained by the two methods are consistent with each other. The standard thermodynamic functions (entropy, enthalpy, and Gibbs energy) between 80 and 470 K were calculated. Full article

Emerging contaminants are being detected at a high frequency, posing significant environmental and human health challenges. This study aimed to investigate the potential of using commercial granular activated carbon for adsorbing nine aqueous emerging contaminants (carbamazepine, phenacetin, pentoxifylline, norfloxacin, iprobenfos, isoprothiolane, metolachlor, tebuconazole, and hexaconazole). The adsorption study involved employing kinetic and isotherm models, using various concentrations of emerging contaminants and sorbents in a batch system. Additionally, the study explored the correlation between the characteristics of emerging contaminants and their adsorption values, which displayed a relatively linear relationship. While some previous papers have evaluated the performance of one or two substances, there is a lack of research on the adsorption mechanisms of all nine aqueous emerging contaminants. Therefore, the findings from this study on the adsorption potential of granular activated carbon can serve as a valuable foundation for further investigations into its effectiveness in adsorbing emerging contaminants. Full article

Phenacetin, an antipyretic and analgesic drug, poses a serious health risk to both humans and aquatic organisms, which is of concern since this micropollutant is frequently detected in various aquatic environments. However, rare pure bacterial cultures have been reported to degrade phenacetin. Therefore, in this study, the novel phenacetin-degrading strain PNT-23 was isolated from municipal wastewater and identified as a Rhodococcus sp. based on its morphology and 16S rRNA gene sequencing. The isolated strain could completely degrade 100 mg/L phenacetin at an inoculum concentration of OD₆₀₀ 1.5 within 80 h, utilizing the micropollutant as its sole carbon source for growth. Strain PNT-23 exhibited optimal growth in LB medium at 37 °C and a pH of 7.0 with 1% NaCl, while the optimal degradation conditions in minimal medium were 30 °C and a pH of 7.0 with 1% NaCl. Two key intermediates were identified during phenacetin biodegradation by the strain PNT-23: N-acetyl-4-aminophenol and 4-aminophenol. This study provides novel insights into the biodegradation of phenacetin using a pure bacterium culture, expands the known substrate spectra of Rhodococcus strains and presents a potential new candidate for the microbial removal of phenacetin in a diverse range of environments. Full article

Benzisothiazolinone (BIT), a biocide widely used as a preservative in household cleaning and personal care products, is cytotoxic to lung cells and a known skin allergen in humans, which highlights the importance of assessing its toxicity and pharmacokinetics. In this study, a simple, sensitive, and accurate LC–MS/MS method for the quantification of BIT in rat plasma, urine, or tissue homogenates (50 μL) using phenacetin as an internal standard was developed and validated. Samples were extracted with ethyl acetate and separated using a Kinetex phenyl–hexyl column (100 × 2.1 mm, 2.6 μm) with isocratic 0.1% formic acid in methanol and distilled water over a run time of 6 min. Positive electrospray ionization with multiple reaction monitoring transitions of m/z 152.2 > 134.1 for BIT and 180.2 > 110.1 for phenacetin was used for quantification. This assay achieved good linearity in the calibration ranges of 2–2000 ng/mL (plasma and urine) and 10–1000 ng/mL (tissue homogenates), with r ≥ 0.9929. All validation parameters met the acceptance criteria. BIT pharmacokinetics was evaluated via an intravenous and dermal application. This is the first study that evaluated BIT pharmacokinetics in rats, providing insights into the relationship between BIT exposure and toxicity and a basis for future risk assessment studies in humans. Full article

The solubility of active pharmaceutical ingredients is a mandatory physicochemical characteristic in pharmaceutical practice. However, the number of potential solvents and their mixtures prevents direct measurements of all possible combinations for finding environmentally friendly, operational and cost-effective solubilizers. That is why support from theoretical screening seems to be valuable. Here, a collection of acetaminophen and phenacetin solubility data in neat and binary solvent mixtures was used for the development of a nonlinear deep machine learning model using new intuitive molecular descriptors derived from COSMO-RS computations. The literature dataset was augmented with results of new measurements in aqueous binary mixtures of 4-formylmorpholine, DMSO and DMF. The solubility values back-computed with the developed ensemble of neural networks are in perfect agreement with the experimental data, which enables the extensive screening of many combinations of solvents not studied experimentally within the applicability domain of the trained model. The final predictions were presented not only in the form of the set of optimal hyperparameters but also in a more intuitive way by the set of parameters of the Jouyban–Acree equation often used in the co-solvency domain. This new and effective approach is easily extendible to other systems, enabling the fast and reliable selection of candidates for new solvents and directing the experimental solubility screening of active pharmaceutical ingredients. Full article

Obtusifolin, a major anthraquinone component present in the seeds of Cassia tora, exhibits several biological activities, including the amelioration of memory impairment, prevention of breast cancer metastasis, and reduction of cartilage damage in osteoarthritis. We aimed to evaluate the inhibitory effects of obtusifolin and its analogs on CYP1A enzymes, which are responsible for activating procarcinogens, and investigate its inhibitory mechanism and chemopreventive effects. P450-selective substrates were incubated with human liver microsomes (HLMs) or recombinant CYP1A1 and CYP1A2 in the presence of obtusifolin and its four analogs. After incubation, the samples were analyzed using liquid chromatography-tandem mass spectrometry. Molecular docking simulations were performed using the crystal structure of CYP1A2 to identify the critical interactions between anthraquinones and human CYP1A2. Obtusifolin potently and selectively inhibited CYP1A2-mediated phenacetin O-deethylation (POD) with a K_i value of 0.031 µM in a competitive inhibitory manner in HLMs, whereas it exhibited negligible inhibitory effect against other P450s (IC₅₀ > 28.6 µM). Obtusifolin also inhibited CYP1A1- and CYP1A2-mediated POD and ethoxyresorufin O-deethylation with IC₅₀ values of <0.57 µM when using recombinant enzymes. Our molecular docking models suggested that the high CYP1A2 inhibitory activity of obtusifolin may be attributed to the combination of hydrophobic interactions and hydrogen bonding. This is the first report of selective and potent inhibitory effects of obtusifolin against CYP1A, indicating their potential chemopreventive effects. Full article

CYP1A2, one of the most abundant hepatic cytochrome P450 enzymes, is involved in metabolism of several drugs and carcinogenic compounds. Data on the significance of CYP1A2 genetic polymorphisms in enzyme activity are highly inconsistent; therefore, the impact of CYP1A2 genetic variants (−3860G>A, −2467delT, −739T>G, −163C>A, 2159G>A) on mRNA expression and phenacetin O-dealkylation selective for CYP1A2 was investigated in human liver tissues and in psychiatric patients belonging to Caucasian populations. CYP1A2*1F, considered to be associated with high CYP1A2 inducibility, is generally identified by the presence of −163C>A polymorphism; however, we demonstrated that −163C>A existed in several haplotypes (CYP1A2*1F, CYP1A2*1L, CYP1A2*1M, CYP1A2*1V, CYP1A2*1W), and consequently, CYP1A2*1F was a much rarer allelic variant (0.4%) than reported in Caucasian populations. Of note, −163C>A polymorphism was found to result in an increase of neither mRNA nor the activity of CYP1A2. Moreover, hepatic CYP1A2 activity was associated with hepatic or leukocyte mRNA expression rather than genetic polymorphisms of CYP1A2. Consideration of non-genetic phenoconverting factors (co-medication with CYP1A2-specific inhibitors/inducers, tobacco smoking and non-specific factors, including amoxicillin+clavulanic acid therapy or chronic alcohol consumption) did not much improve genotype–phenotype estimation. In conclusion, CYP1A2-genotyping is inappropriate for the prediction of CYP1A2 function; however, CYP1A2 mRNA expression in leukocytes can inform about patients’ CYP1A2-metabolizing capacity. Full article

In the current research work, the title compounds 5-ethoxy-benzimidazole, were synthesized by nitration of phenacetin with concentrated nitric acid it gives N-(2-nitro-5-ethoxyphenyl) acetamide (I), which on reduction with alcohol gives 5-ethoxy-2-nitroaniline (II). Reaction of hydrazine hydrate with 5-ethoxy-2-nitroaniline produced 5-ethoxy ortho phenylene diamine (III). The substituted acids reacted with 5-ethoxy ortho phenylene diamine then yielded the corresponding 5-ethoxy-benzimidazole (IV). The identification and characterization of the synthesized compounds were carried out by Elemental analysis, melting point, Thin Layer Chromatography, FT-IR, NMR and Mass data. The synthesized compounds were evaluated for anti-tubercular activity. The test compounds were subjected to in vitro screening by the tube dilution technique employing the human virulent H₃₇R_V strain of M. tuberculosis. The test compounds IVa, IVc and IVd showed significant anti-tubercular activity against H₃₇R_V strain of Mycobacterium tuberculosis. The minimum inhibitory concentration (MIC) values were found in the range of 0.8 to 12.5 μg/mL compared with the standard drugs Isoniazid. Full article

Cytochrome P450 1A2 (CYP1A2), which accounts for approximately 13% of the total hepatic cytochrome content, catalyzes the metabolic reactions of approximately 9% of frequently used drugs, including theophylline and olanzapine. Substantial inter-individual differences in enzymatic activity have been observed among patients, which could be caused by genetic polymorphisms. Therefore, we functionally characterized 21 novel CYP1A2 variants identified in 4773 Japanese individuals by determining the kinetic parameters of phenacetin O-deethylation. Our results showed that most of the evaluated variants exhibited decreased or no enzymatic activity, which may be attributed to potential structural alterations. Notably, the Leu98Gln, Gly233Arg, Ser380del Gly454Asp, and Arg457Trp variants did not exhibit quantifiable enzymatic activity. Additionally, three-dimensional (3D) docking analyses were performed to further understand the underlying mechanisms behind variant pharmacokinetics. Our data further suggest that despite mutations occurring on the protein surface, accumulating interactions could result in the impairment of protein function through the destabilization of binding regions and changes in protein folding. Therefore, our findings provide additional information regarding rare CYP1A2 genetic variants and how their underlying effects could clarify discrepancies noted in previous phenotypical studies. This would allow the improvement of personalized therapeutics and highlight the importance of identifying and characterizing rare variants. Full article

The thermodynamic properties of phenacetin in solid state and in saturated conditions in neat and binary solvents were characterized based on differential scanning calorimetry and spectroscopic solubility measurements. The temperature-related heat capacity values measured for both the solid and melt states were provided and used for precise determination of the values for ideal solubility, fusion thermodynamic functions, and activity coefficients in the studied solutions. Factors affecting the accuracy of these values were discussed in terms of various models of specific heat capacity difference for phenacetin in crystal and super-cooled liquid states. It was concluded that different properties have varying sensitivity in relation to the accuracy of heat capacity values. The values of temperature-related excess solubility in aqueous binary mixtures were interpreted using the Jouyban–Acree solubility equation for aqueous binary mixtures of methanol, DMSO, DMF, 1,4-dioxane, and acetonitrile. All binary solvent systems studied exhibited strong positive non-ideal deviations from an algebraic rule of mixing. Additionally, an interesting co-solvency phenomenon was observed with phenacetin solubility in aqueous mixtures with acetonitrile or 1,4-dioxane. The remaining three solvents acted as strong co-solvents. Full article

Mertansine, a tubulin inhibitor, is used as the cytotoxic component of antibody–drug conjugates (ADCs) for cancer therapy. The effects of mertansine on uridine 5′-diphospho-glucuronosyltransferase (UGT) activities in human liver microsomes and its effects on the mRNA expression of cytochrome P450s (CYPs) and UGTs in human hepatocytes were evaluated to assess the potential for drug–drug interactions (DDIs). Mertansine potently inhibited UGT1A1-catalyzed SN-38 glucuronidation, UGT1A3-catalyzed chenodeoxycholic acid 24-acyl-β-glucuronidation, and UGT1A4-catalyzed trifluoperazine N-β-d-glucuronidation, with K_i values of 13.5 µM, 4.3 µM, and 21.2 µM, respectively, but no inhibition of UGT1A6, UGT1A9, and UGT2B7 enzyme activities was observed in human liver microsomes. A 48 h treatment of mertansine (1.25–2500 nM) in human hepatocytes resulted in the dose-dependent suppression of mRNA levels of CYP1A2, CYP2B6, CYP3A4, CYP2C8, CYP2C9, CYP2C19, UGT1A1, and UGT1A9, with IC₅₀ values of 93.7 ± 109.1, 36.8 ± 18.3, 160.6 ± 167.4, 32.1 ± 14.9, 578.4 ± 452.0, 539.5 ± 233.4, 856.7 ± 781.9, and 54.1 ± 29.1 nM, respectively, and decreased the activities of CYP1A2-mediated phenacetin O-deethylase, CYP2B6-mediated bupropion hydroxylase, and CYP3A4-mediated midazolam 1′-hydroxylase. These in vitro DDI potentials of mertansine with CYP1A2, CYP2B6, CYP2C8/9/19, CYP3A4, UGT1A1, and UGT1A9 substrates suggest that it is necessary to carefully characterize the DDI potentials of ADC candidates with mertansine as a payload in the clinic. Full article

The inhibitory effect of new chemical entities on rat liver P450 marker activities was investigated in a functional approach towards drug development. Treatment of colorectal cancer (CRC) and chemoprevention using salicylic acid has gained a lot of attention, mainly in the prevention of the onset of colon cancer. Thus, an in vitro inhibitory effect of salicylic acid on rat CYP2C11 activity was examined by using high performance liquid chromatography (HPLC). High performance liquid chromatography analysis of a CYP2C11 assay was developed on a reversed phase C₁₈ column (SUPELCO 25 cm × 4.6 mm × 5 µm) at 243 nm using 32% phosphate buffer (pH 3.36) and 68% methanol as a mobile phase. The CYP2C11 assay showed good linearity for all components (R² > 0.999). Substrates and metabolites were found to be stable for up to 72 h. Additionally, the method demonstrated good reproducibility, intra- and inter-day precision (<15%), acceptable recovery and accuracy (80%–120%), and low detection (1.3501 µM and 3.2757 µM) and quantitation limit values (4.914 µM and 9.927 µM) for 16α-hydroxytestosterone and testosterone, respectively. Salicylic acid acts reversibly as a noncompetitive (weak) inhibitor with K_i = 84.582 ± 2.67 µM (concentration of inhibitor to cause 50% inhibition of original enzyme activity (IC₅₀) = 82.70 ± 2.67 µM) for CYP2C11 enzyme activity. This indicates a low potential to cause toxicity and drug–drug interactions. Full article